ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2014, Vol. 45 ›› Issue (9): 1432-1439.doi: 10.11843/j.issn.0366-6964.2014.09.008

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Effects of Abomasal Glucose Infusion on Milk Fat Synthesis in Lactating Goats

ZHANG Ya-bin#，LIN Xue-yan#，YAN Zhen-gui，HOU Qiu-ling，SHI Ke-rong，WANG Zhong-hua*   

  1. (College of Animal Science and Technology，Shandong Agricultural University，Tai’an 271018，China)
  • Received:2013-12-27 Online:2014-09-23 Published:2014-09-23

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Abstract:

The aims of the present study were to investigate if high concentrate diets with high concentration blood glucose and insulin depress milk fat synthesis and the underlying mechanism.4 Laoshan dairy goats in early lactation fitted with abomasal and jugular artery catheters were used in a repeated 2×2 crossover experiment.Treatments were abomasal infusion of saline or 200 g•d-1 glucose.The experiment was consisted of two periods.Each period lasted 8 d and there was a 14 d interval between the two periods.RT-PCR was used to detect the mRNA expression of ACC,FAS,LPL,H-FABP,GPAT and SCD.The results indicated that glucose infusion elevated blood glucose (P<0.05) and tended to elevated plasma insulin (P=0.06).Glucose infusion increased milk yield，decreased both milk fat yield and milk fat percentage (P<0.05).Analysis of fatty acid profile of milk fat reveled that glucose infusion decreased the yield of C18∶0 and c9C18∶1 (P<0.05) but had no significant effect on the yields of those de novo synthesized fatty acids (C4-C14) and those dual source fatty acids that may be preformed or de novo synthsized (C16).Glucose infusion had no significant effects on the mRNA experssion of acetyl coenzyme A carboxylase，fatty acid synthetase，lipoprotein lipase，fatty acid bonding protein，glycerol-3-phosphate acyltransferase，stearoyl CoA desaturase and fatty acid transfer protein.It was concluded that abomasal glucose infusion decreased milk fat synthesis mainly by decreasing the amount of pre-formed fatty acids used for milk fat synthesis，had no significant effect on the expression of genes related to milk fat synthesis.The regulation of abomasal glucose infusion on milk fat synthesis occurred after transcription.

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