Shrimp production is currently limited by emerging infectious diseases outbreaks. Most of these outbreaks are not caused by a single pathogen, but by a combination of pathogens, with a significant contribution to pathogenicity from environmental factors and high stress levels on farm animals. Shrimp humoral immune response is key to responding to these infectious pathogens and promoting faster recovery. Antimicrobial peptides (AMPs), such as penaidin and crustin, are extremely important in this immunocompetence, efficient infection response, disease recovery and maintenance of performance. This work presents laboratory and field studies evaluating the feed application of a phytobiotic-based additive (Sanacore GM) under conditions of co-infection and multiple infections.
The first part of the study aimed to evaluate the impact of the additive (Sanacore® GM, Adisseo) supplementation towards immunocompetence optimization. The relative mRNA expression of AMPs penaidin and crustin in hepatopancreatic tissue was measured after a period of supplementation of 28 days with treated feeds. Test animals were challenged with WSDV (2.7 x 109 WSDV copies/shrimp) and Vibrio parahaemolytycus (4.6 x 108 CFU/ml) applied in feed with a 48hours-time difference between pathogens. Results show a three- and seven-fold statistically significant increase in crustin and penaidin levels in hepatopancreas, respectively, in the additive group. These results are aligned with a numerical improvement in survival of 40% in the additive group at 24 hours after challenge.
The second part of the study aimed to evaluate the effect of different application strategies of the health promoting additive (Sanacore® GM) in a shrimp farm with a history of multiple outbreak infections, including WSDV, EHP, IMNV and Vibrio spp. Two strategies were evaluated: (1) corrective strategy, and (2) combined preventive + corrective strategy. The two strategies were compared to reference historical data. Results show improvements in survival of 58% and 169% by the corrective and the combined strategy, respectively. Feed conversion ratio (FCR) was statistically significant reduced by 5% and 32% by the corrective and combined strategy, respectively. The corrective strategy also increased statistically biomass by 10%, while the combined strategy achieved a 64% improvement. These two trials clearly demonstrate the efficacy of the phytobiotic-based additive (Sanacore® GM) as a strategy to minimize the impact of co-infections and multiple infections and accelerate recovery in shrimp farming.
Key words: shrimp farming, multiple infections, functional additive, performance.