The use of automatic belt feeders in a Penaeus vannamei pilot scale super-intensive nursery and grow-out with biofloc system

Abstract

This study aimed to evaluate the effect of using automatic belt feeders (BF) on water quality, growth of Penaeus vannamei, and partial budget in super-intensive pilot scale systems with biofloc technology. A nursery phase (2300 shrimp m⁻²) and a grow-out phase (400 shrimp m⁻²) were carried out with the following feeding management strategies, all with three repetitions: T1: by hand, T2: by hand + BF12h; T3: BF24h. In the nursery, a spike in total ammonia concentration was observed in the first weeks of the trial in treatment T1, possibly due to nutrients from uneaten feed. Nitrite was higher in T1 treatment than in T2 and T3. Nitrate was lower in the treatment T1 than in T2 and T3. At the grow-out trial, nitrite was higher in treatment T1 than in T2 and T3. These results indicated a slower nitrification process in T1 and more efficient in treatments where automatic feeders were used since an accumulation of nitrate was observed throughout the trials and low concentrations of nitrite were observed both in the nursery and the grow-out. In the nursery and the grow-out, the T3 treatment had a higher final weight and a lower feed conversion ratio. Furthermore, the T3 treatment had a higher yield than the T1 treatment. Treatment T3 had the highest net benefit/cost, considering the entire production cycle (nursery and grow-out). Our results strongly indicate that using automatic belt feeders allows an improvement in water quality, promotes shrimp growth, improves yield, reduces feed use, and improves the net benefits in P. vannamei super-intensive nursery and grow-out with biofloc systems.