The Effects Of Vitamin C On Growth, Proximate Compositions, Tissue Vitamin C Concentrations And Immunity Of Field Rice Eels

Nine hundred field rice eels we chosed in this test are all physical health, specifications similar (average weight 35±0.53g), using single-factor design to study that adding different doses of vitamin C on growth performance, nutrients, vitamin C accumulation, immune function, antioxidant capacity and the attack rate of drug protection. Trial eel were randomly divided into six treatment:groupⅠwas the control group that the basal diet was without vitamin C;the remaining groupⅡ-Ⅵas test group, respectively, in the basal diet supplemented with vitamin C50,100,200,400 and 800mg/kg. Each treatment three replicates of 50. During the trial,quality of water, recording food intake, and removing the bait. the temperature of water is 23-33C°. The results showed that:1.Adding the appropriate dose of vitamin C can improve the production performance of eel, in which 200mg/kg (groupⅡ) the best. GroupⅡ-Ⅳweight gain, protein utilization were significantly higher than groupⅠcontrol group (P<0.05), groupⅡ,ⅣFCR was significantly lower than groupⅠ(P<0.05), the other groups were not significant (P>0.05). GroupⅡ-Ⅵweight gain rate had increased by 16.89%, 21.26%,37.72%,9.65% and 5.30%; protein utilization increased by 15.46%,16.11%, 43.18,7.14% and 4.86%, feed conversion ratio decreased by 16.85%,14.04%,32.58%, 9.55% and 5.06%. However, different levels of dietary vitamin C on survival rate of eel in each group had no significant effect (P>0.05).2.Different dietary levels of vitamin C on the content of conventional ingredients of crude ash, crude protein and crude fat of whole eel fish had no significant effect (P>0.05). Feed vitamin C can reduce the eel serum cholesterol and glucose levels. With dietary vitamin C levels increased, the serum cholesterol and glucose content decreased. GroupⅤ,Ⅵcholesterol content was significantly lower than groupⅠ(P＜0.05), respectively decreased 45.05%,32.66%. GroupⅢ-Ⅵglucose were significantly lower than groupⅠ(P＜0.05), respectively decreased 41.22%,32.11%, 27.10% and 42.82%.3.Adding vitamin C in dietary can increase the storage capacity of the body in the eel. With dietary vitamin C levels increased, the improvement of eel liver, blood, muscle vitamin C content increased. GroupⅢ-Ⅵserum and muscle of vitamin C content were significantly higher than groupⅠ(P<0.05); groupⅡ-Ⅵliver of vitamin C content was significantly higher than groupⅠ(P＜0.05); groupⅥserum, liver and muscle had the highest content of vitamin C, increased by 382.56%,82.07% and 368.49% than groupⅠ.Moreover, between serum,muscle content of vitamin C and vitamin C content of the feed there had a obvious linear correlation (serum R2=0.962, muscle R2=0.859).4.Adding vitamin C in dietary can improve on Serum complement and immunoglobulin M (IgM) levels, and enhance eel serum ACP and LSZ activities. with the addition of vitamin C increased, Serum C3,C4 and IgM levels were also increasd, when adding vitamin C content equal to or higher than 100mg/kg,the C3,IgM levels were significantly higher than groupⅠ(P<0.05), in which C3,IgM were 800mg/kg (groupⅥ) was the highest. GroupⅡ-ⅥC4 levels were significantly higher than groupⅠ(P＜0.05), in which C4 was 800mg/kg (groupⅥ) was the highest, increased 53.13% than groupⅠ.The test group of ACP and LSZ had a increasing trend compared to the groupⅠ(control group),groupⅢ-ⅥACP were significantly higher than groupⅠ(P＜0.05), in which 800mg/kg (groupⅥ) was the highest, increased 110.35% than groupⅠ. When the addition of vitamin C is equal to or higher than 200mg/kg LZM activities were significantly increased (P＜0.05). In addition, vitamin C can increase WBC,RBC counts and phagocytic activity of leukocytes. GroupⅣ(200mg/kg) WBC,RBC counts were significant than groupⅠ(P＜0.05), respectively increased 16.64%,47.85%. When the addition of vitamin C is equal to or higher than 100mg/kg,the phagocytic activity of leukocytes was significantly increased than groupⅠ(P＜0.05).5.Adding vitamin C in dietary can enhance the antioxidant properties of rice field eel. The test group of GSH-Px, CAT have a higher trend than groupⅠ(control group), SOD, MDA showed a downward trend. GroupⅢ,ⅣGSH-Px levels were significantly higher than groupⅠ(P<0.05), in the dose of 200mg/kg the activity was highest, and the ratio increased 23.34% than groupⅠ. GroupⅢ-ⅤCAT activity were significantly higher than groupⅠ(P<0.05), in the dose of 100mg/kg the activity was highest,and compared with groupⅠincreasing 72.50%. GroupⅣ,ⅥSOD activity were significantly lower than groupⅠ(P<0.05), compared with groupⅠ,groupⅣactivity decressed 47.60%. The MDA activity was lowest when the dosage of 800mg/kg (groupⅥ) and significantly different with groupⅠ(P<0.05), lower 27.16%.6.Adding vitamin C in dietary can increase the survival rate after posion attacking by Aeromonas hydrophila.GroupⅣ,Ⅵsurvival rates were significantly higher than groupⅠ(P<0.05), compared with groupⅠincreasing by 26.67%,18.19%.