Study Of Different Dietary Protein Sources On Black Sea Bream (Sparus Macrocephalus)

Protein is an important nutrient composition for aquatic animals. This study aims to research the effect of different dietary protein sources on growth performance, body proximate composition, tissue biochemical indices and digestive enzyme activities on black sea bream (Sparus macrocephalus).The black sea bream were randomly allotted to four groups (Control, T-1, T-2, and T-3) with triplicate of 35 fish (aver wt 45.50±0.21g). Four experimental diets were formulated as follows: Control diet (69% FM), Diet 1 (43% SPC and 25% fish meal), Diet 2 (43% SPC with 2500U per kilo gram phytase), and Diet 3 (trash fish). The above diets were assigned to four groups (Control, T-1, T-2, and T-3) correspondingly. After 9-week feeding, fish were killed to collect samples of carcass, liver, alimentary canal, muscle and plasma, and then body proximate composition, plasma biochemical parameters, liver and gastrointestinal digestive enzymes activities were analyzed.The result suggested that different dietary protein sources could affect the growth of black sea bream. Survival of fish in all groups were no significant (P>0.05) differences. In the control, weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) were the best among the five groups, WGR and SGR of T-1, T-2 and T-3 had no significant (P>0.05) differences. HSI (hepatosomatic index) of fish in control was the lowest. No difference of condition factor (CF) existed in groups.The result also suggested that the phytase could improve growth performance of black sea bream. The fish of T-2 was better than T-1 in WGR, SGR, FE, PER (P>0.05) .The moisture content of fish in all groups were no significance on whole body and muscle (P>0.05) , but was significantly high on liver of the trash fish group (P<0.05). Crude protein content in muscle was also of no significance, but in whole body of Control, T-2 and T-3 was better (P＜0.05) ,and the fish of Control and T-3 was significantly higher than others on liver protein content (P<0.05) .SPC groups was significantly higher than Control and T-3 about crude lipid content both in whole body and muscle (P<0.05), crude lipid content of liver was the highest in T-1, which was 52.59% higher than trash fish groups (P<0.05) .There were significances on whole body, muscle and liver about crude ash, Ca and P among different protein source (P < 0.05) . The whole body crude ash Ca an P content of T-1 was the lowest (P < 0.05). The muscle crude ash and P content of T-2 was lower than others (P < 0.05), but Ca content was higher. The liver crude ash was the highest in T-1 (P < 0.05) .Different dietary protein sources had some influence on plasma cholesterol (CHO) triglycerides (TG), glucose (GLU), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) of black sea bream. The fish of plasma T-CHO content in Control and T-3 was significantly higher than SPC groups (P < 0.05) . The fish of plasma TG content in T-3 was the lowest (P < 0.05) , 4.82mmol/L. The fish of plasma GLU content in Control was significantly higher than the trial groups. There were no significance among Control, T-1 and T-2 on the activities of two transaminase (P>0.05) , T-3 were the lowest about the activities of two transaminase.Different dietary protein sources had no influence on total amino acid, total essential amino acid and total flavor amino acid content on muscle of black sea bream, the ratio of Met and Lys on total essential amino acid, too.Different dietary protein sources had some influence on three mostly digestive enzymes in liver and pancreas, stomach and intestines. The fish of T-1 pepsin activities was the lowest (P < 0.05) , the fish of T-2 protease activities was high in every segment of alimentary canal. Lipase of stomach and mid-gut of T-2 fish was the highest. The fish about T-2 was of active amylase activities in all tissue.Based on such factors as the growth performance and meat quality of black sea bream, feed cost, material supply an so on, soy protein concentrate partial substitute fish meal on the diets of black sea bream is of good synthetical benefit.