Feed probiotic adoption in aquaculture feeds is limited due to bottle necks related to feed processing such as high temperature and pressure. Top-coating applications with oil can successfully overcome this issue, enabling probiotic supplementation in commercial feed operations. However, probiotic efficiency in the gut can still be restrained by the fast feed transit rate and body temperature, especially in the case of spore-forming bacteria as Bacillus spp.
A trial was carried out at to evaluate the effects of a multi-strain probiotic Microsaf® (Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus pumilus) primed with the GO Technology® (Germination Optimization Technology; patents US 9,447,376, US 9,932,543 and EU application 14749483.5), intended to improve and accelerate bacteria germination and activity. Shrimp (0.83 ± 0.07g) were stocked under super-intensive conditions (250 shrimp/m2) with water exchange limited to 1% per week, only for sludge removal. Shrimp were fed twice daily for 10 weeks with commercial diets top coated with Microsaf® at Log5 and Log6 CFU per gram of feed and compared to a control group only coated with fish oil.
Supplementation of Microsaf® at Log6 CFU/g significantly increased shrimp survival and, reduced feed conversion rate (FCR). No differences were observed in biomass gain, that was numerically higher in the group supplemented with Log6 CFU/g. In the health-related parameters, a reduced Vibrio spp. counting in the hepatopancreas trend was observed in the probiotic supplemented groups. Phenoloxidase activity in the hemolymph was significantly higher in the group at Log 6 CFU/g. No significant differences were observed in the Vibrio spp. counting in the water and total hemocytes counts in the hemolymph. Feeding cost per kg of shrimp produced biomass was significantly reduced with the probiotic supplementation.
This study demonstrated that shrimp feed supplementation with probiotic at Log6 CFU/g can improve survival, productivity, and feed efficiency under super intensive system, with further health improvements and demonstrated economic feasibility.