Research Of Taurine Addition In Low Fish Meal Diet Of Juvenile Black Carp(Mylopharyngodon Piceus)

An8-week feeding experiment was conducted to evaluate the effect of taurine on growth、 blood biochemical indexes and resistance to crowding stress of juvenile black±carp[initial average weight of (5.90±0.03)g].The basal diet contained20%fishmeal by study of fish meal replacement by dietary soybean meal levels on growth and biochemical indices in juvenile black carp. All the other groups contained10%fishmeal and supplemented with0%,0.05%,0.1%,0.2%and0.4%taurine, respectively. Each diet was randomly fed to triplicate groups of30fishes per tank (300L).The results showed that:1-. Suitable fishmeal contentThe weight gain rate and specific growth rate of juvenile black carp were significantly lower than those fed the control diet when fish fed the diet with FM level up to15%(P<0.05), and growth performance of juvenile black carp could not be improved by adding CAA. The delicious amino acid(DAA) and total amino acid(TAA) contents of muscle were significantly reduced in fish fed diet with FM level up to15%than those fed the control diet(P<0.05). No significant differences in serum triglyceride (TG), total cholesterol (TC), total protein (TP) contents and ALT activity were observed among dietary treatments, but GLU content and AST activity in serum were significantly higher in15%FM diet and15%FM+CAA diet than those fed the control diet(P<0.05). Based on these observations above, the fish meal content for juvenile black carp should not be less than the level of20%, and supplementations of CAA in low fish meal diet could not improve the growth performance of juvenile black carp.2、 GrowthThe diets with taurine had no significant differences on the survival of juvenile black carp, When the inclusion level was0.1%, the diet could increase significantly the specific growth rate (%)(P<0.05). In aspect of digestive enzymes, no significant differences in intestinal protease, but the activity of amylase and lipase was significantly higher than other groups When the diet with levels of taurine of0.1%(P<0.05). In terms of body composition, all the tests had no significant differences on moisture、 crude protein and ash content of juvenile black carp, but the crude lipid content of juvenile black carp was significantly decreased When the diet with levels of taurine of0.4%.3、 Blood biochemical indicesThe diets with taurine had significantly increased the activity of SOD、T-AOC、 GSH GSH-Px、 C3、 C4and LSZ (P<0.05), and could significantly decreased the activity of MDA in serum of juvenile black carp(P<0.05). Adding with taurine in diet had no significantly differences in the content of HDL-C and BUN. Compared with the0%taurine content Io group, adding with taurine in diet had significantly reduced the content of TC and TG (P<0.05). When the diet with levels of taurine of0.4%, the content of LDL-C had significantly decreased (P<0.05), when the diet with levels of taurine not less than0.1%, the content of TP had significantly increased (P<0.05). The results indicates that taurine could promote the body’s protein and fat metabolism.4、 Resistance to crowding stress After crowding stress, serum cortisol content first significantly increased and then reduced. After24h, serum cortisol content was still higher than before, while the difference was not significant. And serum cortisol content of Io group was significantly higher than the contro、 I0.1group and I0.4group (P<0.05). Changes in GLU content showed a similar trend with serum cortisol. Before crowding stress, Io group was significantly higher than the control(P<0.05), afer it, the difference was not significant between the control and Io group. And to24h, the level of GLU had recovered; Serum LSZ、 C3、 SOD and GSH all first significantly increased and then reduced. The activity of LSZ in I0.1group and I0.4group had significantly higher than that in Io group before rowding stress(P<0.05), and the difference between was not significant. The activity of C3in I0.1group and I0.4group had significantly higher than that in control and Io group before rowding stress and to2h(P<0.05). The activity of C3in I0.4group had reached the highest when it to2h. The activity of SOD and GSH in I0.1group and I0.4group had significantly higher than that in I0group (P<0.05) and had reached the highest in I0.4group when it to8h. Based on these observations above, adding taurine with the content of0.1or0.4can improve body’s immunity and antioxidant capacity, thereby can increase the ability of resistance to crowding stress...