Dietary supplementation with chia polyphenols alleviates oxidative stress and improves egg nutritional quality in Japanese quails under heat stress

Abstract

Heat stress in poultry is a major concern, especially in tropical and subtropical regions with hot summers and scarce cooling infrastructure. Dietary supplementation with antioxidants, such as polyphenols, has risen as a strategy to mitigate the physiological consequences of heat stress. A by-product of the extraction of oil from chia seeds, which is discarded if not used, could be possible source of polyphenols. The aim of the present study was to evaluate the effects of dietary supplementation with polyphenols from defatted chia seed cake on the general welfare, and oxidative status of Japanese quail exposed to heat stress. Furthermore, production performance, egg quality and yolk fatty acid composition were also assessed. A total of 36 females were randomly assigned to 1 of 3 different diets: BASAL (control), LDCP (low dose of chia polyphenols), or HDCP (high dose of chia polyphenols). Half the animals in each diet group were exposed to 34 °C for 9 h a day (Heat Stress; HS), while the other half remained at the standard 24 ºC (No Heat Stress; NHS). After 23 days of experimental conditions, no significant differences were observed in body weight gain between groups. However, animals under HS showed higher body temperatures (~1 °C) and time spent panting, but lower egg laying rate. Moreover, HS modulated the activity of catalase (CAT) and glutathione peroxidase (GPx) enzymes, increasing lipid peroxidation (LPO) in serum and liver; and saturated fatty acids in liver and egg yolk. Supplementation with chia polyphenols helped to mitigate the HS effects, especially on glutathione peroxidase activity, greatly decreasing lipid peroxidation. In addition, supplementation with HDCP showed the highest proportion of polyunsaturated fatty acids in liver and egg yolk, exceeding NHS birds. In conclusion, the use of defatted chia seed cake seems to be a promising sustainable strategy to mitigate heat stress effects on female Japanese quail. This is due to its capacity to help decrease oxidative stress in animals, and improve the nutritional quality of egg (yolks with higher polyunsaturated fatty acids), while decreasing the amount of waste generated by the food industry.