Introduction to Animal Nutrition & Feed Composition PDF

Introduction to Animal Nutrition & Feed Composition CU: Animal Nutrition Margarida Cardoso Duarte, PhD www.egasmoniz.com/pt www.egasmoniz.com/pt Concepts For teaching...

Introduction to Animal Nutrition & Feed Composition CU: Animal Nutrition Margarida Cardoso Duarte, PhD www.egasmoniz.com/pt www.egasmoniz.com/pt Concepts For teaching purposes only! Nutrition: is defined as the science that interprets the interaction of nutrients and other substances in food that influence the maintenance, growth, development, reproduction, and health of animals. Nutrition = health and well-being - Nutrition includes: Master Degree in Veterinary Medicine (1) food intake; (2) digestion, absorption, assimilation, biosynthesis, and catabolism of nutrients; (3) excretion of metabolites. Bromatology: studies the food nature, composition, quality and dietary uses Nutritional science is a cluster of scientific disciplines related to biology, which include biochemistry, food chemistry, immunology, molecular biology, pediatrics, pharmacology, physiology, public health, reproductive biology, and toxicology. www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Animal nutrition includes essentially every biological science that can be applied to the study of nutrient utilization and nutritional problems in livestock, poultry, fish, and other species. - Master Degree in Veterinary Medicine Animal nutrition, like medicine, is a field for both scientists and practitioners, and it can be considered a unique discipline because of its specific objective: improving the survival, growth, and health of animals by understanding their metabolism and the roles of dietary nutrients. www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Food is material that, after ingestion by animals, is capable of being digested, absorbed and utilized. The term “food” is used to describe edible material that contains nutrients. e.g. grass and hay (feno) are described as foods, but not all their components are digestible. - A nutrient is defined as a compound or substance needed to Master Degree in Veterinary Medicine support the maintenance, growth, development, lactation, reproduction, and health of animals. Food for farm animals (e.g., livestock, poultry, fish, and shrimp) is commonly known as feed. www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Digestion is defined as chemical disintegrations of foodstuffs in the digestive tract into smaller molecules that are suitable for assimilation by the animal. BIOACCESSIBILITY - fraction of nutritional elements that was released from - the food during digestion and that presumably becomes accessible for absorption through the small Master Degree in Veterinary Medicine intestine walls. - pre-requisite for bioavailability Bioavailability is defined as the fraction of nutrients or food components that have been efficiently digested in vivo, assimilated, and then absorbed in the body. www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Feeds are classified as (on the basis of their composition and use): (1) dry forages (e.g., dried pasture, leaves, stems (pedúnculos), green chop, and hay) and roughages (e.g., hay, straws, and hulls (cascas) with >18% crude fiber); (2) green pasture, range plants, and freshly fed green forages (e.g., forage feeds); (3) silages (e.g., ensiled corn, alfalfa, and grass); (4) energy feeds (e.g., corn, wheat, barley, and rice); and - (5) protein feeds (e.g., soybean meal, meat and bone meal, blood meal, poultry meal, fish meal, and milk Master Degree in Veterinary Medicine replacer). Also may be included to feeds: synthetic amino acids, mineral supplements, vitamin supplements, other additives (e.g., antibiotics, coloring materials, flavors, phytochemicals, hormones, and medicines) ….to prepare complete diets for animals www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Feed ingredients may be grains, milling byproducts, animal byproducts, vitamin premix, mineral premix, fats, oils, and other nutritional sources. - Master Degree in Veterinary Medicine A diet is a mixture of feedstuffs (= feed ingredients) that supplies nutrients to an animal. The sources of feedstuffs vary among animal species. The ration is the daily allowance or amount of feed provided to an animal. A meal is the feed consumed by an animal on regular occasions (e.g., morning and evening). www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Essential nutrients are those that cannot be synthesized by the animal in sufficient quantities for physiological functioning. Essential nutrients* are: 10 amino acids, - 13 vitamins, 7 macrominerals, Master Degree in Veterinary Medicine 9 microminerals (trace), 2 fatty acids, *although there are differences between animal species. Nutrients interact with one another to reduce absorption and utilization, often inducing deficiencies. www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! The law of limiting nutrients means that there will be no animal response to other nutrients until the ‘first-limiting’ nutrient is provided. Once this nutrient is supplied a ‘second-limiting’ nutrient limits further response and so on. - Liebig used a barrel with different length staves to represent the relative supply of Master Degree in Veterinary Medicine nutrients to the plant. Providing more of any other nutrient will have no impact on performance (barrel’s volume) until the limiting nutrient is provided. Hynd P.I. (2019) Animal Nutrition – from theory to practice. www.egasmoniz.com/pt Concepts (cont.) For teaching purposes only! Energy in animal feed and energy required by animals are measured as heat. The unit of energy is the Calorie or food Calorie (1 kcal is the energy required to raise the temperature of 1 kg of water by 1°C). The SI unit is the Joule (= Calories × 4.182). - Master Degree in Veterinary Medicine The energy available to an animal for maintenance, growth, gestation, lactation and physical activity is called the Net Energy (energia limpa). The system used to describe energy availability for most animal species is based on Metabolisable Energy (ME), the energy available after digestion and losses of energy in urine and methane. www.egasmoniz.com/pt Importance of Animal Nutrition understanding For teaching purposes only! Nutrition is the single major determinant of animal health, welfare, production and the economic viability of animal enterprises. Feed costs account for 50–70% of the costs of production in most animal production systems and the - global feed manufacturing industry is worth more than US$500 billion per year! Master Degree in Veterinary Medicine Poor nutrition is a major welfare issue, contributing to specific deficiency diseases, metabolic diseases, digestive disorders, obesity, diabetes, orthopaedic problems, cardiovascular problems, and predisposition to infectious and parasitic diseases. The global demand for animal feeds and feed additives is rapidly increasing, as the global demand for animal protein expands in line with global per capita incomes. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition For teaching purposes only! All animals depend on feed for survival, growth, and reproduction. Classes of animals: Herbivores – the plant eaters (ruminants, horses and small animals such as rabbits and guinea pigs); Omnivores – which eat all types of food (pigs and poultry); -- Medicine Veterinary Medicine Carnivores – which eat mainly meat (dogs, cats). in Veterinary But the range of foods that animals are now offered is far greater than they might normally consume in the wild, e.g.: 1) ruminants are given plant by-products of various human food industries; Degree in Master Degree 2) some dog foods contain appreciable amounts of cereals. Nevertheless, plants and plant products form the major source of nutrients in animal nutrition, Master although some foods of animal origin, such as fishmeal and milk, are used in limited amounts. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) For teaching purposes only! Feed basic components: dry matter (DM) and water. (e.g., urea, ammonia, nitrite, and nitrate) -- Medicine Inorganic matter (ash) is composed of Veterinary Medicine macrominerals and microminerals, and cannot be burned in a furnace (e.g., 500°C). Master Degree Master in Veterinary Degree in Whu G. (2018) Principles of Animal Nutrition www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - WATER For teaching purposes only! The water content of the animal body varies with age: - newborn animal contains 750–800 g/kg water, - mature fat animal contains less: about 500 g/kg VITAL to the life of the organism that the water content of the body be maintained: an animal will die -- more rapidly if deprived of water than if deprived of food. Medicine Veterinary Medicine Functions as solvent in the body, transporting nutrients, and in which waste products are excreted. Many enzymatic reactions in the body involve hydrolysis. in Veterinary Because water can absorb and transfer heat well, the human/animal body uses it to stabilize temperature: Degree in Master Degree High specific heat of water: large changes in heat production can take place within the animal with very little alteration in body temperature. Master High latent heat of evaporation: its evaporation from the lungs and skin (to expel excess heat) gives it a further role in the regulation of body temperature. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - WATER For teaching purposes only! The animal obtains its water from three sources: 1) drinking water, 2) water present in food 3) metabolic water - formed during metabolism by the oxidation of hydrogen- containing organic nutrients. -- Medicine Veterinary Medicine The water content of foods range from 60 g/kg (concentrates) to over 900 g/kg (some root crops). in Veterinary Because of this great variation in water content, the Degree in Master Degree composition of foods is often expressed on a dry matter basis, which allows a more valid comparison of nutrient Master content. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - WATER For teaching purposes only!  The water content of growing plants is related to the stage of growth, being greater in younger plants than in older plants. --  In temperate climates, the acquisition of drinking water is not usually a problem and animals Medicine Veterinary Medicine are provided with a continuous supply. in Veterinary  There is no evidence that under normal conditions an excess of drinking water is harmful, and animals normally drink what they require. Degree in Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) – DRY MATTER For teaching purposes only! Dry Matter of foods is divided into organic and inorganic material. -- Many organic compounds contain mineral elements as structural Medicine Veterinary Medicine components. in Veterinary Proteins, for example, contain sulphur, and many lipids and carbohydrates contain phosphorus. Degree in Master Degree Master McDonald P. et al. (2022) Animal Nutrition 8th ed. Master Degree in Veterinary Medicine - www.egasmoniz.com/pt CARBOHYDRATES For teaching purposes only! www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! The carbohydrates are produced by plants during photosynthesis, and are degradaded in metabolism -- energetic reserve Medicine Veterinary Medicine (e.g. starch, glycogen, fructans) in Veterinary structure materials (e.g. cellulose, chitin, Degree in pectin) Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! The main carbohydrates occurring in foods include: - Monosaccharides: glucose, fructose, arabinose, xylose and ribose; -- Medicine Veterinary Medicine - Disaccharides: sucrose and maltose; (lactose occurs in milk); - Polysaccharides: starch, hemicellulose and celulose Master Degree Master in Veterinary Degree in www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Carbohydrates, sugars or saccharides are  polyhydroxy aldehydes or ketones – contain carbonyl group (C=O);  polymers that yield such compounds on hydrolysis;  some also contain nitrogen, phosphorus, or sulfur; -- empirical formula  found specially in plant foods. Medicine Veterinary Medicine (CH2O)n in Veterinary (n > 3) Carbohydrate with an Aldehyde group aldehyde group: aldose Degree in Master Degree monosaccharides act as reducing substances Master Carbohydrate with a ketone group: ketose Ketone group www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Monosaccharides are simple sugar molecules which have asymmetric centres (optically active isomeric forms (D & L)). -- Master Degree Master in Veterinary Degree in Medicine Veterinary Medicine www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Under physiological conditions the monosaccharides exist mainly in cyclic forms, which can be α- or β-isomers. 1 1 -- Medicine Veterinary Medicine e.g. cyclic structures of glucose: in Veterinary anomers  and  Degree in 1 1 Master Degree Anomers: isomers that differ at a new Master asymmetric carbon formed on ring closure. Glucose: greater stability of  form  Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Monosaccharides Oligosaccharides Polysaccharides www.egasmoniz.com/pt www.egasmoniz.com/pt (simplest oses) (2-20 oses) (> 20 oses) Do not exist free in nature, are products from metabolism In some plants components of hemicelluloses and found in silage, grass, herbage as a result of their hydrolysis -- present in all living cells as a constituent of RNA and also component of several vitamins Medicine Veterinary Medicine and coenzymes; can be synthesized by animals in Veterinary The more abundant monosaccharides in Nature Degree in Master Degree Glucose and fructose - most important naturally occurring hexose sugars; Master Mannose and galactose occur in plants in a polymerised form as mannans and galactans. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Monosaccharide derivatives Deoxy sugars Amino sugars – tissue formation -- Medicine Veterinary Medicine in Veterinary Deoxyribose (derivative of ribose): component of D-glucosamine - major component of chitin deoxyribonucleic acid (DNA). (not degraded by animals); Degree in Master Degree D-galactosamine - component of the Rhamnose (derivative of mannose) and Fucose polysaccharide of cartilage (derivative of galactose) are components of certain Master heteropolysaccharides. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Monosaccharide derivatives Glycosides  galactose forms galactosides and fructose forms fructosides -- The term glycoside is used collectively to describe these derivatives which are recognized as toxic and Medicine Veterinary Medicine usually are present in one part of the plant (tubers, leguminous seeds, …). in Veterinary Degree in Master Degree The glycoside itself is not toxic and must be hydrolyzed before poisoning occurs. Master It is easily broken down to its components by means of an enzyme that is usually present in the plant. McDonald P. et al. (2022) Animal Nutrition, 8th ed. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Oligosaccharides Disaccharides Sacarose (-1,2 glu,fru) (C12H22O11) Lactose (-1,4 glu,gal) Maltose (-1,4 glu,glu) Trehalose (-1,1 glu,glu) -- Trisaccharides Maltotriose (glu, glu, glu) products resulting Medicine Veterinary Medicine (C18H32O16) from starch hydrolysis Raffinose (gal, fru, glu) -in vegetables (bean, cabbage, broccoli, asparagus) in Veterinary Tetrasaccharides Stachyosis (2Gal, Glu, Fru) Degree in -in vegetables (green bean, soybean, beans) (C24H42O21) Master Degree and other plants Master Pentasaccharides Verbascose (3Gal, Glu, Fru) (C30H52O26) www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Oligosaccharides Animals cannot degrade these more complex sugars (e.g. raffinose, stachyosis, verbascose) – also -- called “flatulence” sugars – too large to be absorbed and subjected to microbial fermentation which can result in production of a large amount of gas (H2 and CO2), Medicine Veterinary Medicine only bacteria that have α-galactosidases can hydrolyse galactoses. in Veterinary Nowadays, feed are treated with α-galactosidases to allow the digestion of these sugars by Degree in Master Degree animals. Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Polysaccharides, also called glycans, are polymers of monosaccharide units. Homoglycans (or homopoly-holosides)- contain only a single type of monosaccharide unit; -- Heteroglycans (or heteropoly-holosides) - on Medicine Veterinary Medicine hydrolysis yield mixtures of monosaccharides and derived products. in Veterinary Degree in Master Degree Polymers result from the formation Master of glycoside bonds between the constituent oses. McDonald P. et al. (2022) Animal Nutrition, 8th ed.  Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Starch and glycogen www.egasmoniz.com/pt www.egasmoniz.com/pt Polysaccharides Cellulose Glucose polymers: -- -Starch Medicine Veterinary Medicine -Cellulose in Veterinary -Glycogen (glucose reserve in animal muscle - resembles Degree in starch in properties (& Master Degree functions), and often called “animal starch”) Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Starch (amylose (15-20%) and amylopectin (80-85%)) is a glucan and is present in many plants as a reserve carbohydrate. It is most abundant in seeds, fruits, tubers (tubérculos) and roots. Starch occurs naturally in the form of granules, whose size and shape vary in different plants. Amylose Amylopectin Molar mass 50 000-200 000 > 100 000 -- Glicosidic bond type -1,4 -1,4 and -1,6 Medicine Veterinary Medicine Molecular structure Linear Branched Products resulting from Maltose Maltose, in Veterinary -amylase action (action β-dextrins at non reducing end) Degree in Products resulting from Oligossacharides, -dextrins, maltose, Master Degree -amylase (action at any maltose, glucose, glucose Master region) maltotriose Starch gelatinization: granules in hot water may swell and eventually gelatinize. Dextrins are soluble in water and produce gum-like solutions.  Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Cellulose: main structural component of plant cell walls www.egasmoniz.com/pt www.egasmoniz.com/pt (associated to lignin, hemicelluloses) Chemical structure -- Polymer of D-glucose with Medicine Veterinary Medicine glycosidic bonds -1,4 in Veterinary By hydrolysis (cellulases - microbial Degree in Master Degree enzymes in ruminant digestive tract) produces cellobiose Master (glu+glu, -1,4) www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Heteroglycans Pectic substances. soluble in hot water;. constituents of primary cell walls and intercellular -- regions of higher plants. Linked to cellulose and hemicellulose by covalent Medicine Veterinary Medicine bonds in Veterinary Apple pulp: 10-15% pectin Citric pulp: 20-30% pectin Degree in Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Heteroglycans Unlike cellulose (crystalline, rigid, Hemicellulose resistant to hydrolysis) hemicelluloses. alkali-soluble cell wall polysaccharides; have an amorphous structure, little. associated with cellulose; resistant and easily hydrolyzed by acids --. xylose always present in higher quantity; or bases and several hemycellulolytic enzymes Medicine Veterinary Medicine in Veterinary Resulting from hydrolysis of: Xylans More frequent oses: Glucoronoxylans Degree in Master Degree D-xylose, L-arabinose, D-galactose, Arabinoxylans D-mannose, L-ramnose, D-glucose Glucomannans Master Xyloglucans Galactanans Arabinogalactanans www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - CARBOHYDRATES For teaching purposes only! Lignin: is not a carbohydrate but is closely associated with this group of compounds, confers chemical and biological resistance to the cell wall, and mechanical strength to the plant. Lignin is of particular interest in animal nutrition because of its high resistance to chemical degradation. Physical -- incrustation of plant fibres by lignin Medicine Veterinary Medicine renders them inaccessible to enzymes that would normally digest them. in Veterinary There is evidence that strong chemical bonds exist between lignin and many plant polysaccharides and cell wall proteins, which render these compounds unavailable during digestion. Degree in Wood products, mature hays and straws are rich in lignin and consequently are poorly digested unless Master Degree treated chemically to break the bonds between lignin and other carbohydrates Master Several bacteria with lignin degradation potential have been identified and in some cases their enzymes were also found useful for the degradation of lignin in industrial scale Master Degree in Veterinary Medicine - www.egasmoniz.com/pt LIPIDS For teaching purposes only! www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - LIPIDS For teaching purposes only! The lipids are a heterogeneous group of compounds, including fats, oils, steroids, waxes, and related compounds, that are related more by their physical than by their chemical properties. They have the common property of being Waxes are chemically inert, have (1) relatively insoluble in water and little or no nutritive value, and are (2) soluble in nonpolar solvents such as ether and chloroform. mainly protective in function. -- They are important dietary constituents (supply 45% of the energetic needs) not only because of the high Medicine Veterinary Medicine energy value of fats but also because essential fatty acids, fat-soluble vitamins (A, E, D, K), and other lipophilic micronutrients are contained in the fat of natural foods. in Veterinary Degree in Master Degree Main food energy source: lipids (9 kcal g-1), Master carbohydrates (4 kcal g-1) and proteins (4 kcal g-1) McDonald P. et al. (2022) Animal Nutrition, 8th ed. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - LIPIDS For teaching purposes only! Lipids are classified as simple (fats and waxes which are esters of fatty acids with various alcohols) or complex (esters of fatty acids, which always contain an alcohol and one or more fatty acids, but which also have other groups). The structural lipids of membranes include both glycerophospholipids and sphingolipids. -- Master Degree Master in Veterinary Degree in Medicine Veterinary Medicine The alcohol is glycerol The alcohol is sphingosine www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - LIPIDS For teaching purposes only! Fats and oils are major sources of stored energy in both plants and animals. They are esters of fatty acids with glycerol. Their physical and chemical nature is determined by their fatty acid composition: high-molecular-weight saturated acids confer chemical stability and physical hardness, unsaturated acids confer chemical reactivity and physical softness. -- Medicine The hydrocarbon chain Veterinary Medicine may be saturated (containing no double in Veterinary bonds) or unsaturated (containing one or more double bonds) Degree in Master Degree Master Usually solid at room Usually liquid at temperature room temperature www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - LIPIDS For teaching purposes only! ESSENTIAL FATTY ACIDS: linoleic acid and α-linolenic acid Eicosanoids are formed from 20-carbon polyunsaturated fatty acids, including the essential fatty acids linoleate and α-linolenate, or dietary arachidonate and eicosapentaenoate. -- in Veterinary Degree in Master Degree Medicine Veterinary Medicine The eicosanoids are active compounds known Master as prostaglandins (PG), thromboxanes (TX), leukotrienes (LT), and lipoxins (LX). McDonald P. et al. (2022) Animal Nutrition, 8th ed.  Feed composition (cont.) - LIPIDS For teaching purposes only! Cholesterol and steroid hormones www.egasmoniz.com/pt www.egasmoniz.com/pt Cholesterol is the precursor of a large number of equally important steroids that include the bile acids, adrenocortical hormones, sex hormones, vitamin D and cardiac glycosides. -- Medicine Veterinary Medicine VLDL – very low density lipoproteins; LDL – low density lipoproteins; in Veterinary HDL – high density lipoproteins Degree in Master Degree Cholesterol is present in all animal cells and is particularly important in the myelinated structures of the brain and nervous tissue. Master There is strong evidence that the risk of coronary heart disease is directly related to the concentration of low-density lipoprotein cholesterol in the blood. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - LIPIDS For teaching purposes only! Fat-soluble vitamins: A, D, E, K Vit A, D, E, K are 7-Dehydrocholesterol stored in lipidic and ergosterol are fractions of animal important as the and vegetable species precursors of vitamins (adipose tissues and D3 and D2, respectively. -- liver of mammals and Present in vegetables marine animals, as β-carotene The human organism Medicine Veterinary Medicine butter, oils, eggs) synthesizes vit D (through solar light) from cholesterol in Veterinary The main vit A source In unrefined oils: olive oil Tocopherols are in vegetables are the hydrophobic, so they carotenoids associate with cell Degree in membranes, lipid Master Degree deposits, and lipoproteins The human organism in the blood. Master uses vit K produced by Tocopherols are biological gastrointestinal antioxidants. microbiota Master Degree in Veterinary Medicine - www.egasmoniz.com/pt COMPOUNDS NITROGENOUS For teaching purposes only! www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - PROTEINS For teaching purposes only! Proteins are polymers of amino acids with specific biological and physiological functions in living organisms (animals and plants). Chemical composition of proteins: C (50-55%), O (20-23%), N (15-18%), H (6-8%), S (0-4%), P, Fe, Cu, Zn -- Medicine Veterinary Medicine Plants and many microorganisms are able to synthesize proteins from simple nitrogenous compounds such as nitrates. in Veterinary Degree in Master Degree Animals cannot synthesize the amino group, and in order to build up body Master proteins they must have a dietary source of amino acids.  Feed composition (cont.) - PROTEINS For teaching purposes only! Structural organization of polypeptide chains www.egasmoniz.com/pt www.egasmoniz.com/pt -- Medicine Veterinary Medicine in Veterinary The shape and function of the protein molecule is determined by the sequence of amino acids, which, in turn, is genetically determined by the cell’s DNA. Degree in Master Degree Proteins have colloidal properties and can be denatured by heat, creating new linkages between Master the chains, some of which are resistant to hydrolysis. Proteins may be simple, either fibrous or globular, or conjugated to a non-protein molecule. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - PROTEINS For teaching purposes only! Proteins are made up from a pool of 20 amino acids, about 10 of which are essential (indispensable) for non-ruminants. This list of essential amino acids is similar to the Essential AA for growth in rat ones required by: Arginine Threonine - Pig (without Arginine which can be Methionine Leucine synthesized by the pig); - Chick (adding Glycine); -- Histidine Tryptophan - Poultry (adding Proline - have limited Phenylalanine Lysine capacity to synthesize it); Medicine Veterinary Medicine Isoleucine Valine - Horse (Lysine is 1st limiting amino acid, and Threonine is considered to be 2nd limiting) in Veterinary Ruminants: all the essential amino acids can be synthesized by the rumen microorganisms. HOWEVER supply of amino acids from microbial protein is limiting in quantity and sometimes quality for: Degree in  maximum rates of growth in young animals and Master Degree  maximum milk production Master microbial protein must be supplemented with a supply of dietary amino acids (foods, synthetic amino acids - suitable form that is protected from degradation by the microorganisms in the rumen) www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) – NUCLEIC ACIDS For teaching purposes only! Nucleic acids store genetic information, which is utilized in the synthesis of proteins. -- There are 2 types of nucleic acids: Medicine Veterinary Medicine Deoxyribonucleic Acid – DNA Ribonucleic Acid – RNA Master Degree Master in Veterinary Degree in www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) – NUCLEIC ACIDS For teaching purposes only! On hydrolysis, nucleic acids yield a mixture of - nitrogenous bases (purines and pyrimidines), - pentose (ribose or deoxyribose) and - phosphoric acid. -- Nucleotide structure: The cyclic compounds with nitrogen have a Medicine Veterinary Medicine Nitrogen-containing base Nucleoside general designation: nitrogenous base. Pentose sugar in Veterinary Phosphate group The nitrogenous bases derive from the purine and pyrimidine structures. Degree in Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) – AMINES For teaching purposes only! Amines are basic compounds present in small amounts in most plant and animal tissues. Many occur as decomposition products in decaying organic matter and have toxic properties. -- Biogenic amines are formed by enzymatic decarboxylation Medicine Veterinary Medicine of amino acids; may be produced in the rumen under certain conditions; in Veterinary or resulting from microorganisms or plants metabolism. Degree in Master Degree Biogenic amines may give rise to physiological symptoms: e.g., histamine is an amine formed from the amino acid Master McDonald P. et al. (2022) Animal Nutrition, 8th ed. histidine and in cases of anaphylactic shock is found in the blood in relatively large amounts. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) – AMIDES For teaching purposes only! The principal difference in structure between amines and amides is that amides contain a carbonyl group (C=O) attached to the nitrogen. -- Urea is an amide that is the main end product of nitrogen metabolism in mammals, but it also occurs in many plants and has been detected in wheat, soya bean, potato and Medicine Veterinary Medicine cabbage. Master Degree Master in Veterinary Degree in www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) – OTHER NITROGENOUS COMPOUNDS For teaching purposes only! Nitrates may be present in plant materials and, whereas nitrate itself may not be toxic to animals, it is reduced readily under favorable conditions, as in the rumen, to nitrite, which is toxic. Alkaloids are poisonous nitrogen-containing compounds formed by some plants and fungi. In plants, their presence is restricted to a few orders of the dicotyledons. -- Master Degree Master in Veterinary Degree in Medicine Veterinary Medicine McDonald P. et al. (2022) Animal Nutrition, 8th ed. Master Degree in Veterinary Medicine - www.egasmoniz.com/pt VITAMINS For teaching purposes only! www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! Vitamins are required by animals in very small amounts compared with other nutrients (e.g. the vitamin B1 (thiamin) requirement of a 50 kg pig is only about 3 mg/day). A continuous deficiency in the diet results in disordered metabolism and eventually disease. -- Medicine Veterinary Medicine The lack of a vitamin prevents the synthesis of a specific coenzyme, blocking a metabolic pathway in Veterinary Degree in Master Degree 14 vitamins have been accepted as essential food factors, and with Master nutritional importance McDonald P. et al. (2022) Animal Nutrition, 8th ed. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! Many vitamins are destroyed by oxidation which is speeded up by the action of heat, light and certain metals such as iron. -- the final vitamin potency is affected by the Medicine Veterinary Medicine conditions under which a food is stored in Veterinary Some commercial vitamin preparations are dispersed in wax or gelatin, which act as a protective Degree in Master Degree layer against oxidation. Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! Supplementation of diets with vitamins Most food mixes prepared as supplements for ruminants and horses, or as complete and complementary foods for pigs, poultry, dogs and cats, are supplemented with vitamins. Vitamins are usually supplied at levels greater than those shown to be required under experimental conditions. -- This oversupply allows for uncertainties met under practical conditions: Medicine Veterinary Medicine - variable vitamin content and availability in foods, The vitamin must remain - loss of vitamin potency in storage, stable and yet be biologically in Veterinary - range of management practices, available when consumed by - quality of the environment, the animal. - health status or extra requirements due to stress. Degree in Master Degree Vitamins may be obtained form: isolation from plant products (low yields and expensive); Master produced from m.o. (yields can be increased this way); multi-stage chemical processes that are controllable (predictable yields) www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! e.g., use of antibiotics for www.egasmoniz.com/pt long periods of time can Hypovitaminosis – deficiency of vitamins; cause hypovitaminosis Both may lead to specific disease. Avitaminosis – absence of vitamins (modified gastrointestinal microbiota) Hypervitaminosis – excess of vitamins also cause problems, especially in the case of fat-soluble vitamins that are more difficult to eliminate (through bile). -- Absorption: Medicine Fat soluble vitamins: require fat to be absorbed (hepatobiliary system must function correctly); Veterinary Medicine Water soluble vitamins: absorbed in the intestine and transported by circulatory system to tissues. in Veterinary Storing: Fat soluble vitamins: well stored, exception for vit K (necessary for the synthesis of prothrombin in the liver); Water soluble vitamins: not well stored, exception for vit B12 (most complex structure of all the vitamins). Degree in Master Degree Excretion: Fat soluble vitamins: excess ingestion may achieve toxic levels inside the organism; Master Water soluble vitamins: excess is excreted mainly through urine. The synthesis of water soluble vitamins and vitamin K occur in gastrointestinal tract for ruminants, swines, birds and rabbits. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! Vitamins are involved in metabolic pathways as coenzymes and in the expression of genes, and some act as protectors in antioxidant and immune systems. e.g., Vitamin D -- Medicine Veterinary Medicine in Veterinary This most biologically active form of the vitamin, induces the synthesis of a calcium- Degree in binding protein, which is involved in the Master Degree absorption of calcium from the intestinal lumen. Master McDonald P. et al. (2022) Animal Nutrition, 8th ed. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! e.g., Vitamin E Vitamin E functions in the animal mainly as a biological antioxidant. It protects cells against oxidative damage caused by free radicals, preventing its formation. Free radicals are formed during (oxidative) cellular metabolism and, as they are capable of damaging cell membranes, enzymes and cell nuclear material, they must be converted -- into less-reactive substances if the animal is to survive. Medicine Veterinary Medicine What are ROS (reactive oxygen species)? in Veterinary Superoxide O2 High reactive molecules containing one Degree in Hydroperoxide H2O2 or more unpaired electrons, which they Master Degree try to gain or lose to achieve stability. Hydroxyl OH Master oxygen singlet 1O 2 ROS are eliminated by antioxidant mechanisms of the cells ROS = espécies reactivas de oxigénio www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - VITAMINS For teaching purposes only! Animal’s cells require protection mechanisms and these are provided by the antioxidant system to keep the integrity of cells: …combination of vitamins and enzymes, containing trace -- elements (microminerals), working in a complementary way in Veterinary Degree in Medicine Veterinary Medicine All classes of biological molecules are vulnerable to free radical Master Degree damage, but especially lipids, proteins and DNA. Master www.egasmoniz.com/pt www.egasmoniz.com/pt -- Degree in Master Degree Master Medicine Veterinary Medicine in Veterinary Feed composition (cont.) - VITAMINS For teaching purposes only! McDonald P. et al. (2022) Animal Nutrition, 8th ed. www.egasmoniz.com/pt www.egasmoniz.com/pt -- Degree in Master Degree Master Medicine Veterinary Medicine in Veterinary Feed composition (cont.) - VITAMINS For teaching purposes only! McDonald P. et al. (2022) Animal Nutrition, 8th ed. Master Degree in Veterinary Medicine - www.egasmoniz.com/pt MINERALS For teaching purposes only! www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Minerals are inorganic elements present in tissues in small quantities (approx 4%), many are thought to be present merely because they are constituents of the animal’s food and may not have an essential function in the animal’s metabolism. Major elements: -- Ca, Cl, Mg, P, K, Na, S Medicine Necessary to organism in high quantities (mg/kg feed) Veterinary Medicine in Veterinary Trace elements: I, Fe, Zn, Se, Co, Cr, Cu, Mn, Mo Degree in Necessary to organism in small quantities (μg/kg feed) Master Degree Master McDonald P. et al. (2022) Animal Nutrition, 8th ed. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Essential minerals – must have metabolic function. Its absence causes symptoms of deficiency, and its supplementation removes symptoms. It is very difficult, for experimental purposes, to completely remove a single mineral and not remove others, so this category is not well defined. -- Minerals fulfil physiological, structural and regulatory functions. Some examples: Medicine Veterinary Medicine  Tissue growth and repair: teeth and bones,  Regulation of metabolic cycles, acid-base equilibrium, muscle activity in Veterinary  Milk production Degree in Master Degree Excretion/ elimination of minerals: - faeces (non absorbed material) (e.g., Ca); Master - urine (e.g., Na); - sweat (e.g., Na e Cl); - milk (e.g., K, Na, Ca, Mg, Cl e P). www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Minerals with more than one function have a problem of deciding on the criterion for adequacy. Dietary levels of mineral that are sufficient for one function may be inadequate for another: -- Medicine Veterinary Medicine e.g., 1) short period of growth of animals slaughtered for meat may not cover the long-term in Veterinary needs of breeding (reprodução) and longevity of adult stock; 2) minerals involved in bone formation: there are many criteria, such as bone dimensions, Degree in strength, histology and composition. Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Some mineral elements, such as calcium and molybdenum, may interfere with the absorption, transport, function, storage or excretion of other elements. The three major ways in which minerals may interact involve: 1. formation of unabsorbable compounds, -- 2. competition for metabolic pathways, 3. induction of metal-binding proteins. Medicine Veterinary Medicine Some examples: in Veterinary  the excess of one element can cause deficiency of another;  Vitamin C improves the absorption of iron (Fe) but decrease that of copper (Cu);  iron deficiency turns the organim more susceptible to lead (Pb) toxicity Degree in Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Although minerals have an essential role in animal nutrition, many are toxic – causing illness or death – if given to the animal in excessive quantities. (e.g., copper (Cu), selenium (Se), molybdenum (Mo), fluorine (F), vanadium (V) and arsenic (As)). -- Medicine Veterinary Medicine Minerals should be added to concentrate foods via in Veterinary premix and thoroughly mixed to avoid ‘hot spots’ of high concentration and potential toxicity. Degree in Master Degree Master www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! THE ANTI-NUTRITIONAL FACTORS Oxalates Tannins Phytic acid/ phytate -- resulting in mineral’s Medicine Veterinary Medicine low absorbability and bioavailability in the animal organism in Veterinary Phosphorus is present Degree in in many foods as a constituent Master Degree of phytic acid and its availability Master depends on the presence of phytases of animal, microbial or exogenous origin. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Plants and plant products form the main supply of nutrients to animals, and the composition of plants will influence the animal’s mineral intake. Important conditioning factors: species and stage of maturity of the plant, type of soil and climate, seasonal conditions. -- Medicine Veterinary Medicine  Legumes tend to be richer in the major minerals and certain trace elements than are grasses, in Veterinary (this is also the case with the seeds of legumes compared with the seeds of grasses and cereals). Degree in  Soil conditions and mineral content affect the uptake of minerals by plants, and this can be Master Degree further influenced by fertilizer application. Master One of the major influences is soil pH, the effect of which differs among the elements. www.egasmoniz.com/pt www.egasmoniz.com/pt Feed composition (cont.) - MINERALS For teaching purposes only! Generally, the mineral elements in foods exist in one of three forms: 1) as metallic ions in solution – readily absorbed; 2) as constituents of soluble metallo-organic complexes (some are quelates) – show variable availability; 3) as constituents of insoluble metallo-organic complexes – not absorbed at all. -- Medicine Veterinary Medicine Some mineral elements can be converted from one form to another and their availability depends on the form present in food, and the extent to which conditions in the gut favour in Veterinary conversion from one form to another. Degree in Master Degree Mineral supplements may take various forms: mineral salts, rumen boluses, ‘organic’ compounds and pasture applications. Master www.egasmoniz.com/pt www.egasmoniz.com/pt For teaching purposes only! Roles of individual mineral elements and the effects of -- their deficiencies. Degree in Master Degree Master Medicine Veterinary Medicine in Veterinary McDonald P. et al. (2022) Animal Nutrition, 8th ed.