The beneficial properties of the flavanones hesperidin and naringin as feed additives in poultry have lately been under investigation. In broilers, both flavanones have been shown to exhibit antioxidant properties while their individual effects on fatty acid (FA) composition and the underlying molecular mechanisms of their activity have not been explored. Here, we studied their effects on broiler meats' FA profiles and on the expression of genes related to lipid metabolism, antioxidant defense and anti-inflammatory function. The experimental design comprised six treatment groups of broilers, each supplemented from day 11 until slaughter at 42 days with hesperidin, naringin or vitamin E, as follows: the E1 group received 0.75 g of hesperidin per kg of feed, E2 received 1.5 g hesperidin/kg feed, N1 received 0.75 g naringin/kg feed, N2 received 1.5 g naringin/kg feed, vitamin E (VE) received 0.2 g a-tocopheryl acetate/kg feed, and the control group was not provided with a supplemented feed. The VE treatment group served as a positive control for antioxidant activity. An analysis of the FA profiles of the abdominal adipose tissue (fat pad), major pectoralis (breast) and biceps femoris (thigh) muscles showed that both hesperidin and naringin had significant effects on saturated FA (SFA), polyunsaturated FA (PUFA) and omega n-6 content. Both compounds reduced SFA and increased PUFA and n-6 content, as well as reducing the atherogenicity and thrombogenicity indices in the breast muscle and fat pad. The effects on the thigh muscle were limited. An analysis of gene expression in the liver revealed that naringin significantly increased peroxisome proliferator-activated receptor alpha (PPARα), Acyl-CoA oxidase 1 (ACOX1) and glutathione disulfide reductase (GSR) expression. In the breast muscle, both hesperidin and naringin increased fatty acid synthase (FASN) expression and hesperidin increased the expression of adiponectin. In brief, both hesperidin and naringin supplementation beneficially affected FA profiles in the breast meat and fat pad of broiler chicken. These effects could be attributed to an increase in FA β-oxidation since the increased expression of related genes (PPARα and ACOX1) was observed in the liver. Furthermore, the antioxidant activity of hesperidin and naringin previously observed in the meat of broilers could be attributed, at least partly, to the regulation of antioxidant defense genes, as evidenced by the increased GSR expression in response to naringin supplementation.
Keywords: FA beta-oxidation; antioxidants; citrus flavanones; fatty acids; glutathione; hepatic gene expression; lipid metabolism.