ABSTRACT. This study aimed to determine whether feeding betaine to cows elevates their production performance during summer heat stress. Thirty-two lactating Holstein cows were randomly divided into 4 groups: the control group, which received a total mixed ration (TMR), and 3 experimental groups that received TMR blended with 10 g/day (group I), 15 g/day (group II), and 20 g/day (group III) betaine for 8 weeks. Milk and blood were sampled throughout the experimental period. The average maximum and minimum air temperatures were 28.3 and 24.1°C, respectively. The average temperature-humidity index was 78.6 units. The results showed that feeding betaine to cows increased feed intake, milk yield, milk lactose, milk protein, plasma cortisol, glutathione peroxidase, superoxide dismutase, and malondialdehyde levels (P < 0.05); however, it caused HSP70 levels to decrease (P < 0.05). The milk performance of group II was significantly affected. These results indicate that supplementing betaine to the diet of dairy cows increases their milk performance and improves their antioxidant capacity; these processes help relieve the cow from heat stress. In conclusion, supplementing dairy cows with 15 g/day betaine generated the most positive influence on performance and productivity, and hence caused the greatest reduction in heat stress.

This study investigated the effects of short-term food restriction or supplementation on folliculogenesis and plasma and intrafollicular metabolite and hormone concentrations. Ewes were randomly assigned to three groups: the control group received a maintenance diet (M) while the supplemented group and restricted group received 1.5!M and 0.5!M respectively on days 6-12 of their estrous cycle. Estrus was synchronized by intravaginal progestogen sponges for 12 days. On days 7-12, blood samples were taken. After slaughter, the ovarian follicles were classified and the follicular fluid was collected. Compared with restriction, supplementation shortened the estrous cycle length, decreased the number of follicles 2.5-3.5 mm and follicular fluid estradiol (E 2 ) concentration, increased the number of follicles O3.5 mm and plasma glucose, insulin and glucagon concentrations, and augmented the volume of follicles O2.5 mm. Restricted ewes had higher intrafollicular insulin concentration, but it was similar to that of supplemented ewes. Compared with follicles %2.5 mm, the intrafollicular glucose and E 2 concentrations were increased and the testosterone, insulin, and glucagon concentrations and lactate dehydrogenase (LDH) activity were decreased in follicles O2.5 mm. Only in restricted ewes were intrafollicular LDH and testosterone concentrations in follicles %2.5 mm not different from those in follicles %2.5 mm. In conclusion, the mechanism by which short-term dietary restriction inhibits folliculogenesis may involve responses to intrafollicular increased E 2 , testosterone, and LDH levels in late-stage follicles. This may not be due to the variation of intrafollicular insulin level but rather due to decreased circulating levels of glucose, insulin, and glucagon.

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BackgroundThis study was conducted to clarify the effect of the inhibiting action of inhibin on porcine granulosa cell proliferation and function, and to investigate the underlying intracellular regulatory molecular mechanisms.MethodsPorcine granulosa cells were cultured in vitro, and were treated with an anti-inhibin alpha subunit antibody, with or without co-treatment of follicle-stimulating hormone (FSH) in the culture medium.ResultsTreatment with anti-inhibin alpha subunit antibody led to a significant increase in estradiol (E2) secretion and cell proliferation. Anti-inhibin alpha subunit antibody worked synergistically with FSH at low concentrations (25 microg/mL) to stimulate E2 secretion, but attenuated FSH action at high concentrations (50 microg/mL). Immunoneutralization of inhibin bioactivity increased FOXL2, Smad3, and PKA phosphorylation, and mRNA expression of the transcription factors CEBP and c-FOS. The expression of genes encoding gonadotropin receptors, FSHR and LHR, and of those involved in steroidogenesis, as well as IGFs and IGFBPs, the cell cycle progression factors cyclinD1 and cyclinD2, and the anti-apoptosis and anti-atresia factors Bcl2, TIMP, and ADAMTS were upregulated following anti-inhibin alpha-subunit treatment. Treatment with anti-inhibin alpha subunit down regulated expression of the pro-apoptotic gene encoding caspase3. Although expression of the pro-angiogenesis genes FN1, FGF2, and VEGF was upregulated, expression of the angiogenesis-inhibiting factor THBS1 was downregulated following anti-inhibin alpha subunit treatment.ConclusionsThese results suggest that immunoneutralization of inhibin bioactivity, through augmentation of the activin and gonadotropin receptor signaling pathways and regulation of gene expression, permits the development of healthy and viable granulosa cells. These molecular mechanisms help to explain the enhanced ovarian follicular development observed following inhibin immunization in animal models.