The Study On Effects Of Dietary Vitamin D₃ Supplementation Of Juvenile Mirror Carp(C. Carpio Songpu Mirror Carp)

This experiment was conducted to study the effects of different vitamin D₃ levels on growth, body composition, serum biochemical indexes and vitamin D₃ metabolites of juvenile mirror carp (C. carpio Songpu mirror carp.) to estimate the effect of different vitamin D₃ levels on juvenile mirror carp, which can provide a theory evidence of the vitamin D₃ level in the diet of juvenile mirror carp. 525 juvenile mirror carps, weighting an average of 2.4 g were randomly assigned to seven dietary treatments with three replicates and 25 carps with each pen. Seven levels of vitamin D₃(0,200,400,800,1600,3200 and 1×10⁵ IU/kg) of the dietary were fed to seven groups. The feeding trial lasted for 56 days, the water temperture was 24℃, and the dissolved oxygen was 7.46～8.61mg/L.The results were:1. The growth rate of 400IU/kg vitamin D₃ treatment group was significantly higher than 0IU/kg vitamin D₃ treatment group(P<0.05), but had no significantly different with the other groups(P>0.05). The survival rate, feed coefficient and special growth rate of every treatment groups had no significantly different(P>0.05).2. The moisture, crude protein, crude lipid contents of the body and concentration of phosphorus in the serum were not significantly affected by vitamin D₃(P>0.05). The crude ash, calcium and phosphorus contents of the body, concentration of calcium and activity of ALP in the serum were significantly affected by vitamin D₃(P<0.05), compared to the experimental group which without vitamin D₃. Calcium and phosphorus contents of the body, concentration of calcium and phosphorus and activity of ALP in the serum were increased and then decreased with increasing of dietary vitamin D₃ supplementation.3. The activity of ALT of 3200IU/kg vitamin D₃ treatment group was significantly higher than 0,200,400 and 1600IU/kg vitamin D₃ treatment groups in serum(P<0.05), but had no significantly different with 800 and 1×10⁵IU/kg vitamin D₃ treatment groups(P>0.05). The activity of AST of 0IU/kg vitamin D₃ treatment group was significantly higher than 400IU/kg vitamin D₃ treatment group in serum(P<0.05), but had no significantly different with the other groups(P>0.05). The content of DBIL and TBIL of 200IU/kg vitamin D₃ treatment group was significantly higher than 3200IU/kg vitamin D₃ treatment group in serum (P<0.05), but had no significantly different with the other treament groups(P>0.05). The content of CREA of 800 and 1600IU/kg vitamin D₃ treatment group was significantly higher than 200IU/kg vitamin D₃ treatment group in serum(P<0.05), but had no significantly different with the other treatment groups(P>0.05). In the other serum biochemical indexes,there were no significantly different with C3, C4, TP, ALB and URIC of vitamin D₃ treatment groups(P>0.05).4. The activity of ALP of 800IU/kg vitamin D₃ treatment group was significantly higher than 0 and 400IU/kg vitamin D₃ treatment group in the liver(P<0.05), but had no significantly different with 200, 3200 and 1×10⁵IU/kg vitamin D₃ treatment groups(P>0.05), 1600IU/kg vitamin D₃ treatment group was significantly higher than the other groups(P<0.05). The activity of SOD of 1600IU/kg vitamin D₃ treatment group was significantly higher than 400IU/kg vitamin D₃ treatment group in the liver(P<0.05), but had no significantly different with the other groups(P>0.05). The content of MDA of 3200IU/kg vitamin D₃ treatment group was significantly higher than 400IU/kg vitamin D₃ treatment group in the liver(P<0.05), but had no significantly different with the other groups(P>0.05). The activity of LYZ of 400IU/kg vitamin D₃ treatment group was significantly higher than 200, 1600 and 1×10⁵IU/kg vitamin D₃ treatment groups(P<0.05), but had no significantly different with 0,800 and 3200IU/kg vitamin D₃ treatment groups(P>0.05), the activity of LYZ of 1×10⁵IU/kg vitamin D₃ treatment group had no significantly different with 1600IU/kg vitamin D₃ treatment group in the liver(P>0.05), but was significantly lower than the other groups(P<0.05).5. The concentration of 2,5-OH-D₃ of 400IU/kg vitamin D₃ treatment group was significantly higher than 0, 200IU/kg vitamin D₃ treatment groups in the liver(P<0.05), but had no significantly different with the other groups(P>0.05). The concentration of 1,25-(OH)2-D₃ of 400IU/kg vitamin D₃ treatment group was significantly higher than 0IU/kg vitamin D₃ treatment group in the liver(P<0.05), but had no significantly different with the other groups(P>0.05).6. Compared with normal liver structure of juvenile mirror carp, the liver structure of 0IU/kg vitamin D₃ treatment group was compact, liver cell and lymphocyte was less; the liver structure of 1×10⁵IU/kg vitamin D₃ treatment group was compacter than 0IU/kg vitamin D₃ treatment group, liver cell and lymphocyte was less too,but blood corpuscle was more.Conclusion1. The growth rate of 400IU/kg vitamin D₃ in diet of juvenile mirror carp showed the best growth, and lack of or excessive adding vitamin D₃ had no significantly effect on growth performance.2. Compare with lack of or excessive added vitamin D₃, the calcium and phosphorus contents of the body, concentration of phosphorus, activity of ALP in serum and vitamin D metabolites in liver were significantly increased with added regular vitamin D₃. The immune ability of juvenile mirror carp was improved in a certein extent.3. The indicators of juvenile mirror carp had no significantly different with lack of or excessive vitamin D₃, but had some degree of damage on the liver, without influence to the kidney, which could show a high tolerance of juvenile mirror carp with lack of or excessive vitamin D₃.4. The suitable requirement of juvenile mirror carp is about 708.3⁷69.8IU/kg diet, based on establishing indexes line model to calculate the calcium, phosphorus contents of the body and ALP activity of mirror carp in the serum.5. The suitable requirement of juvenile mirror carp is about 317.0⁴03.9IU/kg diet, based on establishing indexes line model to growth rate and concentration of vitamin D metabolites in the liver.