Hazelnut Skin in Ewes’ Diet: Effects on Colostrum Immunoglobulin G and Passive Transfer of Immunity to the Lambs

SIMPLE SUMMARY: A ewe’s diet in the last period of gestation can modify the immunoglobulin G composition of the colostrum and consequently the health status of lambs. This study aims to determine the role of hazelnut skin on the immunological colostrum quality and the passive immunity transfer in newborns. The results show that hazelnut skin supplementation in the diet positively affects the immunoglobulin G composition of the colostrum. The experimental trial underlines that the use of by-products in livestock feeding provides a paramount opportunity to create a circular economy system with health benefit on farmed animals. ABSTRACT: Passive immunity transfer has a pivotal role in newborn lambs, where the colostrum represents the primary source of immunoglobulins. This study hypothesized that the high content in polyphenolic compounds, mono- and poly-unsaturated fatty acids, and vitamin E of hazelnut skin affects blood and colostrum immunoglobulin G (IgG) concentration and related gamma-glutamyl-transferase (GGT) and lactate dehydrogenase (LDH) levels in sheep and their lambs. In the last 45 days of pregnancy, ewes were divided into a control (CTR) and a hazelnut skin supplemented group (HZN). Blood and colostrum were collected from ewes and lambs before the first suckling, at 24 and 48 h after birth, then IgG concentration, GGT and LDH activity levels were measured. IgG concentration in the colostrum and in lamb’s serum were significantly greater in HZN than CTR. No significant difference was detected for ewe’s blood. A significant positive correlation was found between IgG and GGT in lambs’ serum and colostrum, between IgG and LDH, as well as between GGT and LDH in lambs’ serum and colostrum. Our results suggest that hazelnut skin supplementation influences IgG colostrum concentration, with improved immune passive transfer to the suckling lambs. The transfer of maternal derived immune factors is confirmed by the GGT and LDH enzyme activity levels.