Effects Of Dietary Vitamin A On Digestive And Immune Function Of Juvenile Jian Carp(Cyprinus Carpio Var.Jian)

The trial was conducted to study the the effects of vtamin A on digestive and immune function of juvenile Jian carp(cyprinus carpio Var.Jian). In trial, 1320 juvenile Jian carps with initial weight 6.24±0.35g were averagely allocated to 8 treatments with 3 replications, feeding diets with added vitamin A 0IU.kg^-1, 4000IU.kg^-1, 25000IU.kg^-1, 30000IU.kg^-1, 35000IU.kg^-1, 40000IU.kg^-1 , 50000IU.kg^-1 and 60000IU.kg^-1 respectively for 90 days.The results showed as follows: vitamin A has great effect on weight gain, feed intake, feed conversion efficiency, hepatopancreas weight, intestine weight, intestine length, height of intestinal folds. Besides, activity of protease, activity of lipase, activity of alkaline phosphatase, activity of Na⁺,K⁺-ATPase, phago-rate of leukocyte, vitamin A levels of serum, protein of intestine and hepatopancreas, serum albumin, survival rate and anti-AH antibody titers at 17d after vaccination against Aeromonas hydroPhilaand were significantly affected by vitamin A. The significant correlation existed between weight gain and retention ration of protein, activity of lipase, activity of Na⁺,K⁺-ATPase, activity of trypsin, activity of chymotrpsin (r1=+0. 9780, P < 0. 01; r2=+0.9634, P <0.01; r3=+0.9870, P < 0.01; r4=+0.8742, P < 0.05; r5=+0.9710, P < 0.01) . The significant correlation existed between feed conversion efficiency and intestine weight, activity of trypsin, activity of chymotrpsin, content of intestine protein, activity of alkaline phosphatase and activity of Na⁺,K⁺-ATPase (r1=-0.8650, P < 0.05; r2=-0.9450, P < 0.01; r3=-0.8470, P < 0.05; r4=-0.9650, P < 0.01; r5=-0.9880, P < 0.01; r6=-0.9530, P < 0.01) . There were significant correlation between phago-rate of leukocyte and serum complement C3, lectin, white cell counts (r1=+0.9580, P < 0.01; r2=+0.8700, P < 0.05; r3=+0.9940, P < 0.01) . The path-analysis results indicated that there were significant direct effect of feed intake, feed efficiency on weight gain (path coefficient +0.4270,+0.5130, decision coefficient d0.1=0.1823, d0.2=0.1263) , retention ration of protein, retention ration of fat on feed conversion efficiency(path coefficient +0.4630, +0.3790, decision...