Effects Ofdietary Fish Meal Replacedby Soybean Meal And Poultry By-Product Mealon Growth Performance, Digestive Enzyme Activitiesand Energy Budgets Of Juvenile Turbot(Scophthalmus Maximus)

A study was conducted to evaluate the effects of soybean meal(SBM) and poultry by-product meal(PBM) as the replacement of fish meal in the diets on growth performance, protein metabolism and energy budgets of juvenile turbot Scophthalmus maximus to determine the optimal replacement level by SBM and PBM. Results of the study are presented as follows:1.Effect of different level of soybean meal in diets on growth performance, whole-body proximate composition and feed apparent digestibility of juvenile turbotJuvenile turbot(initial weight, 22.82±0.08 g) were fed five isoenergetic and isonitrogenous diets which fish meal was replaced with a graded amounts of SBM at 0%, 10%, 20%, 30% and 40% level(SBM0, SBM20, SBM40, SBM60, SBM80 respectively). The result showed that:(1) There are significant differences in feed coefficient ratio and protein efficiency fed with the fishmeal replaced diets, weight gain rate is significant decreased when SBM replaceing 20% of fish meal.(2) There are no significant differences(P > 0.05) in whole-body proximate composition among the treatments fed with SBM replacement of fish meal.(3) A significant reduction in apparent digestibility coefficients was observed when SBM was used as partial substitute of fish meal protein(P<0.05).2.Effect of different level of soybean meal in diets on protein metabolism, serum biochemical indices and digestive enzymes activities of juvenile turbotJuvenile turbot(initial weight, 22.82±0.08 g) were fed five isoenergetic and isonitrogenous diets which fish meal was replaced with a graded amounts of SBM at 0%, 10%, 20%, 30% and 40% level(SBM0, SBM20, SBM40, SBM60, SBM80 respectively). The result showed that:(1) There are no significant differences(P>0.05) in serum biochemical indices among the treatments fed with SBM replacement of fish meal.(2) The serum aspertate transferase(AST),alanine transferase(ALT) activities are significantly affected when fish meal was replaced by 40% of SBM.Liver AST activities increased significantly when fishmeal is replaced by 40% of SBM, There are no significant differences(P>0.05) in w Liver ALT activities among the treatments fed with PBM replacement of fish meal.(3) Gastrointestinal protease activities is affected significantly when fishmeal was replaced(P<0.05).There are no significant differences(P>0.05) in Liver and pancreas digestive enzymes activities among the treatments fed with SBM replacement of fish meal.3.Effect of different level of soybean meal in diets on protein metabolism, serum biochemical indices and digestive enzymes activities of juvenile turbotJuvenile turbot(initial weight, 22.82±0.08 g) were fed five isoenergetic and isonitrogenous diets which fish meal was replaced with a graded amounts of SBM at 0%, 10%, 20%, 30% and 40% level(SBM0, SBM20, SBM40, SBM60, SBM80 respectively). The result showed that:(1) Different different level of soybean meal have no significant effect on feeding energy, energy proportion of growth and metabolism of juvenile turbot(P>0.05), Energy proportion of defecation was significantly higher with the SBM replacing level(P<0.05),(2) Different level of soybean meal in diets have no significant effect on feeding nitrogen and growth proportion of nitrogen(P>0.05). Nitrogen proportion of defecation was significantly affected by different level of soybean meal in diets(P<0.05).(3) No significant difference was observed among all groups in feeding phosphorus and excretion proportion of phosphorus(P > 0.05), growth proportion of phosphorus was significantly decreased when SBM replaceing level reach to 30%(P<0.05).4.Effect of different level of poultry by-product meal in diets on growth performance, whole-body proximate composition and feed apparent digestibility of juvenile turbotJuvenile turbot(initial weight, 22.82±0.08 g) were fed five isoenergetic and isonitrogenous diets which fish meal was replaced with a graded amounts of PBM at 0%, 20%, 40%, 60% and 80% level(PBM0, PBM20, PBM40, PBM60, PBM80 respectively). The result showed that:(1) There are significant differences in growth performance among all treatments fed with the experimental diets(P<0.05).(2) There are no significant differences(P>0.05) in whole-body proximate composition among the treatments fed with PBM replacement of fish meal except crude fat which significantly decreased(P<0.05) compare with the Control group.(3) A significant reduction in apparent digestibility coefficients was observed when PBM was used as partial substitute of fish meal protein(P<0.05).5.Effect of different level of poultry by-product meal in diets on protein metabolism, serum biochemical indices and digestive enzymes activities of juvenile turbotJuvenile turbot(initial weight, 22.82±0.08 g) were fed five isoenergetic and isonitrogenous diets which fish meal was replaced with a graded amounts of PBM at 0%, 20%, 40%, 60% and 80% level(PBM0, PBM20, PBM40, PBM60, PBM80 respectively). The result showed that:(1) There are no significant differences(P>0.05) in serum biochemical indices among the treatments fed with PBM replacement of fish meal.(2) The serum aspertate transferase(AST),alanine transferase(ALT) activities are significantly affected when fish meal was replaced by 40% of PBM,serum AST, ALT activities increased significantly when fishmeal is replaced by 40% of PBM(P<0.05).(3) Gastrointestinal protease activities is affected significantly when fishmeal was replaced(P<0.05). There are no significant differences(P>0.05) in Liver and pancreas digestive enzymes activities among the treatments fed with PBM replacement of fish meal6.Effect of different level of poultry by-product meal in diets on protein metabolism, serum biochemical indices and digestive enzymes activities of juvenile turbotJuvenile turbot(initial weight, 22.82±0.08 g) were fed five isoenergetic and isonitrogenous diets which fish meal was replaced with a graded amounts of PBM at 0%, 20%, 40%, 60% and 80% level(PBM0, PBM20, PBM40, PBM60, PBM80 respectively). The result showed that:(1) Different dietary level of PBM have no significant effect on feeding energy, energy proportion of growth and metabolism of juvenile turbot(P>0.05), PBM20’s energy proportion of growth was highest compare with all treatment, Energy proportion of defecation was increased significantly when PBM replacing level reach to 40%.(2) Different dietary level of PBM have no significant effect on feeding nitrogen, growth and excretion proportion of nitrogen of juvenile turbot(P>0.05), Nitrogen proportion of defecation was significantly affected when fishmeal was replaced by PBM(P<0.05).(3) No significant difference was observed among all groups in feeding phosphorus, the growth and excretion proportion of phosphorus(P>0.05), PBM20’s growth proportion of nitrogen was highest compare with all treatment, PBM replacement level reached 20%, the defecation proportion of phosphorus was significantly higher compare with Control group(P<0.05).