Integrated multitrophic culture of shrimp Litopenaeus vannamei and mullet Mugil liza in biofloc system with different feeding rates for fish

This study aimed to evaluate the effect of different feeding rates for mullets on the zootechnical performance of Litopenaeus vannamei and Mugil liza in an integrated multitrophic culture of shrimp and mullet in a biofloc system and on the efficiency of the system. For this, an experimental study of 46 days was carried out at the Marine Shrimp Laboratory of the Federal University of Santa Catarina. The experiment had four treatments, each one with four replicates: A0 (feed offer for shrimp and no feed offer for mullets), A1 (feed offer for shrimp and offer of 1% of fish biomass of feed for mullets), A2 (feed offer for shrimp and offer of 2% of fish biomass as feed for mullets) and A3 (feed offer for shrimp and offer of 3% of fish biomass for feed for the mullets). Each experimental unit consisted of an 800 L tank, in which shrimp were stocked, and a 90 L tank, used for mullets, connected to a recirculation system. Shrimp were stocked with an initial weight of 2.36 g ± 0.02 g. Mullets’ inicial weight was 17.06 g ± 0.65 g. The stocking density used was 375 shrimp m-3 (300 shrimp per tank), while the fish density was 167 fish m-3 (15 fish per tank). Animal growth performance, water quality, as well as total heterotrophic bacteria and Vibrio sp. concentration in the system were evaluated. It was observed that shrimp performance was not affected by different feed offer for fish, having in the end a survival above 82%, weekly growth around 1.50 g and feed conversion factor close to 1.60 in all treatments. Despite the higher input of nutrients into the system with higher food supply, there was no change in the water quality parameters with the treatments, or in the count of total heterotrophic bacteria and Vibrio sp. [1] In conclusion, the best feed supply rate in the integrated cultivation of shrimp and mullet was 2%, due to the proximity of the results of zootechnical performance with the 3% rate, without affecting water quality or the count of total heterotrophic bacteria and genus Vibrio sp.