Hemp seed ( L.) cake as sustainable dietary additive in slow-growing broilers: effects on performance, meat quality, oxidative stability and gut health.

Hemp seed cake (HSC) ( L.) is a rich source of polyunsaturated fatty acids, high-quality proteins and essential amino acids. The aim of this study was to evaluate the effects of dietary inclusion of HSC on growth performance, meat quality traits, fatty acids profile and oxidative status, and intestinal morphology in slow-growing broilers. A total of 180 male slow-growing broilers were randomly assigned to one of three dietary treatments containing different levels of HSC: 0 (HSC0), 5 (HSC5) or 10% (HSC10). Birds were slaughtered at 49 days of age: breast and thigh muscles were analysed and duodenum mucosa histomorphological features were evaluated. Regardless the level of HSC inclusion, no differences among groups were found for performance and meat quality traits. The thigh and breast fatty acid profile were significantly improved in both HSC groups, with an increase of the long chain fatty acids of n-3 series and decrease of n-6/n-3 ratio. The HSC diets lowered the MDA concentration and lipid hydroperoxides in breast meat. Histomorphometrical analysis revealed a significant increase in villus height, surface area and villus/crypt ratio, with a decrease of crypt depth, suggesting that dietary supplementation with HSC may boost intestinal health status in poultry. In conclusion, dietary HSC did not affect performance, carcass traits and meat quality, while it positively influenced the lipid profile of meat, and improved the oxidative status and gut health, thus representing a valuable and sustainable alternative ingredient in broiler diet.