Thirty-six 7-month-old gilts were used to study the effects of different levels of a-tocopherol (13, 48, 136 mg/kg food) and different source of fat (50 g/kg sunflower oil or animal fat) in gestation and lactation diets on α-tocopherol concentration in serum, colostrum and milk and on cell-mediated and humoral immune response of lactating sows.
Blood samples were taken from six sows per treatment after farrowing and at weaning (28 days of lactation) and were analysed for α-tocopherol concentration, total number of leucocytes and T- and B-lymphocyte counts. In blood lymphocyte stimulation with concanavaline, lysozyme activity and immunoglobulin concentration were also measured. In milk samples α-tocopherol and immunoglobulin concentration were determined at farrowing and at weaning. It was concluded that a high α-tocopherol level in the sow's diet including either sunflower oil or animal fat increased as expected the serum α-tocopherol concentration (P < 0·05) just after farrowing and at weaning. In colostrum the combination of high α-tocopherol with animal fat gave the highest (P < 0·05) α-tocopherol concentration. At weaning α-tocopherol in milk fat was highest in both fat groups with extra high α-tocopherol in the diet. The cell-mediated immunity of sows as tested were not systematically affected by α-tocopherol supplementation or fat addition to diet. However, the humoral immune system may be affected by the combinations of α-tocopherol and fat given.