Effects of intravenous glucose infusion and nutritional balance on serum concentrations of nonesterified fatty acids, glucose, insulin, and progesterone in nonlactating dairy cows

Abstract

The objective of this study was to evaluate serum concentrations of nonesterified fatty acids, glucose, insulin, and progesterone in nonlactating dairy cows according to nutritional balance and glucose infusion. Ten nonlactating, ovariectomized Gir x Holstein cows were stratified by body weight (BW) and body condition score (BCS) on d -28 of the study, and randomly assigned to 1) negative nutrient balance (NB) or 2) positive nutrient balance (PB). From d -28 to d 0, cows were allocated according to nutritional treatment (5 cows/treatment) into 2 low-quality pastures with reduced forage availability. However, PB cows individually received, on average, 3 kg/cow per day (as-fed) of a concentrate during the study. All cows had an intravaginal progesterone releasing device inserted on d -14, which remained in cows until the end of the study. Cow BW and BCS were assessed again on d 0. On d 0, cows within nutritional treatment were randomly assigned to receive, in a crossover design containing 2 periods of 24h each, 1) intravenous glucose infusion (GLU; 0.5 g of glucose/kg of BW, as a 5% glucose solution administered, on average, at 32 mL/min over a 3-h period), or 2) intravenous saline infusion (SAL; 0.9% solution infused on average at 32 mL/min over a 3-h period). Prior to the beginning of each period, all cows were fasted for 12h. Blood samples were collected, relative to the beginning of the infusion, at -12 and -11.5h (beginning of fasting), and at -0.5, 0, 0.5, 1, 2, 3, 4, 5, and 6h. Following the last blood collection of period 1, cows received (PB) or not (NB) concentrate and were returned to their respective pastures. Changes in BCS and BW were greater in NB cows compared with PB cows (-0.60 and -0.25+/-0.090 for BCS, respectively; -22.4 and 1.2+/-6.58 kg for BW, respectively). Cows receiving GLUC had greater glucose concentrations from 0.5 to 3h relative to infusion compared with SAL cows. Insulin concentrations were greater in PB cows assigned to GLUC compared with SAL cohorts at 0.5 and 3h following infusion, whereas NB cows assigned to GLUC had greater insulin concentrations compared with SAL cohorts at 0.5, 1, 2, and 3h. Progesterone concentrations were greater in PB cows assigned to GLUC at 2, 3, and 4h following infusion compared with SAL cohorts. In conclusion, the effects of glucose infusion on serum concentrations of insulin and progesterone in nonlactating dairy cows were dependent on cow nutritional status.

Effect of lactation induction on milk production and composition, oxidative and antioxidant status, and biochemical variables

“…However, the use of this hormone seems to be associated with an increase in the activity of the enzyme GGT, which may explain a marked elevation on GGT activity found on day 15 on all animals from group A, differing from the control group and exceeding the amounts related to the species. Similar results were found by Vieira et al (2010) and Araújo (2014), who verified the increase of this hepatic enzyme after using BST, but they did not give a plausible explanation for this fact. In this case, it is necessary to analyze very carefully this parameter because GGT is an indicator of cell damage and dysfunction of hepatic metabolism.…”

Effects of supplementation of calcium salts of polyunsaturated fatty acids on serum concentrations of progesterone and insulin of pregnant dairy cows

“…Previous results from our laboratory have shown that peripheral concentrations of insulin potentially modulates the hepatic metabolism of P 4 (Moriel et al, 2008;Lopes et al, 2009;Vieira et al, 2010Vieira et al, , 2013. Elevated insulin concentrations reduced hepatic expression of P 4 catabolic enzymes P450 2C and P450 3A (Lemley et al, 2008;Vieira et al, 2013), which may further increase circulating concentrations of P 4 (Moriel et al, 2008;Lopes et al, 2009;Vieira et al, 2010).…”

“…Elevated insulin concentrations reduced hepatic expression of P 4 catabolic enzymes P450 2C and P450 3A (Lemley et al, 2008;Vieira et al, 2013), which may further increase circulating concentrations of P 4 (Moriel et al, 2008;Lopes et al, 2009;Vieira et al, 2010). Accordingly, Vieira et al (2013) reported that dairy cows in adequate nutritional status receiving jugular glucose infusion (3 h at a rate of 0.5 g/kg of BW) had greater circulating insulin concentrations and reduced hepatic mRNA expression of P 4 catabolic enzymes CYP2C19 and CYP3A4 compared with cohorts receiving saline infusion.…”

Produção embrionária, perfil endócrino, metabólico e molecular de vacas holandesas não-lactantes recebendo dieta à base de milho ou polpa cítrica

“…Alguns estudos sugerem haver uma menor metabolização de P4 em situações de alta insulina sanguínea (COOKE et al, 2012;LEMLEY et al, 2008SMITH et al, 2006;VIEIRA et al, 2010). Como a concentração da insulina pode ser maior após a ingestão de alimento, parece contraditório poder haver um efeito protetor dela sobre a metabolização de hormônios, já que, como mencionado acima, a IMS aumenta o fluxo sanguíneo hepático e favorece a metabolização de hormônios esteroides.…”

“…Diferenças nos padrões de fermentação ruminal ou nos dados relativos à produção leiteira e desempenho de ruminantes recebendo milho e polpa cítrica são descritas em inúmeros estudos (BAMPIDIS; ROBINSON, 2006;BEN-GHEDALIA et al, 1989;BRODERICK;SIMONS, 2002 COOKE et al, 2012;MORIEL et al, 2008;SMITH et al, 2006;VIEIRA et al, 2010). No presente estudo, no entanto, esse efeito "protetor" não foi relacionado à menor expressão gênica das enzimas que metabolizam a P4 (CYP2C19, CYP3A4, AKR1D1, AKR1C4), visto que não foi encontrada diferença na expressão gênica (Tabela 10), diferente do descrito por Lemley et al (2008).…”