According to the United Nations, about two billion people in the world cannot count on regular access to safe and sufficient food, and in 2018 some 821 million people suffered from hunger or malnutrition. A key to tackle this challenge is the ability to develop sources of available and nutritious food even in challenging conditions. Research led by Ben-Gurion University of the Negev scientist Prof. Itzhak Mizrahi together with colleagues from the Agricultural Research Organization and The Hebrew University of Jerusalem might help expand the possibilities of carrying out aquaculture – growing fish in ponds – in harsh environments, providing an extraordinary alimentary resource. As explained in a recent article in Nature Microbiology, the group identified the functionality of fish’s core microbiomes, an element that has a deep impact on living organisms and on how they survive and operate.“It’s very little known, but microbiome communities live in the gut environment of multicellular organism from fish to human beings and they interact deeply with their hosts and with their well-being,” Mizrahi explained to The Jerusalem Post. “Fish have microbial communities in their guts, called gut microbiome, that we presume that they affect the fish’s ability to cope with a changing environment.”Core microbes are those found in multiple fish species, the researcher pointed out. A key question explored by the study is what enables them to be maintained inside their host organism in such a persistent way, a question that so far has not been completely answered for any creature, humans included.“We decided to tackle this issue for fish. We looked for core microbiomes and indeed we found eight microbes in the first two species we considered and in many others as well. Afterwards, we tried to identify which specific features enable them to persist in multiple species and gut environments,” Mizrahi said.Indeed, what the scientists found out is that those microbes are more genetically viable than others. Looking at their interaction, they also discovered that the core microbes facilitate each other.“Each one of them consumes different parts of the fish diet and by doing so they produce chemicals and they cross-feed each other, a feature that allow them to better survive in various conditions,” the professor said.“Why is this important? Because this finding will really enable us, I hope in the near future, to better design such microbial communities to support the well-being of fish and their ability to survive in harsh environments also considering that these animals do not adapt very well since they are ectothermic organisms which cannot control their body temperature,” he explained, adding that based on a previous study. experts believed that microbiomes are also responsible for helping fish to maintain their temperature.The expectation is that this study, whose main goal was to achieve results that could support aquaculture activities and increase their productivity, will also help to tackle the challenges posed by global warming, since sea temperatures are expected to rise dramatically in the coming years.The study was conducted on tilapia, the most common species grown through aquaculture, and European bass, especially relevant to the Mediterranean area. According to a joint report by World Bank, FAO, and the International Food Policy, by 2030, it is estimated that over 60% of fish for food will come from aquaculture rather than wild catches.“Our next step is to use what we discovered to actually engineer the microbiomes or their composition to support specific features of the host, for example swimming faster or surviving better in specific environments. Our hope is to synthetically design microbiomes specifically for aquaculture,” Mizrahi concluded.