Effect of different physiological stages on plasma adropin, insulin, nonesterifid fatty acids, and glucose concentration in lactating dairy cows

H. M. EDVARDSON; A. E. RELLING

Pittsburgh

Congreso; 2017 American Dairy Science Association® Annual Meeting; 2017

ine"></The objective of this research was to investigate the effect of physiological stage on plasma concentrations of adropin, nonesterifid fattyacids (NEFA), glucose, and insulin in lactating dairy cows. Twenty-threelactating dairy cows were selected based on days in milk (DIM) and dailyaverage milk yield. There were 7 early lactation cows (EL, < 50 DIM), 8in mid-lactation high producing (HPML) and 8 in mid-lactation low producing (LPML). High and low production mid-lactation (100?200 DIM)were determined by taking an average of all DIM appropriate cows, andusing plus or minus a standard deviation to create the minimum milkyield for the HPML cows and the maximum milk yield for the LPMLcows. Blood samples from the cows were drawn once via the coccygealvein before feeding time and the plasma was used for glucose, NEFA,insulin, and adropin assays. Data were analyzed as a complete randomizedesign with a mixed model (SAS 9.4) considering each treatment as afied variable and the cow as a random variable. The option PDIFF ofSAS was used for mean separation if overall treatment effect has a Pvalue < 0.05. We were able to validate a human adropin assay as a validmethod to measure bovine adropin, using parallel displacement andrecovery points. Plasma glucose (EL: 72.15 mg/dL, HPML: 73.88 mg/dL) and insulin (EL: 0.25 ng/mL, HPML: 0.33 ng/mL) concentrationsof EL and HPML cows were similar (P > 0.1) while LPML had greater(P < 0.05) concentrations (79.82 mg/dL and 0.5382 ng/mL for glucoseand insulin respectively). Average NEFA concentrations of HPML (218µEq/mL) and LPML (254 µEq/mL) were similar (P > 0.1) while EL hadmuch greater concentrations (537 µEq/mL, P < 0.05). There was a trend(P < 0.1) for adropin to have a lower concentration in EL (0.48 pg/mL)than HPML (0.78 pg/mL), while LPML had similar concentrations toboth (0.63 pg/mL, P > 0.1). Our results show that different stages oflactation tend to have different concentrations of adropin, insulin NEFAand glucose and the concentration is not dependent of physiologicalstage or milk yield but the interaction between them.