Efficacy of feeding grape by-products on performance, nutrient digestibility, gut morphology, gut microbial community, oxidative stress and immune response in fast-growing broilers

Abstract

By-products from winemaking, such as grape pomace, grape seeds, grape skins, or extracts made from them, represent a cost-effective and sustainable bioresource. These by-products are a source of polyphenolic compounds, plant fibers and—in the case of seeds—essential fatty acids with various health-promoting effects for livestock. Numerous studies involving fast-growing broiler breeds—which often suffer from metabolic inflammation and oxidative stress due to disproportionate breast muscle growth leading to issues like cardiorespiratory insufficiency—indicate that supplementing feed with grape by-products improves performance, particularly weight gain and feed efficiency. This literature review demonstrates that the performance-enhancing effects of grape by-products in fast-growing broiler breeds can be attributed to various mechanisms such as improved nutrient digestibility, a positive influence on intestinal morphology and integrity, the favorable modulation of the microbial community in the gut, the inhibition of oxidative stress or the enhancement of the antioxidant defense system, and the stimulation of the immune response.