ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2009, Vol. 40 ›› Issue (12): 1761-1768.doi:

• 动物营养 • Previous Articles     Next Articles

Effect of Duodenal Soybean Small Peptides Infusion on Mammary Uptake of Amino Acid and Expression of APN in Lactating Goat

LIU Hui 1,2,3, WANG Ling 1,2,4, LI Shengli 1,2*, WANG Libin 1,2
  

  1. 1.SinoUS Dairy Research & Development Center, China Agricultural University,Beijing 100193, China； 2.State Key Laboratory of Animal Nutrition, Beijing 100193,China；3.Sanyuan Lvhe Dairy Cattle Center, Capital Agribusiness Group, Beijing 100076, China; 4. College of Agriculture, Ningxia University, Yinchuan 750021, China
  • Received:2008-11-28 Revised:1900-01-01 Online:2009-12-24 Published:2009-12-24
  • Contact: LI Shengli

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Abstract: The aim of this study was to investigate effect of duodenal soybean small peptides (SSP) infusion on mammary uptake of amino acids (AA). Eight Chinese Saanen goats with duodenal fistula and catheter were used in a crossover design trial. Goats were infused 0, 60, 120, 180 g·d1SSP. The experiment period lasted for 14 d. The results showed: 1) milk protein yield and content were increased, increment of milk protein yield were significant (P<0.05). Milk fat yield and content were decreased with the increased of the amount of SSP infusion (P<0.05). 2) Mammary plasma flow were no changed by SSP infusion though the average was slightly higher (P>0.05). Mammary plasma flow/milk yield was decreased by SSP infusion and there was significant difference between the 120 g·d1treatment and the control (P<0.05). 3) Compared with the control treatment, uptakes of most free amino acids were increased in the 60 and 120 g·d1 treatments, and decreased in 180 g·d1treatment. The uptakes of all peptidebound essential amino acids (PBEAA) were increased except for PBIle. Uptake of PBVal, PBLeu, PBPhe, PBThr, PBMet and PBLys was the highest in the 120 g·d1 treatment. Among peptidebound nonessential amino acids (PBNEAA), uptake of PBSer, PBTyr, PBPro was increased (P<0.05). However, that of PBGly was drop down (P>005). 4) Secretion of all essential AA (EAA) was increased by SSP infusion apart from Lys, that of those EAA was increased with increment of the amount of SSP infusion from 0102 g·d1 treatment (P<0.05), however increment of their secretion in milk were not significant in the 180 g·d1 treatment and were lower than in the 120 g·d1 treatment. 5) The expression of APN was improved by SSP, that in 60, 120, 180 g·d1 treatment was 13.55, 18.69, 10.01fold in control treatment. Conclusion: SSP might be used as substrate of milk protein synthesis by mammary gland, and improved milk protein synthesis and secretion. However, when the concentration of AA was stature, increment of AA resulted in absorption inhibition. Increment of APN expression accorded with the variety of PBAA uptakes by mammary gland, which suggested APN was one of peptidase regulated small peptides absorption in mammary tissue.