This study evaluated the impact of a low metabolizable energy diet supplemented with a multienzyme blend on the growth performance, carcass traits and meat quality of chickens. From findings, the low metabolizable energy supplemented with the enzyme complex did not influence most of performance parameters and carcass traits of chickens; however, adding enzymes to a low-energy diet is an effective strategy to improve the meat quality criteria and small intestine characteristics.

Increased dietary inclusion levels of vitamin E and/or polyphenols improved the antioxidant status of broilers fed low-quality oil. Dietary supplementation with vitamin E and/or polyphenols improved meat quality by better colour, higher concentrations of n-6 polyunsaturated fatty acids, hypocholesterolemic fatty acids and a lower atherogenicity index. Polyphenols combined with vitamin E can be a valuable component of diets for broiler chickens when the problem of low-quality oil occurs.

Dietary supplementation with either 1.15, 1.30 or 1.45 times the Met requirements (as NRC recommendation) in breeder quails can alleviate the adverse effects of heat stress and improve the performance, reproduction, antioxidant status and immunity, as well as maternal antibody transmission. Supplementation of diet with 1.30 times the Met requirements could be used as a nutritional strategy in breeder quails for the alleviation of the adverse effects of heat stress.

Herbs and herbal feed additives are a valuable component in broiler chicken diets, affecting, e.g., health status, productivity and meat quality. In our study a herbal formula was applied in broiler chickens fed lower energy concentration diets. An interaction between experimental factors was not found, although a gainful effect on the productivity was noticed in broiler chickens fed diets with a herbal formula.