Effects of salinity on growth and metabolism in blue tilapia (Oreochromis aureus)

Tilapia were acclimated to the water source which had 8 precipitation (ppt) of salinity in the experimental unit before the experiment started and then, they were transfered to five different saltwater (SW) treatments: SW (8 ppt), 50% SW (12 ppt), 100% SW (16 ppt), 150% SW (20 ppt), and 200% SW (24 ppt). The objectives of this study were; to investigate the effects of five different salinities on specific growth rate (SGR), weight gain (WG), food intake (FI) and survival of tilapia in the long term trial (30 days) and find out how salinity affects muscle water content, hematosomatic index (HSI), and blood chemistry (sodium, chloride, potassium, glucose, total protein and triglycerides) in the short term trial (6 to 12 h). In the long-term trial, six fish were stocked in each aquarium. They were fed with commercial feed (Bagcı trout) to satiation twice a day and individually weighed at ten-days interval. Growth rate was highest in the 50% SW (SGR 0.95 ± 0.18% per day); there was no significant difference among the first three treatments. Growth rate was lowest in 200% SW (SGR 0.23 ± 0.08% per day). Weight gain and food intake showed identical results as SGR. Survival was high in the first three groups (72.2 ±1 9.2 to 100.0 ± 0.0) but it was lowest in the 200% SW treatment (22.2±19.2%). In the short-term trial, six tilapia were placed per aquarium. They were exposed to SW, 50, 100, 150 and 200% SW treatments and the fish were gradually acclimated to salt water. Blood samples were taken to analyse plasma sodium, chloride, potassium, total protein and triglycerides. Liver and muscle samples were collected for HSI and moisture values. Plasma sodium chloride increased in parallel with salinity rise. Total protein and triglycerides significantly reduced as salinity increased. Glucose and potassium were not altered significantly. HSI and muscle water content decreased when salinity concentration was elevated. Blood chemistry demonstrated that isosmotic water concentration was between 8 and 12 ppt. Salinity did not affect HSI and moisture until it reached as much as 16 ppt (100% SW). The results show that the optimum condition for farming blue tilapia, Oreochromis aureus, both with respect to growth rate and metabolic parameters is at salinities lower than 12 ppt. This is an important finding for the tilapia industry.Keywords: Tilapia, salinity, growth, survival, metabolismAfrican Journal of Biotechnology Vol. 12(19), pp. 2715-272

Effects of cold temperature and vitamin E supplementation on oxidative stress, Troponin-T level, and other ascites-related traits in broilers

WOS: 000261440200005The present study was conducted to determine effects of low ambient temperature and dietary vitamin E supplementation on growth performance and ascites- related traits in broilers, and to assess oxidative stress status in broilers with ascites. Male broiler chicks (Ross) were randomly assigned to one of four experimental groups. Control or low temperature groups were fed a standard commercial diet with (200 mg Vitamin E/kg) or without supplemental vitamin E from 0 to 6 week of age. Low rearing temperature caused growth depression and induced the development of ascites syndrome as indicated by clinical signs and higher hemotocrit level, RV/TV ratio, and serum Troponin-T level. Ascitic broilers exhibited significantly lower SOD, CAT and GSH-Px activities, and higher MDA level suggesting the presence of oxidative stress. In spite of some decrease in ascites-induced mortality, dietary vitamin E supplementation could not improve growth performance and was not effective in protecting tissues from oxidative damage