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Some biochemical characteristics of common carp (Cyprinus carpio) and silver carp (Hypophtalmichthys moltrix) surimi prepared by a conventional washing method and protein isolated using alkaline-acid-aided processes were investigated. Solubility of protein in silver carp and common carp were found to be highest by using the conventional washing method. Decreases in myoglobin and lipid contents in both fish were found in the alkaline- or acid-aided process when compared to the conventional process (p<0.05). The percentage of protein recovery with the alkaline- aided process of silver carp was highest. The whiteness score in the alkaline solubilization process was higher than acid solubilization process and conventional method in silver carp. This result was different than the result obtained in common carp. There was no significant difference between treatments regarding total sulfhydryl (SH) groups (p>0.05). In protein patterns of Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the lowest intensity of the myosin heavy chains (MHC) band was found in silver carp by the conventional washing process.

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Effects of dietary synbiotics on growth performance, survival, stress resistance, body composition and immune response in the Caspian roach (Rutilus rutilus) were evaluated. Fish with an initial average weight of 4.14±0.25 g were randomly distributed into tanks (50 fish per tank) and triplicate groups were fed a control diet or diets containing 1 g kg^-1 and 2 g kg^-1 synbiotics. After an 8-week feeding period, a general enhanced growth performance and feed efficiency were observed in fish fed on the diet containing 2 g kg^-1synbiotics (p<0.05). Subsequently, immune responses (Ig levels, lysozyme activity and ACH50) were significantly higher in 2 g kg^-1 synbiotics fed fish (p<0.05). Although all levels of dietary synbiotics significantly increased resistance to a salinity stress challenge (p<0.05), the highest survival rate was observed in this group. The intestinal tract of the fish with synbiotic diet supplementation had higher concentrations of lactic acid bacteria (7.13±0.32 log CFU g^-1). The protein and lipid contents in the whole body increased in the 2 g kg^-1 synbiotics fed group. At the end of experiment the fish fed synbiotics had the highest survival index after 40 hours exposure to salinity stress (13.8 ppt). Results showed that the addition of synbiotics to the diet of Roach (Rutilus rutilus) stimulates the beneficial intestinal microbiota and alters their immune defense system.

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The proximate composition, amino acids and fatty acids composition in the muscle of wild, inshore and offshore cage-cultured large yellow croaker, Pseudosciaena crocea (Richardson, 1846), were determined to identify nutritional differences. Wild fish groups showed highest content of moisture and crude protein, but the lowest lipid content. Offshore cage-cultured fish showed significantly higher content of moisture and crude protein content, but lower crude lipid content than inshore cage-cultured fish. The content of aspartic acid, glutamic acid, and alanine was higher in wild large yellow croaker than inshore cage-cultured groups, but similar to offshore cage-cultured fish. Significant lower contents of total amino acids, essential amino acids, non-essential amino acids and flavor-enhancing amino acids content were recorded in two cultured fish groups than those in wild group. While no major differences in fatty acids composition were found between wild and cage-cultured groups except for linoleic acid. The fish from offshore cages has much better nutrient profile than inshore cage-cultured fish, but was still inferior compared to wild fish.