Effects of dietary leucine and phenylalanine on pancreas development, enzyme activity, and relative gene expression in milk-fed Holstein dairy calves
Effects of dietary leucine and phenylalanine on pancreas development, enzyme activity, and relative gene expression in milk-fed Holstein dairy calves
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日粮亮氨酸和苯丙氨酸对牛奶喂养荷斯坦奶牛胰腺发育、酶活性和相关基因表达的影响
DOI：
10.3168/jds.2017-13987
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发表时间：
2018-05-01
影响因子：
3.5
通讯作者：
Yao, J. H.
中科院分区：
文献类型：
--
作者：
Cao, Y. C.;Yang, X. J.;Yao, J. H.
本研究旨在探讨饲粮中添加亮氨酸和苯丙氨酸对荷斯坦公犊胰腺发育、酶活性及相关基因表达的影响。将20头雄性荷斯坦小牛[1日龄，38 +/- 3 kg体重（BW）]随机分配至以下4个处理组之一，每组5头小牛：对照组、亮氨酸补充组（1.435 g/L乳汁）、苯丙氨酸补充组（0.725 g/L乳汁）以及亮氨酸和苯丙氨酸（1.435 + 0.725 g/L乳汁）。在每个相应的处理中，使饮食等氮，包括丙氨酸。饲养试验共8 wk，其中适应期1 wk，饲养试验期7 wk。亮氨酸倾向于增加总胰腺蛋白的浓度（mg/kg BW）。苯丙氨酸增加血浆胰岛素，胆囊收缩素，胰腺DNA（mg/g）和胰蛋白酶基因的表达，但降低胰腺蛋白质：DNA的比例，并倾向于降低胰腺重量（g/kg BW）的浓度。在总胰腺DNA（mg/胰腺和mg/kg BW）、胰腺蛋白（mg/胰腺）或α-淀粉酶、胰蛋白酶和脂肪酶活性方面未观察到差异。编码α-淀粉酶和脂肪酶的基因的相对表达水平在4组之间没有差异。亮氨酸和苯丙氨酸的补充显示出对胰腺重量（g和g/kg BW）的相互作用以及对胰腺蛋白浓度（mg/g胰腺和mg/kg BW）和血浆葡萄糖浓度的相互作用的趋势。亮氨酸倾向于增加胰腺细胞的大小，而苯丙氨酸倾向于增加胰腺细胞的数量。然而，无论是AA影响的小牛的胰腺酶的活动。这些结果表明，亮氨酸和苯丙氨酸补充牛奶喂养的荷斯坦犊牛差异影响胰腺的生长和发育。
This study aimed to investigate the effect of dietary supplementation with leucine and phenylalanine on pancreas development, enzyme activity, and related gene expression in male Holstein calves. Twenty male Holstein calves [1 d of age, 38 +/- 3 kg of body weight (BW)] were randomly assigned to 1 of the following 4 treatment groups with 5 calves in each group: control, leucine supplementation (1.435 g/L of milk), phenylalanine supplementation (0.725 g/L of milk), and leucine and phenylalanine (1.435 + 0.725 g/L of milk). The diets were made isonitrogenous with the inclusion of alanine in each respective treatment. The feeding trial lasted for 8 wk, including 1 wk for adaption and 7 wk for the feeding experiment. Leucine tended to increase the concentration of total pancreatic protein (mg/kg of BW). Phenylalanine increased the concentrations of plasma insulin, cholecystokinin, and pancreatic DNA (mg/g) and the expression of trypsin gene but decreased the pancreatic protein: DNA ratio and tended to decrease the pancreas weight (g/kg of BW). No differences were observed in total pancreatic DNA (mg/pancreas and mg/kg of BW), pancreatic protein (mg/pancreas), or activities of a- amylase, trypsin, and lipase. The relative expression levels of the genes encoding a- amylase and lipase did not differ among the 4 groups. The supplementation of both leucine and phenylalanine showed an interaction on the pancreas weight (g and g/kg of BW) and a tendency of an interaction on the pancreatic protein concentration (mg/g of pancreas and mg/kg of BW) and the plasma glucose concentration. Leucine tended to increase the size of the pancreatic cells, whereas phenylalanine tended to increase the number of pancreatic cells. However, neither AA affected the activities of the pancreatic enzymes of the calves. These results indicate that leucine and phenylalanine supplementation in milk-fed Holstein calves differentially affect pancreatic growth and development.