Effect Of Vitamin A Levels On Immune Function Of Juvenile Jian Carp (Cyprinus Carpio Var.Jian)

Two expriments were conducted to study the effect of vitamin A levels on immune function of juvenile Jian Carp (Cyprinus carpio Var. Jian).In trial I , 240 juvenile Jian carps(inital weight 11. 37?. 55g) were ran domly allocated to 2 groups feeding the semi-purified diet containing vitamin A 0 or 3969 IU. kg-1 respectively for 70 days. In trial II, 600 juvenile Jian carps(inital weight 11.32 + 0.69g) were randomly allocated to 5 groups feeding semi-purified diet containing vitamin A 3969, 23816, 39693,99233 and 158773 IU. kg-1 respectively for 70 days.In trial I .vitamin A deficiency symptoms in juvenile Jian carps were anorexia, growth retardation, pale coloration, haemorrhage of skin and fins, exophthalmia, spinal deformities and haemorrhage of hapatopancreas. The another symptoms, such as survival rate, feed intake, weight gain, feed conversion efficiency, protein retention rate(PRR), hepatopancrease weight/body weight, vitamin A contend in hepatopancrease, head kidney weight, spleen weight, post kidney weight, blood hematocyte and leukocyte counts serum lysozyme activity and intestinal folds s hight decreasing significantly(p<0. 01), were determined in fish feeding vitamin A deficiency dietary, but were not significant differences in head kidney weight/body weight and serum antibody level at 10d, 17d and 24d after vaccination against Aeromonas hydrophila between two groups (P>0.05). These results indicate that anorexia, pale coloration, haemorrhage of skin and fins, exophthalmia, spinal deformities and haemorrhage of hapatopancreas hapatopancreas growth retardation were vitamin A deficiency symptoms of juvenile Jian carp(ll-65g). Juvenile Jian carps feeding vitamin A deficiency diet appeared the resisting diseases s ability decreasing, with spleen growth retardating, blood hematocyte, leukocyte counts and non-specific immune function decreasing.In trial II, indices, such as feed intake, weight gain, feed conversion efficiency, PRR, hepatopancrease weight, and intestinal folds s, post kidney weight, spleen weight/body weight, blood hematocyte counts, blood leukocyte counts, serum lysozyme activity and serum antibody level at 17d and 24d after vaccination against Aeromonas hydrophila were great significantly or significant differences among experimental groups (p<0. 01or 0.05), but another indices, such as head kidney weight, head kidney weight/body weight and serum antibody level at 10d after vaccination against Aeromonashydrophila were not (P>0. 05) . Fish feeding diet contai-ningvitamin A 39693 IU.kg-1 appeared feed intake, weight gain, feed conversion efficiency, PRR, intestinal folds s hight, post kidney weight, blood hematocyte and leukocyte counts, serum lysozyme activity and serum antibody level at 17d and 24d after vaccination against Aeromonas hydrophila increasing great significantly or significantly (P<0.01 or p<0. 05) , but these indices decreased great significantly or significantly while fish intaking diet containing vitamin A 158773IU. kg-1 (P<0.01 orp<0.05) .There was significant quadraticly relationship between serum lysozyme activity or serum antibody level at 17d after vaccination and vitamin A levels (RM). 4230, P<0. 015 R2=0. 5635, P<0. 01) . Significant correlations between serum lysozyme activity and 17d or 24d antibody level after vaccination existed (r=+0.6700, P<0. 01; r=+0.6340, P<0.01) .These results indicate that hight level vitamin A were able to increase growth and resisting diseases s ability of juvenile Jian carps by affecting head kidney growth, non-specific and specific immune function. But hypervi-taminosis A over 158773IU. kg-1 was toxicity to ll-65g juvenile Jian carps. When dietary vitamin A content was 39693 IU. kg-1, 46677or 49977 IU. kg-1, juvenile Jian carps appeared best growth performance, non-specific immune function or specific immune function respectively.In summary, vitamin A difficiency symptoms of juvenile Jian carp were anorexia, pale coloration, haemorrhage of skin and fins, exophthalmia, spinal deformities and haemorrhage of hapatopancreas.