Effect Of Different Absorbable Amino Acid Patterns In The Small Intestine On Amino Acid Utilization In The Skin Of Cashmere Goats

This paper mainly studied on the effect of different amino acid patterns (AAPs) at the duodenum on amino acid utilization in the skin tissues of Inner Mongolian White Cashmere (IMWC) goats. Firstly, it was studied in a animal level that the dynamic changes of AAPs at the duodenum by nutrients infusion technique and arterio-venous technique, and it was also studied that the effect of different AAPs at the duodenum on the concentrations of GH, IGF-1, PRL and other biochemical indexes. Then, it was studied in a local level that the effect of different AAPs at the duodenum on the metabolism and utilization of the amino acids in the skin tissues, fibre production and its genes expression in follicle by skin arterio-venous technique and RT-PCR technique. The paper was divided into two parts.Part 1 Effect of different AAPs at the duodenum on the metabolism and utilization of the amino acids in PDV tissues and in liver and on the concentrations of plasma hormones in IMWC goats In Exp. 1, six wethers of IMWC goats (21-23kg) with the same father, fitted with permanent cannulas at the proximal duodenum, and with femoral artery, mesenteric, portal and hepatic venous catheters were used to study on the metabolism and utilization of the amino acids in PDV tissues and liver of IMWC goats fed diets with different dietary AAPs at the duodenum. In Exp. 2, nine wethers of IMWC goats (21-23kg, 1.5 years old) with the same father were used to study on the effect of different AAPs at the duodenum on the concentrations of plasma hormones and other biochemical indexes. The results showed that different AAPs at the duodenum had significantly effect on net flux and pattern of plasma free amino acids in the mesenteric vein, portal vein and hepatic vein when the animals were fed diets above maintainance level. When the disappearance of Met and Lys in small intestine increased, that the net flux of Met and plasma Lys in the mesenteric vein, portal vein and hepatic vein was increased significantly (P<0.05). The results also showed that when the values of amino acid balance index (AABI) increased, the of plasma PRL decreased significantly (P<0.05). It also indicated that when the dietary AA was balance, there was increase tendency in the goats of the fibre production.Part 2 Effect of different AAPs at the duodenum on the metabolism and utilization of the amino acids in skin and on fibre performance and study on the mechanism for control cashmere fibre growth in IMWC goatsNine wethers of IMWC goats (21-23kg weight,1.5 years old) with the same father were used in part 2. In Exp 1, Exp 2 and Exp 3 respectively that effects of different AAPs at the duodenum on the metabolism and utilization of the amino acids in skin and on fibre performance and the mechanism for controling cashmere fibre growth in IMWC goats were studied. The results showed that different AAPs at the duodenum had significantly effect on the disappearance of plasma free amino acids in skin, When the disappearance of Met and Lys in small intestine increased, the disappearance of plasma Met and plasma Lys in skin was increased significantly (P<0.05), and there was increase tendency of the disappearance of plasma TAA. IGF-1mRNA was not founding the follcles, which indicanted that IGF-1 effected differentiation and multiplication of follicle cells maybe by paracrine. The AAPs, which had higher value of AABI, would promoted the express of IGF-1mRNA, there was not significantly difference among the express of PRLr in different groups. When the AABI of different AAPs was increased, there as increase tend of the length of cashmere fibre and guard hair fibre.