Abstract:

This experiment was conducted to study the effects of intraduodenally infusion of soybean small peptide (SSP) on absorption of small peptide and free amino acids in dairy goats. Seven dairy goats ((37.88±3.03) kg) were used in a 4×4 Latin square design. Goats were fitted with duodenal cannulas and implanted with indwelling catheters in carotid artery, mesenteric vein and portal vein. Each goat received four treatments respectively: infusion of normal saline, 60, 120 and 180 g·d-1 SSP into duodenum. Increased SSP duodenal infusion elevated the net fluxes of peptide bound amino acids (PAA) across mesentericdrained viscera (MDV) (P<0.05), but decreased the net appearance rates of PAA in mesenteric vein blood flow. SSP infusion increased net fluxed of PAA across portaldrained viscera (PDV) compared with that of the control (P<0.05), but there was no significant difference among those of three SSP infusion treatments（P>0.05）. SSP infusion did not change concentrations of glucose, insulin, growth hormone and IGF1 (P>0.05), but increased the concentration of urea nitrogen (P<0.05) in the plasma of jugular vein. The results indicated that SSP infusion increased the net fluxes of PAA and free amino acid (FAA) across the MDV and PDV, but decreased the net appearances of PAA in the MDV, which may be a result of decreased absorption, increased degradation of PAA in the absorptive cell, or both.