| The effects of different dietary ω3 to ω6 polyunsatUrated fatty acid (PUFA) ratio were studied for 70 days on the immune function of juvenile jian carps. 600 juvenile jian carps with initial body weight 11.8g?. Ig were randomly allocated to 5 exprimental groups, feeding diets with different ratio of ω3 to ω6 PUFA, 0.108, 0.316, 0.481, 0.704 and 1.000 respectively (all diets containing ω3PUFA + ω6PUFA 5.7%).The results showed that there were significant differences in head kidney weight (P<0. 05) , head kidney weight:body weight, serum lysozyme activity, serum antibody level at 10d, 17d and 24d after vaccination agaist Aeromonas hydrophilawere significantly influenced by dietary ratio of ω3 to ω6 PUFA (P<0. 01) , but were not significant differences in survival rate, feed intake, weight gain and feed conversion efficiency, post kidney weight, post kidney weight:body weight, spleen weight, spleen weight:body weight, hepatopancreas weight,hepatopancreas weight:body weight, blood hematocyte and leukocyte counts among exprimental groups (P>0. 05) .There was significant quadraticly relationship between serum lysozyme activity or serum antibody level at 17d after vaccination and the ratio of dietary to ω3 to ω6 PUFA (P<0.05) .There were significant correlations between any two indces in serum lysozyme activity, serum antibody level at lOd, 17d and 24d after vaccination (P<0. 05) . There were significant partial correlations between head kidney weight:body weight and serum lysozyme activity or serum antibody level at 17d after vaccination (P<0. 05) when spleen weight:body weight was controlled.In summary, the ability of jian carps (12-46g) to resist diseases was effected by the ratio of dietary ω3 to ω6 PUFA (with total amount of ω3PUFA and ω6PUFA being 5.7%) through affecting head kidney growth, non-specific48as well as specific immune function. When dietary ratio of ω3 to ω6 PUFA (with total amount of ω3PUFA and ω6PUFA being 5.7%) was 0.56, jian carps(12-46g) got optimal immune function. |
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