Study On Partitioning Of Proteins (Amino Acids) In White Cashmere Goats Fed Diets With Different Dietary Metabolizable Glucose Levels

This paper mainly studied on partitioning of proteins (amino acids) in Inner Mongolian White Cashmere (IMWC) goats fed diets with different dietary metabolizable glucose (MG) Levels by nutrients infusion technique, arterio- venous technique, isotope technique and comparative slaughter technique. Firstly, It was determinated that amount of ruminal propionate yield, bypass starch and ruminal microbial protein (MCP) in IMWC goats in vivo. Then the values of dietary MG and metabolizable protein (MP) in basal diets were calculated. It was studied also that the amino acid flow into the duodenum and the digestibility of amino acids in the small intestine of IMWC goats fed the basal diets. Secondly, Three dietary MG levels with the same M85+C15 ideal absorbable amino acid pattern were designed to investigated the effect of dietary MG level on metabolism and utilization of amino acids in IMWC goats by arterio- venous catheter technique and digestion trials, so as to find the rule and mechanism of amino acids utilized by IMWC goats at different dietary MG Level. Finally, The partitioning of proteins (amino acids) in IMWC goats at different MG levels were studied by isotope technique and comparative slaughter technique, so as to find the rule of the partitioning of proteins (amino acids) in IMWC goats. The results showed that dietary MG levels could have a great impact on the metabolism and partitioning of amino acids in IMWC goats, and it was also suggested that there was an proper ratio between MG and MP, the proper MG/MP ratio was about 1.06 for cashmere production and 1.64 for whole body.Part 1 Determination of values of MG and MP in basal diet and study on amino acid flow and digestion in the small intestine of IMWC goats fed the basal diet Exp.1 Determination of the propionate yield and absorption rate in the rumen of IMWC goats fed the basal diet by in vivo technique Three wethers of IMWC goats (20-23kg) with the same father, fitted with permanent cannulas in the rumen were used to determinate the propionate yield and absorption rate in the rumen and fed the basal diet by in vivo technique. The results showed the propionate yield, outflow rates, absorption rate and absorptivity were 5.53mmol/h, 2.57 mmol/h, 2.96 mmol/h and 452.94%, respectively. Before infusion of propionate, and 9.80 mmol/h 4.96 mmol/h, 4.84 mmol/h and 49.21% respectively after infusion of propionate .Exp.2 Determination of the quantities and the digestibility of bypass starch in the small intestine of the growing goats fed the basal dietsThree wethers of IMWC goats (20-23kg) with the same father were used to investigate the quantities and digestibility of bypass starch of the diets in the small intestine in vivo. The results indicated that the quantities of bypass starch of the basal diets were 59.50g/d; the disappear proportion of starch in the rumen was 54.47 %, the digestibility of bypass starch in the small intestine was 58.23%, was 5.55% in large intestine and 82.05% in whole intestine, respectively.Exp.3 Study on amino acid flows and digestion in the small intestine and ruminal MCP production of IMWC goats fed the basal diet Three wethers of IMWC goats (20-23kg) with the same father fitted with permanent cannulas in the rumen, at the proximal duodenum and terminal ileum were used to investigate amino acid flows and digestibility in different sites of the digestive tract and ruminal MCP production of IMWC goats fed the basal diet. The results showed the average apparent digestibility of TAA, EAA and NEAA in the small intestine was 68.41%, 68.68% and 68.11%, respectively. The average apparent digestibility of Lys was 74.77% being the highest in TAA, the average apparent digestibility of Cys was 52.72%, being the lowest in TAA. The balance index of absorbable amino acid in the duodenum was 0.69.The flow of nitrogen of MCP into the duodenum was 1.93g/d.Exp.4 Determination of MG value of the dietsAccording to the results of Exp.1, Exp.2 and Exp.3, the dietary POEG, BSEG and MG were calculated as 6.40 g/d, 29.16 g/d and 35.56...