Animal Feeding and Nutrition PDF

Anatomy of Digestive Tract in Vertebrates Digestive Tract in FISHES Headgut - Articulated jaw - or absence - Cyclostomes - no stomach + no gallbladder - different diets, different types of teehts - No teeth - Microphagus lter fe...

Anatomy of Digestive Tract in Vertebrates Digestive Tract in FISHES Headgut - Articulated jaw - or absence - Cyclostomes - no stomach + no gallbladder - different diets, different types of teehts - No teeth - Microphagus lter feeders, Pharyngeal teeth - to grind the food - Teeth - vary depending on their diet. - Esophagus - Stomach - absent in cyclostomes and some adv. species Midgut - Pancreatic tissue - pancreas - produces digestive enzymes (like amylase, lipase, and proteases) that aid in the breakdown of carbohydrates, fats, and proteins - Gallbladder (or absence) - stores bile, produced by the liver, to help digest fats - Gizzard - muscular organ contains ingested sand or small stones, which help grind food, aiding in the mechanical breakdown of tough materials - Intestine - carnivorous sh tend to have shorter intestines, while herbivorous sh have longer intestine - Pancreas - Pancreatic tissue: Midgut ceca (cyclostomes) / Along the midgut - Pancreas: compact organ. Rest of shes and vertebrates - Pyloric ceca - projections near the junction of the stomach and intestine, play a role in secreting digestive enzymes and increasing the surface area for nutrient absorption - to increase the absorptive surface and digesta retention time (specially in sp. with short midgut) Hindgut - Intestine - Anus - Short and dif cult to distinghish from the midgut - Herbivore shes are not common due to masticatory and gut capacity limitations. To solve this problem, some species have developed 4 different mechanisms to feed on vegetables. 1. No mechanical trituration. Just a long midgut (acid lysis) 2. Mechanical trituration thanks to a gizzard 3. Pharyngeal teeth and no stomach 4. Two sphicters in distal intestine. Fermentation Digestive tract in AMPHIBIANS The Key: Metamorphosis - From herbivorous larvae (long digestive tract) to carnivorous adults (short digestive tract) Tadpoles - mostly herbivores - types of mouths depending on feeding system - Feeding System in Amphibian Tadpoles : a) Engulf entire prey (mosquito larva, worm...) b) Horny teeth for removal encrusted material in rocks, plants... c) Filter feeders (bacteria, phytoplankton...) - Key characteristics: Lack a stomach. Gastric region: Mucus + proteolytic cathepsin + low pH (no pepsin) - Long intestine Adults - carnivores - Glands 1. Mouth glands: to secrete mucus (+venom Gymnophiona) 2. Esophageal glands: to secrete pepsinogen 3. Gastric glands - Weak dentition, distensible tongue to capture the prey Digestive tract in REPTILES - Mouth: Beak (Chelonians), Teeths (in the rest of reptiles) - In some groups, teeths able to inject toxins or digestive enzymes. - Glands in oral cavity: To secrete mucus - To secrete venoms and digestive enzymes (some sp.) - Snakes: Divided lower jaw (and even disarticulation ) to help in the ingestion of prey - Distensible tongue: In many species, is a sensing organ fi fi fi fi fi fi  Different diets, different tracts - Carnivorous - In crocodilians, larger stomach, with muscular pylorus separated from the remainder of the stomach by a constriction. - Short and simple digestive tract + Gastroliths: Stones, sand that are swallowed to help crush food - Herbivorous - Midgut shorter in herbivores, Hindgut longer in herbivores - Digestive tract more complex and longer that carnivores one. - Proximal colon, Caecum - slow digesta passage and increase the absorptive surface area. - Common traits: In general, in reptiles, the stomach tends to be tubular. Digestive tract in BIRDS Modi cations for ight - to y you must lose weight - Abscence of teeth - Reduction in the weight of the jaw skeleton and muscles - Gizzard as organ for trituration Beak - Very diverse, but not very useful for crushing food - lter feeding, insect catching, fruit eating.. Headgut - Salivary glands: Lubrication + adhesive substance or + amylase (in some sp.) - Esophagus + Crop (storage of food) + Provetriculus (production go HCl+pepsinogen) + Gizzard (trituration thanks to chinitous plates teeths, a horny material) + 2 cecum Different diets, Different tracts - In carnivores, smaller crop and smaller and less muscular gizzard - In nectarivorous, frugivorous and pollen eaters, less developed gizzard (nothing to triture) - In herbivores and granivorous, well developed crop and gizzard (the ostrich is an exception: no crop) - Ceca well developed in birds with diets rich in plant ber and invertebrates (Ceca, is the place where the fermentation occurs). Not in carnivores, not in granivores. Herbivores - different strategies to solve the same problem - In the ceca - Ruffed Grouse, Darwins Rhea - In enlarged crop and distal esophagus - Hoatzin, Emu, Ostrich - long colon, almost unique in ostriches. Digestive tract in MAMMALS Headgut - A key advance in mammals: an ef cient Masticatory apparatus - Complex musculature in the articulation - Incisors (cutting) / Canines (grasping) / Premolars and molars (grinding) / Mobile tongue - Exceptions: Baleen as lter feeder system / Edentates - Weak jaws, Simple teeth (or absent), Long tongue - Salivary glands (3 pairs) : Parotid gland (serous uid), Mandibular (mucus), Sublingual (mucus) Foregut - In mammals, the stomach is quite simple but can vary in: Epithelial lining - Size - Shape - 50% of the mammals orders have stomach with a non-glandular region: Strati ed squamous epithelium, that can occupe a large area of the stomach like occurs in Echidnas or Anteaters why ? Protection Against Mechanical Damage - diet consists of rough materials like insects (with hard exoskeletons), dirt, and debris + Storage and Pre-digestion - The non-glandular region can serve as a storage area where food is held before it moves into the glandular region for digestion + Prevention of Chemical Damage - Since the non- glandular part does not secrete acids or digestive enzymes (like the glandular part of the stomach), it provides a safe region where food can be temporarily held without being exposed to the corrosive effects of digestive juices - Cetaceans, some marsupials, sirenians, hyrax, most artiodactyls, some rodents all of them have a Expanded forestomach, but why ? Food Storage: The forestomach acts as a storage chamber, allowing animals to consume large quantities of food at once. Fermentation: It provides an environment for microbial fermentation, aiding in the breakdown of complex plant materials, particularly in herbivores. Ef cient Digestion: By fermenting food before it enters the glandular stomach, these animals can extract fi fl fi fl fi fi fl fi fi fi  more nutrients from brous diets. Adaptation to Diet: The expansion of the forestomach allows these species to ef ciently process their speci c diets, which may include tough plant materials or, in the case of cetaceans, large quantities of smaller prey. Hindgut - Is a really variable structure, from really simple to a voluminous, sacculated, multicompartmental organ, with or without caecum. - Usually, in mammals is longer than in other vertebrates - large colon, caecum, small colon, rectum CARNIVORES - In carnivore mammals, usually the digestive tract is quite simple (the stomach is simply a unilateral dilatation) - Usually they have a cecum (but neither cecum nor colom are haustrated in the most of the species) - In Insectivora, cetaceans and marsupials, hindgut quite short and dif cult to distinghish from midgut - Exceptions : Cetaceans: Large multicompartmental stomach (herbivorous ancestors), Vampire bat: Complex stomach. Convoluted and 2x body lenght - because of ying OMNIVORES - The stomach is simple and noncompartmentalized - Exceptions: Some rodents, some frugivorous or nectivorous bats... - Intestine quite variable in lenght and ratio midgut/ hindgut (ex. Bears, really long intestine with indistinct hindgut. Opossum, same size midgut and hindgut...) - Usually, hindgut with cecum HERBIVORES - A diet hard to manage (full of the dif cult to digest cellulose), needs a complex gastrointestinal tract - great solution - And, sometimes, this solution is ask for help: To bacterias able to digest the cellulose thanks to a key procedure: fermentation - in an expanded colon, cecum or forestomach 1. Colon fermentors : Wombats, sirenians, elephants, equids, rhinos, herb. apes... 2. Cecum fermentors : Lagomorphs, herb. rodents, arboreal marsupial herb., koala, rabbit.. 3. Forestomach fermentors : Sloths, macropod marsupials, colobid monkeys and herbivorous artiodactyls RUMINANTS In the ruminants, the forestomach is divided in 4 spaces to improve digestion of the plants: - Rumen: Fermentation tank (larger in grazers) - Reticulum: Aditional chamber of fermentation / Regurgitation - Omasum : Mechanical processing - Abomasum : “True stomach”, low pH and enzymatic digestion - Rumen microbes ferment feed and produce volatile fatty acids, which is the cow’s main energy source. Rumen microbes also produce B vitamins, vitamin K and amino acids. - In calves, the esophageal grooves allows milk to bypass the rumen and directly enter the abomasum. Rumen development occurs following a change in diet and microbial growth. - Browsers: Smallest rumen and omasum, largest cecum - The most well developed forestomach , smallest cecum Foregut Fermentation - Fermentation prior to enzymatic digestion and absorption: Use of bacterial protein, bacterial products (B- Vitamins) - ‘Loss’ of easily digestible substrates and bacterial modi cations - Endogenous nitrogen products (urea) can be recycled by introducing them into the fermentation chamber - use by microbes - re- digestion of N as bacterial amino acids Hindgut Fermentation - Fermentation after enzymatic digestion and absorption: ‘Loss’ of bacterial protein, bacterial products (B- Vitamins?) (coprophagy) - Use of easily digestible substrates - Urea could be available for bacteria in hindgut fermenters, but it would not be recycled fi fi fl fi fi fi fi  Feeding of cats / felines - Cats are obligate carnivores, which means that they rely on nutrients found only in animal products. Cats evolved as hunters that consume prey that contains high amounts of protein, moderate amounts of fat, and a minimal amount of carbohydrates, and their diet still requires these general proportions today - The diet typically contains large amounts of protein and fat and small amounts of carbohydrates. The digestive apparatus of cats has adapted to such a diet, not only anatomically, but also through the development of speci c metabolic adaptations. - Protein is the main source of energy in cats and cats have high requirements for its content in their diet. It is also used for blood glucose synthesis. The essential amino acids include arginine, taurine, methionine and cysteine. Cats cannot synthesize them and their need is higher in cats than in other species. - In the wild, a cat will eat its prey whole, including bones and gut contents. The diet of feral cats contains 69.5 % water, while the dry matter contains 62.7 % protein, 22.8 % fat and 2.8 % non-structural carbohydrates. What is an amino acid? is an organic compound that serves as the building block of proteins What is an essential amino acid? is one that the body cannot synthesize and must be obtained through the diet What is a limiting amino acid? is the essential amino acid that is present in the smallest amount in a food source, limiting the body’s ability to make proteins / essential amino acids in digested protein that are in shortest supply relative to body requirements for absorbed amino acids Taurine - organic acid, cysteine derivative - Is an essential / limiting amino acid for all felids; but only for felids - Is crucial for maintaining the health of the retina, the light-sensitive part of the eye. Speci cally, it helps support the function of photoreceptor cells, which are necessary for normal vision. A de ciency in taurine can lead to a condition called feline central retinal degeneration (FCRD), which can result in blindness. - Essential for the proper function of the eye, heart muscle, nervous, reproductive, immune and gastrointestinal systems. Its de ciency leads to retinal degeneration, dilated cardiomyopathy, and in pregnant cats, stillbirths, low birth weight or developmental defects in kittens. Taurine is essential for bile acid conjugation. - Its de ciency causes blindness, baldness, teeth lost, cardiomyopathy... - Present in the meat, disappear with food processing, and not all the brands add it to the kibbles in adequate amounts Arginine - Why felids (and canids) need Arginine? - arginine plays a critical role in the urea cycle, which is essential for the detoxi cation of ammonia, a byproduct of protein metabolism. Since cats have evolved to consume a diet high in animal protein, their bodies produce large amounts of ammonia, which must be quickly detoxi ed. Arginine is necessary for converting ammonia into urea, which is then excreted via the urine - arginine contributes to the biosynthesis of keratin from which the claws are composed - is also involved in protein synthesis, which is essential for growth, tissue repair, and maintaining muscle mass - plays a role in the immune system by supporting the production of nitric oxide, which helps ght infections and promotes wound healing - is involved in the release of hormones such as insulin, which helps regulate blood sugar levels, and growth hormones that contribute to overall development and metabolism Understanding Animal Feeding - Common themes across taxa - Food ows through a web of wildlife. In the Arctic, willows provide nutrients for herbivores such as migrating caribou and habitat for songbirds such as snow buntings. Grizzly bears prey on salmon while herring gulls scavenge the salmon carcasses. Animal tissues decompose and return their nutrients to soils and plants as the cycle of nutrition continues. We observe changes in populations that re ect changes in food and habitat for wildlife such as geese and snowshoe hares. - Our ability to effectively conserve and manage wildlife species depends on understanding their needs in changing habitats with changing food supplies. - Nutrition spans a wide range of mechanisms, from the acquisition of food to digestion, absorption and retention of nutrients. - Comparative Nutrition borrows this knowledge and applies similar techniques to studies of ecology and physiology of wildlife. - Wildlife Nutrition connects behavioural, morphological and biochemical traits of animals to the life history of species and, thus, the dynamics of populations. What integrates animal feeding ? Nutritional biochemistry, comparative nutrition, ecology, animal physiology, behaviour,morphology What does animal feeding affect? Population dynamics, conservation biology, wildlife management fl fi fl fi fi fi fi fi fi fi  Why Animal Nutrition and Feeding? Will your population decline? Why? What does your population need? - Doesn’t matter which is “your species’' there are few things that you can do for it if you don’t understand its feeding The nutritional environment - Contextualize the environment: - Abundance of the resource (high to low), Range of variability (broad to narrow) - Spatial distribution (uniform to patchy), Timing of availability (frequent to infrequent; constant to erratic) - The ecosystem supplies but also exert demands : - Low ambient temperatures increase the demand for energy to heat the body - High ambient temperatures decrease the needs for energy, but increase the need for water to cool the animal. - Contextualize the animal: - Ectotherms vs. Endotherms - Metabolism controlled by temperature - Necessary to understand the supply of water.When it rains, they use the urinary bladder to accumulate water! - Growth / Maintenance / Reproduction : Males waiting for females, apparently low needs for energy - but they need energy to keep the muscles / Lactating females - female seals use body fat and protein to produce milk when fasting - The most important is the transfer of nutrients and energy - The water content of a foodstuff is essential information for several reasons: The nutritional value is meassured in dry matter basis. Too much water dilute the nutrient content. The water content determines the durability of a foodstuff. - Dry matter = Organic matter + Minerals : The mineral fraction is the reason for multiple amazing behaviours. - The organic matrix can be divided into protein, carbohydrate and fat - These components are the source of energy: Fat 9 kcal/g; Protein 4 kcal/g; Carbohydrates 4 kcal/g - These de ne the (relative) nutritional value of food (depends on the specie of animal) The nutritional niche - Scaling demands: - The relationship between body size and resource demands is always critical, especially within species with huge size variability. - Canadian geese→Up to 50% BM differences among populations / White-tailed deer → Many subspecies, from 30 to 130 kg. - The nutrient demands of large animals is usually smaller - because they have a larger body surface area - correlation with heat production - Allometric relationships: Y= a·Mb - For example, scalars for ungulates are: Greater than one for home range area, equal to one for digestive tract capacity - Less than one for energy demand - Large ungulates require much greater areas but use less food than the same total mass of smaller animals. - Requirements - Amount of water, nutrients or energy needed by an animal from its diet. - Maintenance (zero gain or loss of nutrient) - Net gains (seasonal mass gain, growth or reproduction) - Metabolic differences: - Energy→carbohydrates, protein, and fat. - Essential nutrients→May be very different across taxa due to lack of certain metabolic routes. Taurine is essential for Felids. Vitamin C is required by some birds, some rodents, humans, other primates and bony sh. - Essential nutrients→Complete or Conditional. - Complete→Total lack of necessary enzymes. Total dependence of dietary sources. - Conditional→Required in the diet when demands are elevated by growth or reproduction. The enzyme pathways are present, but they are not suf cient. - Histidine is not essential by adult rodents and humans, but is during growth. Requirements for copper (Cu) are much higher in young animals or when bacterial infections exists. - Intake ranges: From de ciency through suf ciency to toxicity. - Vitamin A de ciency in mammals →Night-blindness - Overconsumption→Bone and skin loss. - How to measure needs? Minimal approach / Optimal approach” (mass gain; number of eggs; growth of the offspring.. fi fi fi fi fi fi Food and population dynamics - As wildlife biologists you will work monitoring populations of free-ranging species, reintroducing from captive breeding programs... - Your work will bee valuated by gains in a population of threatened or endangered species. - Wildlife nutrition is the link between the individual condition and the demography of a population. - The size of a population at the end of a year (Nt+1) is related to the number of animals at the start of the annual cycle (Nt) and the activities of animals over the year: - production of young (Pt), deaths (Dt), immigration (It) into, and emigration (Et) out of the area - Nt+1 = Nt + Pt - Dt + It – Et - all them are mediated by food availability - Incremental changes in a population may be either positive or negative: Nt+1 = Nt × (1+R) - Rmax is the maximum possible value of ‘R’, or the intrinsic growth rate of the population. - Organisms achieve Rmax when supplies for production greatly exceed any demands that result in death. - If a population can reach its Rmax, growth of the population can be exponential. Rabbits in Australia, rats in islands... - As the population grows constraints appear: carrying capacity reached, food limitation, increased requirements (diseases) - Correct management of the feeding resources may lead to fast recovery of populations: American salmon (Oncorhynchus tshawytscha): Very fast recovery after protection of nutrient rich habitats in the Gulf of Alaska. - Low food availability may be the biggest nightmare: Saiga (Saiga tatarica): not very productive habitats = slow growth, low fecundity, impossible to deal with diseases, overharvesting - The main regulation of the population by the food is through the breeding rate: Red deer: Only females with an adequate body condition reproduce - The main regulation of the population by the food is through the breeding rate: Reindeer: Females breed only over a minimum fat threshold, but also over certain protein threshold (for foetus development) - Food limitation also : - Reduces juvenile survival, increases the age of rst reproduction, decreases recruitment into the breeding cohort, increase the risk of mortality in all age classes - especially in the young and the old (susceptibility to bad weather and diseases) - Trophic Relationships: ow of energy and nutrients between trophic levels. - Transfer depends on the ef ciency: Energy or nutrients in the producer. Assimilation by consumers. Energy expended for daily maintenance. - Fishes - the most ef cient vertebrates - in feed conversion ratios - In carnivores/omnivores, trophic relationships are key in the regulation of populations - An increase in the number of species in a trophic system may reinforce the structure of the community through multiple feedbacks and tolerances. - Beware the key predators: Extinctions of gray wolves and grizzly bears have been associated with declines in habitat for migrant songbirds because larger moose populations have changed the structure of shrubs and trees. - Also important to understand facilitation processes: Barnacle geese select the growing tips of plants, which delays the maturation of the plant and results in a higher-quality diet for resident European hares during summer. - The environmental conditions: Temperature, light, water and nutrients in soil and water drive - the primary production, and subsequently the whole system - Seasonal and annual cycles, (North Atlantic Oscillation and El Niño Southern Oscillation) ENSO affect sex ratio progeny in captive Iberian red deer despite a steady feeding regime - Weather patterns have two effects: Primary plant production (amount, duration and timing) - Changes in day length accompany primary plant production, and coincides with lactation or incubation in temperate areas. - In arid environments, plant growth and reproduction of wildlife is linked to rainfall - Weather patterns have two effects: Demands on individuals and risk of death. - Storms and ice expose animals to greater demands for thermoregulation and body maintenance. - Animals living at high density (close to the carrying capacity) are more vulnerable to the unpredictable risks of adverse weather fi fl fi fi  How to choose the right diet? - Decision is based on the interrelationship between a food’s avour and its post-ingestive feedback (consequences) - Senses (smell, taste and sight) enable animals to discriminate among foods and provide sensations which are linked to a food’s avour - Post-ingestive feedback calibrates sensory experiences – like or dislike – according to a food’s utility to the body - Quite linked to PSC (Plant Secondary Compounds) - Thus, avour–feedback interactions come out from a food’s chemical characteristics and an animal’s physiological state - Affective (non-cognitive) changes in palatability through avour– feedback interactions occur automatically - Animals do not need to think about, or even remember the feedback event - Self-medication: To overcome internal parasite burdens by eating foods high in tannins - Individual factors: Unique experiences with the foods, Social Learning Herbivores Carnivorous Herbivores - Chicks of arctic terns were found with cleanly amputated wings, legs and heads. It was caused by sheep (UK) - Manx shearwater chicks were killed by red deer and it was the principal predator at this time rather than eagles, ravens and crown - Main ingested items (for both) were bones and feathers in order to obtain calcium, phosphorus and magnesium - Zinc, Proteins.. - The rst ever record of hippos eating meat was done at Hwange National Park, Zimbabwe in 1995 - since then, there is evidence of hippos eating impala, baby elephants and even their own kind - Not predators but are driven to scavenge meat when food or particular nutrients are scarce Other feeds: aquatic vegetation - Moose - Higher content of Na, Ca, P, K, Mg, Fe, Mn, I and protein - Higher consumption in the summer - Each sex at peak of needs - Aquatic vegetation is low in bre, however it is used by a wide range of herbivores Osteophagia - Chewing bones or antlers - common behaviour among ungulates and other species - Natural mineral supplement - Each sex/age class use this resource at different times according to differential needs in calcium and phosphorus - Recently, it has been suggested that herbivores were already chewing bones at least 780,000 years ago - In the last decades, osteophagia has been reported in several Cervid species, cattle, sheep, goats, giraffes, gemsbok, kudu, wildebeest, sable antelope, wild boar, grizzly bear, cape porcupine, squirrels… Geophagia - Deliberate consumption of soil and clay - Common practice among invertebrates and vertebrates worldwide - A few hypotheses for geophagia: Mineral supplementation, alleviation of hyperacidity and gastrointestinal upsets, detoxi cation of the body from anti-nutritional compounds ingested by feeding - Special places so-called mineral licks, no exact pattern in soil composition - It has different functions for different species and individual, there are wet and dry soil licks - Disadvantages are: Parasites / diseases, energetic costs, tooth abrasion, predation risk The Alpine ibexes that are native here are climbing the almost vertical wall of the dam- they have been seen licking the bricks of the structure and gnawing on the lichen growing in the cracks of the brick - Omnivores: Everything means everything, Eliminate cues for predators (mother-calf), Rabbits(caecotrophy) - obligate - Panda,koala,elephants,horses - Get microbiome from parents, Guinea pigs, mole rats – Get vitamins (large intestine) - Primates(omnivores) - Re-processing of seeds - Pigs (omnivores) – Food is food - Dogs (carnivores) - Unclear but very common / Rebalance microbiome in the digestive tract fl fi fl fl fi fl fi  Feeding and nutrition of FISHES - How to feed them in captivity Understanding Fishes - Fishes evolved in a very diverse environment, and 20,000 species exploit every possible niche - First records of sh farming from 2500 BC (Ciprinus carpio in China; Oreochromis in Egypt) - Currently, there are ~140 species being farmed - Aquaculture production is growing at 9-10% annually, the fastest sector of animal production Top species farmed - Freshwater → Carps (grass, silver, Indian, common, bighead...), Nile tilapia, Trout - Saltwater → Salmon / Brackish water → Greasy grouper Herbivores: < 5% of all bony shes, no cartilaginous shes - Browsers (selective; eat only the plant) / Grazers (less selective; include sediments)/ limitations in the masticatory apparatus and gut capacity Detritivores: 5 - 10% of all species, feed on decomposing organic matter Carnivores: Zooplanktivores: Suction feeding + Ram feeding, Benthic invertebrate feeders, Fish feeders Behaviour tightly linked to morphology (co-evolution) - Behaviouraly, shes tend to optimize when choices are available (maximize bene t:cost ratio): select the prey that yields the greatest energetic or nutrient “return” on the energy invested in search, pursuit, capture, and ingestion - Fish exist in neutral gravity, no need for a heavy skeleton - dietary calcium and phosphorus needs are low, energy expenditures for locomotion are low Fish excrete ammonia via the gills - Lower metabolic cost than excreting urea or uric acid - Higher caloric energy yield from the metabolism of amino acids Fish are cold-blooded: Rates of metabolism, digestion, etc. decrease in cooler water Many sh exhibit indeterminate growth: Growth continues after rst maturation and spawning Special nutritional requirements - Ascorbic acid (vit. C) , polyunsaturated fatty acids (PUFAs) - Carnivorous species have a limited ability to utilize or metabolize starch (evolved using protein and lipid for metabolic energy) - Many minerals obtained via the water High conversion rates, around 1:1.1 for salmon and cat sh, 1.5:1 for tilapia (1.6-1.8 for chickens, 3 for pigs, 8-10 for cattle) Fish Digestive Systems Fish are monogastric, but - Gastric stomached sh (carnivores like salmon/trout) - adaptation to increase gut surface area (linked to species with short tract) - Agastric (carp) Two major groups: with stomach (cold-water salmonids, warm- water cat sh, tilapia, eels, grouper), without (cyprinids) - Stomach: large in carnivores, small in herbivores-omnivores - Intestine: short in carnivores, long in herbivores-omnivores Oral Cavity - Mouth, Teeth +Esophagus + Stomach - Cardiac and Pyloric - No valves/sphincters Intestine - Pyloric caeca, Small, large and rectum Mouth / Esophagus - Head shows a wide range of divergence with respect to diet - Jaws are absent in the cyclostomes (hag sh and lampreys), which are parasitic on other sh, but present in all other sh - Inferior, terminal, sub - terminal, superior - The teeth vary in both their location (jaw, tongue, pharynx, or other surfaces of the orobranchial cavity) and function - In most species they are used for grasping, cutting, or tearing - The ability to reduce food to very small particles is limited to lter- feeders, grazers, or those that triturate their food with pharyngeal teeth (linked to lack of stomach) - Potential loss of small food particles through the gills is prevented by gill rakers in many species - The oesophagus of sh is generally short Stomach - When present, the stomach is either straight, U- shaped, or Y-shaped with a big blind sac - Gastric mucosa, which secretes HCl, pepsinogen, and mucus + Pyloric mucosa, which secretes HCO3 and mucus fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi  Digestive Process - Stomach - Similar to that of most monogastric animals - Low pH (around 2.0) - Food enters the stomach; neural and hormonal processes stimulate digestive secretions - As the stomach distends, parietal cells secrete pepsin, assisting in digestion - Some sh have cirulein instead of gastrin - Pepsin lyses protein into small peptides for easier absorption - Minerals are solubilized; however, no lipid or carbohydrate is modi ed - The mixture of gastric juices, digesta and mucous is known as chyme - Flow of digesta out of the stomach is controlled by the pyloric sphincter Pancreas - Secretion of insulin, glucagon and digestive enzymes (proteases, amylases, chitinases, lipases) for carbohydrate, fat and protein metabolism - Exocrine pancreatic tissue is present in primitive ceca along the midgut of cyclostomes and some species in the more advanced classes of sh - However, the pancreas is a compact organ in sharks, skates, rays, many teleosts Liver - Process and storage of lipids and carbohydrates (glycogen), production of plasma proteins - Formation of bile - Compact organ Gall Bladder - Stores bile and secretes bilirubin into gut - Absent in many shes - In lampreys, absent just in adults Midgut / Small intestine - From short and straight to a longer structure with spirals and loops - Species with small or absent stomach + short intestine: folds of the midgut extend varying distances into the lumen to form a spiral valve, which increases its surface area and delays the digesta passage - Species with stomach: surface area and retention time are increased by the presence of 1 to 1,000 pyloric ceca Digestive Process - Intestine - Chyme entering the small intestine stimulates secretions from the pancreas and gall bladder (bile) - Proteolytic enzymes, amylases, lipases - Bile contains salts, cholesterol, phospholipids, pigments, etc - Pancreatic secretions include bicarbonates which buffer the acidity of the chyme - Alkaline pH (7.0 - 9.0) - Cellulase: not secreted by pancreas, but produced by gut bacteria - Intestinal mucosa also secretes digestive enzymes Absorption - Intestine - Diffusion into mucosal cells (electrolytes, monosaccharides, some vitamins, smaller amino acids) - Phagocytosis/pinocytosis by mucosal cells - Active transport via carrier molecules - Cross-section of the intestinal luma shows that it is highly convoluted, increasing surface area Hindgut - Large intestine - The hindgut of most shes is short and dif cult to distinguish from the midgut - Divided into two distinct segments, separated by the ileocecal valve in a few species - Small cecum is found in a few species - Relative gut length (RGL) high in species consuming detritus (high proportion of indigestible matter) Herbivores - Relatively rare - four types, based on adaptations designed to degrade cell walls of algae and/or bacteria by acid lysis, mechanical trituration, or microbial fermentation A) No mechanisms for the trituration of food. Acid lysis. Relatively long intestine B) Thick-walled, gizzard-like segment of the stomach. Intestine of variable length C) Pharyngeal teeth that grind food to a small particle. No stomach and a relatively short haustrated intestine D) Large intestine and distinct hindgut with valves Fish Nutrition Ef ciency - More ef cient than other vertebrates: Conversion factor = kg feed required to produce 1 kg growth in sh esh - Maintenance ration (MR) = the amount of food needed to remain alive, with no growth or reproduction (% body wt./day) fi fi fi fi fl fi fi fi fi fi  - MR is temperature-dependent - MR increases as temperature increases - MR is size-dependent - MR decreases as size increases Requirements - Protein, Lipids - Omega-3 fatty acids (1% of diet), Energy - Supplied mainly from lipids and protein, Vitamins - 15 essential vitamins, Minerals - 10 minerals known to be essential, Carotenoids - Needed for viable eggs Protein - The most expensive part of sh feed, High protein diet (30-40%), Linear relationship between daily protein and growth - Proteins ALWAYS needed for growth of new tissue, Few side-effects - ease of NH4+ excretion - The 10 essential amino acids for shes are: methionine, arginine, threonine, tryptophan, histidine, isoleucine, lysine, leucine, valine and phenylalanine - Of these, lysine and methionine are often the rst limiting amino acids - Fish feeds prepared with plant protein (soybean meal) are low in methionine - Requirements are usually lower for herbivorous and omnivorous - Requirements generally are higher for smaller shes. As sh grow, protein requirements usually decrease - Requirements also vary with rearing environment, water temperature and quality... higher for sh reared in high densities - Protein is used for sh growth if adequate levels of fats and carbohydrates are present in the diet. If not, protein may be used for energy and life support rather than growth Carbohydrates - Not very important for most sh species - Most shes lack the enzyme cellulase (unable to break down cellulose) - Fibre is usually considered to have 0 nutritional value - Negatively affects trouts ́ health - Levels of 10 to 20% have resulted in growth depression in rainbow trout - Cat sh digest starch well - When possible to feed inexpensive source of energy for sh diets - Improves binding during feed manufacturing (starch is useful in the extrusion manufacture of oating feeds) - In sh, carbohydrates are stored as glycogen that can be mobilized to satisfy energy demands Lipids - Typically supplied in diets from 7-16% - High-energy nutrients. Can partially substitute protein in aquaculture feeds - Recent trend to use higher levels of lipids in the diet (reduce the high costs of diets, but create problems as excessive fat deposition in the liver and decreased health and quality) - Supply essential fatty acids (EFA) and serve as transporters for fat-soluble vitamins - Fish require fatty acids of the omega 3 and 6 families-Marine sh require n-3 HUFA for optimal growth (0.5-2.0%) - Freshwater sh n-3 linolenic acid (0.5 to 1.5%) Energy - The ratio of protein to energy must be determined separately for each sh species - Excess energy relative to protein content in the diet may result in high lipid deposition - Fish feed to meet their e.requirements → diets with excessive energy levels may result in decreased intake and reduced weight gain Minerals - Formation of skeletal tissue, sh can uptake some from water through their gills and skin - Osmoregulation (Saltwater = high minerals/salts requirements, Freshwater = lower) Vitamins - E - Tocopherol - antioxidant in sh diets - B8 - Inositol - reduced growth rates - B4 - Choline - poor growth and conversion - C - Ascorbic Acid - Important - Collagen skeletal systems, Wound healing, disease resistance, antioxidant, Fish cannot synthesize Carotenoid pigments - Synthesized products: Carophyll red, Carophyll pink, Astaxanthin - essential for salmon to produce viable offspring - Natural products: Krill meal, Phaf ayeast, marine algae, Crustacean waste - (crab, shrimp, cray sh) Attractants - Attract sh by sight or smell (shrimp meal, sh oil, sh meal, etc.) Food sources - Carbohydrates: Cereal crops, Fat: Vegetable oil, sh oil, Protein: meat and sh ( rst class) vegetable (low class), Mineral salts: Water - Vit. A Retinol: Liver, and sh liver oil, Vit. D Calciferol: Cod liver oil, salmon, sardines and other oily sh, Vit. E Tocophenol : Soya beans, vegetable oil, Vit. K Phylloquinone: Liver fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fl fi fi  Fish feeding - Feed represents 40-50% of the production costs - Current research focuses on the development of new species- speci c diet formulations to satisfy the increasing demands for cheap, safe, and high-quality sh and seafood products - Prepared or arti cial diets may be either complete or supplemental: Arti cial diet - Complete diets supply all the ingredients (protein, carbohydrates, fats, vitamins, and minerals) necessary for the optimal growth and health of the sh. Most used. When sh are reared in high density indoor systems or con ned in cages and cannot forage freely on natural feeds, they must be provided a complete diet - Farmed sh on this system typically are fed 1-4% of their body weight per day - Supplemental (incomplete, partial) diets are intended only to help support the natural food (insects, algae, small sh) normally available to sh in ponds or outdoor raceways. Mainly used to fortify the naturally available diet with extra protein, carbohydrate and/ or lipid Early feeding - Some sh spawn large eggs (Salmon & Trout; 2000-15,000 eggs/female) - Incubation requires 50-100 days depending on water temperature - First feeding fry are 200-400 mg and can be fed small, particulate feed - Many sh spawn very small eggs (Most marine species; > 1 million small eggs per female) - Incubation requires 3-7 days - First- feeding fry are very small and must be fed live-feed through metamorphosis or until they reach a decent size (challenging) - Right live feed at the right time - Correct nutritional content of live prey (need PUFA enrichment) - Specialised particulate feeds are produced for hatcheries for the rst group-Rotifers and Artemia should be used for the second group - Rotifers are usually bred in the hatchery while brine shrimp are generally collected from the wild, e.g. salt lakes Feed types - Commercial sh diets are manufactured as either extruded ( oating) or pressure-pelleted (sinking) feeds - Both oating or sinking feed can produce satisfactory growth, but some sh species prefer oating, others sinking - Extruded feeds are more expensive, but the farmer can directly observe the feeding and adjust feeding rates - Variety of sizes ranging from ne crumbles for small sh to large pellets - The pellet size should be approximately 20-30% of the size of the sh species mouth - Too small pellets result in inef cient feeding because more energy is used in nding and eating more pellets - Too large pellets will depress feeding and cause choking Dry feeds - Made from all dry ingredients with the addition of liquid fat ( sh or oilseed oil) - Pellets, crumbles, or akes - Increase lipid content (energy) by spraying extruded feeds after process - Enhanced digestibility of some ingredients Microencapsulated - Small particles of uniform nutritional make-up, Slurry of ne ground ingredients - Encased in proteinaceous membrane (microcapsule), Expensive, but used for some species (larval marine) Gels - Meal preparation, to be mixed with boiling water and let to cool down - Also commercially available Traditional moist and semi-moist feeds - Formulated with a high % of whole sh (wastes) - 30% moisture - Stored frozen Fish become sh food - 88% of global sh oil consumption goes to aquaculture (to maximize growth and enhance avour) - Fishmeal and sh oil made from less valuable wild-caught species, including anchoveta and sardine - In 2006, about 20 million tons of wild sh were used ✓Impact of sh oil and meal: around 5kg of wild sh is needed to produce 1kg of salmon - Several sh-feed substitutes are currently being investigated, such as protein made from grain and livestock by-products and omega-3 oils extracted from genetically modi ed plants and microorganisms - Fishmeal and sh oil are essential for raising carnivorous sh (salmon, trout, tuna) - "Vegetarian" shes (carp, tilapia...), can be raised on feed made from plants - In the early 1990's, vegetarian sh farms started adding shmeal to their feeds to increase their yields - In 2007, tilapia and carp farms together consumed more than 12 million tons of shmeal (more than 1.5 times the amount used by shrimp and salmon farms combined) Products for aquaculture - insects, carnivore: Low in Starch (Similar to the carbohydrate content of wild-type diets). Stabilized source of Vitamin-C (Improve Shelf Life), herbivore: High Content of Carbohydrate and Fiber that plant-eating sh needs, omnivore, shark… fi fl fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fi fl fi fi fi fi fi fi fi fi fi fi fi fl fl fi fl fi fi  Feeding Rate, Frequency, and Timing Feeding rates and frequencies depends mainly on sh size - Small larval sh and fry need to be fed a high protein diet frequently and usually in excess. Have a high energy demand and must eat nearly continuously (hourly) - As sh grow, feeding rates and frequencies should be lowered, and protein content reduced (or reduce the amount) - Growth and feed conversion increase with feeding frequency - In intensive sh culture systems, may be fed as many as 5 times per day in order to maximize growth Feeding rates are affected by time of day, season, water temperature, dissolved oxygen levels, and other water quality variables - Feeding sh grown in ponds early in the morning when the lowest dissolved oxygen levels occur is not advisable - In recirculating aquaculture systems where oxygen is continuously supplied, sh can be fed at nearly any time - During the winter and at low water temperatures, feeding rates in ponds decline and feeding rates should decrease proportionally - Feed acceptability, palatability and digestibility vary with the ingredients and feed quality Fish Wastes - The most important rule in sh nutrition is to avoid overfeeding (waste of expensive feed) - It also results in water pollution, low dissolved oxygen levels, increased biological oxygen demand, and increased bacterial loads - Usually, sh should be fed only the amount of feed that they can consume quickly (less than 25 minutes) - Even with careful management, typically about 10% of feed are uneaten Automatic Feeders - Fish can be fed by hand, by automatic feeders, and by demand feeders - Large cat sh farms often drive feed trucks with compressed air blowers to distribute (toss) feed uniformly throughout the pond - Some growers use night lights and bug zappers to attract and kill ying insects and bugs to provide a supplemental source of natural food for their sh Feed Care and Storage - Commercial sh feed is usually purchased by large farms as bulk feed in truckloads and stored in outside bins - Feed should not be stored longer than 90 to 100 days Smaller farms often buy prepared feed in bags - Bag feed should be kept in dark and as cold as possible - Vitamins, proteins, and lipids are especially heat sensitive and can be readily denatured by high storage temperatures - High moisture stimulates mould growth and feed decomposition - Avoid unnecessary handling and damage to the feed bags which may break the pellets Medicated Feeds - When sh reduce or stop feeding, it is a signal of problems - Relatively few therapeutic drugs are approved for sh, but some medicated feeds for sick sh are available: - Terramycin® contains oxytetracycline. Control of Aeromonas and Pseudomonas infections in cat sh and trout. Should be fed for at least 10 days, followed by a 21-day withdrawal period. It is only available in a sinking pellet - Romet® is a combination of sulfadimethoxine and ormetoprim. It is approved for the treatment of Edwardsiella infections in cat sh and Aeromonas in salmonids. Romet® should be fed for at least 5 days followed by a 3-day withdrawal. Is available commercially in a oating pellet Feeding and nutrition of AMPHIBIANS Basics about amphibians - 99.999% Carnivorous - Sirens can eventually eat some plants - Larval amphibians include carnivores, omnivores, and herbivores - have a longer intestine for digesting plant material Digestive system of amphibians - Digestive tube - Mouth - Adults commonly have large mouths and can engulf their entire prey - Tongue (Sticky, Shooting) - Simple Teeth - Salamanders and caecilians have teeth on all the jawbones - Most frogs lack teeth on the lower jaw and a few lack teeth on the upper jaw - Pharynx - Air to lungs, food to the oesophagus fl fi fi fi fi fi fi fi fi fi fi fi fi fl fi fi fi fi - Oesophagus - With peristaltic movements - Single stomach - Pyloric valve - Amphibians have a relatively simple J-shaped stomach - Small intestine - Low folding (villi) - divided into the duodenum and ileum - Large intestine - Not clearly differentiated - Ileocolic valve in advanced frogs - Anus → Cloaca Digestive glands - Mouth - Unicellular and multicellular glands: Lubricate surface - Also all along the tract - Intermaxillary gland: Sticky compound - Less in aquatic taxa/stages - Stomach - Cardiac and pyloric areas - Cathepsin, no pepsin - Livers - Gallbladder→bile duct→duodenum - Pancreas - digestive enzymes (trypsin, amylase) and bicarbonate for digestion in the small intestine Water and salt balance - osmoregulation - Skin, gills, digestive tract - Water gain - Highly water-permeable skin facilitates gas exchange (O₂ and CO₂) - Food digestion - Do not drink - instead, they absorb water through their skin via osmosis, primarily in a region called the pelvic patch (a highly vascularized area of the ventral skin) Freshwater amphibian - Hyperosmotic - The ionic concentration of the body is greater than that of the environment - Freshwater amphibians live in a hypotonic environment where water tends to ow into their bodies, and ions tend to diffuse out. - Constantly gain water via osmosis and lose ions via diffusion - Much water? Cell may explode! Solutions - Fewer ions in the blood - Very effective nephrons (excretion of water) - Cannot survive in salt water for a long time – dehydration - no marine species Terrestrial species - can lose water by evaporation - wax to decrease permeability - Big bladder - terrestrial species, such as Litoria platycephala, can store signi cant amounts of dilute urine in their bladder (up to 50–130% of their body mass). This bladder serves as a water reservoir, reabsorbing water when needed. - Aquatic species typically have smaller bladders (less than 5% of body mass). - Litoria platycephala: "Water-holding Frog," it stores large amounts of water in its bladder (up to 130% of its body weight) - can survive prolonged droughts by burrowing underground, where it forms a cocoon to conserve water - Antidiuretic hormones: modify skin and bladder permeability - vasotocin regulate kidney function, concentrating urine and reducing water loss - Pelvic patch: highly vascularized - Behavioural adaptation - Active time - nocturnal or remain active during periods of high humidity to reduce water loss - Body posture - minimize surface area exposed to air, such as crouching tightly to the ground - Coccons - form cocoons by shedding layers of skin that harden and reduce water loss - seen in desert-dwelling species Nitrogen Management and Urine Concentration in Amphibians - Reduce water in urine Nitrogen management - Ammonia (ammonotelic; lot of water; toxic) - ammonia is highly toxic and requires large volumes of water for safe excretion - Aquatic species - Urea (ureotelic; less water; less toxic) - Most terrestrial adult amphibians excrete urea. - Phyllomedusa sp. are uricotelic (like reptiles; much less water; much less toxic; high energy needed) - uric acid is the least toxic and requires very little water for excretion - especially those in arid environments fl fi Gaining energy - Resource availability vs. costs and risks - Ectothermic -Do not use energy for body temperature - Invest energy in body maintenance / or reproduction - Brumation and aestivation - Slowing down the metabolism - Spea over 90% of life inactive - buried, temperatures don t́ drop under 4°C (better under ponds or open water!) - If freezing, cryoprotectants - substances produced by certain amphibians to prevent cellular damage during freezing temperatures order: Gympnophiona - Caecilians - Diet: Carnivores, detritus eaters, preys: Insects, earthworms, prey location: Chemoreception, prey catch: Strong bite - Long digestive tract - Venom glands - Curved teeth - Simple tongue - Teeth on both jawbones - Skin-feeding caecilian (Microcaecilia dermatophaga) - Parental care, small yolk, skin feeding young, special teeth, eat modi ed layer of the skin of their mother, drink from her cloaca order: Urodela - Caudata - Diet: Carnivores, cannibalism - Prey location: Sight, vibrations (terrestrial), smell (water) - Prey catch: Mouth, sticky tongue, sucking in mouth (underwater) - Preys: Up to sh and mammals by sucking (Andrias japonicus) Urodela larvae - Predators, feeding mainly on insects, catching prey with sucking (water) or bite - Intrauterine cannibalism – Adelphofagia (Salamandra salamandra) order: Anura - Diet: Carnivorous (tadpoles mostly herbivores), cannibalism - Prey location: Mainly sight, hearing - Prey catch: Mouth+forelimbs, sticky tongue, shooting sticky tongue Digestive system - Short digestive tract, weak dentition. Simple teeth, sometime differentiated curved teeth - Usually only on upper jaw (sometimes only on lower, or both), simple tongues, shooting tongues, sticky tongues American Bullfrog (Lithobates catesbeianus) - eat everything that ts in its mouth Poison dart frogs (Dendrobatidae) - Hunt with shooting sticky tongue, toxicity through eating alcaloid-sequester ants Tadpoles - Larvae have complex, microphagous, ltering mechanisms for ingestion of bacteria, zooplankton, or phytoplankton - Some have a large mouth and can engulf their entire prey of crustaceans, mosquito larvae, or worms - Can be aided by the removal of encrusted material with horny teeth - Most larval anurans lack a stomach or gastric pouch - The gastric region usually forms a thickened sheath, which produces mucus, a proteolytic cathepsin, and a low pH - Long intestine. No midgut/hindgut separation - Metamorphose of anurans is accompanied by profound changes in diet, feeding practices, osmoregulation, and the structure and function of the gastrointestinal tract - Some are fed with nutritional eggs - also called trophic eggs - to support the development of their offspring. These eggs are not fertilized and serve solely as a source of nutrition for developing tadpoles or larvae - Glass Frogs (Centrolenidae) Feeding amphibians in captivity - All are carnivores - the size of the food should t in between the eyes of the animal - Feeding Drosophila and Collembola - Provide food with vitamin and minerals mixture! - The correct Ca:P ratio for amphibians is 1,5:1 – 2:1 - Drosophila and Collembola have very low amounts of vitamins A, B1, D3… - Carotenoids - contribute to sexual coloration, hatching success and survival of larvae - fertilize eggs Anurans - Usually fruit ies, crickets, mealworms, earthworms, some larger species also mice - Tadpoles: algae, zooplankton in case of carnivorous tadpoles Urodela - Usually earthworms, crickets, mealworms, small crustaceans - Fish, mice – giant salamanders - Larvae: plankton, microcrustaceans, insect larvae Nutritional disorders of captive amphibians - Metabolic Bone Disease – due to calcium de ciency / badly grown insects / hypervitaminosis A / lack of vitamin D or UV light supplementation (poorly understood for most amphibian species, but encouraged) / water hardness and phosphate levels - Short Tongue Syndrome – due to hypovitaminosis A. Often observed in bufonids: animals lose the ability to apprehend prey despite vigorous effort fl fi fi fi fi fi fi - Lipid Keratopathy – frequently observed in captive frogs. Discoloration and opacity of the cornea. Corneal deposits of cholesterol associated with fatty diets (crickets) - Inanition and Maladaption Syndromes – common nding in recently imported animals - Gastric Overload, Impaction and Foreign Bodies – due to ingestion of large preys or foreign bodies like stones or other cage substrate can occur as prey items are consumed - Observed intestinal obstruction associated with ingestion of acrylamide-based products available commercially for providing hydration to domestic crickets - Occasionally, insect mouthparts or ovipositors can traumatize or perforate the stomach wall - B1-Vitamin De ciencies – Thiamine de ciencies associated with the feeding of sh containing thiaminases - Urinary Calculi – urinary bladder stones can be observed in the uricotelic species Feeding and nutrition of REPTILES - Ectotherms (heliotherms, tigmotherms) - Except Dermochelys sp – Leatherback sea turtle - Breath with lungs only - Marine, Terrestrial, Aquatic, Semi-aquatic, Arboreal, Underground - Most reptiles are carnivores or omnivores - Herbivorous are limited to about 50 species of lizards, 40 species of tortoises, and a few terrapins and turtles Digestive system of reptiles Mouth (oral cavity) - Beak in Chelonians, Well-developed tongues, Jacobson ś organ, Differentiated teeth - Used for grasping, cutting, and tearing their food, scissors-like teeth, not good for grinding Fangs in snakes - Aglypha - No specialized teeth Most common - Opisthoglypha - Rear-fanged Venom injected by a pair of enlarged teeth at the back of the maxillae. Only in Colubridae -Careful with boomslang - Proteroglypha - Shortened maxillae with few teeth and two large fangs pointing downwards - Need some time to inject their venom - Includes spitting cobras - Only in Elapidae - Solenoglypha – Most advanced venom delivery method. Couple of hollow fang teeth - Long fangs, can be folded against the roof of the mouth - The fangs rotate into biting position when the jaws open - Mouth opens almost 180 degrees - Lower toxicity but immediate injection - Only in Viperidae Toxicofera - Toxicity in other reptiles - Neurotoxicity x Hemotoxicity Heloderma spp. - Strong neurotoxin, but very small amounts, glands in the lower jaw. Grooved teeth - Venom mixes with saliva - Quick bite, holds and chew - Not deadly, but probably the most painful venom produced by any vertebrate Why? Feed on eggs... Varanidae - Komodo dragon - Similar to heloderms, lower jaw, mixed with the saliva, not deadly - Mild envenomation: inhibition of blood clotting, lowering blood pressure, muscle paralysis, induction of hypothermia - All Toxicofera keep genes for venoms, even may produce them in very small amounts Digestive system of reptiles - Stomach: Pyloric valve - Mainly tubular - Large with pockets in Crocodilians - Small intestine: Pancreatic and hepatic ducts end - Long in carnivores and short in herbivores - Large intestine: Short in carnivores and long in herbivores, caecum in herbivores, the proximal colon of herbivorous (Iguanidae, Agamidae, and Scincidae) are compartmentalized, which slows digesta passage and increases absorptive surface area → Anus→Cloaca Digestive glands - Mouth: Unicellular and multicellular glands - lubricate surface, salivary glands: Labial, lingual, sublingual, palatine and dental - Venom glands are modi ed salivary glands - Digestive glands in the stomach: Enzymes, acid - Livers: Largest glands, produce bile, nutrient storage - Gallbladder, bile duct, duodenum fi fi fi fi fi - Pancreas: Digestive uids, insulin production - Most reptiles are carnivores or omnivores - many subsist on insects during their early or entire life - Herbivores are limited to some lizards, tortoises, and a few turtles - Terrestrial, freshwater and marine species (Chelonia mydas) - Limited in minimum body size (relative gut capacity), juveniles are commonly carnivorous/omnivorous - Handicaps: Poor masticatory apparatus, ectothermy Turtles - Aquatic, semi-aquatic, terrestrial, marine - Mouth: No lips, no teeth, Keratinous jaw sheaths („beak“) - Carnivorous, herbivorous, omnivorous - C: Fresh water turtles, sea turtles, H: Tortoises and green turtle, O: Some tortoises - Prey location: Eyes, smell, prey catch: Bite, Long neck quick attack, prey lure: Specialized tongue in Snapping turtle Water and salt balance in marine species - Hyposmotic marine species - Ionic concentration of the body is lower than in the environment - Water moves out of the body – causing dehydration - Skin permeability decreased, concentrated urine Crocodiles - Freshwater, Marine, Semi-terrestrial species, carnivorous, usually not cannibalistic, oportunistics - Prey location: Eyes, hearing, vibrations, prey catch: Strong jaws, drawn its prey by rotating its body, no chewing, gharials: Specialized teeth for catching shes - Stomach with two chambers - The most acidic stomach of any vertebrate - for horns, bones, hooves - Very low metabolic rate Gastroliths (stones, gravel, or sand) are common - Also in chelonians, and lizards - Found in 100% of the stomachs of Crocodylus nyloticus over 2 m in length - Triturative function, as the gizzard in birds Lizards and Tuatara - Arboreal, Terrestrial, Semi-aquatic, „Marine“ - Carnivorous, omnivorous, herbivorous - Prey location: Eyes, smell, hearing - Prey catch: Bite, sticky tongue - Some food specialists: Snail eaters - Dracaena - Mouth: Flexible skin fold lips, teeth in most species are used for grasping, piercing and fragmenting the food - Flesh cutting and slicing teeth in Monitor lizards - Crushing teeth in Caiman lizard (Dracaena, for snails) - no side movement - Tongues - simple: Geckos, sticky: Agamas, projectile: Chameleons, telescopic: Monitor lizards Amphisbaenia - Small, usually legless reptiles (Bipes spp.) - Burrowers, carnivores - Ants / eggs Squamata - Snakes - Arboreal, Terrestrial, Semi-aquatic, Marine - Venomous vs. Non-venomous - Venom injection vs. constriction - Carnivores, cannibalism - Prey location: Chemoreception – Tongue, Jacobson ś organ, Smell + Thermovision – Ability to distinguish warmer objects, Pit organ + Mechanoreception - Vibrations + Eyes - Prey catch/kill: Venom injection (Spitting venom is only defence), constriction, swallow whole prey in one piece - Mouth: Flexible skin fold lips, differentiated teeth, venomous (Front and rear), help swallowing - Long oesophagus - Food specialists : Egg-eating snake - Some snakes lure their prey with special modi cations: Spider-tailed viper Feeding reptiles in captivity - Most reptiles do not eat every day - Beware overfeeding - Always provide water - Some drink only owing water or dew Omnivores - Depend on what part of the diet prevails (meat vs. herbal), fruit (no limes, oranges), vegetable: carrot, Chinese cabbage, chamaeleons: apples, carrots, red pepper, bananas every few days Carnivores - Best by live or dead insects or vertebrates - Invertebrates: Crickets, meal worms, wax worms, earthworms, snails - Vertebrates: Homeothermic (mice, rats, rabbit, chicken) Mice – Beware colouration for wild animals! - The stomach content is also food… Poikilothermic – Fish, amphibians, reptiles... may be switched to homeothermic diets - Scent transfer techniques - wash the mouse and rub it with a bit of shed lizard skin, frog mucus, or sh oil fi fl fi fi fl - Right size of the food should be carefully chosen - Better to feed several small pieces than one big (not in snakes) - Bigger vertebrates are better fed dead, to prevent bites - Live prey: Watch during feeding, Ensure the prey was killed before you leave - All feeding animals should be well-fed and healthy Herbivores - Best fed with naturally grown plants, put them on pasture, dandelion, plantain, clover, lamb ś lettuce, arugula, Chinese cabbage - Fruit, gels and pellets, fat-soluble vitamines may be supplemented Vitamins and minerals - All reptiles should be provided by a mixture of vitamins and minerals - Adding to water or more often used as a sticky powder, dusted on the food - No need for vitamin/mineral supplements in crocodiles / snakes Metabolic Bone Disease - Very high prevalence, common even when enough UV light is provided - Ca de ciency / Ca:P disbalance - When clinical signs are visible, there is already 30-80% bone loss - not detectable by X-rays Feeding and Nutrition of BIRDS Feeding strategies of birds - Meat eaters - carnivores, Fish eaters - piscivores, Carrion eaters - scavengers, Insect eaters - Herbivore insectivorous, Fruit eaters - fructivores, Seed eaters - granivores, Flower nectar - nectivorous, Leaves - folivorous, Plant and animal matter - omnivores Traditional classi cation of birds - Domestic fowls→eat seeds but also insects and their larvae, owers, fruits, leaves, and stones - Parrots→eat seeds, but also insects and their larvae, owers, fruits, leaves, tree bark, and clay Granivore Digestive tract - Beak /Mouth - Esophagus - Crop - Proventriculus - Gizzard/Ventriculus - Duodenal loop/ Duodenum - Pancreas - Liver - Spleen - Gall bladder - Small intestine -Ileum - Ceca - Large intestine - Cloaca - Beaks different - different diet Head modi cations for ight - Absence of teeth, Reduction in the weight of the jaw skeleton and muscles, Acquisition of a gizzard as the organ for trituration Salivary glands - Lubrication, adhesive substance (in some species), amylase (in some others) Crop - Large in herbivores and granivores, not important in carnivores, nectarivorous, frugivorous - (same as gizzard) - Absent in ostrich Proventriculus - Glandular stomach Gizzard - Mechanical stomach - large and muscular gizzard in herbivores and granivores, small in carnivores, nectarivorous... - Koilin, a horny material consisting of protein and carbohydrates Ceca well developed in birds with diets rich in plant bre and invertebrates - not in carnivores, scavengers, granivores, nectarivorous, fructivorous Excretion - Birds excrete their nitrogenous wastes as uric acid in the form of a paste, metabolically more expensive - but allows more ef cient water retention (which can be used for the eggs) - Seabirds can also excrete salt via specialized nasal salt glands, the saline solution leaving through nostrils in the beak GRANIVORES - Small Seed-Eaters - Passerine birds – estrildid nches, weavers, Parrots – budgerigar (parakeet), grass parrots (Neophema), Lovebird (Agapornis) fi fi fl fi fi fi fl fl fi  - Millet - foxtail millet, sorghum, oats (peeled), sprouted proso millet (vit.E) + green feed (herbs, lettuce, Chinese cabbage, grass, alfalfa, grass seeds) + insects if they like Bigger Seed-Eaters - Parrots – almost all - Ara, Cockatoos, Budgerigars, Kea... - Sun ower seed, oats, wheat, barley, millet, buckwheat, corn, pea, lentils, rice+ vegetable, fruits, branches & buds, green feed, berries, peanuts (fat!) + insects if they like Seed problems - cheap to transport and store - but animal choose some seeds so no good diet - Limiting in the following nutrients: Vitamin A, D, K, B group (ribo avin, panthothenic acid, niacin, biotin) - Minerals iodine, iron, copper, manganese, selenium, sodium, calcium, zinc, Amino acids lysine and methionine Alternatives: Commercial mixtures (expensive), Extruded diets (Expensive; but rule out the possibility of bird self-selection) - Eggfood as a supplement - (But not accepted by all species) - During breeding and rising - Mashed hard boiled eggs & carrot, breadcrumbs, seeds, green feed, curd... Vitamin A hypovitaminosis - Most common de ciency in parrots, Chronic rhinitis and respiratory fungal infections - Blue/green algae (source of ß- carotene - vit. A precursor) - Vitamin A hypervitaminosis: Similar symptoms, combination of pelleted diets with other supplements Calcium + Phosphorus - Seed-based diets are very low in calcium and high in phosphorus, Calcium source = grit - 2:1... 12:1 - egg shells - Calcium carbonate Vitamin D - Important role in the uptake of calcium, Vitamin D3 (animal origin) is 20 - more potent than vitamin D2 (plant origin) - D3 synthesized in the skin under the in uence of UV-light (can be a problem in captivity) De ciencies of calcium and/or vitamin D: Poorly calci ed bones (bent bones/fractures) - Over-supplementation with vitamin D3: Intoxication – polyuria and polydispia: polyuria (excesive production of urine), polydipsia (excessive thirst or excess drinking) , cockatiels and macaws are particularly sensitive to hypervitaminosis D Iron de ciency - High requirements (contrary to fruit eating birds), espiratory problems and death Iodine de ciency - common in budgerigars (millet seeds – low in protein and iodine) Regurgitation and respiratory distress caused by the enlarged thyroid gland, treatment - adding iodine to the drinking water Obesity - common problem connected also with the restricted movement and boredom (overeating) - Galahs, amazon parrots and budgerigars are particularly prone to obesity - restriction of the amount of food Transferring birds to pellet feeding - can prevent frequently recurring nutritional disorders 1) Portion method – fast and safe, especially in the case of larger species - Pellets are mixed with the current diet - Percentage of pellets will be increased 2) Combination method – suitable for smaller bird species (last 5 to 6 weeks) - The mixture of pellets and seeds (percentage of pellets is increased) is served every 3rd day (the food is only refreshed when the eating tray is almost empty) 3) Free choice method - the easiest - Takes much longer time - The most satisfying for fruit eating birds 4) Alternate day method Columbiformes - Doves and pigeons - whole grains, smaller species - millet, poppy, rapeseed - Tropical species - berries, fruit, insects - Complete compound feed or Supplemental comp. feed, pigeon milk from crop - Doves and pigeons : From granivorous to frugivorous - Nutritional value highly variable - Crop milk replacers available NECTARIVORES - Diet consisting mainly or exclusively of the sugar-rich nectar produced by owering plants, rich in simple sugars - Poor in proteins and amino acids - Hummingbirds, sunbirds and honeyeaters - Very ef cient excreting the excess of water, any species is exclusively nectarivore, but include insects in the diet - use glucose arti cial feeders - Iron toxicosis! FRUGIVORES - Passerine birds - mynahs, Parrots - lories and lorikeets, Toucans, ibis, spoonbills, hornbills, tanagers, starlings, nches, thrushes, robins, softbills, and more - Common use of liquid nectar solution, and lory powder - Zoo diet: Tropical fruits (whole, pulp & juice), apple, banana, grapes, and melon, Carrot, vegetable, compote, honey, boiled rice, Salt milk , Grains in low amounts (sun ower, oats), Insect, worms, minced meat (fresh or boiled)..Recommended CP is about 10 % DM - Low-iron levels soft pellets fi fl fi fi fi fi fi fl fl fi fl fl fi  Hornbills - 3-6 kg, up to 100 cm - Nature: Reptiles, frogs, snails, insects and small mammals, lesser fruits, seeds, carrions - Zoo diet: Rice, minced meat (fresh & boiled), boiled eggs, curd, mice, worms, locusts, chicks, grapes, bananas, compote FOLIVORES Hoatzin (Opisthocomus hoazin) - Eats leaves and to a lesser degree fruits and owers 82% leaves, 10% owers, and 8% fruit - Digestive system unique among birds: Very large crop with two chambers, multi-chambered oesophagus, bacterial fermentation , small stomach and gizzard - Smelly and bad yer - Very dif cult to feed in captivity Kakapo (Strigops habroptila) - very dif cult to feed in captivity - Small gizzard Hindgut fermentor, Loves the rimu-tree! not only leaves but also seeds, bark... CARNIVORES Birds of Prey - Diet for sh-eating and carnivorous birds - Eagles, Hawks, Storks, Cranes, Vultures, Bustards, Owls,... - Porcine, poultry & sh meal, eggs, shredded, large cubes or strips Scavengers - New world vultures: an excellent sense of smell (gas mercaptan), long and horizontal nostrils - Old world vultures: lack a strong sense of smell, amazingly acute vision, large feet for grasping - Stomach acid exceptionally corrosive: immune to the toxins (safely digest putrid carcasses infected with Botulinum toxin, hog cholera, and anthrax bacteria) - Low diversity of microbiota -but that on the face is important! Essential carotenoids - Capable to use tools Bone: 49% water, 16% fat and carbohydrate, 12% protein, and 23% minerals - bone tissue digestibility 50%, energy 387 kJ, do not rot. Meat: 70% water, eat tissue digestibility 75%, 100g of meat 586 kJ, energy 440 kJ - Energy value of 100g of Bearded vulture food (70% bones, 25% tendons, and 5% skin) to be 674 kJ Penguins - The diet vary among species but also across different institutions, 40 % of zoos feed penguins only by one type of food Zoo diet: Mostly herring, sprat, mackerel and capelin, lesser squid, shrimp, anchovy, sardine, whiting, krill, smelt and mussels, stripes – porcine by-products, sh, poultry, shrimp and algae meal, dried bakery products, peanuts, kelp, corn syrup, egg... Insectivorous Birds - Insect, worms, minced meat, curd, earthworms, berries, eggs, degrades quickly mainly in hot climates, pellets reinforced with taurine! Secretary bird - Diet in captivity: Mice, young mice, one day old chicks, Insects (locusts, crickets or worms) OMNIVORES Galliformes - Turkey, grouse, chicken, quail, pheasant, peafowl… - Adults: wheat, oats, rice, millet, corn, green feed, berries, soft fruit, insect, worms - CCF or SCF - Chicks: higher needs of protein (up to 30 %), Egg food + insect, Best: complete compound feed for rearing chickens, turkeys.. Guinea Fowls - Common diet includes: Fruits, berries, seeds, grass, spiders, insects, worms, molluscs and frogs - Starter, Grower 1, Grower 2, Breeder..Commercial turkey diet is possible to feed Japanese Quails - Natural feeding:Millet, wheat, grass seeds, insects - Ideal is complete compound feed for Quails - First 6 weeks of age: 25 % CP; 12.6 MJ/kg; 1.0 % Ca - Turkey starter or chicken starter (lower grow) - Laying: 20 % CP, 11.7 MJ/kg; 2.5%–3.0% Ca - Possible to feed compound feed for laying hens (+ CP) Waterfowls - ducks, geese and swans - nature: herbivorous (water-plants, pasture), sh, molluscs, or aquatic arthropods - Zoo: adults - grated cabbage, carrot & apples, Chinese cabbage, pasture - Young: + eggs, curd, pellets, wheat bran Mergansers : piscivorous ( sh) - Young ones: Higher protein requirements (invertebrates) Ducks feeding - specially growing ducks are very intolerant to anticoccidials and mycotoxins, good hygiene of food - Wheat, oats, meals, cooked root crops, green matter, grated vegetable - For growing: + egg mixture, grind meat (CP) - submersible feeding increase intake - (but not gains) - (increase searching activity) Geese feeding - Grazers - Fibre = 6-9 % (higher in hot climates), green forage well cut, more pasture is recommended - Extensive: pasture + supplementary feed fi fi fi fi fi fl fl fi fl fi  Flamingos - Filter feeders - Feed also suitable for Scarlet Ibis and Roseate Spoonbills - High protein (41% in DM) diet with vitamin, mineral and supplements, pellets + warm water - Poultry, sh & shrimp meal, wheat products, bread, kelps, peanuts, oyster shell, alfalfa meal, rice, ground meat, salt, amin oil, dog meal - Colour enhancements: Roxanthin red, Carotene, Cantaxantin, carophyll - Also produce crop milk (high variability) Order Struthioniformes - ratites - Family Struthionidae – ostriches, family Rheidae – rheas, family Casuariidae – cassowaries and emus, family Apteryidae – kiwis Feeding of Ostriches - In nature: mainly pasture, but also fruit, insect, owers x In captivity: green matter or hay (Lucerne, meadow), vegetable, fruit, corn, wheat, oats, soybean, sun owers seeds, brans, oil cakes, molasses, sh meal & additives, water – ad libitum , grit - Food with high CP (17-18 % in adults, 13-17 % in growing) - Restricted nutrients in growing (fast growing = defects) - Complete compound feeds – not often available - Mainly – pasture + additional compound feeds Emus & rheas Nature - Forage, seeds, roots, fruits, insect, small vertebrates - Zoo diet: Grated cabbage, carrot & apples, eggs, curd + pellets Feeding and Nutrition of OMNIVORES - Animals which have the capability to obtain energy and nutrients from plant and animal matter - Teeth and digestive system adapted to eat both, diet is often seasonal dependent - Balance the diet according to their nutritional needs, food quality and availability of alternate foods Feedstuff for omnivores - Root vegetables (carrot, parsley, celery, beet), Green vegetables (cabbage, leek, lettuce, broccoli, cucumber), Fruit (apple, grapes) - Boiled rice or potatoes, curd, raw or boiled mincemeat, omnivore biscuits Digestive Tract - Have simple stomachs (except some rodents), intestine is generally longer than in carnivores - High variability in midgut- hindgut ratio - Bear vs opossum, caecum may be absent or present (well-developed in rodents) - Foregut in hippos, peccaries, colobus and langur monkeys (bacterial counts similar to the ruminant forestomach) Feeding pigs Order: Artiodactyla - Family: Suidae - Subfamily: Babyrousinae - babirusas, Phacochoerinae - warthogs , Suinae - Genus: Hylochoerus – giant forest hogs , Potamochoerus – African bushpigs Peccaries Order: Artiodactyla - Family: Tayassuidae (peccaries) - Much smaller than Old World pigs - omnivorous, but tend to prefer plant material (more than the Old World Suidae) - Peccaries are foregut fermenters - Gastric pouch, 2 blind sacs and a glandular compartment - Diet: roots, grass, seeds, vegetable, fruit, cactuses (Chacoan) and small animals - Collared peccaries may prey snakes fi fi fl fl fl  - In zoos is very often bred Collared peccary: Ideal is dry grassy paddock with small pond - Diet: root vegetable (carrot, parsley, celery) with top, cabbage, Chinese leaves, beet, cauli ower, broccoli, cucumber, fruit (apple, pears, grapes, banana), boiled rice or potatoes, raw or boiled mincemeat, once a week chickens. Sometimes hard fodder, grass, leaves..Tendency for getting fat Feeding bears - Carnivorous (polar bear), omnivorous (brown bear, most of Ursidae), herbivorous (giant panda) - Opportunistic omnivores: tree fruits - smaller species able to climb prefer greater proportion of fruits than animal sources - Hunt: small and young animals, sh, ungulates occasionally, carcasses after other predator Diet - Almost exclusively carnivore - polar bear - kodiak bear - Typical omnivores - brown bear, black bear - food intake of captive bears varies widely with the season (maximal during summer and early fall and minimal during winter – hibernation) - Mainly herbivorous omnivores - tropical species (Sun, Sloth, Spectacled) - Diet of Malaysian Sun Bear: birds, small mammals, termites, the young tips of palm trees and the nests of wild bees. They have been known to cause crop damage, particularly to oil palms - Spectacled Bear Diet: fruit, varieties of bromeliads, rodents and insects. Con icts with farmers develop when the bears feed in corn elds - Almost exclusive herbivores - the giant panda - Nature: between 90-99% bamboo, including leaves, shoots, and stems, occasionally small fauna and other types of vegetation - Can t́ digest cellulose→big amounts of food! - zoo: only bamboo, can be supplemented with high- bre primate biscuits Feeding of Red Panda - suborder: Caniformia - Family: Ailuridae - Have an extremely slow metabolism, Can t́ digest cellulose→big amounts of food! - Additional bre source - ground beet pulp (possibly unsweetened porridge) or source of grass and plants - Fruit and vegetables - absolutely extraordinarily Feeding Primates - High-protein monkey biscuits (25% crude protein) should be fed to New World primates to ensure that their higher protein requirements - larger Old World speci