جستجوی مقالات مرتبط با کلیدواژه « oreochromis niloticus » در نشریات گروه « زیست شناسی »

The study was designed to compare the chemical composition of cultured and wild Redbelly tilapia (Coptodon zillii), and Nile tilapia (Oreochromis niloticus) collected from the Shatt Al-Arab River(Southern Iraq) and fish farms (earthen ponds of Marine Science Center, University of Basrah). Twenty fish from each species weighing (77.17-141.56g)were collected. Chemical analysis was conducted for the two groups to determine moisture, protein, fat, ash, and nutritive value. The results showedthat the two groups' protein, fat, and nutritional values differ significantly (P<0.05) between wild and cultured tilapia species. Wild fish have the highest percentage of fat, protein, and nutritional value. Information about the chemical composition of freshwater fishes is useful to nutritionists looking for low-fat, high-protein food sources.

This study was conducted to assess the species composition, abundance and metrological data influencing fish species diversity based on catch data from landing site of the Sunye Lake. The finding represented that 25 species belonging to 13 families. Cypriniformes was highest composition in community. Both diversity and evenness were low and only a few species were dominated. Low diversity value (H) and highest dominance index values (1-D) were associated with lower diversity estimates for this community. Major dominant species Oreochromis niloticus was the most widely distributed species with a 100% occurrence occurring in the lake. Highest occurrence was recorded during summer. Seasonal abundance of commonly captured species were O. niloticus, Amblypharyngodon atkinsonii, Puntius sophore, Parambassis ranga and Notopterus notopterus. In this community O. niloticus was recorded in the late monsoon and winter whereas A. atkinsonii and P. sophore were recorded in greater abundance during the early monsoon and summer. Finding results indicated that no significant (P<0.05) difference in diversity pattern among the seasons. According to metrological data, we observed similar seasonal pattern trends during two years study. However, productivity was different and their percentage of contribution also differs from each other seasonally. Percent similarity indicated that winter and summer were most similar season in terms of species richness. Seasonal difference in relative abundance indicated that late monsoon and winter were most dissimilarity.

The main purpose of the present study was to investigate the effect of pultry by-product powder replacement instead of fish meal at levels of 0, 25, 50, 75 and 100% on structure of skin tissue of Nile tilapia. After 8 weeks, 5 specimens of each treatment were selected. After biometrics 0.5 centimeter specimen dorsal of head, middle of the trunk and caudal stalk were removed and immediately were placed in 10%formalin buffer. Rutine procedure of tissue prepration was done and sections of 4-6 micron thicknesses were stained by hematoxylin-eosin (H&E), periodic acid schiff (PAS) and massonchr('39')s trichrome histochemistry staining. Microscopic results showed that in control group mucosal cells count, taste buds count, epiderm thickness and collagen thickness increased compared to other groups. Instead in group fed100% pultry by-product increased club cells count and chromatophore thickness compared to other groups and there was a significant difference to some groups (p≤0.05). According to the results of this study, it can be concluded that pultry by-product powder replacement instead of fish meal up to 100 % is tolerable for Nile tilapia. Because according to this study, no lesions or adverse effects on the histomorphology of skin were reported.