UNIT-III.-LIPIDS.pdf

Veterinary Zootechnics 53 (VZT53) Principles of Animal Nutrition 1st Semester, S.Y. 2023-2024 C ATHERINE T. ALBAN O, DVM D ELWIN D. C AP U YO, DVM, LPT D EPARTMEN T OF MED IC IN E, SU RG E RY & ZOOTEC HN IC S COLLEG E OF VE TE RIN ARY ME...

Veterinary Zootechnics 53 (VZT53) Principles of Animal Nutrition 1st Semester, S.Y. 2023-2024 C ATHERINE T. ALBAN O, DVM D ELWIN D. C AP U YO, DVM, LPT D EPARTMEN T OF MED IC IN E, SU RG E RY & ZOOTEC HN IC S COLLEG E OF VE TE RIN ARY MED IC IN E C E N TRAL MIN DAN AO U N IVERSITY UNIT III Lipids Course Objective CO2. Determine the composition and function of various nutrients of feeds. Unit Objectives 1. Define lipids; 2. Determine the functions of lipids; 3. Enumerate the main sources of lipids for livestock feed formulation; 4. Classify lipids according to composition and discuss their functions; 5. Enumerate and discuss the constants for measuring chemical properties of lipids; and 6. Enumerate the conditions related to lipids/EFA deficiency. Lipids group of substances found in plant and animal tissues Made up (by % mol wt) of C (77%), H (12%) and O (11%) insoluble in water but soluble in common organic solvents such as benzene, ether and chloroform in proximate analysis of foods, they are included in the ether extract fraction Classification of Lipids: Plant Lipids Structural Lipids ◦ present as constituents of various membranes and protective surface layers and make up about 7% of the leaves of higher plants ◦ Surface Lipids ◦ mainly waxes, with relatively minor contributions from long-chain hydrocarbons, fatty acids and cutin ◦ Membrane Lipids ◦ present in mitochondria, the endoplasmic reticulum and the plasma membranes, are mainly glycolipids (40–50%) and phosphoglycerides Classification of Lipids: Plant Lipids Plant Storage Lipids ◦ Identified almost 300 fatty acids ◦ occur in fruits and seeds and are, predominantly, triacylglycerols ◦ most abundant: a-linolenic acid ◦ most common saturated acid: palmitic acid ◦ most common monounsaturated acid: oleic acid Classification of Lipids: Animal Lipids For animals, lipids are major energy storage (as fats) Fats in obese animals may be contained in adipose tissue at ~ 97% Fat yield energy after complete oxidation: 39 MJ/kg DM vs glycogen (CHO) 17 MJ/kg DM FAT GLYCOGEN Energy yield after oxidation 39 MJ/kg DM 17 MJ/kg DM Water Content Anhydrous Highly hydrated Stored energy source Six times as effective Functions of Lipids Animals: Dietary energy supply Source of heat, insulation, and animal protection Carrier for fat-soluble vitamins absorption Act as electron carriers Component of biological membrane Source of essential fatty acids (EFA) In animal feeds: improve the physical appearance by enhancing color and reduce dustiness of the feeds Human Food: In cattle, marbling is desirable interspersion of fat particles in lean meat (intramuscular fat) Natural Sources of Lipids Location: Animal body: Subcutaneous Surrounding internal organs Marbling and milk Plant Seed germ/ embryo Natural Sources fat level-cereal grains, forages, animal products, etc.- 20% fat-oil Classification of Lipids Classification of Lipids Classification of Lipids (based on saponifiability) Saponifiable Lipids ◦ complex lipids that contain fatty acids as components ◦ consists of open-chain compounds with polar head groups and nonpolar tails ◦ to this group belong the acylglycerols, sphingolipids, phosphoacylglycerols, glycolipids and waxes Non-saponifiable Lipids ◦ simple lipids that do not contain fatty acids ◦ consists of fused-ring compounds, the steroids and polymers of isoprene, the terpenes Lipids- Fats Fats vs. Oils fats and oils are constituents of both plants and animals and are important sources of stored energy both have the same general structure but have different physical and chemical properties fats are solid and oils are liquid, at room temperature Example of animal fats beef tallow, lard, mixed animal fat and grease FATS Glycerides/Acylglycerols fatty acid esters of glycerol referred to as neutral fats when all the three hydroxyl groups of glycerol are esterified with fatty acids, the structure is called a triacylglycerol those with only a single kind of fatty acid are called simple triacylglycerols, while those with two or more different kinds of fatty acids are mixed triacylglycerol simple triacylglycerols are named after the fatty acid they contain (eg. tripalmitin, tristearin and triolein) Lipids- Structure of Fat Glycerides/Acylglycerols they accumulate in adipose tissue and provide a means of storing fatty acids, particularly in animals they do not play an important role in plants Fatty Acids has a carboxyl group at the polar end and a hydrocarbon chain at the non-polar tail occurs in a living system normally contains an even number of carbon atoms and the hydrocarbon chain is usually unbranched classified as SATURATED (when there are only single bonds) and UNSATURATED (when there are carbon-carbon double bonds) Fatty Acids Fatty Acids NO. OF C- FATTY ACID NOTATION FORMULA ATOMS Lauric acid 12 12:0 CH3(CH2)10COOH Myristic acid 14 14:0 CH3(CH2)12COOH Palmitic acid 16 16:0 CH3(CH2)14COOH Stearic acid 18 18:0 CH3(CH2)16COOH Arachidic acid 20 20:0 CH3(CH2)18COOH Palmitoleic acid CH3(CH2)5CH=CH(CH2)7COOH 16 16:1 Oleic acid 18 18:1 CH3(CH2)7CH=CH(CH2)7COOH Linoleic acid 18 18:2 CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH Linolenic acid 18 18:3 CH3(CH2CH=CH)3(CH2)7COOH Arachidonic acid 20 20:4 CH3(CH2)4(CH=CHCH2)4(CH2)2COOH Fatty Acids Fatty Acids Fatty Acids  Fats- Composition of Fats Butyric Acid and Caproic Acid found in significant amounts in milk fats of ruminants Caproic Acid and Caprylic Acid present in few oils like palm kernel and coconut (lauric acid) Examples of fats and oils sources rape seed, soya bean, rye grass, cocks foot, butter fat, lard, beef tallow, men haden, Cod liver, herring Fats- Composition of Fats Plant and Marine Oils ◦ more highly unsaturated (esp fishes) because of varying amounts of linoleic and linolenic acids in addition to mono-unsaturated oleic (major fatty acid in most natural fats) ◦ fish and plant sources are softer and frequently are oils Mammalian depot fat higher proportion of saturated acids like: palmitic and stearic acids Has smaller but significant amount of lauric and myristic acids Reason why pig lard, and beef and mutton tallow are firm and hard Fats- Essential Fatty Acids (EFAs) Linoleic and ᾳ-Linolenic Acid are essential fatty acids that form part of various membranes and play a part in lipid transport and certain lipoprotein enzymes source materials for the synthesis of eicosanoids help regulate functions like blood clotting, blood pressure, smooth muscle contraction and immune response also involved in maintaining the fluidity of mammalian cell membranes.  Sources of EFA Oil seeds are rich sources of linoleic acid and linseed is a good source of ᾳ-linolenic acids. Pigs and poultry having oil seed residues in their diet will have adequate supply of essential fatty acids unlike ruminants. Accessed from https://www.istockphoto.com/photo/oil-seeds-and-nuts-gm153005557-15641833 on August 28,2022 Glycolipids Glycolipids compounds consisting of a carbohydrate bound to an alcohol group of a lipid by a glycosidic linkage Location in animals: Brain and nerve fibers Glycolipids Galactolipids ◦ lipids of grasses and clovers (forms the major part of dietary fat of ruminants) ◦ the fatty acids of the galactosides of grasses and clovers consist largely of Linoleic and ᾳ-linolenic acids ◦ rumen microorganisms can breakdown galactolipids to : galactose, fatty acids and glycerol Phospholipids Phosphoacylglycerol/ Phospholipids Contents: phosphorus in addition to carbon, hydrogen and oxygen constituents of the lipoprotein complexes of biological membranes Location in animals: heart, kidneys and nervous tissues Myelin of the nerve axons (myelin sheath) contains 55% of phospholipids. Sources: Animals: Eggs Plants: Soya beans Phosphoacylglycerol/Phospholipids Phosphoglycerides white waxy solids that turn brown when exposed to the air(oxidation) followed by polymerisation. Appears to be water soluble but true solubility is low are surface active and play a role as emulsifying agents in biological systems (duodenum) Esters of glycerol ; 2 alcohol esterified by fatty acids ; 3rd esterified by phosphoric acid E.g. Lecithin and Cephalins Phosphoacylglycerol/ Phospholipids Phosphoacylglycerol/Phospholipids Ether Phospholipids ◦ may form up to 50% of the phospholipids of heart tissue, but their function is unclear ◦ E.g. platelet activating factor - highly potent aggregator of blood platelets Classification of Lipids Lipids- Non-glycerol-based Sphingolipids these do not contain glycerol, but they do contain the long-chain amino alcohol sphingosine. found in both plants and animals they are particularly abundant in the nervous system the simplest compounds of this class are ceramides, which consist of one fatty acid linked to the amino group of sphingosine by an amide bond Sphingolipids  Sphingolipids Sphingomyelins the primary alcohol group of sphingosine is esterified to phosphoric acid, which in turn is esterified to another amino alcohol, choline surface-active and are important as components of membranes, particularly in nervous tissue may constitute up to 25% of the total lipid in the myelin sheath that protects the nerve cells, Maybe absent from, or present only in very low concentrations in energy-generating tissue Waxes are simple non-popular lipids, water-insoluble, solid esters of long chain fatty acid with long-chain monohydroxylic fatty alcohols or with sterols usually solid at ordinary temperature but are soft and pliable when warm widely distributed in plants and animals where they often have protective function as coatings on skin, fur, and feathers, on leaves and fruits of higher plants, and on the exoskeleton of many insects Waxes ◦ hydrophobic nature of the wax coating reduces water loss caused by transpiration in plants, and provides wool and feathers with water proofing in animals ◦ the major components of beeswax are palmitic acid esters of long- chain fatty alcohols with 26 to 34 carbon atoms ◦ Lanolin - obtained from wool. A mixture of fatty acid esters of the sterols lanosterol and agnosterol. ◦ Spermaceti - product of marine animals. Steroids Biologically important compounds such as the sterols, the bile acids, the adrenal hormones and the sex hormones Sterols ◦ Phytosterols ◦ in plants (eg. stigmasterol and sitosterol) ◦ Mycosterols ◦ in fungi (not absorb in the gut and not found in animal tissues) ◦ belongs here is ergosterol, a precursor of vitamin D ◦ Zoosterols ◦ in animal origin Steroids A. Sterols 1. Cholesterol zoosterol present in animal cells, low solubility in water (0.2mg/100ml) major sterol in human constituent of various biological membrane and particularly important in the myelinated structures of the brain and CNS precursor of the steroid hormones and bile acids. normal concentrations in the blood plasma range from 1200-2200mg/liter, 30% of free state and remainder being bound to lipoproteins Steroids A. Sterols 2. 7-Dehydrocholesterol derived from cholesterol is important as the precursor of vitamin D3, which is produced when the sterol is exposed to ultraviolet light 3. Ergosterol A phytosterol, widely distributed in brown algae, bacteria and higher plants precursor of Ergocalciferol or Vitamin D2,into which it is converted by ultraviolet irradiation Steroids B. Bile Salts synthesised from cholesterol and this constitutes the major end point of cholesterol metabolism under physiological conditions the acids exist as salts produced in the liver, stored in the gall bladder and secreted into the upper small intestine  Steroids B. Bile Salts (Importance) 1. Provide the major excretory pathway for cholesterol, which cannot be catabolised to CO2 and H2O by mammals. 2. Assist, along with the detergent action of phospholipids, in preventing the cholesterol in the bile fluid from crystallising out of solution. 3. Acts as emulsifying agents in preparing dietary triacylglycerols for hydrolysis, by pancreatic lipase, in the process of digestion. 4. May have a role in activating pancreatic lipase. 5. Facilitate the absorption, from the digestive tract, of the fat-soluble vitamins. Steroids C. Steroid Hormones these includes: ◦ Estrogens- the female sex hormones ◦ Androgens- the male sex hormones ◦ Progesterone-pregnancy hormone ◦ Cortisol, Aldosterone and Corticosterone - produced in the adrenal cortex the adrenal hormones have an important role in the control of glucose and fat metabolism. Terpenes found in plants, have strong characteristic odours and flavors and are components of essential oils such as lemon or camphor oil. ex. phytol moiety of chlorophyll, the carotenoid pigments, plant hormones such as giberellic acid and vitamins A, E and K. in animals, some of the coenzymes, including those of the coenzymes Q group, are terpenes Properties of Fat 1. Hydrolysis/Saponification ◦ fats may be hydrolysed by boiling with alkalis to give glycerol and soaps: Saponification Hydrolysis of fat by boiling with alkalis giving off glycerol and soap Natural process: saponification with enzyme lipase (lipolysis) Products: glycerol, sodium or potassium salts of fatty acids, which are called soaps Free fatty acid products are usually tasteless and odorless except butyric and caproic acid Lipolysis Location: duodenum and in their absorption in small intestine  Saponification when soaps are used in hard water the calcium and magnesium ions in the water react with the fatty acids and form a precipitate – the characteristic scum left on the insides of sinks and bathtubs. the other product of saponification, glycerol, is used in creams and lotions as well as in the manufacture of nitroglycerin Properties of Fat 2. Oxidation ◦ the unsaturated fatty acids readily undergo oxidation at the carbon atom adjacent to the double bond to form hydroperoxides. ◦ products of oxidation include shorter-chain fatty acids (free radicals) , fatty acid polymers, aldehydes (alkanals), ketones (alkanones), epoxides and hydrocarbons ◦ the acids and alkanals are major contributors to the smells and flavours associated with oxidised fat, and they significantly reduce its palatability ◦ Oxidation of saturated fatty acids yields sweet, heavy taste and smell (ketonic rancidity) due to methyl ◦ Soft and blue cheeses taste are product of oxidation following mould-induced lipolysis Properties of Fat 3. Antioxidants natural fats possess a certain degree of resistance to oxidation, owing to the presence of compounds termed antioxidants they prevent the oxidation of unsaturated fats until they themselves have been transformed into inert products Properties of Fat 3. Antioxidants ◦ common examples of antioxidants ◦ phenols, quinones, tocopherols, gallic acid and gallates ◦ propyl, octyl or dodecyl-gallate, butylated hydroxyanisole, butylated hydroxytoluene and ethoxyquin (European Union) ◦ Vitamin E ◦ Most important naturally occurring antioxidant which protects fat by preferential acceptance of free radicals Properties of Fat 4. Hydrogenation ◦ hydrogen is added to the double bonds of the unsaturated acids of a fat, thereby converting them to their saturated analogues. Constants for Measuring Chemical Properties of Lipids 1. Iodine Number (IN) denotes the degree of unsaturation of a fat or fatty acid an unsaturated fat unites easily with iodine, 2 atoms of this element being added for each double bond thus, IN is the amount of iodine in grams that can be taken by 100g of fat a high IN denotes a high degree of unsaturation Constants for Measuring Chemical Properties of Lipids 2. Saponification Number measure of the average chain length of the 3 fatty acids in a fat number of milligrams of alkali required for the saponification of 1 g of fat the smaller the fatty acid molecules, the greater is the number of these molecules per gram of fat and thus, the larger the amount of alkali required for saponification Constants for Measuring Chemical Properties of Lipids 3. Reichert-Meissl (RM) Number ◦ Measures the amount of water soluble, steam-volatile fatty acids present in a fat ◦ Number of milliliters of 0.1N KOH solution required to neutralize these volatile fatty acids obtained by hydrolysis of 5 g of fat ◦ Lard (no VFA) vs. Butterfat (RM 20-33) 4. Melting Point ◦ temperature at which a fat changes from a solid to liquid state ◦ dependent on chain length and degree of unsaturation of the molecule Symptoms of EFA Deficiency Energy (from lipids) Sources (The Philippine Recommends for Livestock Feed Formulation, DOST-PCARRD 2006) Fish oil Coconut oil (crude or refined) Coconut acid oil Palm kernel Oil Peanut oil meal Soybean oil meal Full fat soybean meal Tallow Vegetable fat References Cunningham, M., & Acker, D. (2001). Animal Science and Industry, 6th Edition. New Jersey, USA: Prentice Hall, Inc. Chapter 3 (3.4) pp. 64-65 Jurgens, M. H. & Bregendahl, K. (2007). Animal Feeding & Nutrition, 10th Edition. Iowa, USA: Kendall/Hunt Publishing Company. pp. 24-32 McDonald, P., Edwards, R. A., Greenhalgh, J. F. D., & Morgan, C. A., Sinclair, L.A. & Wilkinson, R. G. (2011). Animal Nutrition, 7th Edition. United Kingdom: Pearson Education Limited. Chapter 3 References Perry, T. W., Cullison, A. E., & Lowrey, R. S. (2000). Feeds & Feeding, 5th Edition. Singapore: Pearson Education Asia Pte Ltd. pp. 2-5 The 1999 Livestock Feed Formulation Committee. The Philippines recommends for livestock feed formulation. Los Baños, Laguna: PCARRD-DOST and PARRFI, 2003. 208p. – (Philippines Recommends Series No. 64-A). pp. 9-16 Wu, G. (2018). Principles of Animal Nutrition. Florida, USA: CRC Press. Chapter 3 https://www.doctorkiltz.com/beef-tallow/ https://www.newsnationnow.com/us-news/5-reasons-cooking-oils-may-get-more-expensive/