RESUMO
This study investigated the hypothesis that methionine supplementation of Japanese quail (Coturnix coturnix japonica) hens can reduce the effects of oxidative stress and improve the performance of the offspring exposed to heat stress during growth. For that, the quail hens were fed with three diets related to the methionine supplementation: methionine-deficient diet (Md); diet supplemented with the recommended methionine level (Met1); and diet supplemented with methionine above the recommended level (Met2). Their chicks were identified, weighed, and housed according to the maternal diet group from 1 to 14 d of age. On 15 d of age, chicks were weighed and divided into two groups: thermoneutral ambient (constant temperature of 23 °C) and intermittent heat stress ambient (daily exposure to 34 °C for 6 h). Methionine-supplemented (Met1 and Met2) hens had higher egg production, better feed conversion ratio, higher hatchability of total and fertile eggs, and offspring with higher body weight. Supplemented (Met1 and Met2) hens showed greater expression of glutathione synthase (GSS) and methionine sulfoxide reductase A (MSRA) genes, greater total antioxidant capacity, and lower lipid peroxidation in the liver. The offspring of hens fed the Met2 diet had lower death rate (1 to 14 d), higher weight on 15 d of age, weight gain, and better feed conversion ratio from 1 to 14 d of age. Among chicks reared under heat stress, the progeny of methionine-supplemented hens had higher weight on 35 d, weight gain, expression of GSS, MSRA, and thermal shock protein 70 (HSP70) genes, and total antioxidant capacity in the liver, as well as lower heterophil/lymphocyte ratio. Positive correlations between expression of glutathione peroxidase 7 (GPX7) and MSRA genes in hens and offspring were observed. Our results show that maternal methionine supplementation contributes to offspring development and performance in early stages and that, under conditions of heat stress during growth, chicks from methionine-supplemented hens respond better to hot environmental conditions than chicks from nonsupplemented hens. Supplementation of quail hens diets with methionine promoted activation of different metabolic pathways in offspring subjected to stress conditions.
The deficiency of nutrients such as methionine in the diet of birds is affecting fertility rate, egg production, egg weight, and progeny weight. In addition, the maternal environment influences gene expression through epigenetic mechanisms, where the conditions experienced by the parental generation during embryonic development can produce effects on the progeny. This study investigates how methionine supplementation in the diet of quail hens can reduce the effects of oxidative stress and improve the performance of progeny subjected to heat stress during growth. For that, the quail hens were fed with diets containing three different levels of methionine; and their chicks were created (15 on 35 d of age) into thermoneutral and/or intermittent heat stress ambient. It was observed that methionine supplementation in the quail hens had a positive effect on mortality during the initial phase and greater weight gain in the progeny growth phase. In addition, genetic inheritance was observed through the positive correlation between the expression of genes (maternal and progeny) related to oxidative stress. The results show that methionine supplementation in the maternal diet contributes to the development and performance of the progeny when subjected to heat stress during the growth phase.