Search

A feeding trial was conducted to investigate the effects of different dietary amino acid patterns on growth performance, feed utilization and body composition of juvenile Nibea japonica. Four semi-purified diets were formulated to simulate the dietary amino acid profiles of juvenile giant croaker whole body protein ( GCP), Peru fishmeal protein ( PFP), red sea bream eggs protein ( REP) and soybean meal protein ( SMP) by supplementing with pre-coated crystalline amino acids ( CAA). A control diet contained only intact protein sources provided by the fishmeal and casein (2:1). Each experimental diet was fed to satiated triplicate groups of juveniles (10.73 ± 0.07 g) twice a day for 8 weeks. The highest weight gain ( WG) was observed in the juveniles fed the control diet, whereas no significant differences were found between the juveniles fed the GCP and control diets. Fish fed the control, GCP, PFP and SMP diets did not exhibit any significant difference in protein efficiency ratio ( PER), feed conversion ( FCR) or nitrogen ( N) retention. The results of this study suggest that the amino acid ( AA) patterns of juvenile whole body protein could be used as a guideline in the formulation of dry diets, which also confirms that the juvenile giant croaker is able to utilize high amounts (20%) of CAA in coated form for growth. [ABSTRACT FROM AUTHOR]

Six experimental diets were designed with two phospholipid ( PL; 0% and 1.5%) and three fish oil levels (0%, 1% and 3%) to evaluate the effects of dietary fish oil and PL levels on growth, survival and fatty acid composition of juvenile swimming crab, Portunus trituberculatus. Diets were iso-energetic and iso-nitrogenous and each diet was fed to triplicate groups (initially weight, 24.88 ± 0.04 g per crab) for 59 days. Weight gain ( WG) and specific growth rate ( SGR) increased with dietary PL addition to 0% fish oil-supplemented diets ( P < 0.05). On the other hand, WG and SGR decreased with dietary PL addition to 3% fish oil diets ( P < 0.05). Crabs fed PL supplemented diets had higher haemolymph low-density lipoprotein cholesterol concentrations and muscle crude lipid levels ( P < 0.05) than crabs fed a none PL supplemented diet. The percentage of highly unsaturated fatty acids ( HUFA; % total FA) in both polar and neutral lipids fractions of muscle tissue only increased in case of PL addition to 0% and 1% fish oil-supplemented diets ( P < 0.05). HUFA levels in the neutral lipids fraction of the hepatopancreas increased by dietary PL addition at each dietary fish oil level ( P < 0.05 ). In this study, both dietary fish oil and PL addition contributed to a high n-3/n-6 ratio in muscle and hepatopancreas of P. trituberculatus. In conclusion, PL addition is only meaningful with fish oil-deficient diets, in which case it enhanced lipid transport and HUFA absorption efficiency, hence improving the nutritional value of the diet. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to investigate the effect of dietary carbohydrate level on the growth performance, body composition of giant croaker, Nibea japonica. The six diets were designated as carbohydrate level from 0% to 30%. Each diet was fed to triplicate groups of 18 giant croaker (initially weighing, 7.40 ± 0.15 g fish−1) in flow-through sea water system. The weight gain ( WG) and special growth ratio ( SGR) had tendency to increase with carbohydrate level from 0% to 12% after that decreased, and significantly lower in fish fed diet with 30% carbohydrate level than in other groups. Moreover, fish fed diet with 30% dietary carbohydrate has significantly higher feed conversion ratio (1.48 ± 0.18) and lower protein efficiency ratio (1.69 ± 0.21) than other groups ( P < 0.05). The intraperitoneal fat ratio and condition factor had no significant difference in different groups ( P > 0.05), hepatosomatic index value increased with dietary carbohydrate increased ( P < 0.05). The result of this study also suggested that excess carbohydrate level (30%) led to lower lipid content in whole body. Based on the second-order polynomial regression analysis of WG and SGR, 12.2-12.7% dietary carbohydrate provided maximum growth of N. japonica. [ABSTRACT FROM AUTHOR]