Daily Protein Restriction Under Different Protein Levels in Whiteleg Shrimp (Penaeus vannamei): Growth, Digestive...

Daily protein restriction, for the first time, under various protein levels for 8 weeks, was tested on growth, hemolymph parameters, digestive and serological enzyme activities, antioxidant defense, immune system, and its relative genes in whiteleg shrimp (Penaeus vannamei) (initial weight: 1.73 ± 0.17 g). We hypothesized that the protein levels in a protein restriction schedule can be decreased to maximize the benefits of protein restriction. The results indicate that a schedule of feeding 1 day of dietary 390 g/kg followed by 2 days of dietary 330 g/kg (1P392P33) is possible without significant impairment of growth, feed efficiency, digestive enzymes, immune system, and antioxidant defense. Further, the P26, P33, and 1P392P26 groups showed a decline (p < 0.05) in growth, flesh quality, and health, showing that dietary 260 and 330 g/kg protein is not enough for this species, even when we put this diet in a protein restriction schedule. Any whiteleg shrimp group fed dietary 260 g/kg protein experienced lower protease activity (p < 0.05), highlighting the impact of protein malnutrition on this digestive enzyme. These groups also had lower catalase activity and expression of penaeidin-3a and lysozyme genes (p < 0.05). There was no clear trend in hemolymph parameters among groups, except for lower triglycerides in experimental groups (but not 1P392P33) than in the control. In conclusion, feeding 66% of the farming period of whiteleg shrimp with the dietary 330 g/kg protein and the rest of the time with the dietary 390 g/kg protein is possible without growth, flesh quality, and health impairment.