Modulation of Negative Effects of Physiological Stress on Frozen-Thawed Semen with Nutrition of Organic Selenium in Ross 308 Rooster.

Current experiment was carried out in factorial 2×2 arrangement to study the effects of stress (with or without dexamethasone administration) and addition of dietary selenium (with or without selenium supplementation in the diet) in male broiler breeder on the quality of frozen-thawed sperm under oxidative stress induced by dexamethasone. A total of 24 broiler breeder roosters with the age of 28 weeks were used based on a completely randomized design with four therapeutic approaches (factorial 2×2) and six birds in each approach. The experimental treatments were: 1) basal diet without selenium supplementation and injection of saline (CON), 2) basal diet with dexamethasone injection (4 mg/kg BW, three times every other day for one week), (DEX), 3) without dexamethasone injection and supplementation with 0.3 mg/kg selenium (Sel-Plex), and 4) dexamethasone injection and basal diet supplemented with 0.3 mg/kg of diet selenium (Sel-Plex+Dex). Sperm samples were collected from roosters. Motility, progressive motility, plasma membrane integrity, viability, malondialdehyde concentration and antioxidant parameters were evaluated in fresh and frozen-thawed semen. In spite of non-significant interaction effects, factorial analysis indicated the significant effect of every factor on different experimental parameters in fresh and frozen-thawed semen (P<0.05); The results revealed that total and progressive motility, plasma membrane integrity and viability were lower in DEX group when compared with other treatments (P<0.05). On the other hand, malondialdehyde concentration was higher in DEX group in comparison with Con, Sel-Plex and Sel-Plex+DEX groups (P<0.05). Moreover, total antioxidant capacity, level of glutathione peroxidase and superoxide dismutase were lower in DEX group as compared with other treatments (P<0.05). Our findings indicated that administration of selenium in dexamethasone-receiving roosters (Sel-Plex+DEX) improved the parameters of fresh and frozen-thawed sperm; but the best results were observed in Sel-Plex treatment. Therefore, selenium supplementation in the diet of roosters without dexamethasone injection improved total motility, progressive motility, membrane integrity, viability, malondialdehyde, total antioxidant capacity, glutathione peroxidase and superoxide dismutase pre- and post-freezing. It can be concluded, selenium in organic forms in stressed and non-stressed rooster's diet might improve all motility and antioxidant parameters in fresh and frozen-thawed sperm.

Role of the ventromedial hypothalamic orexin-1 receptors in regulation of gastric Acid secretion in conscious rats.

Orexins play an important role on the central nervous system to modulate gastric acid secretion. The orexin receptors are distributed within the hypothalamus, and expression of orexin-1 receptors (OX1R) is greatest in the anterior hypothalamus and ventromedial nucleus. Therefore, we hypothesised that ventromedial hypothalamic OX1R may be involved in the control of gastric acid secretion. To address this question, we examined the effects of orexin-A and a selective OX1R antagonist, SB-3345867, on gastric acid secretion in pyloric-ligated conscious rats. Intraventromedial injection of orexin-A (0.5-2 microg/microl) stimulated gastric acid secretion in a dose-dependent manner. This stimulatory effect of orexin-A persisted over 3 h. In some experiments, SB-3345867 (10 mg/kg i.p.) was administered 30 min before orexin-A or saline injections. We found that i.p. injection of SB-334867 suppressed stimulated gastric acid secretion induced by orexin-A (2 microg/microl). Atropine (5 mg/kg) also inhibited the stimulatory effect of central injection of orexin-A on acid secretion. In conclusion, the present study suggests that endogenous orexin-A acts on the ventromedial hypothalamus to stimulates acid secretion. This stimulatory effect is probably mediated through OX1R.