This experiment was conducted to study hydrolysis, absorption and transportation characteristics of Alanyl-glutamine amino acid (Ala-Gln) and Glycyl-glutamine amino acid (Gly-Gln) in small intestine of weaned piglet by detecting the dipeptide and glutamine monomer in culture solution, serosal fluid and tissue of cultured reversal intestine segments in vitro. The results showed that, in experiment 1, the content of Ala-Gln and Gly-Gln dipeptides were 9.00±1.57 mmol/L, 8.85±1.78 mmol/L, respectively. In experiment 2, both Ala-Gln and Gly-Gln were detected in the incubated intestinal sac tissue and serosal fluid. The content of Ala-Gln dipeptide transported into the sac was 10.26±0.74 mmol/L, significantly greater than that of Gly-Gln dipeptide, 7.25±1.47 mmol/L (P<0.05). The content of Gln absorbed in Ala&Gln treatment and in Gly&Gln treatment was 7.28±0.54 mmol/L, 4.79±0.54 mmol/L,respectively, with no difference (P>0.05). Absorption content of dipeptides was significantly greater that absorption content of Gln in relative free amino acids treatment. The absorption rate of dipeptides or Gln monomer had the same changing characteristic as the absorption content of dipeptides or Gln monomer. The results suggested that these two dipeptides (Ala-Gln and Gly-Gln) were not totally hydrolyzed in jejunum segments of weaned piglets, and their content gradual decreased. They were absorbed by intestinal cells as intact form, and quickly hydrolyzed. The absorption rate of Ala-Gln was faster than that of Gly-Gln. Dipeptides absorption rate were faster from solutions containing the same amount of amino acids in dipeptide than Gln absorption rate in free form. This study provided the theoretical groundwork for dipeptide nutrition. This suggests that either Ala-Gln or Gly-Gln dipeptides can be used to substitute Gln monomer in weaned piglets feeding.

Keyword: Weaned piglet, Glutamine Dipeptides, Glutaminate, Hydrolysis, Absorption

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