Solid state fermented plant protein sources as fish meal replacers in whiteleg shrimp Litopaeneus vannamei

Six different types of solid state fermented plant proteins and soy protein concentrate were evaluated as fish meal replacers in whiteleg shrimp, Litopaeneus vannamei. In the first experiment, eight experimental diets consisted of a control diet without fish meal replacement (CON), and seven other diets replacing 30 % of fish meal with fermented soybean meal with Bacillus subtilis (FSMB), sterilized FSMB (FSMBS), fermented soybean meal and corn gluten meal with B. subtilis (FSCB), sterilized FSCB (FSCBS), fermented soy protein concentrate with B. subtilis (FSPB), fermented soybean meal with lactic acid bacteria (FSML), and soy protein concentrate (SPC). At the end of eight weeks, weight gain, specific growth rate and serum lysozyme activity of shrimp fed FSMB and FSCB diets were significantly higher than those of shrimp fed CON and FSML diets (P < 0.05). Feed efficiency and protein efficacy ratio of shrimp fed diets FSCB and FSCBS were significantly higher than those of shrimp fed the FSPB diet. Total intestinal B. subtilis count of shrimp fed FSMB, FSCB and FSPB diets were significantly higher than those of shrimp fed the other diets. After eight days of challenge test against Vibrio parahaemolyticus, average cumulative survival rate of shrimp fed diet FSCB was significantly higher than those of shrimp fed CON, SPC, FSMBS, FSCBS and FSML diets. In the second experiment, CON, FSMB, FSCB and FSPB diets, with (O) and without (X) bacterial water treatments were used for four weeks. Total ammonia nitrogen and NO2-N showed significantly lower values for FSCB(O) and FSPB(O) tanks compared to the CON(X) tank (P < 0.05). Total water B. subtilis counts, after 2 and 4 weeks, were significantly lower for both CON(O) and CON(X) tanks compared to all other tanks (P < 0.05). These results indicate that fish meal replacement with FSCB can improve growth, feed utilization, immune response and disease resistance in whiteleg shrimp while improving the water quality indices when administered with bacterial water treatment.