Prepartum dietary energy intake alters adipose tissue transcriptome profiles during the periparturient period in Holstein dairy cows

Background:The aim of the study was to investigate the effect of energy overfeeding during the dry period on adipose tissue transcriptome profiles during the periparturient period in dairy cows.Methods:Fourteen primiparous Holstein cows from a larger cohort receiving a higher-energy diet(1.62 Mcal of net energy for lactation/kg of dry matter;15%crude protein)for ad libitum intake to supply 150%(OVR)or 100%(CTR)of energy requirements from dry off until parturition were used.After calving,all cows received the same lactation diet.Subcutaneous adipose tissue(SAT)biopsies were collected at−14,1,and 14d fromparturition(d)and used for transcriptome profiling using a bovine oligonucleotide microarray.Data mining of differentially expressed genes(DEG)between treatments and due to sampling time was performed using the Dynamic Impact Approach(DIA)and Ingenuity Pathway Analysis(IPA).Results:There was a strong effect of over-feeding energy on DEG with 2434(False discovery rate-corrected P<0.05)between OVR and CTR at−14 d,and only 340 and 538 at 1 and 14 d.The most-impacted and activated pathways in the Kyoto Encyclopedia of Genes and Genomes(KEGG)database that were highlighted by DIA analysis at−14 d in OVR vs.CTR included 9 associated with carbohydrate metabolism,with‘Pyruvate metabolism’,‘Glycolysis/gluconeogenesis’,and‘Pentose phosphate pathway’among the most-activated.Not surprisingly,OVR led to marked activation of lipid metabolism(e.g.‘Fatty acid biosynthesis’and‘Glycerolipid metabolism’).Unexpected metabolic pathways that were activated at−14 d in OVR included several related to metabolism of amino acids(e.g.branched chain)and of cofactors and vitamins(thiamin).Among endocrine and immune system pathways,at−14 d OVR led to marked activation of‘PPAR signalling’and‘Antigen processing and presentation’.Among key pathways affected over time in OVR,a number were related to translation(e.g.mTOR signaling),endocrine/immune signaling(CXCR4 and IGF1),and lipid metabolism(oxidative phosphorylation)with greater activation in OVR vs.CTR specifically at−14 d.Although statistical differences for several pathways in OVR vs.CTR nearly disappeared at 1 and 14 vs.−14 d,despite the well-known catabolic state of adipose depots after calving,the bioinformatics analyses suggested important roles for a number of signaling mechanisms at−14 vs.14 than 1 vs.-14 d.This was particularly evident in cows fed to meet predicted energy requirements during the dry period(CTR).Conclusions:Data underscored a strong activation by overfeeding energy of anabolic processes in the SAT exclusively prepartum.The study confirmed that higher-energy diets prepartum drive a transcriptional cascade of events orchestrated in part by the activation of PPARγthat regulate preadipocyte differentiation and lipid storage in SAT.Novel aspects of SAT biology to energy overfeeding or change in physiologic state also were uncovered,including the role of amino acid metabolism,mTOR signaling,and the immune system.

Effect of Hypoglycemia on Performances,Metabolites,and Hormones in Periparturient Dairy Cows

In this research work, 24 multiparous holstein cows were used to evaluate the effect of hypoglycemia on periparturient metabolism and lactation performance. The cows were arranged into two groups of hypoglycemia （L） and normal plasma glucose （N） based on plasma glucose level. The same diets were fed ad libitum from 28 days before expected calving date to 28 days after calving. The parameters relative to energy balance, such as dry matter intake （DMI）, body weight （BW）, milk yield （MY）, and concentrations of plasma glucose, nonesterified fatty acids （NEFA）, β-hydroxybutyric acid （BHBA）, insulin （INS）, glucagons （GLN）, leptin （LP）, neuropeptide Y （NPY） in plasma were measured at regular intervals. Incidence of hypoglycemia was higher prepartum than that of postpartum （88% vs. 50%）, and the recurrence of hypoglycemia was reversed （31% vs. 100%）. Hypoglycemia did not affect feed intake before and after calving. With the increase of postpartum feed intake, incidence of hypoglycemia decreased rapidly, even disappeared at 28 days of postpartum. Hypoglycemia had no impact on prepartum BW, but BW in L group was lower than that of cows in N group at 1 day and 14 days of postpartum （P〈0.05）. Milk yield was not affected by hypoglycemia. Cows in L group had higher plasma NEFA concentration than cows in N group. It reached a peak （1442 μmol L^-1 vs. 1052 μmol L^-1） at day 1 of postpartum （P〈0.05）. Plasma BHBA concentration of cows in L group was higher than that in N group, which reached a peak （2.01 mmol L^-1 vs. 1.34 mmol L^-1） at 14 days of postpartum （P〈0.05）. Plasma concentration of INS and GLN was unaffected by treatment, but postpartum plasma GLN concentration obviously increased, especially in L group. Plasma concentration of LP and NPY before calving was unaffected by treatment, but postpartum LP level in L group was slightly lower than that in N group, and NPY level in L group was significantly higher than that in N group （P〈0.05）. Overall, periparturient dairy cows are easy to develop hypoglycemia, which stimulates lipid metabolism. Adaptive changes of some metabolites and hormones, such as NEFA, BHBA, INS, GLN, LP, NPY are of benefit to increase feed intake and recovery of NEB in periparturient period, but there still are some issues on interaction of those endocrine factors in the energy balance of periparturient cows to be understood further.