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Efficient food supply is the most important factors which must be considered to introduction of white fish (Rutilus frisii kutum) in an aquaculture system

Therefore, in order to evaluate the effect of dietary protein and zinc on the growth performance and survival of this species, 360 pieces of white fish with an average weight of 0.5 ± 0.56 g were placed in twelve tanks (60 liters) .Juvenile fish was fed with four different levels of protein diets (36 and 44%) and zinc (50 and 200 mg kg feed) for 83 days.

The results showed that the growth and survival of Kutum significantly affected by different levels of protein and dietary zinc.

The highest weight gain (0.79 ± 0.06), percent of  weight gain (154.88 ± 8.7) and specific growth rate (1.13 ± 0.04) were observed in fish which  fed  with a diet containing 44 % protein and 0.005% zinc, But the diet containing 36% protein and 0.02 zinc  96.67 ± 0.00 percent) was revealed the highest survival rate. High With increasing levels of protein in the diet, whole-body protein contents are promoted. Overall, relativity the better response base on growth and body composition was observed in juvenile fish which with fed a diet containing 44% protein and 50 mg per kg zinc.

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 This study was conducted to evaluate the influence of exogenous supplement Natuzime plus enzyme on growth performance, body composition and survival rate of beluga (Huso huso) juveniles. Juveniles (n = 17 fish per each tank with initial weight of 30 g) were randomly distributed in 150-L tanks and fed with four diets (each in three replicates) containing 0, 2, 5 and 10 % of Natuzime plus multi enzyme for eight weeks. Results showed that survival rate of the fish were in the range of 83-95 % and there were significant differences between treatments. The highest weight gain was recorded in fish fed with 2 % enzyme and being different from the other groups. The specific growth rate was to be ranged from 1.96 (10 % enzyme) to 2.32 (2 % enzyme). Feed conversion ratio, protein efficiency ratio and daily growth rate were significantly higher in the diets containing enzymes compared to the control group; and the best performance was attained in 2 % enzyme in the diet. The highest (69.5 %) body protein content was recorded in the fish fed with 2% enzyme in the diet. The results obtained suggest that dietary inclusion of 2% Natuzime plus enzyme can improve the growth performance and survival rate of beluga juveniles.

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In this study, body composition and digestive enzymes activity was assessed in rainbow trout fry (weight 2.51 ± 0.55 g) fed by bacterial single cell (BSC) as a dietary protein source replaced with fish meal as completely randomized design with triplicate for 6 weeks. Experimental diets were prepared in 5 treatments as isonitrogenous with different levels of fish meal and BSC (100% fish meal (A), 75% fish meal and 25% BSC (B), 50% fish meal and 50% BSC (C), 25% fish meal and 75% BSC (D) and 100% BSC (E)). The body composition findings showed that the highest amount of lipid and protein and the lowest amount of moisture and ash was revealed in fish fed by diet C while the lowest amount of lipid and protein and the highest amount of moisture and ash was observed in fish fed with diet E (P <0.05). Enzymatic assessment from pyloric caeca and intestine were showed that trypsin and α-amylase were increased significantly in fish fed by diet C while alkaline phosphatase activity had the highest amount in diet D than did that from diet E (P <0.05). Based on the results of this study, it is recommended that BSC could be properly replaced up to 50 % with fish meal in rainbow trout fry diet.
 

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To investigate the effect of its various aspects and the effect on growth, nutrition, and biochemical composition of body, Asian Sea bass fish with an average initial weight of 33 ± 0.9 gr were experimented in three hundred-liter polyethylene circular tanks in three repetitions. Feeding was done twice a day for up to 60 days. The results showed that growing Asian sea bass in fresh-water and seawater did not have a significant effect on growth performance indicators (except for the average final length) (P > 0.05). The mean secondary length in saltwater treatment was significantly higher (P < 0.05). Therefore, In addition, among the calculated nutritional parameters, only the food index received between treatments had a significant difference (P < 0.05) and other indicators and biochemical body compounds did not show a significant difference (P > 0.05). Cultivation of freshwater fish has a lower feed conversion ratio (0.92 ± 0.06); however, these changes were not significant. Overall, the study showed that it can withstand a wide range of different salinities for 60 days and grow well without showing any casualties.

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The aim of this study was to determine the effect of anthocyanin from roselle (Hibiscus sabdariffa) supplemented diets on growth, survival and body composition of rainbow trout (Oncorhynchus mykiss) for 60 days. Fish were fed 0 % (control), 0.5 %, 1 %  and 2 % anthocyanin extract in complete random design.  Fifteen fish with the same initial weight (14 ± 0. 1 g) were selected and randomly distributed into experimental treatments in triplicates and were fed 4 % biomass. Growth performance, feed efficiency, survival and body composition were assed at the end of the rearing period. The result showed that there were no significant difference between the control and anthocyanin treatments in final weight, weight gain (%), specific growth rate (SGR % day^-1), protein efficiency ratio (PER), feed conversion ratio (FCR)  and feed intake (% day^-1), although, growth performance and feed efficiency were  higher in anthocyanin 0.5% compared to the other treatments. Morever, There was no significant difference in survival rate between the control and anthocyanin treatments.  No significant differences was observed in nutritional carcass between the control and anthocyanin supplement. No significant differences was observed in AST, ALP and LDH between anthocyanin treatments and control group, although ALT significantly increased in 1% anthocyanin extract.The present study demonstrates that anthocyanins from roselle has no effect on growth performance, feed efficiency and body composition of rainbow trout.