Glucose metabolism and the somatotropic axis in dairy cows after abomasal infusion of essential fatty acids together with conjugated linoleic acid during late gestation and early lactation

Abstract

Sufficient glucose availability is crucial for exploiting the genetic potential of milk production during early lactation, and endocrine changes are mainly related to repartitioning of nutrient supplies toward the mammary gland. Long-chain fatty acids, such as essential fatty acids (EFA) and conjugated linoleic acid (CLA), have the potential to improve negative energy balance and modify endocrine changes. In the present study, the hypothesis that combined CLA and EFA treatment supports glucose metabolism around the time of calving and stimulates insulin action and the somatotropic axis in cows in an additive manner was tested. Rumencannulated German Holstein cows (n = 40) were investigated from wk 9 antepartum (AP) until wk 9 postpartum (PP). The cows were abomasally supplemented with coconut oil (CTRL, 76 g/d); 78 g/d of linseed and 4 g/d of safflower oil (EFA); Lutalin (CLA, isomers cis-9,trans-11 and trans-10,cis-12 CLA, each 10 g/d); or the combination of EFA+CLA. Blood samples were collected several times AP and PP to determine the concentrations of plasma metabolites and hormones related to glucose metabolism and the somatotropic axis. Liver tissue samples were collected several days AP and PP to measure glycogen concentration and the mRNA abundance of genes related to gluconeogenesis and the somatotropic axis. On d 28 AP and 21 PP, endogenous glucose production (eGP) and glucose oxidation (GOx) were measured via tracer technique. The concentration of plasma glucose was higher in CLA than in non-CLA-treated cows, and the plasma β-hydroxybutyrate concentration was higher in EFA than in non-EFA cows on d 21 PP. The eGP increased from AP to PP with elevated eGP in EFA and decreased eGP in CLA-treated cows; GOx was lower in CLA than in CTRL on d 21 PP. The plasma insulin concentration decreased after calving in all groups and was higher in CLA than in non-CLA cows at several time points. Plasma glucagon and cortisol concentrations on d 21 PP were lower in CLA than non-CLA groups. The glucagon/insulin and glucose/insulin ratios were higher in CTRL than in CLA group during the transition period. Plasma IGF-I concentration was lower in EFA than non-EFA cows on d 42 AP and was higher during the dry period and early lactation in CLA than in non-CLA cows. The IGF binding protein (IGFBP)-3/-2 ratio in blood plasma was higher in CLA than in non-CLA cows. Hepatic glycogen concentration on d 28 PP was higher, but the mRNA abundance of PC and IGFBP2 was lower in CLA than non-CLA cows on d 1 PP. The EFA treatment decreased the mRNA abundance of IGFBP3 AP and PCK1, PCK2, G6PC, PCCA, HMGCS2, IGFBP2, and INSR at several time points PP. Results indicated elevated concentrations of plasma glucose and insulin along with the stimulation of the somatotropic axis in cows treated with CLA, whereas EFA treatment stimulated eGP but not mRNA abundance related to eGP PP. The systemic effects of the combined EFA+CLA treatment were very similar to those of CLA treatment, but the effects on hepatic gene expression partially corresponded to...

Modulation of colostrum composition and fatty acid status in neonatal calves by maternal supplementation with essential fatty acids and conjugated linoleic acid starting in late lactation

“…Nevertheless, there might be effects on the postnatal growth regulation by the somatotropic axis in these calves. At least, the CLA and EFA+CLA treatments affected parameters of the somatotropic axis in dairy cows during the transition period (Vogel et al, 2021). Feeding goats or ewes variable amounts of n-3 FA during late gestation had no effect on the birth weight of the offspring in previous studies (Duvaux-Ponter et al, 2008;Coleman et al, 2018;Nickles et al, 2019).…”

“…Furthermore, EFA can serve as a precursor for CLA, which is synthesized in the rumen (Bauman et al, 2000;Shingfield et al, 2010). Some CLA isomers have healthpromoting effects in mammals (Nagao and Yanagita, 2005;Shokryazdan et al, 2017) but also reveal metabolic effects in dairy cows (Bauman et al, 2000;Hötger et al, 2013;Vogel et al, 2021). Studies in rats and pigs indicate placental and mammary transfers of CLA and that maternal CLA supply influences FA status, fetal development, and metabolism of the offspring (Park et al, 2005;Segovia et al, 2015).…”

Effect of maternal supplementation with essential fatty acids and conjugated linoleic acid on metabolic and endocrine development in neonatal calves

“…Because fetal endogenous glucose production is low and calves are often born in a hypoglycemic state, maternal EFA treatment might have improved neonatal glucose status at birth (Fowden et al, 2009;Hammon et al, 2012). Although plasma glucose concentration immediately after birth was positively correlated with maternal plasma glucose, maternal plasma glucose concentration was not affected by fatty acid treatments at parturition (Vogel et al, 2021). We speculate that maternal EFA treatment may have facilitated placental glucose transport during late pregnancy.…”

“…However, the ratio of IGFBP-3 to IGFBP-2 on d 2 of life increased most in EFA calves. The ratio of IGFBP-3 to IGFBP-2 indicates the nutritional energy supply and is a good proxy for validating nutrient status in cattle (Breier et al, 2000;Renaville et al, 2002;Vogel et al, 2021). Whether elevated EFA status led to improved nutrient absorption in newborn calves could not be determined from the present study.…”

“…The present study examined the offspring of 37 German Holstein cows that were evaluated in a comprehensive experiment that investigated the effects of EFA and CLA during late pregnancy and early lactation (Vogel et al, 2020(Vogel et al, , 2021. The planned number of animals and group size were chosen to ensure a type I error probability of 0.05 and a type II error probability of 0.20 (i.e., power of 0.8).…”