Replacement of fish meal with soybean meal in diets for pink shrimp (Farfantepenaeus paulensis)
This study aimed to evaluate the replacement of fish meal with soybean meal in practical diets for the pink shrimp, Farfantepenaeus paulensis. Six iso-protein and iso-energy diets, containing different proportions of fish meal and soybean meal, were provided to post-larvae of this shrimp for 28 days. The levels of fish meal substitution for soybean meal were 0% (control), 12%, 24%, 36%, 48% and 60%, with the experimental diets being named according to the respective levels of substitution. A water recirculation system with 24 plastic boxes containing 40 liters of sea water and a 200 liter biological filter was used. One hundred post-larvae (PL10) of shrimp, with an initial weight of 1.22 mg (± 0.44) and a total length of 7.77 mm (± 0.93),were randomly assigned to each of the experimental units. The means (± standard deviation) of temperature, salinity and pH during the experimental period were 27.6ºC (± 0.9), 34.2 (± 1.0) and 8.09 (± 0.05), respectively, while that of dissolved oxygen was 7.30 mg / L (± 0.37). The mean concentrations of total ammonia and nitrite were 0.05 mg / L N-AT (± 0.02) and 0.03 mg / L N-NO2- (± 0.05), and at the end of the experiment , the nitrate reached 2.27 mg / L N-NO3 -. The 60% fish meal replacement diet resulted in the greatest weight gain (p <0.05). The control diet resulted in the lowest growth (p <0.05). Similarly, TBI was also higher for the 60% diet and lower for the 0% diet (p <0.05). The final weight ranged from 20.84 to 27.37 mg and the specific growth rate (TBI) was between 9.1 and 10.7% / day.The survival rate of the different treatments ranged from 70 to 80%, with no significant differences being detected (p> 0.05). According to the conditions of the present study, we can conclude that the replacement of up to 60% of fishmeal by soy meal in practical diets results in a higher specific growth rate and, consequently, in the final weight of F .paulensis pink shrimp, without change survival.