جستجوی مقالات مرتبط با کلیدواژه "(piaractus brachypomus)" در نشریات گروه "شیلات"

The main aim of this research is study of growth، survival، nutritional indices and stress response of P. brachymous in rearing conditions in a recirculation system. An experiment carried out in 3 recirculation treatments with 3 replications in 250-liter tanks with a volume of 200 litres water. An extra 100-liter tank prepared as biological filter. Tanks were stocked in 3 densities 50، 75 and 100 fingerling. m-3 with an average weight as 3. 52±0. 11 for duration of 3 months. Water replacement was 10% per day. Survival was determined with counting of dead fish daily and growth with monthly biometry. Blood was collected to determine cortisol and glucose as stress response indices. The results showed that intensity of 100 pis. /m3 has a negative effect on some of the growth indices: average of body weight، absolute growth rate، and daily gained weight (P<0. 05)، but no effect on Specific Growth Rate (SGR)، Relative Growth Rate (RGR) and Condition Factor (CF) (P>0. 05). In addition، the intensity 100 pi/m3 has negative effect on nutritional indices; FCR، protein production value، fat production value (P<0. 05). This stocking increased cortisol and glucose values in the fish (P<0. 05). It is concluded that since the intensity 100 pi/ m3 decreased the gain weight and increased stress responses in Pacu fish، it is suggested that 75 pi/m3 is the best intensity to produce edible fish with the defined experiment.

The effect of replacing fish meal with soybean meal in diets for red pacu on growth performance, body composition and hematological indices was evaluated in an 8-week trial. Five isonitrogenous and isocaloric diets formulated containing 32.04 ± 0.46 crude proteins and 17.26 ± 0.31 KJ gross energy g-1 diet. The control diet was formulated to contain 50% fish meal, whereas in the other four diets soybean meal was included at 16.5, 33, 49.5 and 66% to replace 25 (SBM25), 50 (SBM50), 75 (SBM75) and 100% (SBM100) of the fish meal protein. One hundred and ninety fish (with average weight 1.8 ± 0.07g) were randomly distributed into five treatments (each treatment included 3 replicates). Weight gain and specific growth rate in fish fed SBM25 and SBM50 diets were significantly higher than any of other treatments. Feed consumption in fish fed SBM50 diet was significantly higher than other treatments. Feed conversion ratio in fish fed SBM100 diet was significantly higher than fish fed other treatments, while no statistical significant difference was observed between the four other treatments. Whole body composition fish fed SBM50 diet had significantly lower crude protein, lipid, ash and higher moisture compared with other treatments. Fish fed SBM100 diet had a significantly higher hemoglobin and lower hematocrit than other treatments. The results indicated that an economical diet can be formulated using 50 percent soybean meal in red pacu diets without adverse effect on growth performance.