Protein restriction and fish meal (FM) replacement are crucial for the sustainability of aquaculture. The effects of protein restriction (1 day feeding with dietary 40% protein and followed by 2 days feeding with dietary 35% protein, and using this cycle for 56 days) and FM replacement with an alternative protein mixture (yellow mealworm, spirulina, and rice concentrate; 4:1:4.5 ratio) on growth, body composition, hemolymph parameters, digestive enzymes, serological enzymes, immune and antioxidant system, and relative genes expressions in whiteleg shrimp ( Penaeus vannamei ) (0.63 ± 0.04 g) were tested. The levels of 0%, 33%, and 66% FM replacement (Control includes 25.5% FM, 40% protein, and 9% lipid) with and without protein restriction were adjusted (six treatments and three replicates per group) for 56 days. Applying protein restriction and 33% FM replacement simultaneously without impairment of weight gain, feed efficiency, immune and antioxidant parameters, and serological enzymes was possible. However, 66% FM substitution is excessive and resulted in reduced growth, body protein, digestive enzymes, immune and antioxidant system parameters, and serological enzymes. In conclusion, applying protein restriction along with 33% FM replacement is recommended for whiteleg shrimp farming.
Dehghani et al. (Fri,) studied this question.