engleski

Immune and oxidative response to linseed in the diet of periparturient Holstein cows

The aim of this research was to determine the influence of dietary replacement of n-6 with n- 3 polyunsaturated fatty acids on cellular immunity and oxidative stress in the transition period dairy cows. The experiment was conducted on 20 dairy Holstein cows from 3 ± 1 weeks before parturition until the 6th week of lactation. Both groups were fed an iso- energetic and iso-nitrogenous diet. Soybean meal from control (C) group was replaced with linseed in the experimental (LS) group. Cellular immunity and oxidative stress were measured on days −10, 1, 21 and 42 relative to parturition. During the entire experimental period, the proportion of CD45+ cells was lower ( P<0.05) in LS group compared with the C group. The phagocytosis ability and phagocytosis index of cows fed with n-3 fatty acids were significantly reduced ( P<0.05) compared with the group of cows fed with n-6 fatty acids. The most severe decrease in phagocytosis ability was on day −10 and 1 relative to parturition. The activity of superoxide dismutase ( P<0.05) and plasma glutathione peroxidase ( P<0.05) increased around calving, although activities were not influenced by dietary treatment. Increased malondialdehyde concentration ( P<0.05) was influenced by dietary n-3 fatty acids and the time relative to parturition. The immune suppression was most pronounced during periparturient period. In that matter we can conclude that not only dietary n-3 fatty acids but also oxidative stress, which reached peak at time of parturition, contributed to the reduced cellular immunity during the periparturient period.

dairy cows ; immune response ; oxidative stress ; linseed ; fatty acids

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