Advances in nutrient partitioning in liver of ruminants
Liver is the biggest organ in dairy cattle,and plays significant roles in lipid and protein metabolism of dairy cows.The function of liver has close relationship with its structure.Liver has hepatic artery and portal vein double blood supply.It obtains various metabolic substance from body circulation by hepatic artery and performs substance exchange with different tissues of whole body.Meanwhile,it obtains various nutritional substance absorbed from digestive tract by portal vein and carries out transformation,utilization and partitioning.During early and middle stage of lactation,in order to pursue high production,dairy producers enhance milk production by increasing dietary ratio of concentrate to forage to make sure the maximum of dairy food intake and energy absorption.Yet,taking in high concentrate low forage ration will result in quick fermentation of rumen micro-organisms in dairy cattle and produce too much volatile fatty acids and lactic acid,which enhances the risk of suffering from subacute ruminal acidosis.Feeding high concentrate low forage ration or changing high concentrate ration too quickly results in reduction of rumen pH value,which makes a large quantity of Gram-negative bacteria die,decompose and release large amount of endogeneous lipopolysaccharides (LPS).Poisonous ingredients produced by abnormal rumen metabolism such as LPS etc.are important endogeneous factors which result in nutritional repartition by the liver.LPS goes into liver from portal vein and leads to inflammation reaction and function alteration of liver,resulting in nutritional repartition in liver.After the model animal dairy goats were fed with high concentrate low forage ration,the results showed that in early stage hepatic metabolism enhanced and milk lactation increased.However,the function of endocrinology decreased and the liver appeared inflammation reaction.Meanwhile,the relative factors of stress protein increased remarkably.With the feeding time continued,the health status of dairy goats went down gradually.In particular,hepatitis got much severe,and fmally the milk quality went down.The influence of high concentrate feeding depended on the continued time.The results of dairy cows was similar with that of dairy goats.High concentrate diet led to abnormal function of rumen metabolism in dairy cattle and then affected metabolic function of liver,which resulted in nutritional repartitioning and milk function of dairy cows was damaged at last.
liver ruminants repartifioning nutrient high concentrate
X.Z.Shen Y.S.Zhang S.Zhuang Y.D.Ni G.Y.Yang L.F.Wang
Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, College of Veterinary Key Laboratory ofRegulation on Animal Growth and Development, Ministry of Agriculture, College of An
国际会议
3rd International Symposium on Dairy Cow Nutrition and Milk Quality(第三届“奶牛营养与牛奶质量国际研讨会)
北京
英文
32-37
2013-05-11（万方平台首次上网日期，不代表论文的发表时间）