Graduate Student Literature Review: Mitochondrial adaptations across lactation and their molecular regulation in dairy cattle

摘要

As milk production in dairy cattle continues to increase,so do the energetic and nutrient demands on thedairy cow. Difficulties making the necessary metabolicadjustments for lactation can impair lactation performanceand increase the risk of metabolic disorders.The physiological adaptations to lactation involve themammary gland and extramammary tissues that coordinatelyenhance the availability of precursors for milksynthesis. Changes in whole-body metabolism and nutrientpartitioning are accomplished, in part, throughthe bioenergetic and biosynthetic capacity of the mitochondria,providing energy and diverting importantsubstrates, such as AA and fatty acids, to the mammarygland in support of lactation. With increased oxidativecapacity and ATP production, reactive oxygen speciesproduction in mitochondria may be altered. Imbalancesbetween oxidant production and antioxidant activitycan lead to oxidative damage to cellular structuresand contribute to disease. Thus, mitochondria aretasked with meeting the energy needs of the cell andminimizing oxidative stress. Mitochondrial function isregulated in concert with cellular metabolism by thenucleus. With only a small number of genes presentwithin the mitochondrial genome, many genes regulatingmitochondrial function are housed in nuclear DNA.This review describes the involvement of mitochondriain coordinating tissue-specific metabolic adaptationsacross lactation in dairy cattle and the current stateof knowledge regarding mitochondrial-nuclear signalingpathways that regulate mitochondrial proliferation andfunction in response to shifting cellular energy need.