title: Relationships between leucine and the pancreatic exocrine function for improving starch digestibility in ruminants.
abstract: Four Holstein heifers (215 ± 7 kg; means ± SD), fitted with one pancreatic pouch, duodenal re-entrant cannulas, and duodenal infusion catheters, were used in this experiment. In phase 1, the 24-h profile of pancreatic fluid was determined. Pancreatic fluid flow peaked 1h after feeding, but peaks of similar magnitude also occurred before the morning feed, necessitating 24-h collection of pancreatic fluid to estimate daily excretion. In phase 2, the effects of duodenal infusions of 0, 10, 20, or 30 g of leucine on pancreatic fluid flow were determined in a 4 × 4 Latin square design. The leucine was infused for 12h in 2,500 mL of the infusate, and samples of pancreatic fluid and jugular blood were collected in 1-h intervals from the beginning of the infusion for 36 h. The results showed that the secretion rate of pancreatic fluid (mL/h) was significantly higher in 10-g leucine group than the other groups (mL/h). Protein concentration (mg/mL) in pancreatic fluid was elevated proportional to the amount of leucine infused. Leucine infusions increased both the concentration (U/mL) and secretion rate (U/h) of α-amylase. Infusion of 10 g of leucine also increased the secretion rates (U/h) of trypsin, chymotrypsin, and lipase, but did not change their concentrations. No significant effects of leucine infusions on plasma glucose and insulin concentrations were found. The results indicate that leucine could act as a nutrient signal to stimulate α-amylase production and pancreatic exocrine function in dairy heifers.
authors: College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, China, 712100.
authors: K
authors: K
authors: Liu
authors: College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, China, 712100.
authors: Y
authors: Y
authors: Liu
authors: Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia.
authors: S M
authors: SM
authors: Liu
authors: College of Animal Science and Medicine, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China, 01008.
authors: M
authors: M
authors: Xu
authors: College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, China, 712100.
authors: Z P
authors: ZP
authors: Yu
authors: College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, China, 712100.
authors: X
authors: X
authors: Wang
authors: College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, China, 712100.
authors: Y C
authors: YC
authors: Cao
authors: College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, China, 712100. Electronic address: yaojunhu2004@sohu.com.
authors: J H
authors: JH
authors: Yao
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism; D004386:Duodenum / Q000201:enzymology; D005260:Female; D007263:Infusions, Parenteral; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007930:Leucine / Q000008:administration & dosage*; D008049:Lipase / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism; D010189:Pancreatic Juice / Q000201:enzymology*; D013213:Starch / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D007328:Insulin; D013213:Starch; D008049:Lipase; D000516:alpha-Amylases; D002918:Chymotrypsin; D014357:Trypsin; D007930:Leucine
keywords: amino acid; cow; digestive enzyme; duodenal infusion; insulin