Supplementation of grape pomace on broilers fed a high non-starch polysaccharide diet and its effects on growth performance, gut function, intestinal microbiota, and meat quality.

Grape pomace, a byproduct of the wine and juice industry, is rich in bioactive compounds that have been shown to improve intestinal health. Yet, its disposal is costly and contributes to landfill waste and greenhouse gas emissions. With the poultry industry seeking alternatives to antibiotic growth promoters (AGPs) due to rising antibiotic resistance, grape pomace offers a natural, healthier substitute and a valuable ingredient for human food production.

This in vivo feeding trial explored intestinal health parameters using grape pomace and fermented grape pomace as AGP alternatives in broiler feed. A total of 150 Cornish cross broilers were divided into six groups: i) standard diet wheat-corn-soybean meal, ii) 33% rice bran or non-starch polysaccharide (NSP) known to induce chronic low-grade gut inflammation, iii) NSP + zinc bacitracin (AGP), iv) NSP + 0.5% GP (GP), v) NSP + 0.5% Lactobacillus casei fermented GP, and vi) NSP + 0.5% Saccharomyces cerevisiae EC1118 fermented GP. On day 42, 21 birds from each group were euthanized, and blood, duodenum, cecum, and right breast muscle were collected.

Results showed that the NSP-fed group had lower body weight and feed intake, but all treatments mitigated this growth reduction. Breast muscle weights did not differ significantly between STD and both FGP groups, while other treatments resulted in lower weights. Cecal bacterial population changes were similar between the AGP and GP groups. GP inclusion significantly increased (P < 0.05) gut-barrier-integrity-related proteins (OCLN, ZO-2, Claudin-3, Claudin-4). Histological analysis showed variations in villus surface area, muscularis thickness, and crypt depth across different groups.

These findings further demonstrate the nutraceutical benefits of grape pomace and suggest that incorporating 0.5% grape pomace could replace AGPs in broiler production. However, fermenting grape pomace did not provide significant additional benefits. Further studies are needed to investigate the benefits of grape pomace in healthy and compromised intestinal health.