ایمان ناصری فرد

This study aimed to investigate the effects of different temperatures (20, 27 and 33 °C) and two feeding rates (2.5 % biomass per day and satiation) on growth performance, body composition, hematology and blood biochemistry of Asian sea bass (Lates calcarifer). For this purpose, 8 fish with an average initial weight of 99.55 ± 0.24 g were randomly transported to 200 liters tanks (6 treatments with three replicates) and fish feeding was done using a commercial feed for 6 weeks. At the end of the experiment, the growth performance, blood indices and chemical composition of fish carcasses were measured. The results of this study showed that the feeding rate of biomass (2.5%) and satitation had no significant effects on growth performance and nutrition of this fish (P<0.05). However, different levels of temperature showed a significant effect on these indices (P <0.05). The average final weight of fish grown at 33 °C and fed at the biomass level was higher than other treatments, although this difference was not significantly different from that of the stored group at 27 °C. Among the hematology parameters, the number of red blood cells showed significant changes among treatments (P<0.05). Plasma biochemical parameters such as triglyceride, glucose and cholesterol level were significantly affected by water temperature and feeding rates (P <0.05). The activity of liver enzymes in plasma was not significantly different in different treatments (P <0.05). The protein and lipid content of fish carcasses increased with increasing temperature so that the group stored at 33 °C had the highest protein and lipid content (P <0.05). In general, the results of this study showed that temperatures above 27 °C are more optimal for this species and the feed rates of biomass and satiation have no significant effect on the growth and health performance of this fish in this temperature range.

Inroduction & Many fish tolerate natural fasting periods throughout the year, the winter, during reproductive migration, or when they endure a reduction in food in the living environment. In this study effect of long-term starvation periods on liver and intestine structure of Siberian sturgeon, Acipenser baeri, with an initial body weight of 56±0.54 g was carried out for 5 weeks. After adaptation for 2 weeks to experimental conditions, 225 experimental fish were randomly distributed in nine 500L fiberglass tanks. The fish were exposed to 3 different feeding regimes; Control (fed four times daily); T1 (2 weeks starvation) and T2 (3 weeks starvation). At the end of the experiment, to investigate the changes of liver and intestine structure, 6 fish specimens from each treatment was randomly selected and fixed into Bouin solution for histological examination. Then, the samples were placed in Paraffin and 7 µm microscopic slides were prepared using standard histological methods and after coloration were investigated under light microscope. Digestivo and hepato somatic indices (DSI and HSI) and length of villi in the control group were significantly higher (P< 0.05) than the fish starved for 2 and 3 weeks. Length of enterocytes did not show any significant variation among experimental treatments (P> 0.05). The results of microscopy investigations indicated that most pathological signs such as hyperemia, necrosis, fatty degeneration and bile stagnation in the liver of Siberian sturgeon in the deprived fish were observed when compared to the control fish. However, hyperemia, fatty degeneration and bile stagnation in the deprived fish for 2 weeks were lower than that of the deprived fish for 3 weeks, but not significantly. Overall, the results showed that long-term starvation period on liver and intestine structure of Siberian sturgeon, Acipenser baeri, can be effective by utilizing reserves of these tissues.

The present study was conducted to assess the influence of dietary manganese sulfate nanoparticles on the growth performance, hematology, and blood biochemistry of rainbow trout (Oncorhynchus mykiss). 240 rainbow trout with an average initial weight of 0.8±0.1gr distributed into four treatments with three replicates and were fed with four diets including a control diet (without manganese), Mn-M (containing 10mg/kg manganese sulfate), Mn-N10 (containing 10mg/kg nano manganese), Mn-N15 (containing 15mg/kg nano manganese) for 6 weeks. The fish were hand-fed to satiation four times daily. At the end of the experiment, the average final weight of fish fed diets containing nano Manganese were significantly higher compared to control treatment (p<0.05), however, there was no significant difference compared to the group fed with manganese sulfate (p>0.05). Condition factor (CF) in juveniles fed diets containing Mn sulfate nanoparticles did not show a significant difference compared to those fed with manganese sulfate (Mn-M; p>0.05). The levels of hemoglobin (Hb) in fish fed Mn-N10 diet was significantly higher than fish fed with the control diet. Fish fed diets Mn-N10 and Mn-N15 showed higher plasma albumin compared to the control and Mn-M diets. In general, the results of this study showed that dietary supplementation of manganese sulfate nanoparticles compared to manganese sulfate had no significant impact on growth performance, hematological and biochemical composition of rainbow trout.

Aims: In recent years, marine fish farming has been one of the most important aquaculture activities in tropical regions, and their cultivation has grown considerably in most parts of the world. Thus, this study aimed at investigating the effects of different water temperatures on growth performance, biochemical body composition, and hematological indices of Asian sea bass (Lates calcarifer).
In the present experimental study, 3 temperature treatments, including 20, 27, and 33°C with 3 replications for 6 weeks were run on 8 sea bass fish, which were randomly transported to 500 liter tanks and fish feeding was done, using commercial concentrate food. At the end of the experiment, the growth performance, hematological indices, and biochemical body composition of the fish were measured. The data were analyzed by SPSS 18 software, using one-way ANOVA and Duncan tests.
Findings: The final weight of the fish reared in 27°C was significantly higher than the other 2 treatments. Specific growth rate, weight gain, feed intake, and protein efficiency ratio of 27 and 33°C were significantly higher than 20°C group. Hematological parameters did not show significant differences. Among the hematological biochemical compositions, glucose and cholesterol were significantly affected by temperature. The activity of liver enzymes in the reared fish plasma and the biochemical body composition of the fish (fat, protein, ash, and moisture) were not significantly different.
The temperatures of 27 and 33°C are suitable for Asian sea bass farming in sea water. Hematological indices and chemical body composition of the fish are not affected by different temperatures.