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ARS Home » Research » Publications at this Location » Publication #74116
Title: OVINE PANCREATIC RESPONSE TO ABOMUSALLY INFUSED CASEIN

Author
item WALDNER, D. - UNIV OF KENTUCKY
item ELY, D. - UNIV OF KENTUCKY
item HARMON, D. - UNIV OF KENTUCKY
item McLeod, Kyle
item AARON, D. - UNIV OF KENTUCKY

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Eight crossbred wethers (30 kg BW), with T-shaped intestinal cannulas and abomasal infusion and portal vein catheters were used to determine selected physiological changes that occur with increased small intestinal (SI) protein availability. Lambs were maintained on a 10% CP diet with intake limited to 2% BW. All lambs were adapted to a control treatment of 1 g casein/(kg BWùùd) infused abomasally (50 mL/h; 1200 mL/d) 8 D prior to eac experimental period. On d 1 of each 8-d experimental period, four lambs were continued on the control and four were switched to a 2 g casein/(kg BWùùd) infusion treatment. This 16-d procedure was repeated so all lambs received both treatments. Nitrogen balance was determined for a 24-h period on d 1, 2, 4, and 8. Digesta and portal and jugular blood samples were taken 6 times per d at 4-h intervals starting at 0800 on d 1, 2, 4, and 8. There were no adaptation effects to SI protein availability. Therefore, only treatment differences are presented. Nitrogen digestibility increased (P < .01), whereas, daily N retained (% of N digested) was unchanged with increased SI protein availability (casein). Specific and total activities of amylase and trypsin in intestinal digesta were not different. However, chymotrypsin increased (P < .01) with the increased casein infusion. Portal insulin and à-amino N increased (P < .02), while glucose remained unchanged. Cholecystokinin, measured in portal and jugular blood, was not affected by treatment. The amount of protein available for digestion in the SI has a positive impact on chymotrypsin activity in intestinal digesta. However, the physiological mechanisms which control pancreatic exocrine secretion in ruminants remains unclear.