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The growth performance and muscle quality of tilapia (Oreochromis niloticus) were compared between a fish-rice co-culture system (SD3) and a monoculture system (CG3). Tilapia with initial mean weight of 10 g and mean length of 5 cm raised in improved water quality produced by the co-culture system (SD3) showed better growth parameters, as well as better proximate composition with higher protein and lower lipid content. The free amino acid composition of tilapia muscle in SD3 were better than that of CG3. The major nucleotide (adenosine monophosphate (AMP) and inosine monophosphate (IMP)) contents of SD3 were significantly higher, while the major organic acid contents (acetic acid and malic acid) were lower. In SD3 the muscle fiber area was higher but the muscle fiber density was lower than in CG3. Finally, the SD3 fish had enhanced umami, sweetness, and overall flavor, and less of an earthy-musty taste compared to CG3. Overall, the co-culture of tilapia and rice improved the growth performance and muscle quality of tilapia via improved water quality and rich microbes in rice field. This was conducive for providing fish with high quality.

A total of 204 Cirrhinus molitorella at a stocking density of 7 individuals/m3were equally divided between three closed rectangular concrete ponds (4 m × 2 m × 1.6 m; water depth 1.2 m) with dissolved oxygen concentrations above 5.2 ± 0.3 mg/l, and pH 6.5–8.1. Water flow in the ponds was poor. The amount of feed increased from 0.81 ± 0.35 to 13.42 ± 1.89 g/fish-day throughout the experiment. Samples were collected between mid-March and October 2016, and we monitored the Cd, Cr, and Hg concentrations in gills, large intestines, small intestines, intestine contents, longitudinal muscles, and body wall, and in suspended particles and sediment in the ponds. The effect of fish growth on metal concentrations was determined. Simultaneously, the correlations between heavy metal concentrations in suspended particles, sediment, and fish body wall were assessed. The Cd, Cr, and Hg concentrations in large intestines, small intestines, and intestine contents increased over time as feed application increased, and were significantly higher in intestines than in other tissues. The Cd, Cr, and Hg concentrations in suspended particles and sediment increased significantly as time elapsed and feed increased. The Cd, Cr, and Hg concentrations in the intestinal systems increased as fish grew. Strong correlations were found between heavy metal concentrations in the intestine contents and suspended particles; intestine contents and sediment; and suspended particles and sediment, but correlations with concentrations in the body wall and other substances were weak. Positive relationships between feed provided and metal accumulation resulted from uncontrolled feeding. Poor water flow allowed unconsumed feed containing metals to supply suspended particles containing metals; these enriched the sediment and ultimately supplied metals to the fish. The results provide reference data for developing C. molitorella eco-aquaculture systems. [ABSTRACT FROM AUTHOR]