Purpose: The purpose of this study is to investigate the effects of dietary protein restriction, compensatory growth, and fasting on growth performance, body composition, hemolymph parameters, digestive and immune system enzymes, and relative gene expressions in whiteleg shrimp (Litopenaeus vannamei). Methodology: The research was conducted to explore the effects of protein restriction and fasting on whiteleg shrimp (0.3±0.03 g). In this experiment, 6 treatments with varying levels of dietary protein (35%) and fasting durations were applied: 7P40 (one-week fasting), 6P40 (one week feeding with 35% protein), 5P40 (two weeks feeding with 35% protein), 4P40 (three weeks feeding with 35% protein), and 3P40 (four weeks feeding with 35% protein). The Control group was fed continuously with 35% protein without fasting. Parameters measured included growth performance, body composition, digestive enzyme activity, serological enzymes, immune and antioxidant responses, and relative gene expressions.
Findings: The results indicated no significant difference in weight gain among the Control (10.22 g), 7P40 (9.37 g), and 6P40 (9.27 g) groups. Feed efficiency in the 35%P group was significantly lower than in the Control. Treatments 5P40, 4P40, 3P40, and 35%P had lower protein and lipid contents, as well as lower protease, total protein, and cholesterol levels compared to the Control. The immune and antioxidant systems were suppressed in the groups exposed to both fasting and protein restriction, with reduced levels of acid phosphatase, lysozyme, superoxide dismutase, and glutathione peroxidase. Additionally, the expression of the lysozyme gene was lower in the 4P40, 3P40, and 35%P groups. These groups also showed higher levels of alanine aminotransferase than the Control.
Conclusion: The results suggest that the combination of protein restriction and fasting impairs growth and health in whiteleg shrimp. It is recommended that whiteleg shrimp be fed with a 40% dietary protein level