Parental training with phloroglucinol protects their offspring from biotic and abiotic stressors in Macrobrachium rosenbergii

Being one of the fastest growing high protein animal foods producing sector, shrimp and prawn aquaculture has increased in demand worldwide. However, disease outbreak is considered one of the most limiting factors in this industry. Among shrimp bacterial diseases, vibriosis is one of the most important bacterial diseases. Additionally, acute hepatopancreatic necrosis disease (AHPND) in shrimp has been responsible for significant losses globally for the past ten years or so. Hence, for future sustainable shrimp farming, broodstock management and production of high-quality shrimp seed becomes a prerequisite for this industry, as it is considered to contribute to health management in general. Being invertebrates, shrimp and prawn solely depend on their innate immune system to combat the invading pathogens. However, in recent years, there is an increasing number of studies claiming innate immune memory in invertebrates. This implies that priming with pathogens or environmental stress or immune elicitors could induce increased resistance. In a previous study using a brine shrimp model, it was demonstrated that phloroglucinol, a plant-derived heat-shock protein inducing compound increased stress resistance in the parental generation, a phenotype that was passed on to the next generations. Intrigued by this, the present study was conducted to expand and validate these observations in commercial prawn Macrobrachium rosenbergii. First, following exposure of M. rosenbergii animals (juveniles) to phloroglucinol, improved survival, later on in life, was observed. Most interestingly, in the next generation, M. rosenbergii F1 animals originating from phloroglucinol-treated parents showed an increased resistance against AHPND causing Vibrio parahaemolyticus and abiotic stress (lethal heat shock and ammonia stress). To the best of our knowledge, this is the first validation study of parental conditioning in any commercial shrimp/prawn species. It is anticipated that this study will facilitate future research and application of parental conditioning as a unique and powerful management strategy against prophylaxis of infectious diseases in the shrimp farming industry.