Hazelnut skin supplementation during ewes’ peripartum period increases immune-related serum proteins in lambs without affecting their growth

This study explored the effects of hazelnut skin (HZN) supplementation in the diets of pregnantewes on colostrum and milk composition, as well as on the serum levels of immune-related pro-teins in lambs and their growth performance. HZN, an agro-industrial by-product rich in bio-active compounds such as polyphenols and unsaturated fatty acids (FA), was evaluated for itspotential as a sustainable feed ingredient. During the peripartum period, ewes were dividedinto two groups of eight, fed the same hay-based diet but differing for the concentrate compos-ition: a cereal mix including rumen-protected palm oil or HZN. The intake of major nutrients ormilk yield did not differ between groups. However, the HZN group exhibited an enhanced fattyacid profile in their colostrum and milk, including increased levels of unsaturated FA. The HZNlambs displayed higher levels of immune-related proteins (albumin and c-globulins) in theirblood. Nonetheless, no significant differences were observed in lamb growth performance. Thestudy highlights the potential of HZN to enhance the nutritional and immunological quality ofmilk and colostrum without negatively impacting growth performance. This suggests that HZNcould serve as a sustainable feed ingredient potentially improving neonatal immunity while con-tributing to waste valorisation in livestock production systems.