Study On Dietary Protein And Lipid,Three Immunostimulants And Fermented Soybean Meal In Brown Trout (Salmo Trutta)

Exp.1 A study on the proper protein and lipid levels in the diet of Salmo TruttaThis study was conducted to evaluate the effects of dietary protein and lipid levels on the growth performance,body composition,liver biochemical index and intestinal enzyme activity of juvenile brown trout.The experiment used a 3×2two-factor design with protein levels of 42%,46%,and 50%(P42,P46,and P50)and lipid levels of 12% and 16%(L12,and L16).Brown trout with an average initial weight of(2.80 ± 0.10)g were randomly distributed into six groups with three fish per group and fed with one of the six diets for 56 d.The results indicated that the P46L12 group had the highest weight gain(110.34%)and the lowest feed conversion ratio(1.30),while the P50L16 group showed the lowest growth.There was no significant difference in the viscerosomatic index among all groups(P>0.05).The hepatosomatic index decreased with increasing dietary protein and fat levels.With the increase of dietary protein levels,the protein retention and lipid retention first increased and then decreased.Dietary lipid levels significantly affected the activity of intestinal protease,pepsin and gastric amylase activity(P<0.05),while dietary protein levels only affected pepsin activity(P<0.05).The P46L12 group had the highest protease and amylase activities in the stomach and intestine among those of all groups.At the same fat level,glutamic-pyruvic transaminase(GPT)activity and total cholesterol(TC)and triglyceride(TG)contents first increased and then decreased with increasing dietary protein levels.The above results indicated that the proper levels of crude protein and crude lipid in the diet of juvenile brown trout were 46%and 12%,respectively.Exp.2 Effects of synbiotics?azomite and citric acid on growth,liver biochemical indices,and digestive enzyme activities of juvenile Salmo TruttaThis study was conducted to evaluate the effects of synbiotics?azomite and citric acid on growth,liver biochemical indices,and digestive enzyme activities of juvenile brown trout,Salmo Trutta.Four diets were prepared without(the control)or with the addition of 3.0g/kg synbiotics,4.0g/kg azomite and 10.0g/kg citric acid in basal diet,respectively.Brown trout juveniles with an initial weight of(0.5±0.02)g were fed the four diets for 84 days.The results showed that the weight gain of the synbiotics group and citric acid group were significantly higher(8.80%,8.15%)(P<0.05),and feed conversion ratios were lower(-0.1,-0.07)than those of the control group(P<0.05).There was no significant difference in visceral body ratio among all the groups(P>0.05),but synbiotics group showed higher protein retention and lipid retention than the control group(P<0.05).The pepsin activity of synbiotics and citric acid groups,the gastric amylase and intestinal protease activity of synbiotics and Aizomite groups,and the intestinal amylase of citric acid group were significantly higher than those of the control group(P<0.05).Citric acid group showed significantly higher GPT and GOT activity in liver than the control group(P<0.05).In conclusion,the supplementation of 3.0g/kg synbiotics and 10.0g/kg citric acid could promote the growth and feed utilization of juvenile brown trout.Exp.3 A study of fermented soybean meal in juvenile Salmo TruttaThis study was conducted to evaluate the effects of fermented soybean meal in place of soybean meal and fish meal on growth,liver biochemical indices,and digestive enzyme activities of brown trout.Four diets were prepared without(the control)or with the addition of 4%(FSM4 group)? 8%(FSM8 group)and12%(FSM12 group)fermented soybean meal in basal diet,respectively.Fermented soybean meal replaced soybean meal and fish meal(3: 1)in the basic feed to make 4groups of iso-nitrogen isoenergetic feed.Brown trout juveniles with an initial weight of(0.5 ± 0.02)g were fed the four diets for 84 days.The results showed that the weight gain rate was increased by the replacement amount of fermented soybean meal,showing a trend of rising first and then decreasing.The weight gain rate of the FSM4 group were significantly higher 6.44%(P <0.05),and feed conversion ratios were lower-0.06 than those of the control group(P <0.05).There was no significant difference in visceral body ratio among all the groups(P> 0.05).The pepsin,gastric amylase,and metabolic protease activities of the FSM4 group were significantly more than the control group(P<0.05).GPT in the FSM4 group was significantly higher than the control group(P<0.05).In conclusion,replacing soybean meal : fish meal(3:1)with 4% fermented soybean meal has an improvement effect on the growth of juvenile brown trout,but higher percentages of fermented soybean meal(8%,12%)caused reduced fish growth.