Comparative Animal Nutrition Exam IV: Multiple Choice Questions - Prof. Brian J. Bequette, Exams of Animal Biology

Download Comparative Animal Nutrition Exam IV: Multiple Choice Questions - Prof. Brian J. Bequette and more Exams Animal Biology in PDF only on Docsity! ANSC 314 Comparative Animal Nutrition EXAM IV NAME: _____________________________ December 11, 2013 I. TRUE AND FALSE (1 Point each, 22 TOTAL POINTS in this Section) 1. TF Fatty acids derived from adipose tissue triglycerides can be used for synthesis of glucose. 2. T F Both casein and egg protein have high biological values. 3. T F Ruminants absorb acetate and butyrate from the rumen which cannot be converted to glucose. 4. TF Proteins that have a high digestibility will always have a high biological value. 5. T F The concentration of a nutrient in the feed on an as-fed basis is lower compared to the concentration of the nutrient on a dry matter basis. 6. T F Lectins increase endogenous losses from the small intestines. 7. T F Homeotherms have a higher maintenance energy requirement on a metabolic body weight basis compared to Poikilotherms because Homeotherms need to expend additional energy to maintain body temperature. 8. TF The main site of volatile fatty acid absorption in ruminants is the colon. 9. T F Metabolic body weight is an acknowledged way to express maintenance energy requirements and is expressed as kilograms W0.75, where W equals live body weight. 10. T F Apparent digestibility measurements underestimate true digestibility. 11. T F In the Net Energy System, the energy associated with waste product and tissue formation is part of the Heat Increment. 12. T F Alfalfa is a good source of rumen degradable protein. 13. T F The energy deposited into fetal growth and maternal body weight gain are part of the animal’s Net Energy requirement. 14. TF The potential energy of an organic nutrient relates to its Carbon:Hydrogen ratio. 15. T F Leucine cannot be metabolized for synthesis of glucose. 16. T F Lactate is the end-product of anaerobic glycolysis. 17. T F Tannins bind to sulfur-containing amino acids in proteins, which decreases protein 1 digestibility. 18. T F The hydrolysis of casein in the stomach of a 1-day-old suckling piglet is initiated by chymosin. 19. T F For measurement of nutrient digestibility, Chromic oxide can be used as an external feed marker whereas Lignin can be used as an internal feed marker. 20. TF Lysino-alanine in proteins is a good source of Lysine. 21. T F Combining two protein sources that individually have Biological Values of 50% can result in a Biological Value of the combined proteins of >50%. 22. T F Hartnup’s disease in humans is a genetic defect in the transporter for branched chain amino acids. II. FILL IN THE BLANK Use the word bank. Words are used MORE THAN ONCE. (1 point for each blank, 29 TOTAL POINTS in this Section) 1. Browning or over-heating of feeds can cause a decrease in __Protein or Lysine digestibility. 2. Of the volatile fatty acids produced in the rumen, __Butyrate___ is the main and preferred substrate metabolized by the cells of the rumen wall. 3. In ruminants, the difference between Gross Energy and Metabolisable energy is the energy associated with _Rumen Gasses_, Feces and Urine. 4. Under aerobic conditions, complete metabolism of one mole of glucose in the body yields _____38_____ moles of ATP whereas one mole of acetate yields about __10_________ moles of ATP. 5. In all animals, the amino acids __Leucine___ and ___Lysine_____ are strictly ketogenic amino acids. 6. Two enzymes secreted in the mouth are __Amylase__ for starch digestion and __Lysozyme__ to burst and destroy bacteria. 7. The three sources of protein (amino acids) found in the feces are that from __Bacteria__, __Feed__ and __Endogenous losses__. 8. During a long period of starvation when more fat tissue is metabolized, the brain switches from using __Glucose___ for energy to using ___Ketones____ for energy. 2 10. Direct oxidation of 1 mole of Propionate in the body yields how many moles of ATP: a) 2 b) 10 c) 18 d) 25 e) 38 11. Complete oxidation of 1 mole of Acetyl-CoA in the body yields how many moles of ATP: a) 10 b) 11 c) 12 d) 25 e) None of these 12. Following the absorption of 2-monoglycerides and free fatty acids into the intestinal cell, the process of _____________ helps to maintain the concentration gradient between the lumen of the intestines and the intestinal cell. a) hydrogenation b) esterification c) hydrolysis d) carboxylation 13. Post-weaning, six-week-old piglets have ________________ activity of lactase and _________________ activity of sucrase. a) high, high b) high, low c) low, high d) low, low 5 IV. SHORT ANSWER QUESTIONS (23 total points this section) (5 POINTS) Energy expenditures by animals can be measured using either Direct or Indirect calorimetry. What are Direct and Indirect calorimetry? Be sure to include in your answer how they differ in the way each estimates/measures energy expenditures of an animal. Direct Calorimetry (Black) – direct measurement of the heat lost from the animal’s body while in a chamber that allows for measurement of heat or temperature. Remember, the animal body is a combustion engine somewhat like a bomb calorimeter. The animal or human is placed in an enclosed chamber where the inner and outer walls of the chamber are kept at the same temperature so as to eliminate transfer of heat from inside to outside of the chamber (ie adiabatic). The heat generated at biochemical steps is either transformed and locked away into animal tissue (eg. glycogen, muscle, fat) or the heat is lost to the environment. When the heat is lost to the environment, this is heat or calories that are measured and equate to the catabolism of dietary or body nutrients for maintenance and other functions such as movement and product formation (to synthesize protein for example requires energy). Indirect Calorimetry (Lavoisier) – In this approach, we use biochemical principles to derive the heat or energy expended or retained by animals. The animal is again placed into a closed chamber, and we measure carbon dioxide production (oxidation of organic molecules in the body) and oxygen consumption (for oxidation of organics). This approach uses biochemical principles to determine energy expenditures. The concept is based on the laws of thermodynamics wherein the energy released in a series of reactions that lead to complete oxidation of a substrate will always yield the same energy. The route or mechanism of catabolism has no bearing on the total energy of the reaction. Also measured is urinary N, and we can equate this to protein or amino acid oxidation to derive the energy or calories derived from oxidation of these. Using these values and calculation of RQ, we can estimate the composition of substrate oxidized for energy by the animal and the total energy expended. 1. (5 points) Biological value measurement can be used to assess the value of feed proteins in meeting the animal’s maintenance and production requirements for amino acids. How is it possible for a protein that is 100% truly digestible to have a BV of 0%? HINT: What characteristic of the protein does the BV measurement reflect? BV measures the metabolic utilization of that portion of the protein that is digested and absorbed. Thus, only the truly digestible portion of the protein is evaluated. BV is also dependent on the pattern of essential amino acids in that portion of the protein that is digested and absorbed. Thus, the limitation on the metabolic use of the protein depends on the 1st limiting amino acid. In the case of a protein that is 100% digested but which has a BV of 0%, what has occurred is that the protein lacks one of the essential amino acids, such as lysine or methionine or any other essential amino acid. This is the case with gelatin which lacks Tryptophan (an essential amino acid). Or, the amino acid pattern of this protein is so severely imbalance in essential amino acids. 6 2. (5 points) You want to evaluate the apparent digestibility of protein fed in a diet formulated for pigs. But, you are unable to conduct a total collection of feces trial. Instead, you use the indicator method. You feed the pigs 1000 grams (as-fed basis) of the diet per day. The diet was 90% dry matter and the external marker was chromic oxide. Over 5 days you take feed and fecal grab samples, and analyze these for the components in the table below. All the values in the table are on a dry matter basis. a. What is the % apparent digestibility of the protein in this diet? 100 x [(20%/1%) – (30%/3%)]/(20%/1%) = 50% b. How much protein (grams per day) was apparently digested by the pigs. 50% AD x 1000 g feed (as-fed) x 90% DM x 20% CP diet = 90 g AD protein 7 Component Feed (% of diet DM) Feces (% of feces DM) Chromic oxide 1% 3% Protein 20% 30%