Effects of n-6:n-3 polyunsaturated fatty acid ratio on heterophil: lymphocyte ratio and T lymphocyte subsets in the peripheral blood of the Yangzhou gosling.

The objective of this study was to determine the effects of dietary n-6:n-3 polyunsaturated fatty acid (PUFA) ratios on heterophil:lymphocyte (H:L) ratios and T cell subsets in the peripheral blood of the growing Yangzhou goose. A total of 160 healthy Yangzhou geese (0.407 ± 0.023 kg), aged 21 d, were randomly divided into 4 groups consisting of diets with different n-6:n-3 PUFA ratios: 12:1, 9:1, 6:1, and 3:1. White blood cell counts and H:L ratios were measured at 42, 56, and 70 d of age; T lymphocyte subsets were also analyzed using monoclonal antibodies and flow cytometry simultaneously. The results showed that differences were found in white blood cells between groups (P < 0.05) but not within groups (P > 0.05), and white blood cells of 70-d-old geese were significantly higher than those of other ages within the same group. The H:L ratios of all groups decreased as age increased, and differences were found in 6:1 and 3:1 groups between ages (P < 0.05). As for the comparison of H:L ratio between treatments, 6:1 and 3:1 were lower than the other 2 groups at 42 or 70 d of age (P < 0.05), and 3:1 was lower than the other 3 groups at 56 d of age (P < 0.05). Moreover, H:L ratios had a tendency to decrease with the decrease of n-6:n-3 PUFA ratios. Furthermore, cluster of differentiation (CD) 3(+) and CD8(+) increased gradually, whereas CD4(+) and CD4(+):CD8(+) ratios first increased and then decreased as age increased. Differences were detected in T cell subsets among ages (P < 0.05). In addition, CD4(+) and CD4(+):CD8(+) ratios were affected remarkably by n-6:n-3 PUFA ratios but CD3(+) and CD8(+) were not, and 6:1 had much higher CD4(+) percentage and CD4(+):CD8(+) ratio compared with the other groups (P < 0.05). Taken together, diets containing low n-6:n-3 PUFA ratios could decrease H:L ratios in the peripheral blood. Additionally, CD4(+) percentage and CD4(+):CD8(+) ratio were much higher in the 6:1 group, which could be relevant for improving positive immune responses for Yangzhou goslings from 42 to 70 d of age.