Antioxidant response and body composition of whiteleg shrimp co-cultured with Nile tilapia in recirculating aquaculture

Abstract

Co-culture of the high-value tropical species whiteleg shrimp Litopenaeus vannamei and Nile tilapia Oreochromis niloticus may have significant commercial and environmental benefits. However, feeding regimes and holding conditions must meet the animalsí nutritional requirements and minimize stress reactions. In the current study, whiteleg shrimp and a commercially important red strain of Nile tilapia were maintained in monoculture and in co-culture under controlled conditions in a recirculating aquaculture system. Shrimp in monoculture received a commercial food. Shrimp in co-culture either fed only on tilapia waste or on tilapia waste with a low supplement of commercial diet (treatment ëFSDí). To assess the metabolic stress level of shrimp, we measured the relative expression of the antioxidant-related genes cMnSOD and GPX in the abdominal muscles and the activities of digestive proteinases and alkaline phosphatase in the midgut gland. Shrimp in co-culture showed significantly reduced expression of both antioxidants, indicating lower stress levels than monocultured shrimp fed a commercial diet. Digestive enzyme activities, along with hepatosomatic indices and enzyme expression patterns indicate unimpaired food utilization and excellent nutritional status in shrimp across all treatments. Final body weight was significantly higher in shrimp in both co-culture treatments, with highest growth rates in FSD shrimp. Growth rates indicate that tilapia biowaste/faeces can be used as a sole diet for high-value shrimp, irrespective of the feeding regime. Beyond known benefits such as higher yield and efficient resource use, our results show that co-culture of the 2 species is successful in terms of nutritional provision and shrimp health status.