Digestive Anatomy and Animal Feed Study Notes PDF

LESSON 8: DIGESTIVE ANATOMY Classifications of Digestive System AND PHYSIOLOGY OF DOMESTIC ANIMALS Classification Based on Anatomy: Comparative Anatomy 1. Non-Ruminant (Simple Stomach) Anatomical differ...

LESSON 8: DIGESTIVE ANATOMY Classifications of Digestive System AND PHYSIOLOGY OF DOMESTIC ANIMALS Classification Based on Anatomy: Comparative Anatomy 1. Non-Ruminant (Simple Stomach) Anatomical differences in the Pigs digestive tract between species are Non-ruminant omnivores, thus primarily a reflection of the type of consume both plant and animal diets consumed. matter. Carnivores tend to have rather Poultry simpler (shorter and less voluminous) Non-ruminant omnivores, and digestive tracts. they have a complex foregut (three sections that replaces the Herbivores generally have specialized normal stomach) and a relatively regions of their gastrointestinal tracts simple intestinal tract. (e.g. the rumenoreticulum in ruminants, or the cecum and colon in Dogs and Cats horses), which provide a suitable Non-ruminant carnivores. environment (“fermentation vat”) for specialized microorganisms that Horses and Rabbits produce enzymes for digestion and Non-ruminant herbivores (also called utilization of more complex nutrients. pseudo ruminants) and have a rather large and complex large intestine. Less digestible feeds are also fermented by the microflora 2. Ruminant (Complex Stomach) producing fermentation end-products Capable to consume and digest plant (organic acids such as VFA) which can materials and are herbivores. be absorbed and utilized by the host Includes cattle, goats, sheep, animal as energy sources. buffaloes, and camels. In ruminants, acetate is the highest ✓ Camels do not have an omasum. amount of VFA produced. Propionic acid is converted by the Classification Based on the Site of liver to glucose; acetate and butyrate Microbial Fermentation: can be utilized for energy (via the citric acid cycle) or for lipogenesis 1. Pregastric/Foregut Fermenters (synthesis of long-chain fatty acids (Ruminants) and their incorporation for storage in adipose tissue as triglycerides). Predominant site of microbial fermentation preceding the stomach (forestomach or gastric pouch) and small intestine. Route of digesta: Mouth → esophagus → reticulorumen → omasum →  abomasum (true stomach) → Dog Digestive System intestines → anus In young ruminants consuming predominantly milk, esophageal groove or reticular groove allows milk to pass directly from the esophagus through the omasum into the abomasum which permits efficient digestion and utilization of milk (in a manner similar to other young mammals without undergoing fermentation in the reticulorumen). ✓ Which is why abomasum is the Cattle Digestive System largest compartment in young ruminants. Hindgut fermentation (in the cecum and colon) also occurs 2. Hindgut Fermenters (Non- ruminant Herbivores) Predominant site of microbial fermentation is the large intestine (cecum and colon). Pig Digestive System E.g. horses, rabbits, and elephants. 3. Monogastric, Non-functional Cecum (Carnivores and Non- ruminant Omnivores) Do not rely upon plant tissues as a significant source of nutrients. Have no major specialized site of microbial fermentation in their digestive tracts. Horse Digestive System Some microbial fermentation occurs in colon (large intestine). ✓ The appendix is the equivalent of cecum in humans. E.g. carnivores (dog and cat) and non-ruminant omnivores (pig and poultry).  Chicken Digestive System 3. Esophagus Passage of ingested feed from mouth to stomach. Many species of birds have a crop – enlarged portion of the esophagus which as temporary storage location for food and allows the food to be softened before it enters the stomach. 4. Stomach The highly muscular nature of the stomach provides significant mixing of ingested food, saliva, and gastric juices. Monogastric/Non-Ruminant Digestive System Gastric mucosa contains: (Pig, Dog, Cat, Horse, Chicken) a. Chief Cells 1. Mouth (Oral Cavity) Secrete proenzyme pepsinogen. Proximal end of the digestive tract. b. Parietal Cells (Oxyntic Cells) Secrete hydrochloric acid (HCl) that Prehension (bringing food into the functions to denature proteins (to mouth), mastication (chewing), further promote enzymatic action on partial digestion (thru the action of proteins), to kill most ingested salivary amylase). microorganisms, and to activate the pepsinogen to pepsin(an Contains the following structures: endopeptidase). tongue, teeth and salivary gland (secretes saliva which functions to: Secretion of enzyme chymosin moisten consumed feed, lubrication (rennin) in nursing mammals which of feed to facilitate swallowing, serve causes the coagulation of casein as buffer, and initiate carbohydrate (milk protein) to prevent rapid digestion). passage of milk out of the stomach. In birds: beaks or bills replace the Horses have a stomach that is small lips and teeth of mammals. relative to its body size and is less muscular. ✓ Hence, no extensive muscular 2. Pharynx movement to cause mechanical Musculomembranous organ which is a breakdown of ingested feed. common passage for feed and air.  In birds, stomach has two parts: Receives pancreatic enzymes and bile. a. Proventriculus Glandular portion; secretes HCl, Pancreatic enzymes: mucus and pepsin. a. Trypsin – an endopeptidase; b. Ventriculus (Gizzard) secreted as trypsinogen and activated Muscular portion; performs the same by enterokinase (from duodenum). function of the mammalian teeth(grinding of feed); contains b. Chymotrypsin – an endopeptidase; grits (sand grains or small rocks) in secreted as chymotrypsinogen and most birds to aid the grinding activated by trypsin. process. c. Elastase – an endopeptidase; secreted as proelastase and activated 5. Small Intestine by trypsin. Final site of digestion. d. Carboxypeptidase – an exopeptidase; secreted as Walls have finger-like projections procarboxypeptidase and activated called villi that greatly increase its by trypsin. surface area for absorption of nutrient. e. Amylase – a carbohydrase which primarily cleaves alpha-1,4 linked Has three parts: glucose residues of starch (from consumed plants) and glycogen (from a. Duodenum consumed meat and liver). Site of digestion Secretion of enterokinase f. Pancreatic lipases – cleaves the (enteropeptidase) that activates primary ester linkages in trypsinogen (a zymogen from triglycerides. pancreas) to trypsin g. Phospholipase A2 (Lecithinase A) b. Jejunum – acts on lecithins and cephalins. Major site of nutrient absorption Longest segment of the small h. Cholesteryl ester hydrolase – an intestine esterase acting on cholesterol esters. c. Ileum i. Deoxyribonuclease (DNase) and Site of nutrient absorption ribonuclease (RNase) – nucleases Secretions of intestinal juice by the acting on DNA and RNA, respectively. Brunner's and Lieberkuhn's glands Enzymatic components include aminopeptidase, dipeptidases, disaccharidases (maltase, sucrase, lactase)  Bile 6. Large Intestine Produced by the liver, stored in the Includes the cecum and colon. gall bladder and secreted into the duodenum. The undigested food residues and endogenous secretions pass from the Contains bile salts, which reduce ileum to the colon. surface tension and aid the emulsification of fats to aid/promote Microbial fermentation of undigested the efficient digestion and absorption and unabsorbed carbohydrates from of fat and the fat- soluble vitamins). the small intestine results in the production of VFA, CO2, and CH4. Serves a similar neutralizing role as that of the pancreatic secretions. Microbial degradation of proteins and amino acids results in the release of Serves as an excretory route for bile NH3, that is absorbed via the portal acids, cholesterol, bile pigments, blood and converted to urea in the drugs/toxins, and several minerals liver. (e.g. copper, zinc and mercury). Certain amino acids such as Horses have no gall bladder hence tryptophan can be metabolized by the bile is continuously secreted from the microflora to indole and 3- liver t small intestine. methylindole (skatole) responsible for a portion of the characteristic odor of Intestinal movements: feces. a. Peristalsis Site of significant absorption of water. Movement that tends to propel the ingesta along the intestine in a Many herbivorous and omnivorous direction towards the anus. mammals have an intestinal sac/pouch, called the cecum (located b. Segmentation near the junction of the ileum and Movement that does not move the colon; in the human, the appendix is contents along the intestine but the vestigial remnant of the cecum; merely mixes it; facilitates absorption in many birds, a pair of ceca exist. by bringing the ingesta into contact with the villi and by stimulating the In horses, microbial fermentation flow of blood and lymph in the much like in ruminants occurs in the intestinal wall. cecum and large colon (hindgut fermentation) where production of absorption of VFA occurs; however, fiber digestion is less efficient than ruminants due to faster passage rate. In birds, large intestine is reduced to a short connection between the small intestine and cloaca. 7. Rectum There is a large gap between the Terminal segment of the digestive incisors and molars, a configuration system in which feces accumulate that allows harvesting and chewing just prior to discharge. large amounts of fibrous feed. Birds have cloaca (bulbous final The inside of cheeks and palate is holding area for the waste products of rough which helps hold feed in while digestion, as well product of the chewing with a side-to-side motion. reproductive system in hen (egg) and waste product of the urinary system, Ruminants eat rapidly, swallowing until they are voided through the much of their feedstuffs without vent). shewing them sufficiently. Prehensive organs of: 8. Anus Cattle – tongue Terminal opening of the digestive Goat and Sheep – lips tract through which fecal material is Duck – bill excreted. Chicken – beak Also called vent which serves a common opening for excretion waste 2. Pharynx products of digestive and urinary Same with non-ruminants. systems as well as of expulsion of egg. 3. Esophagus Functions bi-directionally, allowing them to regurgitate their cud for Ruminant Digestive System further chewing. (Cattle, Buffalo, Sheep, Goat) 4. Stomach (Four Compartments) A. Reticulum (Honeycomb) Diagrammatic representation of the rumen, reticulum, omasum, and abomasum, of the ruminant, indicating flow of digesta. 1. Mouth Most cranial compartment and not Ruminants have no incisor teeth on completely separated from rumen. the upper raw, they have a dental pad instead.  Involved with rumination. ruminants can eat and digest large amount of roughage. Acts as a trap for foreign objects ingested. The microorganisms digest the plant fiber and produce VFA which are Its location behind the diaphragm absorbed directly through the rumen places it almost in apposition to the and supply 60-80% of the energy heart so any swallowed foreign needed. objects (e.g. wire or nails) lodged in the reticulum are in good position to Rumen fluid normally has pH between penetrate into the heart. 6 and 7. ✓ This is called “Hardware Disease” Each mL of rumen content contains roughly 10 to 50 billion bacteria, 1 Rumination – process of bringing million protozoa, and variable food material back from the stomach numbers of yeasts and fungi. to the mouth for further mastication. The microorganisms produce protein Four Phases of Rumination Cycle: including essential amino acids from 1. Regurgitation the feed. 2. Remastication 3. Reinsalivation Because the microbes can use 4. Reswallowing nitrogen to make protein, ruminants can utilize urea and other sources of NPN that would otherwise be toxic to B. Rumen (Paunch) non-ruminants. The microbes also synthesize vitamins B and k. C. Omasum (Manyplies) Largest compartment With projections called papillae No enzyme secretion Has laminae Contains billions of bacteria, protozoa, molds, and yeasts which It functions as the gateway to the live in a symbiotic manner with the abomasum, filtering large particles animals, and they are the reason back to the reticulorumen and  allowing fine particles and fluid to be prepared for further digestion in the passed to the abomasum. small intestine. It aids in water resorption and recycling of buffers for the saliva and 5. Small Intestine may also absorb some VFA. Digestion and absorption of by-pass Eructation (Belching) nutrients and microbial protein. Process of elimination/releasing of gaseous products of fermentation Enzymes to digest proteins, sugars, process in the rumen (CO2, CH4, and starch flow into the small and H2). intestine from the pancreas, while the gall bladder releases stored bile to Facilitated by the contractions of help digest fats. the upper sacs of the rumen to force the gasses to escape. The small intestine also produces some enzymes to aid in digestion, but Failure to do eructation will lead to its major function is absorption of excessive gas accumulation in the digested nutrients including amino rumen leading to ruminal acids from microbial protein. tympani (bloat) and eventual death of the animal due to Except for the VFA, most of the asphyxiation as expanding rumen nutrients are absorbed in the small interferes with breathing. intestine. D. Abomasum (True Stomach) 6. Large Intestine Absorption of water and a second phase of microbial digestion. The VFA produced in the large intestine are absorbed, but microbial cells are excreted together with undigested food components in the feces. 7. Rectum Same with non-ruminant mammals. It functions much like the non- ruminant stomach, producing acid and some enzymes to start protein 8. Anus digestion. Same with non-ruminant mammals. Microbial cells as well as nutrients which did not undergo rumen digestion (by-pass nutrients) are  LESSON 9: CONCENTRATES Concentrated sources of one or more nutrients used to enhance the Introduction nutritional adequacy of a supplement mix. ❖ Feedstuffs for animals are traditional animal feed resources that provide the basic nutrients needed by the animal. ❖ Classically, feeds are classified as either concentrate or roughage based on proximate analysis of the feed wherein the amount of crude fiber (CF) and total digestible nutrient (TDN) is considered. TDN includes digestible crude protein (CP), CF, nitrogen-free extract (NFE), and crude fat or ether extract (EE). Proximate Analysis – method of determining the nutrient content CARBONACEOUS CONCENTRATES of feed. ❖ Concentrates with 46% CP) and non-dehulled (43% CP). Has high protein quality and can possibly be used as the only protein supplement in the diet. Ground dried leaves of ipil-ipil with Low in methionine; urease activity minimum amount of stems. is used as index in detecting Color is greenish brown. improperly processed soybean oil Contains toxic compound, non- meal. protein amino acid called mimosine Raw soybean contains trypsin which causes alopecia; inclusion in inhibitor. the diet is only 5-10%. Color is bright yellow to golden yellow Source of pigment for poultry. and yellowish brown. b. Copra Meal 3. Cereal Byproducts c. Corn Gluten Feed Produced from processing of cereals. a. Corn Germ Meal Consists of gluten meal and corn bran Obtained after the corn oil has been ground together. partially extracted. Tan to yellowish-brown in color. Golden yellow to brown in color. High in fiber Consists of defatted corn germ that is Usually contains around 22% CP. produced after the corn oil has been Used less than 20% in growing- removed. finishing pigs and less than 10% in Very high in fiber and low palatability. weanling pigs. Reduce palatability at high levels of usage. b. Corn Gluten Meal d. Dried Brewers Grain Byproduct from manufacture of corn starch and oil; dried residue remaining after removal of larger part Dried extracted residue of barley malt of starch, germ, and bran. alone or in mixture with other cereal Golden yellow or brownish yellow in grains or grain products resulting color. from the manufacturing. It contains slightly more TDN than corn. Contains 40-60% CP Low in lysine Unpalatable in high levels The protein in corn gluten is degraded relatively slowly in the rumen; good source of protein for ruminants. Can be a source of bypass protein in ruminants. e. Dried Distiller’s Grain with Color is light brown. Solubles CP is 50-80% Excellent source or essential amino acids, Ca, and P. 2. Poultry Meal Wet distiller’s grain that has beed dried with the concentrated thin stillage to 10-12% moisture. Contains 26% CP Imported from the U.S.A. Dried ground tissue of undecomposed Usually used up to 15% in poultry and meat and bone. swine. Color is usually grayish brown. Contains more than 50% CP, not more than 5% Ca, and not less than B. Animal Origin 3% P. Comes form meat packing or Source of essential amino acids. rendering plants, surplus milk or milk products or from marine sources. Relatively rich in lysine. 3. Poultry Byproduct Meal Likely to be short of either sulfur Ground tissues of undecomposed amino acids (methionine and cystine) neck, head, fat, carcass, and feather, or tryptophan. with or without oil extracted. Usually incorporated at 5-10% in Light tan or light brown to reddish diet. brown in color. Includes porcine meal, poultry and Contains 50% CP byproduct meals, blood meal, Excellent source of amino acids; good plasma meal, feather meal, whole source of Ca and P. milk powder, skimmilk powder, whey powder, and fish meal. 4. Blood Meal 1. Porcine Meal or Pork Meal Obtained from various parts of porcine carcass which have been cleaned, ground, and rendered.  Coagulated blood which has been 7. Skimmillk Powder dried and ground. Color is reddish black Contains high CP (80%) but low in digestibility. Unpalatable 5. Blood Plasma Resulting from the removal of water and fats from clean milk. Color is white or cream. Contains 33% CP and 40% lactose. Use in booster and pre-starter diets and milk replacers. Produced by spray drying blood plasma. Contains active globulin and 8. Whey Powder albumin fractions. Excellent amino acid profile. 78% minimum protein content. 6. Feather Meal Resulting from the removal of water from clean, sound cheese or casein whey. Rich in lactose and unidentified growth factors. Hydrolyzed poultry feathers Pressure-treated, clean, 9. Whole Milk Powder undecomposed feathers. Contains 85% CP and 75% of the CP should be guaranteed digestible.  Obtained by drying milk. Color is white Contains 25% CP and 45% lactose. Good source of energy and protein for piglets. 10. Fish Meals D. Miscellaneous Protein Sources Unconventional protein sources Includes animal wastes and yeasts. Ground dried whole fish or fish 1. Animal Wastes cuttings with or without oil extraction. Color is tan or light brown to reddish brown. Excellent protein quality and source of B Vitamins; used primarily in swine and poultry especially in young animals. C. Non-Protein Nitrogenous Sources Contains 20% CP; 40 (layer) to 60 Used as a source of non-protein (broiler)% TDN. nitrogen (NPN) for protein synthesis Inclusion of 5-10% into poultry or by rumen microorganisms. swine does not alter performance. Inclusion of 20-30% in ruminant have 1. Urea supported gain compared to plant Recommended inclusion rates: protein. 1% of ration (dry matter basis) 2-3% of concentrate mixture (air- dry basis) 25-30% of total dietary protein 2. Biuret (Carbamylurea) Feed grade biuret consists of nitrogen compounds resulting from controlled pyrolysis of urea. 2. Yeasts Includes improved grasses and native grasses. Examples of Improved Grasses: 1. Napier Grass or Elephant Grass (Pennisetum purpureum) Brewer’s fried yeast, grain distiller’s dried yeast, torula yeast, active yeast, and irradiated yeast. LESSON 10: ROUGHAGES Introduction ❖ Feed containing at least 18-20% Most popular improves pasture crude fiber (CF) and