324 Proteins

324 Proteins - PROTEIN HzN - CH - CO ——-- NH - CH - CO...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: PROTEIN HzN - CH - CO ——-- NH - CH - CO —--- NH - CH - CO ——-- NH — CH - COOH l l l I R1 R R R2 N-Terminal AA Interior Amino Acids Carboxyl AA Proteins are polymers or chains of amino acids linked together by peptide bonds. Different types of proteins consist of different combinations of AA. If AA are letters of the alphabet, then proteins are words. Amino Acids: Contain many carbon atoms linked together, with H and 0 attached to the C. ** Just like CH0 and fats. AA contain NITROGEN. ~16°/o calculating the protein content of a feed is determined by multiplying the Nitrogen content by 6.25 (1/.016 = 6.25). A feed containing 1.6% nitrogen has 10% crude protein 1.6 X 6.25 = 10 The value is called Crude Protein because the 6.25 is an average for all proteins. There are 22, or 23, different AA found in proteins. ALL of them are needed to form body proteins. Some can be synthesized by the horse and are therefore NOT required in the diet. These are called the non—essential amino acids. Those AA that CANNOT be produced by the animal from the raw components are called ESSENTIAL AMINO ACIDS. For the horse to be healthy, these EAA must be included in the diet. In addition, these EAA must be present in adguate amounts to meet the horse's needs. Example: Think of the NEAA as lumber for a house and the EAA as the fasteners, plumbing supplies, electrical supplies, etc. To make a proper house you need more than 2 nails, but you don’t need 1000 water faucets. A sink without a faucet is pretty worthless. Protein Quality: Depends generally on the presence and quantity of the 10 EAA and on protein digestability. Cereal grains tend to be considered high quality feedstuffs. They contain most of the EAA, but are generally lacking in lysine, methionine, and tryptophan. These EAA are particularly important to the young growing horse, and are often added to feeds. They are also highly digestible (DP = 75—85% of CP). Protein Rgggirements: The amount of crude protein needed in the diet depends upon: the volume of feed consumed, the digestibility of the protein, the animal's need for protein, and the amino acid content of the feed. VOLUME: The amount of feed consumed generally depends upon the horse's energy needs and the energy content of the diet. Feeds high in energy require a lower volume of feed to meet the energy requirements. Therefore, these feeds must be HIGH in ALL nutrients. Less feed requires a HIGH CF to meet the requirements. DIGESTIBILITY: Protein digestibility varies with the source of the protein, the amount of FIBER in the diet, and the amount of heat produced during processing and storage. The source of the protein: PROTEIN SOURCES: FEEDSTUFF % Crude Protein Digestibilifl % Alfalfa hay 12-22 18 73—83 Coastal hay 6-16 9 67-75 Oats 12 Corn 10.3 ~90 Barley 12.6 Rice bran 14 Soybean Meal 48 92 Cottonseed meal 33 85 The amount of FIBER in the diet indicates where the primary site afd/yesflon will be for a given feed. Feeds high in Starch, Sugars, and Fats will be primarily degraded in the stomach and small intestine. This is also the prime site of protein digestion and absorption. Proteins from these type feeds will be easily digested, and the bulk of AA from these feeds will be absorbed in the foregut and utilized. Feeds high in FIBER rely on fermentation in the cecum. These feeds also have a high percentage of protein digestion occurring in the cecum. Bacterial digestion of the protein breaks dietary protein into short carbon chains and NH3. Any EAA are destroyed. The main nitrogen product absorbed from the hindgut is NH3. Bacteria can form EAA, but protein absorption in the hindgut is, at best, limited. Therefore, feeds high in fiber have a lower digestibility of protein. Digestible Protein (DP): ranges from 30 to 75% Grass hay: DP% = 0.74CP% - 2.5 Grass hay/grain (1:1 ratio): DP"/o : O.80CP°/o - 3.3 Alfalfa hay/grain (1:1 ratio): DP% 2 O.95CP°/o - 4.2 Excessive heating in the processing or storage of feeds alters the peptide bonds making them more difficult to digest. Therefore, the dietary protein is not available for the horse. REQUIREMENTS: Horses do not have a °/oCP requirement. They have a daily AMOUNT requirement and a QUALITY requirement. Maintenance: Energy and protein requirements are inter-related. Adequate protein without adequate energy results in weight loss. Adequate energy without adequate protein results in weak, irregular structures. Crude Protein: Average = BW X 1.26 9 CP/ kg BW/d 1100# = 630 g CP/d Energy = BW X 33.3 kcal DE/kg BW/d 1100# = 16.7 Mcal/d Protein/Energy ratio: 630 g /16.7 Mcal = 38 g CP/Mcal DE Feeding: Concentrate — 12% CP; 1.25 Mca|/# Hay - 8% CP: 0.8 Mcal/# Feed 10# concentrate: 15# hay Concentrate: 10# Energy = 10 X 1.25 : 12.5 Mcal Protein =10# X .12 X 454 g/# = 545 9 CP Hay: 15# Energy = 15 X 0.8 = 12 Mcal Protein : 15 X .08 X 454 = 545 9 CP TOTAL INTAKE = 24.5 Mcal DE; 1090 9 CP Feeding: 25# Hay Energy = 25 X 0.8 = 20 Mcal DE/d Protein 2 25 X .08 X 454 = 908 g CP/d Pregnancy, Lactation, Exercise: All of these physiological processes require an elevation in protein intake. They also require an increase in energy intake. In almost all cases, increasing the feed intake to meet energy requirements will more than meet protein requirements. Class of Horse °/oCP (diet) 1100# horse DE reg. Maintenance 8 630 g/d 16 Mcal/d Pregnancy 10.6 840 19.2 Lactation 13.2 1330 30 Light work 10 700 19 Very Heavy work 11.5 862 30 Growth: The protein requirements for growth depend on the amount of protein, the AA profile of the protein, and the protein/energy ratio of the diet. Qualify is the key for proper growfh/flllllllllwlll The presence and amounT of The EAA dicTaTes The qualiTy of The sTrucTural proTein. Grains are higher in qualiTy Than forages. ProTein supplemenTs are higher in qualiTy Than grains. THEREFORE, growing dieTs need To include grain and supplemenTs. Grains usually are adequaTe in EAA excepT for lysine, and possibly Threonine and meThionine. Corn = 0.27% lysine: OaTs : 0.55% lysine Common proTein supplemenTs are ofTen higher in lysine Than grains. SBM = 3.38% lysine: CSM : 1.85% lysine. Hay lies beTween. Grass hay = 0.63% lysine: Alfalfa = 0.90% lysine. LYSINE is a key AA in many imporTanT proTeins. The lack of lysine limiTs The producTion of Those proTeins. Lysine is The 1" LimiTing AA of The horse. The dieT of The growing horse should conTain a minimum of 0.65% lysine and 0.50% Threonine on a dry maTTer basis. ...
View Full Document

Page1 / 5

324 Proteins - PROTEIN HzN - CH - CO ——-- NH - CH - CO...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online