ANSC 303 1st EditionExam # 3 Study Guide Lectures: 18 - 25Lecture 18What is important about trypsin inhibitors? Trypsin activates other peptidases which cleaves peptide bonds. The result of peptidasesworking on peptide bonds are free AA. Free AA are the only way AA can be used by the body. If a trypsin inhibitor is present, trypsin will not be activated and trypsin cannot activate other peptidases. Digestion will not happen.How are trypsin inhibitors created?The feed is heated which inactivates the trypsin. Example: raw soybeans vs soybean meal.What are the products of protein digestion?Free AA and peptides in the dipeptide and tripeptide form.When does whole protein absorption occur and why is it important?Whole protein absorption only occurs in newborns for 12 – 24 hours. This whole protein absorption allows for the absorption of antibodies from colostrum. How are proteins absorbed into the enterocyte (who are their helpers)? What form are proteinsabsorbed?The proteins need a protein carrier in order to enter the enterocyte or the blood. Proteins are absorbed in all three forms – free AA, dipeptides, and tripeptides – in the enterocyte, but can only be in the free AA form in order to be absorbed into the blood. Which are absorbed more rapidly – peptides or free AA?Peptides. Which are absorbed more rapidly – smaller or larger? Neutral or charged? Nonessential or essential?Smaller. Neutral. Essential.Why is H important to the absorption of peptides in the enterocyte?H and Na maintain the gradient in order to have peptides enter the enterocyte. H is high in the cell and H is low outside of the cell. Na is high outside the cell and low inside the cell. H pairs with a peptide to cross the peptide carrier.Which amino acid does the enterocyte use for energy?Glutamine.Which amino acids are metabolized by the enterocyte?Aspartate, Arginine, Methionine, and Cysteine. What are the three sources of protein to the duodenum in the ruminant?1. MCP2. UIP3. Endogenous proteinWhat is UIP and where is it utilized? DIP?Undegraged intake protein; small intestine. Degraded intake protein; the rumen.Lecture 19Why is it important for the excess ammonia to be recycled?Ammonia increases the pH of the blood; ammonia toxicity.What is the difference between transamination and deamination?Transamination is the synthesis of non-essential AA. Deamination is the breakdown of the AA; there are not changed to other AA. In deamination the AA is lost. The nitrogen isused for other things. When is AA catabolism (transamination or deamination) used?Catabolism is started when a protein surpasses its requirement level, the composition of the AA in the body are off balanced, or gluconeogenesis is increased.Describe the process of transamination.The NH3 is transferred to another carbon skeleton. Requires PLP and the amino transferase.Describe the process of deamination.Transfer of NH# to urea. Urea can then travel to the saliva and reenter the rumen to be reused as another AA. What is protein synthesis?Protein synthesis is transamination. What is protein degradation?Protein degradation is protein deamination.When does the animal increase its weight or grow?The animal will grow whenever protein synthesis is greater than the degradation of protein.Lecture 20Define Proteolysis.The degradation or protein.What factors affect the rate of ruminal degradation?Rate of passage, heat treatment, N or S availability, and energy availability.How do the above factors affect the rate of ruminal degradation?As rate of passage increases, ruminal degradation increases. As heat treatment increases, rate of ruminal degradation decreases. As n or s availability increases, ruminal degradation increases. As energy availability increases, ruminal degradation increases. What is protein fraction A?A protein that is 100% DIP. What is protein fraction C?A protein that is 100% UIP. What is protein fraction B?A protein that has a mixture of DIP and UIP. How do the microbes produce MCP?The microbes take ammonia N and CHO chain to make MCP. If DIP increases, what happens to MCP?Increases.If DIP increases what happens to N?Increases.If NPN increases what happens to MCP? N?Increases (only N part, you have to find CHO elsewhere). Increases.What are the requirements to use NPN to make MCP?The animal will need: active microbes, CHO to use as a carbon skeleton, sulfur (methionine, etc), and other cofactors (energy, etc.)What are the limitations to making MCP?The CHO and N must be in the rumen at the same time, energy is needed as payment forthe microbes, and N needs to be available.What happens if there is excess N in the rumen?The N is recycled. The N is absorbed through the rumen wall into the blood. N travels tothe liver. The liver convers the N to urea. Urea is excreted in the saliva when rumination occurs; the urea enters the rumen where the N can be reused. Lecture 21What are the products of deamination?NH3 and a-keto acid (C skeleton).What is needed to deaminate a protein? A dehydrase enzyme.What are the four potential uses of a-keto acids?Energy, gluconeogenesis, lipogensis, ketogenesis.How is urea excreted in the ruminant? The monogastric?Saliva. Urine.Lecture 22What makes an amino acid a limiting amino acid?An amino acid is limiting when the animal cannot produce the amino acid and the aminoacid is fed in low quantities.What makes an amino acid a first limiting amino acid?The AA is fed in the lowest amount relative to the animal’s requirement. This is the AA that the anima is likely to run out of first. What is the first limiting AA of swine? Chicken? Turkeys? Horses? Humans?Lysine. Methionine&Cyesteine. Lysine and Methionine+Cystine. Lysine. Likely Lysine.What is the problem with increased overall protein in the diet in order to increase the amount of the first limiting AA? How does the industry correct the problem?If you add more protein to the diet, it increases the overall amount of the AA; it does nottarget the single AA you need to add more of in the diet. Crystalline AA. Which stage(s) of life need the largest amount of protein? The lowest?Lactation/Growth. Mature.Lecture 23What are the two problems with lipids pertaining to lipid digestion?Lipids are hydrophobic and large. What makes lipids unique?Lipids are hydrophobic (they do not like polar solvents; they do not mix well with water).They have uses beyond source of dietary energy. Why might it be a good idea to feed lipids to a herbivore with a high energy