| I. This experiment tested the biochemical composition in muscle, digestive enzymes in intestine and hepatopancreas, immunoenzyme in serum and hepatopancreas of two different sizes of wild Procambarus Clarkii (27.0±2.0, 12.0±2.0g). The results showed that the energy of the muscle and the other parts of the large-scale is higher than that of the smaller ones and so are the quantities of Asp, Glu and Arg in the muscle of the large-scale.The activities of the protease and the amylase in the hepatopancreas of both sizes first rise and then drop as the pH goes up progressively, from which the optimal pHs are 7.2 for protease, amylase in the intestinal tracts of both sizes, and 7.6 for protease in the hepatopancreas of the small-scale. The quantity of the hemocyanin in the serum of the bigger is higher than that of the smalll-scale, while the activities of SOD and lysozyme in the serum and hepatopancreas is lower than that of the smalll-scale.II. Based on the biochemical components of wild Procambrus clarkii’s muscle, 5 kinds of semirefined experimental feed, which were of different protein level yet same energy ratio, were compounded. The protein levels were 27%, 30%, 33%, 36% and 39% respectively, by which the Procambrus clarkii(8.41±1.12g) were fed for 60 days. Afterwards, the effects on the growth, biochemical components, digestive enzyme, immunoenzyme, lysozyme activity and the mRNA expression of HSP70 by the protein level were measured.1. A significantly lower survival rates were observed in the protein levels of 27%, 33% and 39%, than the levels of 30% and 36%. The relative weight gain rate and relative growth rate increased significantly with the improvement of protein level. However, when the protein level increased from 33% to 36%, there was no significant difference in the relative weight gain rate, similarly, when the protein level increased from 36% to 39%, there was no significant difference in the relative growth rate(P<0.05). The Feed Conversion Rates of the 27% and 30% protein level groups were 2.08 and 1.80 respectively, which are significantly higher than the other 3 groups. The Lys and Arg contents of the 33%-protein-level group are significantly higher than the 27% and 39%-protein-level groups (P<0.05). As for the amino acid contents, there’s no significant difference(P>0.05).2. The activities of cellulase in hepatopancreas were lower in the groups of protein levels of 30%, 36% and 39%, and highest in the 33% group(P<0.05). The protease in hepatopancreas is highest in the 30%-protein-level group, lowest in 36% and 39%-protein-level groups. The activities of cellulase, amylase and protease first increased and then decreased when the protein level increased, the peaks appeared at the protein levels of 30%, 30% and 36%(P<0.05). The protein level and the growth and enzymatic activites had a significant positive correlation, with the correlation coefficient of 0.669 and 0.936. 3. With the increase of protein level, the hepatopancreas SOD, NOS and serum NOS both had the pattern of a decrease after an increase, and when the protein level was 33%, the enzymatic activity reached its lowest. The lysozyme active enzyme in hepatopancreas and serum and the hemocyanin in serum all had the pattern of first increase and then decrease. The serum SOD took the pattern of decrease. The protein level had a significant negative correlation with the arginine content in muscle composition and the NOS activity of the hepatopancreas, with the correlation coefficient of 0.863 and 0.762.4. The lysozyme mRNA expression in the hepatopancreas and muscle of the 33%-protein-level group was significantly higher than the 27% and 39%-protein-level group. Expression in hepatopancreas was higher than in the muscle. The HPS70 expression of the 27% group was significantly higher than the 33% and 39% group. Expression in hepatopancreas was higher than in the muscle.To sum up, requirement of protein in the feed of Procambrus clarkii’s was 33% to 36% under the condition of this experiment.III. Based on the biochemical components of wild Procambrus clarkii’s muscle, 5 kinds of semirefined experimental feeds, which were of different energy-protein ratios(E/P) yet the same protein content, were compounded. The protein content in the feeds was 35%, the levels of energy-protein ratios were 32, 34, 36, 38and 40MJ/kg. The Procambrus clarkiis(8.41±1.12g) were fed 60 days. Afterwards, the effects on the growth, biochemical components, digestive enzyme, immunoenzyme, lysozyme activity, energy distribution and the mRNA expression of HSP70 by the E/P are measured.1. The survival rates, relative weight gain rate and relative growth rate all had the pattern of first increase and then decrease while the E/P increased, with the peaks showed at 36 MJ/kg, significantly higher than the other groups(P<0.05). However the food conversion ratio was significantly lower than the other groups at 36 MJ/kg. Different E/P’s didn’t have any significant effects on the contents of water, protein and ash(P>0.05). With E/P’s increase, the fat content increased in the muscle. The Met and Arg contents in the 36 MJ/kg group were significantly higher than the 32 MJ/kg and 40 MJ/kg groups(P<0.05).2. With the increase of E/P, the activities of cellulose, amylase and protease in the hepatopancreas and cellulose in intestinal canal took the pattern of first increase and then decrease, with the highest levels at 36, 36, 36 and 34 MJ/kg. The amylase in the intestinal canal took the pattern of first decrease and then increase, the peak and valley values at 36 and 40 MJ/kg respectively(P<0.05). The activities of protease in the intestinal canal of different groups did not show any significant difference (P>0.05). 3. With the increase of E/P, the muramidase and NOS in the hepatopancreas, the serum SOD and the hemocyanin content had the pattern of a decrease after an increase; the hepatopancreas SOD decreased. The 34 MJ/kg and 36MJ/kg groups have the significantly higher serum NOS than the other 3 groups.4. With the increase of E/P, the energy intake had the pattern of a decrease after an increase, the peaks, 52.63 and 51.19KJ, at 36 and 38 MJ/kg, which were significantly higher than the other groups (P<0.05); the G/C and F/C have the pattern of a decrease after an increase, while R/C, U/C and E/C contrary.5. The lysozyme mRNA and HSP70 expression in the hepatopancreas and muscle of the 40MJ/kg group was significantly higher than the other groups (32 MJ/kg and 36 MJ/kg groups)(P<0.05). Expression in hepatopancreas was higher than in the muscle. To conclude, the E/P need in the feed for the Procambrus clarkii was 34 MJ/kg to 36 MJ/kg. |
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