Lallemand-IFREMER partnership shows the benefits and possible modes of action of probiotic Bactocell in Summer Syndrome prevention in New Caledonian shrimp farms

Results of on-going Lallemand-IFREMER partnership on probiotic applications and mechanisms of actions in shrimp farming have been published in peer-reviewed journal Aquaculture1. Thanks to an original experimental system, the joint research program conducted by Mathieu Castex in Nouméa, New Caledonia (South Pacific), demonstrated that the administration of Bactocell® (Pediococcus acidilactici MA 18/5 M) in the feed of marine shrimps (Litopenaeus stylirostris) in farms usually affected by summer syndrome, could reduce vibriosis-associated mortality by up to 15%. As a result, final shrimp yield of the farm is increased.

Moreover, Bactocell modes of action in shrimp were scrutinized and positive effects were highlighted on both digestive functions and gut-associated bacteria populations of the shrimps. These results strengthen previous experimental and field data obtained with Bactocell in various shrimp species under different farming conditions, showing how this particular probiotic bacteria proves to be an effective solution to support sustainable shrimp farming.

M. Castex explains how the present findings, which build on previous laboratory and field results with Bactocell in shrimps, allow to shed some light on the probiotic modes of action in shrimps: “ We looked at the effects Bactocell could have on the shrimps microbiology, digestive function and physiology, and how this could explain the benefits observed on the shrimps growth performance and resistance against vibriosis. First of all, when the shrimps received Bactocell continuously with their diet, their overall gut microbial content was reduced, and in particular, the number of vibrios. There were also less vibrio pathogens in the shrimps heamolymph. This explains why, even though they were in the same ponds, submitted to the same pathogens pressure, the shrimps which received Bactocell survived better to summer syndrome than those on the control diet. Further work is in progress at IFREMER to look closer into the gut microbial populations.”

Concerning the observed effects on shrimp performance, Castex explains: “We showed in our study that Bactocell improved the shrimps nutrient storage process in their digestive gland and enhanced the activity of their digestive enzymes. So, by improving the overall digestive process, Bactocell optimises feed utilisation, resulting in better feed conversion rates and growth performance. This is a property generally associated with probiotics in both aquatic and terrestrial animals, and it has been extensively demonstrated in the case of Bactocell in particular.” Thanks to its use in various terrestrial species, Bactocell (Pediococcus acidilactici MA18/5M) is a probiotic already well-described and characterised.

The present study performed in conditions as close as possible to commercial farming was made possible thanks to an original experimental system designed by Dr Chim of IFREMER2. This system uses floating cages in earthen ponds, allowing to grow “Control” and “Bactocell” -fed shrimps under identical conditions, minimising the impact of the environment on the outcome, a common issue when evaluating a feed additive effect in aquaculture commercial conditions.

Vibriosis are one of the main causes of dramatic losses for major shrimp producing countries. In New Caledonia, where shrimp farming represents a substantial source of revenue, Litopenaeus stylirostris shrimp species is affected by two major vibriosis depending on the season, the summer and winter syndromes. Summer syndrome, caused by Vibrio nigripulchritudo first appeared in New Caledonia in 1997, and quickly became almost enzootic in the first shrimp farm affected. Due to their significant economic impact, the local authorities and shrimp farmers association have now placed the research on vibriosis as a R&D priority for Caledonian aquaculture. The Caledonia Aquaculture Department of IFREMER (the French Research Institute for Exploitation of the Sea), which scientific contribution to global aquaculture and shrimp farming is internationally established, works in this direction and the on-going research partnership with Lallemand is part of a global research program aimed at determining the causes and preventing vibriosis outbreaks in New Caledonia.

If you need more information about this publication or previous research with Bactocell in shrimps as well as images or general information on probiotics, please contact aqua@lallemand.com