Nutritional profile and heavy metal contamination of nursery, grower, and finisher feeds of tilapia (Oreochromis niloticus) in Bangladesh

Abstract

Tilapia, the third most cultured fish, is a part of the daily diet of more than 50% of the population of Bangladesh. Thus, adequate nutrition and toxic metal-free tilapia fish feeds are the prerequisites of sustainable aquaculture. The present study was carried out to investigate the nutritional profile and heavy metal pollution in nursery, grower, and finisher types of feeds of tilapia commercially available in Bangladesh. The proximate composition (moisture, protein, lipid, ash, crude fibre, and carbohydrate), mineral nutrients, fatty acid profile, and heavy metals (Pb, Cd, Cr, Ni, Cu, and Zn) of feed samples were assessed. Low protein content and the absence of essential fatty acids mark the feeds as low-quality diets. A significant amount of trace metals were also detected in the feeds, posing a direct threat to the health of the fish and, ultimately, to consumers. The results revealed the highest Zn concentration in all tilapia feed samples. The descending order of heavy metal concentrations was identified as Zn>Ni>Pb>Cu>Cr in nursery feeds, Zn>Cu>Cr in grower feeds, and Zn>Ni>Cu>Cr>Cd in finisher feeds. Pb and Cr values were higher than the recommended values set by FAO. Therefore, strong monitoring is recommended to ensure the optimum quality and safety feeds.

Keywords

• Tilapia feed
• Proximate composition
• Heavy metal
• Pearson correlation
• Fatty acid nutrition