Replacement of commercial feed with fermented soybean meal for Penaeus vannamei during the nursery phase

Shrimp farming is evolving towards intensification to enhance productivity and optimize resource usage. The growth of this sector is closely linked to the availability of high-quality postlarvae and juveniles. Intensive nurseries in two-phase systems play a crucial role in improving survival and growth rates during the grow out phase. However, this approach necessitates skilled labor and feeds with high crude protein content, which are expensive and potentially risky to water quality, and therefore to animal health. Therefore, it is essential to develop strategies that improve this farming system. The objective of this study was to evaluate the effect of replacing commercial feed with different levels of fermented soybean meal (FSB; 0, 25, 50, 75, and 100%) using a commercial probiotic composed of a mixture of microorganisms during the culture of Penaeus vannamei postlarvae in an intensive nursery. The water quality, zooplankton density, and standard bacterial plate count of Vibrio spp. in water culture were evaluated. Daily weight gain, average final weight, and final productivity were affected by the 75% replacement. Shrimp fed with up to 50% replacement exhibited superior growth. Survival was not impacted by the replacement levels, remaining above 79%. Total zooplankton density was higher in the FSB 25% treatment (P < 0.05). The Vibrio spp. standard plate count was influenced by the different replacement levels, with 50% replacement reaching the highest levels (P < 0.05). Results showed that FSB can replace up to 50% of commercial feed for postlarvae during intensive nursery, maintaining growth rates similar to those achieved with commercial feed protocols.