Study identifies new bacteria that influence animals' ability to adapt to environmental change

Some animals are better able to adapt to environmental change. And the key lies in their DNA and Microbiome. A recent study led by a team from the Universitat Politècnica de València (UPV), part of the Institute of Animal Science and Technology (ICTA), has shown how the immune system is affected differently depending on the bacterial composition of each animal. The results of this study, which also involved researchers from the Universitat Miguel Hernández (UMH) and the Universitat de Lleida (UdL), have been published in the journal Microbiome.

The research is the first in the field of animal breeding to identify gut bacteria that could influence the ability of animals to adapt to environmental changes, i.e., their resilience. Furthermore, these bacteria could, in turn, be regulated by the animals' genes. In this way, the results obtained by the UPV and UMH team could contribute to improving animal welfare and the sustainability of the livestock sector.

"The immune system is key to responding to environmental threats, such as infection by external pathogens. Our identification of these bacterial species highlights the importance of the immune system in regulating resistance. We have identified genes and species that contribute to a better health of the individual and therefore to a better adaptive capacity," explains Cristina Casto, Research Assistant at ICTA and co-author of the study.

A study involving 13 generations of rabbits

To reach these conclusions, the UPV, UMH and UdL teams compared the microbial composition of two lines of rabbits living in the same environment with the same genetic origin but selected in different ways. The lines were divergently chosen at the UMH over 13 generations, considering a specific phenotype: the environmental variance of litter size. The importance of this phenotype lies in its relationship with the animal's ability to counteract or cope with environmental changes without affecting its production or recovering in an optimal and fast way. In other words, it has been observed that animals with lower environmental variance in litter size are more resilient.

Using different bioinformatics tools, the UPV team analysed a representation of animals from both rabbit populations. Using various statistical methodologies, they identified several groups of bacteria and bacterial genes that allowed them to classify and predict which animal belonged to which population with more than 90% reliability. In total, 35 species of bacteria were identified. Although the effect of many of them is unclear or unknown, some of those identified regulate immune activity and could affect the health status of the rabbits and, thus, their resilience.

"Among the bacterial groups, species beneficial to the health of the individual were observed in the most resilient animals, such as Limosilactobacillus fermentum and Odoribacter splanchnicus, while the most harmful species were greater in the least resilient line (Eggerthella sp and Acetatifactor muris)," explains Cristina Casto. The study also identified microbial pathway genes that could contribute to the regulation of the immune system.

"All these results suggest that the immune system is influenced differently by the bacterial composition of each animal population. This work allows the future livestock industry to use this knowledge to study the composition of bacteria in their animals and select those best suited to modulate resistance. Microbiome-based selection would be possible. In addition, we could study the benefits of developing probiotics based on these bacterial species, modifying animal resistance in a simpler, cheaper and more applicable way on a large scale," concludes Noelia Ibáñez, Research Assistant at ICTA.