Ghrelin antagonist overrides the mRNA expression of NPY in hypothalamus in feed restricted ewes.

A negative energy balance (NEB) is detrimental to reproduction in animals. A suggested link between NEB and reproductive failure is the gastrointestinal hormone ghrelin, because of the association between ghrelin and the hypothalamo-pituitary-gonadal axis. The [D-Lys3]-Growth Hormone Releasing Peptide-6 ([D-Lys3]-GHRP-6) is a ghrelin antagonist that acts on ghrelin receptors (GHS-R1). The objective of this study was to evaluate the effect of [D-Lys3]-GHRP-6 on reproduction variables in feed restricted ewes. Two experiments were conducted. Experiment I was conducted for 30 days; and Experiment II for 13 days. In both experiments the ewes (n = 18) were randomly assigned to: Control (CO): fed to meet maintenance requirements; Feed restriction (FR): 80% of maintenance restriction; or Ghrelin antagonist (GA): feed restricted and daily subcutaneous of 7.5µg/kg of [D-Lys3]-GHRP-6. Plasma was collected to measure hormones and metabolite concentration. In Experiment II, the hypothalamus and ovaries were collected on day 13. In both Experiments, sheep allocated to the FR and GA treatments decreased their body weight compared with sheep in the CO group (P < 0.06); progesterone however, did not differ between treatments (P > 0.10). Experiment I: Plasma ghrelin concentration was greater (P < 0.01) in FR and GA compared with CO ewes. Plasma non-esterified fatty acids concentration was greater (P < 0.01) in GA and FR than CO. Experiment II: Kisspeptin1-Receptor (Kiss1-R) mRNA expression was greater in FR (P < 0.01) and tended to be greater in GA (P = 0.10) compared with CO ewes. The neuro peptide-Y (NPY) mRNA expression was greater (P = 0.03) in FR than CO; and tended to be greater (P = 0.06) compared with GA ewes. Growth hormone releasing hormone (GhRH) mRNA expression was greater in GA (P = 0.04) and tended to be greater in FR (P = 0.07) compared with CO ewes. Feed restriction increased GhRH, NPY, and Kiss-R mRNA expression in hypothalamus without affecting reproductive variables.Ghrelin antagonist may prevent an increase inNPY expression in ewes.

Effect of alpha-lipoic acid during preimplantation development of cattle embryos when there were different in vitro culture conditions.

In many species, alpha-lipoic acid (ALA) is essential for embryo development. There, therefore, was investigation of effects of ALA supplementation to culture media for in vitro development of cattle embryos. In Experiment I, there were assessments of embryo production and oxidative status of cattle embryos derived by in vitro maturation and fertilization (IVM/IVF)that were cultured until the blastocyst stage of development using different ALA concentrations (5, 25 and 100 µM), fetal bovine serum (FBS) and amino acids (aa) as well as 20 % oxygen (O2) in the culture atmosphere. In Experiment II, embryos were cultured without FBS, at different ALA concentrations (2.5, 5 and 7.5 µM) and in the presence or absence of aa when there was a 7 % O2 atmosphere. Embryo development rates and blastocyst quality were evaluated. With 20 % O2 concentration, treatment with 100 µM ALA resulted in lesser hatching rates and development to the blastocyst stage (P < 0.01), while with supplementation with 5 µM ALA there were lesser (P = 0.04) glutathione concentrations and greater protein contents of embryos (P < 0.01). Culturing in the 7 % O2 atmosphere, combined with supplementation with 2.5 µM ALA with FBS and aa resulted in a greater blastocyst cell number (P = 0.03) and lesser hatching rates (P = 0.04). Taken together, results indicate supplementation with the greater ALA concentrations resulted in impairment of embryo development, regardless of the O2 concentration imposed during the culture period, while the relatively lesser supplementation-concentrations with ALA led to improvements in embryo quality.

Prepartum fatty acid supplementation in sheep. III. Effect of eicosapentaenoic acid and docosahexaenoic acid during finishing on performance, hypothalamus gene expression, and muscle fatty acids composition in lambs.

The objectives of this study were to evaluate the effect of feeding an enriched diet with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to finishing lambs born from ewes supplemented either with or without EPA and DHA during late gestation on productive performance, muscle fatty acid (FA), and hypothalamus mRNA concentration of metabolic genes and hormone receptors. Lambs born from dams fed during the last 50 d of gestation either with a control diet containing 0.39% Ca salts of palmitic fatty acid distillate (C) or Ca salts enriched with EPA and DHA (PFA) were used. After weaning lambs (n = 70) were blocked by weight (BW) and used in a 2 × 2 factorial into 2 finishing diets containing 1.5% of C or PFA. The 2 factors were the ewe diet and the finishing diet. Lambs (37.9 ± 0.4 kg) were weighed and blood sampled for glucose and NEFA measurements at days 1, 14, 28, and 42. Dry matter intake (DMI) was measured daily. At day 43, 14 females and 14 males were slaughtered, and hot carcass weight, body wall thickness, rib eye area, and FA composition of Longissumus thoracis muscle were evaluated. Female hypothalamuses were obtained and mRNA concentration of hormone receptors, neuropeptides, and their receptors was measured. Lambs born from PFA dams were heavier (P < 0.01). There was a time × finishing diet interaction for BW (P = 0.03), and lambs fed C had a greater BW. Lambs fed C had an increase in DMI (P < 0.01). There were no significant differences in plasma glucose and NEFA concentration (P > 0.1). Lambs born from PFA dams had a greater concentration of C22:0 (P < 0.03). Lambs fed C had higher concentrations of C18:1c15 (P < 0.01), C17:0 (P < 0.09), C18:0 (P < 0.09), and n6/n3 (P < 0.01). Lambs fed PFA had greater concentration (P < 0.05) of C16:1, C22:1, C20:5, C22:5, C22:6, total n3 FA, and total EPA and DHA. There was a significant dam × finishing diet interaction (P ≤ 0.08) on mRNA concentration for MCR3, CCK-R, Cort-R, and CART. Lambs, which had the same treatment as their dams, showed lower overall mRNA concentration than those with different treatments between them and their dams. Lambs born from PFA ewes had lower concentration of MCR4 mRNA (P = 0.09) than C. Agouti-related peptides mRNA concentration was lower in lambs fed PFA (P = 0.06) than C. In conclusion, changes on lamb performance, muscle fatty acid composition, and metabolic neuropeptides depend not only on the lamb diet, but also on the dam diet during late gestation.