Effect of the shrimp farming wastes as co-feed on growth performance and digestibility of juvenile grey mullet, Mugil cephalus

A feeding trial was carried out to evaluate the utilization of residual nutrients from a shrimp farming wastes as co-feed in different proportions in juvenile grey mullets. Four treatments were designed offering shrimp farming wastes at 0, 33, 66, and 100%. The 4 % of feed respecting the total biomass of each experimental tank was offered daily. The total feed ratio was completed with commercial feed for marine fish in the treatments where it was needed. At the end of the feeding trial, final weight, weight gain, relative weight gain, and thermal growth coefficient were reduced in the fish when increasing the amount of SFW as feed. However, the fish showed a digestive capacity to use residual nutrients up to 66 %, increasing their initial weight by up to 25 %. The increase of shrimp farming waste as feed negatively affected the whole-body proximal composition. The digestibility results showed that the fish could digest up to 41 % of the shrimp farming waste protein. Results suggest that juvenile grey mullets are capable of utilizing residual nutrients from shrimp farming waste. However, it is necessary to use an alternative feed source to induce an optimal growth performance for the juvenile grey mullets. It is also recommended that mullets be fed with formulated feed to meet their nutritional requirements to maintain the protein and lipid content of the whole-body under culture conditions.