| A total of 1200 juvenile Jian carp (Cyprinus carpio var. Jian) (9.67±0.03g) were fed six semi-purified diets containing 5.3 (unsupplemented control),8.7,11.8,14.9,18.7 and 20.1 g kg-1 diet for 60 days to investigate the effects of valine on digestive ability, immune function and antioxidative ability. After 60-day feeding trial, thirty fish with similar weight was remendaly slected from each treatment to conduct a challenge trial with Aeromonas hydrophila for 17 days.Specific growth rate, feed efficiency, body protein, lipid content of fish carcasses were significantly improved by dietary valine levels (P<0.05). Patterns of differences in glutamate-oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities in hepatopancreas, GPT activity in muscle, hepatopancreas weight, intestine length, relative gut length, intestine weight, trypsin, amylase, lipase and chymotrypsin activities in intestine and hepatopancreas, intestinal folds height, alkaline phosphatase, gamma-glutamyl transpeptidase and creatine kinase activities in three intestinal segments, Na+, K+-ATPase in mid intestine and distal intestine were similar with that in SGR, whereas the trend of hepatosomatic index, intestosomatic index, GOT activity in muscle and plasma ammonia content were opposite. Intestinal Aeromonas and Escherichia coli decreased with increasing dietary valine, whereas the trends of Lactobacillus and Bacillus were opposite. The positive correlation existed between SGR and WG, FE, FI and PRV (r1=+0.988, P<0.01; r2=+0.999, P<0.01; r3=+0.992, P<0.01; r4=+0.998, P<0.01). The positive correlation existed between FE and FI, PRV (r1=+0.999, P<0.01; r1=+0.998, P<0.01). The positive correlation existed between FE and gut length, intestine weight, trypsin activity in hepatopancreas, Na, K+-ATP activity in PI and DI, gamma-glutamyl transpeptidase and creatine kinase activities in DI, PI, and DI (r1=+0.995, P<0.01; r2=+0.934, P<0.01; r3=+0.932,P<0.01; r4=+0.825, P<0.05; r5=+0.900, P<0.05; r6=+0.961, P<0.01; r7=+0.976, P<0.01; r8=+0.943,P<0.01; r9=+0.849, P<0.05; r9=+0.832, P<0.05). The positive correlation existed between FI and gut length, intestine weight, trypsin activity in hepatopancreas, Na+, K+-ATP activity in DI, gamma-glutamyl transpeptidase and creatine kinase activities in DI, PI, and D1 (ri=+0.960, P<0.01; r2=+0.954,P<0.01; r3=+0.960, P<0.01; r4=+0.915,P<0.01; r5=+0.922, P<0.05; r6=+0.936, P<0.01; r7=+0.845,P<0.05; r8=+0.930,P<0.01; r9=+0.875,P<0.05; r9=+0.856, P<0.05). Valine great significantly (P<0.01) or significantly (P<0.05) affected vaccinated survival rate, head kidney weight, hind kidney weight, spleen weight, red and white blood cell count, tartrate-resistant acid phosphatase, lysozyme, phago-rate of leukocytes, serum total iron binding capacity, addiment C3 and C4. Positive correlation existed between vaccinated survival rate and white blood cell count, phago-rate of leukocytes and white blood cell count (r1=+0.854, P<0.05; r2=+0.831, P<0.05; r3=+0.958, P<0.01). Positive correlation existed between IgM and addiment C3, tartrate-resistant acid phosphatase (r1=+0.970, P<0.01; r2=+0.882, P<0.05; r3=+0.922, P<0.01). The trend of malondialdehyde (MDA) in serum, muscle, hepatopancreas and intestine were opposite with SGR. The trend of protein carbonyl (PC) in serum, hepatopancreas and intestine were opposite with SGR.Patterns of differences glutathione (GSH) content, glutathione-S-transferase (GST) superoxide dismutase (SOD), anti-superoxide anion (ASA), anti-hydroxy radical (AHR) and glutathione reducase (GR) in serum were similar with that in SGR. Patterns of differences glutathione (GSH) content, glutathione-S-transferase (GST) catalase (CAT), superoxide dismutase (SOD), anti-superoxide anion (ASA), anti-hydroxy radical (AHR) and glutathione reducase (GR) in muscle were similar with that in SGR. Patterns of differences glutathione (GSH) content, glutathione-S-transferase (GST) catalase (CAT), superoxide dismutase (SOD), anti-superoxide anion (ASA), glutathione peroxidase (GPX), anti-hydroxy radical (AHR) and glutathione reducase (GR) in hepatopancreas and intestine were similar with that in SGR.In conclusion, the present results indicated that dietary valine improved growth, increased body protein and lipid composition, enhanced hepatopancreatic and intestinal enzyme activities and influence the balance of intestinal microflora of juvenile Jian carp. Valine promoted phagocytosis ability of leukocytes and body sterilization ability to improved the non-specific immunity ability and improved specific immunity ability by enhancing the production of specific antibody. Valine promoted fish antioxidant capacity by removing superoxide anion and lipid peroxidative product. The dietary valine requirement for Jian carp (9.67-76.40 g) estimated by the quadratic regression analysis based on SGR was 13.7 g kg-1 diet (4.0 g100g-1CP). |
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