| The purpose of this study was to investigate the effects of different biomass Aquatic plants and zoobenthos to the eutrophic water body culturing Pseudobagrus fulvidraco. and the effects of immunostimulants on performance, digestion and immunity of Pseudobagrus fulvidraco to provide theoretical basis for culturing Pseudobagrus fulvidraco fry. The experiment included there parts:The first experiment was designed to study the effects of four kinds of aquatic plants on the quality of waters cultured with Pseudobagrus fulvidraco. The water culturing Pseudobagrus fulvidraco(richardson) fry was purified by four kinds of aquatic plants: Alternanthera philoxeroides, Eichhornia crassipes, Pistia stratiotes, Vallisneria natans. Each aquatic plant was made in three gradients and was compared synchronously among them. The biomass of Alternanthera philoxeroides was 357g/m3,715g/m3,1072g/m3 respectively. The biomass of Eichhornia crassipes was 357g/m3,715g/m3,1072g/m3 respectively. The biomass of Pistia stratiotes was 357g/m3,715g/m3,1072g/m3 respectively. The biomass of Vallisneria natans was 4 plants/m3,8 plants/m3,12 plants/m3, and a group without aquatic plants was made. The change of major factors of culture water were analysized. and the fry survival rate and the rate of body weight gain were measured after 60 days. The results showed as follows:When the cultivation of A.philoxeroides was 715g/m3, the removal rate of NH3-N and NO2-N was better, with 74% and 45%, respectively, but the removal rate of TN, TP and COD was no good, and it had no effect on the gain rate, survival rate. When the cultivation of E.crassipes was 1072g/m, the removal rate of TN, TP, COD, NH3-N and NO2-N was better, with 67%,75%,65%,96% and 86%, respectively; and also improve the rate of weight gain and the survival rate of the fry; when the cultivation of P.stratiotes was 1072g/m3, the removal rate of NH3-N and NO2-N was better, with 61% and 33%,respectively. But the removal rate of TN, TP and COD was no good, and it had no effect on the gain rate, survival rate. When the cultivation of V.natans per square meter was 8 plants, the removal rate of TN, TP, COD, NH3-N and NO2-N was better, with 49%,50%,36%,98% and 86%, respectively; and the rate of weight gain and the survival rate were 253.24% and 85.71%, respectively. Therefore, the cultivation of E.crassipes and V.natans could decrease the eutrophic salt of culture water and promote the growth of the fry. The best cultivation of E.crassipes and V.natans were 1072g/m3and 8 plants per square meter, respectively.The second experiment was designed to study the effects of zoobenthos on the Quality of Waters Cultured with Pseudobagrus fulvidraco. The water was purified by hyriopsiscumingii and margaryamelanoides. Each zoobenthos was made in three gradients. The biomass of hyriopsiscumingii was 3600g/m3,7200g/m3,10800g/m3 and margaryamelanoides was 285g/m3,428g/m3,571g/m3 respectively. The TN, TP, COD were measured with 7 days and the NH3-N, NO2-N were measured with 6 days, then the fry survival rate and the rate of body weight gain were measured after 60 days. The results showed that the effect of hyriopsiscumingii on purifying water was better than that of margaryamelanoides, Compared with 3600g/m3 and 10800g/m3, when biomass of hyriopsiscumingii was 7200g/m3, the removal rate of TN, TP, COD, NH3-N and NO2-N was best, with 38%,37%,40%,54% and 30%, respectively. Moreover the rate of weight gain and the survival rate were better. Compared with 285g/m3 and 571g/m3, when biomass of margaryamelanoides was 428g/m3, the removal rate of TN, NO2-N and COD was better. Therefore, It was concluded that it was efficiently controlling the eutrophication and improving the survival rate and body weight ratio by putting 12 piece hyriopsiscumingii per stere in culture water.The third experiment was designed to study the effects of two Immunostimulants on performance, digestion and immunity of Pseudobagrus fulvidraco A total of 180 Pseudobagrus fulvidraco were allotted into three groups (Ⅰ,Ⅱ,Ⅲgroups) randomly in the experiment. The control group (groupⅠ) was fed with basal diet, each group had three triplication. The others were the treated groups fed with basal diet supplemented with 0.01% bacillus and 0.01% prebiotics compound (groupⅡ), and 1% Chinese herbal medicine (groupⅢ) is for 60 days, respectively. The growth rate of Pseudobagrus fulvidraco, the survival rate of Pseudobagrus fulvidraco, activity of digestive enzyme and activity of immunoenzyme were determined. The results showed as follows:There were significantly increased growth gain rates, survival rate in groupⅡ,Ⅲthan those in groupⅠ. There were also significantly increased digestive enzyme activity in the stomach in groupⅡ,Ⅲand protein enzyme activity in the intestine in groupⅡthan those in groupⅠ, but amylase activity in the intestine were decreased in groupⅡ,Ⅲ. Compared with the control, ACP AKP SOD activity in the hepatopancreas and ACP AKP activity in the blood serum were increased in the experiment group. It is concluded that ingestion of immunostimulants could increase ability of digestive and immunity, and boost the growth of Pseudobagrus fulvidraco. |
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