Effect of In Vitro Copper and Zinc Supplementation on Neutrophil Phagocytic Activity and Lymphocyte Proliferation Response of Transition Dairy Cows

Abstract

Three experiments were conducted to assess the effect of in vitro copper (Cu) and zinc (Zn) supplementation on neutrophil phagocytic activity (NPA) and lymphocyte proliferation response (LPR) of transition dairy cows. In the first experiment, six multiparous crossbred (Karan-Fries: Tharparkar × Holstein-Friesian) cows were selected; the neutrophils and lymphocytes were isolated from the blood samples of different peripartum days of each cow. To determine the effect of in vitro Cu and Zn supplementation on the NPA and LPR, 2.360 μM Cu and 9.175 μM Zn were added separately into the culture media of neutrophils and lymphocytes. It was found that the addition of Zn in the culture media increased the NPA and B lymphocyte LPR significantly (P < 0.05) as compared to non-supplemented neutrophils and lymphocytes. In the second experiment, another six multiparous crossbred cows were selected and fed with 20 ppm Cu/cow/day individually from 45 days pre-calving to 45 days post-calving. Their blood samples were collected during different peripartum days and 2.360 μM Cu was incorporated separately into the culture media of NPA and LPR to know whether there is need for extra Cu after Cu supplementation. Addition of Cu in the culture media of lymphocyte of Cu fed animals increased B lymphocytes LPR significantly (P < 0.05). On the day of calving, the B and T lymphocyte LPR increased significantly (P < 0.05) and phagocytic activity increased by 15.38 %. In the third experiment, six more multiparous crossbred cows were selected and fed with 80 ppm Zn/cow/day individually from 45 days pre-calving to 45 days post-calving. Their blood samples were collected during different peripartum days and 9.175 μM Zn was added separately into the culture media of NPA and LPR to know whether there is need for extra Zn after Zn supplementation. A significantly (P < 0.05) higher LPR (T and B) was found on 3 days before parturition with in vitro addition of Zn in the culture media and it remained higher up to 7 days post-partum. Peripartum days had (P < 0.05) significant effect on both in vitro NPA and LPR in all three experiments. It is concluded that extra Cu and Zn supplementation around peripartum period has beneficial effects on in vitro NPA and LPR.