The individual and combined effects of hypoxia and high-fat diet feeding on nutrient composition and flesh quality in Nile tilapia (Oreochromis niloticus).

Hypoxia and high-fat diet (HFD) feeding are two factors commonly existing in aquaculture. However, their individual and combined effects on nutrient composition and flesh quality in fish have not been investigated. The present study evaluated the alterations of growth, nutrient composition and flesh quality in Nile tilapia (initially 7.0 ± 0.1 g and 5.6 ± 0.2 cm) fed with normal fat diet (5.95% fat) or HFD (11.8% fat) at two dissolved oxygen levels (1.1 ± 0.1 and 7.2 ± 0.1 mg/L) for 8 weeks. The results showed that hypoxia and HFD had similar effects in inducing lipid deposition, reducing flesh protein and amino acids content, pH values and water holding ability. Hypoxia had additional adverse effects in decreasing meat yield, flesh contents of n-3 PUFA and glycogen, increasing flesh fragmentation and causing liver damages. The combination of hypoxia and HFD significantly decreased feed intake, survival rate and muscle protein content, but didn't affect flesh quality-related parameters.