Feeding extruded linseed to periparturient ewes does not impair cell-mediated and non-specific immune response.

Several studies have demonstrated that dietary polyunsaturated fatty acids (PUFA) may modulate immune responses. Feeding linseed, which is high in linolenic acid (18:3n-3), is a viable option for improving the n-3 fatty acid concentration in livestock diets. The aim of this study was to investigate the effects of a dietary supplementation of extruded linseed (EL) on non-specific and cell-mediated immunity in periparturient ewes. Sixty Sardinian healthy ewes were synchronized by intravaginal implantation of cronolone-impregnated sponges. Thirty days before expected parturition, ewes were divided into 3 groups of twenty animals each and fed isoenergetic and isonitrogenous diets with different levels of EL: control diet (no EL added) and two EL supplementation levels (10 and 20% as fed). Individual blood samples were taken by jugular venipuncture 30 and 15 days before and 15, 30, 45 and 60 days after parturition. Blood sera were analyzed to measure lysozyme, complement and bactericidal activities. Evaluation of cell-mediated immunity was carried out 10 days after parturition by measuring the increase in double skin fold thickness after the in-tradermal injection of 250 μg of phytohemagglutinin (PHA). Results of the pre-sent study suggest that type of diet (control vs. EL added) was not significantly associated with modifications of lysozyme, complement and serum bactericidal activity. Furthermore, no differences between groups were found for the increase in double skinfold thickness in response to intradermal injection of PHA. We conclude that EL administration does not seem to affect non-specific and cell-mediated immune responses during peripartum period in the ewe.