Methionine, leucine, isoleucine orthreonine effects on lactation performance and mammary cell signaling
Introduction DietaryAA formulation is based on the single limiting amino acid theory laid out by Mitchell and Block (1946).This single limiting AA conceptassumes that transfer of AA from the gut lumen to milk protein occurs at a constant efficiency until requirements are met and at 0 efficiency thereafter(a linear,breakpoint model), and thus the process is substrate limited with no adaptability.However, it has now been demonstrated that AA not only serve as substrates forprotein synthesis, but also regulatetranslation initiation and elongation via one or more cell signaling pathways(Appuhamy et al., 2011a, 2012).Such regulation coupled with variable mammary AA transport activity confers variable AA use efficiency which violates the fixed efficiency assumption that is critical to the framework proposed byMitchell and Block(1946).Individual EAA have different effects on signaling proteins and casein fractional synthesis rates of mammary tissue in vitro (Appuhamy et al.,2012).We hypothesized that supplementation of a protein deficient diet with those specific EAA would independently improve lactational performance through cell signaling responses.There is no whole animal research to support this strategy.We conducted two studies to assess the effects of individual EAA supplementation on lactational performance in mice using litter growth rates as a response variablein vivo.The first was designed to establish a dietary protein response curve, and the second to determine the independent effects of Leu, Ile, Met, or Thr supplementation of a protein deficient diet.
G M.Liu M.D.Hanigan X.Y.Lin K.Zhao F.G.Jiang R.R.White Y.Wang Z.Y.Hu Z.H.Wang
Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P.R.China
国际会议
The 5h International Symposium on Dairy Cow Nutrition and Milk Quality(第五届“奶牛营养与牛奶质量国际研讨会)
北京
英文
312-313
2017-05-05（万方平台首次上网日期，不代表论文的发表时间）