Proximate Composition and Heavy Metal Content of Commercial Tilapia Starter Feeds Sold at Asuogyaman Municipality, Ghana

Abstract

One of the main requirements for sustained aquaculture is high-quality fish feed. The quality of fish flesh, including shelf life, appearance, flavour, colour, and nutritional value, is determined by the feed quality. Consumers today are highly concerned about several issues related to fish farming practices and the different materials used in producing fish feed. The primary objective of the present investigation was to evaluate the proximate composition (protein, lipid, moisture, ash, carbohydrate, and crude fibre) and levels of heavy metals (Cr, Pb, Cd, Zn, and Cu) in selected commercial tilapia starter feeds available in Ghana. There were no significant variations between the nutritional content offered by feed firms and the values identified in this analysis. However, the derived proximate values for the study were lower compared to the feed manufacturers. The findings revealed the presence of different heavy metals in the feeds at varying levels. Chromium (Cr), lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu) were the heavy metals with the highest levels (mg/kg), with values of 0.544, 0.141, 0.020, 1.821, and 7.758, respectively. The concentration of chromium (Cr) in the current study exceeds the maximum allowable limits of 0.05 mg/kg set by international organisations, which may be detrimental to the fish's health. The study suggests that commercial fish feed producers take the necessary precautions to guarantee the nutritional integrity of their products and prevent heavy metal contamination. Otherwise, the final consumers—humans and fish—might be more susceptible to accumulating and assimilating the heavy metals, which could have health implications.