Somatotropin increases plasma ceramide in relation to enhanced milk yield in cows

Recombinant bovine somatotropin (rBST) changes metabolism to spare glucose for milk synthesis in cows. Ceramides inhibit insulin responsiveness adipocytes and are associated with resistance production The mechanisms by which rBST supports lactation may involve ceramide. Eight multiparous lactating Holstein cows were enrolled a 2 × replicated Latin square design 14-d periods. Cows received single injection (Posilac; Elanco Animal Health, Indianapolis, IN; 0.062 mg/kg BW) or no (CON). An epinephrine challenge, tolerance test, liver biopsy performed. Somatotropin enhanced the conversion of feed nutrients into components increased plasma free fatty acid (FFA) concentrations (P < 0.01). Area-under-the-curves FFA response greater rBST-treated In insulin, (20- 30-min post-challenge) area-under-the-curve higher treatment 0.05, <0.10, <0.01), suggesting resistance. modified lipidome. For example, decreased di- triacylglycerol levels (eg, DG-50:1 TG-18:0/16:0/16:1), phosphatidylcholines sphingomyelins 0.05). total very-long-chain (C22:0-, C24:0-, C26:0-) ceramide Liver not modified. Plasma ceramides positively correlated circulating (r ~ 0.57; P 0.05) yield 0.63; We conclude that administration modifies lipidome increases association