Exploring the Effect of Functional Diets Containing Phytobiotic Compounds in Whiteleg Shrimp Health: Resistance to Acute Hepatopancreatic Necrotic Disease Caused by Vibrio parahaemolyticus

SIMPLE SUMMARY: This project explores the effect of feeding whiteleg shrimps with functional diets containing phytobiotics in terms of resistance to acute hepatopancreatic necrotic disease caused by Vibrio parahaemolyticus. This disease brings economic losses of billions of dollars in shrimp production worldwide every year. Our study is one step forward in reducing the use of antibiotics in the control of bacterial diseases in aquaculture. The threat of multiresistant bacteria is an issue of major concern in the current One Health context (mainly in the case of potentially zoonotic bacteria such as V. parahaemolyticus). Here, we provide evidence that feeding shrimps with diets enriched with mixtures of essential oils can be an advantageous strategy to mitigate infectious diseases and, consequently, reduce the rise of antimicrobial resistance of pathogenic bacteria and build an environmentally friendly and sustainable shrimp aquaculture. ABSTRACT: Acute hepatopancreatic necrosis (AHPND) is an emerging severe disease caused by strains of Vibrio parahaemolyticus (Vp(AHPND)) in whiteleg shrimp (Litopenaeus vannamei). Mitigating its negative impact, and at the same time minimizing antibiotics treatments, is the major challenge in shrimp aquaculture. A sustainable strategy could be to include immunostimulants in diet. Phytobiotics, harmless plant extracts with immunostimulatory and biocidal activities, are promising candidates. In this study, we evaluated the effectiveness of two diets (E and F) supplemented with phytobiotics (functional diets) in terms of protecting shrimp against AHPND. For this purpose, groups of animals were fed functional or control diets for 4 and 5 weeks and, subsequently, they were challenged with Vp(AHPND) by immersion. We compared the mortality in infected groups and estimated the percentage of carriers by using a specific qPCR in hepatopancreas tissue. The results showed that mortality was significantly lower in the group fed functional diet E and, after a 5-week feeding schedule. This group also showed the lowest percentage of carriers. The pathological effects were also reduced with diet F. Thus, feeding shrimp with phytobiotic-enriched diets in critical periods will be highly beneficial because it increases the host’s resistance to AHPND pathology.