Effect of abomasal butyrate infusion on net nutrient flux across the portal-drained viscera and liver of growing lambs

Authors: Foote, Andrew; Freetly, Harvey

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2016
Publication Date: 8/1/2016
Publication URL: http://handle.nal.usda.gov/10113/63036
Citation: Foote, A.P., Freetly, H.C. 2016. Effect of abomasal butyrate infusion on net nutrient flux across the portal-drained viscera and liver of growing lambs. Journal of Animal Science. 94(7):2962-2972. doi:10.2527/jas.2016-0485.

Interpretive Summary: Efficient absorption and utilization of nutrients by the gastrointestinal tract, also known as the portal-drained viscera, of animals is important in efficient conversion of feed to body growth of animals. The use of natural compounds such as butyrate has the potential to improve nutrient absorption and utilization by portal-drained viscera of ruminants. This experiment was performed to determine if supplying butyrate to the small intestine of growing lambs would alter flux of nutrients across the portal-drained viscera and liver. The butyrate treatment increased the rate of uptake of glucose, glutamate, glutamine, and oxygen. When analyzed as total flux of nutrients, only glucose flux was affected by the butyrate treatment. Nutrient metabolism by the liver was not affected by the butyrate treatment. It is possible that the butyrate treatment stimulated glycolysis in the portal-drained viscera. It is more likely that the butyrate treatment stimulated growth of the portal-drained viscera tissue which increased the requirements for glucose, glutamate, glutamine, and oxygen by the portal-drained viscera but did not alter the energy flux across the gut. There are situations in animal production where it may be desirable to stimulate growth of the gut, without increasing the energy requirement of the animals.

Technical Abstract: The purpose of this experiment was to determine if supplying butyrate to the post-ruminal gastrointestinal tract of growing lambs alters blood flow and nutrient flux across the portal-drained viscera (PDV) and hepatic tissues. Polled Dorset wether lambs (n = 10; initial BW = 55 ± 3.3 kg) had catheters surgically implanted into the portal vein, a branch of the hepatic vein, a mesenteric vein, and the abdominal aorta. A cannula was placed in the abomasum to deliver the treatment. Lambs were fed a pelleted ration once daily consisting of 69.7% dehydrated alfalfa, 30.0% ground corn, and 0.3% salt at 1.3 × NEm. The experimental design was a crossover, so that each lamb received both treatments. Treatments consisted of either a bolus infusion of butyrate (buffered solution) to supply butyrate (10 mg • kg BW-1 • d-1) or a buffered saline solution (10 mL•kg BW-1 • d-1) at the time of feeding. On d 14 of the treatment period, a nutrient flux study was conducted using para-aminohippuric acid as a blood flow marker. Blood samples were collected from the aorta, portal vein, and hepatic vein every h for 9 h beginning at 30 min prior to treatment/feeding. There was a tendency for a treatment × time interaction (P = 0.053) for portal vein blood flow indicating that blood flow began to decrease earlier post-prandial in lambs receiving butyrate. The butyrate treatment tended to increase the uptake of O2 (P = 0.072), and increased the uptake of glucose (P = 0.002), glutamate (P = 0.037), and glutamine (P = 0.017) by the PDV. There was a treatment × time interaction (P < 0.012) for flux of acetate, propionate, butyrate, isobutyrate, and valerate across the PDV. The interaction was mainly due to an earlier post-prandial peak and associated decrease in the flux rate of the VFA. This trend for VFA was basically mirrored in hepatic fluxes of VFA. It appears that supplying butyrate to the post-ruminal tissues through an abomasal cannula changes glucose, glutamate, and glutamine metabolism by the PDV, which could be due to an increase in cell proliferation.