1 / 23

Chapter 18: Nutrition

Chapter 18: Nutrition. Chapter overview: Chapter 18 presents the principles of nutrition, to include: composition of plants and animals definition of the nutrient classes feed and food analysis procedures. Nutrition :.

morey
Download Presentation

Chapter 18: Nutrition

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 18: Nutrition • Chapter overview: • Chapter 18 presents the principles of nutrition, to include: • composition of plants and animals • definition of the nutrient classes • feed and food analysis procedures

  2. Nutrition: • Nutrition is the science that deals with food and the nutrients it contains, to include: • Water • Carbohydrates • Lipids • Protein • Vitamins • Minerals

  3. The Nutrients: Water • Water is the most abundant and important constituent in plant and animal tissues • An embryonic calf is 90% water and a market steer is 40+% water • Sources of water are: • drinking water • ingested as a component of feed and food • metabolic water arising from metabolism in tissues

  4. The Nutrients: Carbohydrates • Organic compounds composed of C-H-O • Most abundant organic compounds in plants • Formed by photosynthesis in plants • Generally provide 50 to 75% of dry matter of food animal diet

  5. Carbohydrate Classification: • Monosaccharides - simple sugars (5 to 6 C’s) • Disaccharides - two molecules of simple sugar linked together • Polysaccharides - many molecules of simple sugars linked together • Starch - polysaccharide that is readily digestible • Cellulose - polysaccharide that is only digested by microbes such as those in the rumen

  6. The Nutrients: Lipids • Organic compounds composed of C-H-O • Higher proportion of C-H than carbohydrates • “Fat” is the main energy providing lipid • Composed of a glycerol backbone and 3 fatty acids • Provide 2.25 times as much energy as carbohydrate when metabolized

  7. Fat Classification: • Saturated fats • Solid at ordinary room temperature • No double bonds within carbon chains of the fatty acids • Unsaturated fats • Liquid at ordinary room temperature • Double bonds exist within carbon chains of the fatty acids; “polyunsaturated” have multiple double bonds

  8. Other Lipids: • Lipids of importance, but not providing energy to the diet include: • Sterols such as ergosterol (pre-vitamin D) and cholesterol • Carotenes such as the precursor to vitamin A • Essential oils that give plants flavor and odor • Phospholipids such as lecithin

  9. The Nutrients: Protein • Proteins are primarily composed of C-H-O-N with lesser amounts of sulfur and phosphorus • Proteins constitute the active protoplasm in plants and animals • Amino acids are the individual units of protein; chains of amino acids form proteins • Amino acids not produced in animal tissues are termed “dietary essentials”

  10. Amino Acid Classification: • Based upon need in the diet, because all amino acids are needed at the tissue level • Essential - not synthesized in the animal body at a rate adequate to meet demand; the list is dependent on species, age, and level of productivity • Nonessential - synthesized in the animal’s body at a rate adequate to meet demand

  11. lysine tryptophan phenylalanine leucine isoleucine threonine methionine valine arginine histidine Essential Amino Acids:

  12. alanine aspartic acid cysteine cystine glutamic acid hydroxyproline proline tyrosine serine (may be essential for poultry) glycine (may be essential for poultry) Nonessential Amino Acids:

  13. Protein and Ruminant Animals: • Adult ruminants do not require dietary essential amino acids • Rumen microorganisms synthesize amino acids • Microorganisms convert nonprotein nitrogen and inferior proteins to their own body proteins • Rumen microorganisms flow to the abomasum and small intestine to become a high quality protein source for the host

  14. The Nutrients: Minerals • Many inorganic minerals are dietary essentials for specific metabolic functions and bone structure • Macrominerals: those required in larger amounts, for example 0.5% calcium in some diets • Microminerals: those required in minute amounts, for example 40 mg/kg (0.004%) iron in some diets

  15. The Nutrients: Vitamins • Vitamins are • Organic substances required in very small amounts in the diet • Composed of C-H-O-N, and vitamin B12 also contains cobalt • Not closely related in chemical formula • Divided into two groups: fat soluble (A, D, E, K) and water soluble (B complex and C)

  16. Unique Comments on Vitamins: • Some are required by all animals while others may be required by only a few • Some are synthesized by microbes in the rumen and large intestine • Some are converted from precursors • Example: vitamin D is converted from a sterol by sunlight action on the skin in some animals

  17. Analysis of Feedstuffs: • Dry matter - for comparison of feeds on a standardized basis, dry matter is determined by drying a sample in an oven until constant weight is attained • Crude protein - feeds are analyzed for nitrogen and “crude” protein is estimated based upon protein being approximately 16% nitrogen (%N x 6.25 = % CP)

  18. Analysis of Feedstuffs: • Crude fat - fat (lipid) is soluble in ether; therefore ether extraction is used to determine a “crude” fat value by weight loss • Crude fiber - fiber is estimated by successive boiling of sample in dilute acid and alkali to give a “crude” fiber value by difference

  19. Analysis of Feedstuffs: • Mineral matter - though not very useful in practical nutrition, a total mineral value called “ash” is determined by burning a feed sample • Digestible carbohydrates - the estimation of digestible carbohydrates (called nitrogen-free extract) was historically calculated by subtracting all of the previous analytical results from 100%

  20. Digestibility of Feeds: • Chemical analysis of feeds cannot determine the extent of digestibility • Digestion trials can give reasonably accurate results for complete feeds and components of complete feeds • Feeds are analyzed and fed to an animal; feces are collected and analyzed; digestibility is estimated by difference

  21. Determination of Feed Energy: • Energy is necessary for animals to perform productive processes, such as weight gain • Comparison of feeds on an energy basis leads to estimation of impact on productive processes • The “net energy” system gives various levels of information about energy loss and availability for maintenance and production

  22. Steps to “Net Energy” Value: • Gross energy (GE) = heat of combustion of a feed sample • Next: measure energy loss in feces (FE) • Digestible energy (DE) = GE minus FE • Next: measure energy loss in urine (UE) and rumen gas (GPD, ruminants only)

  23. Steps to “Net Energy” Value: • Metabolizable energy (ME) = DE minus UE and GPD • Next: measure heat resulting from digestion and absorption (heat increment, HI) • Net energy (NE) = ME minus HI • Net energy can be further subdivided into maintenance energy and energy for production, such as growth or milk production

More Related