The gut microbiota as a predictor of feed efficiency and feeding behavior in Iberian pigs.

In recent years, the production system of Iberian pigs has been significantly intensified, with new technologies playing a crucial role in recording traits such as feed efficiency. These advances also allow the study of different traits related to feeding behavior. In addition, the composition of the gut microbiota has previously been associated with animal health and performance. This study evaluated the relationship between the host genetics, the gut microbiota, and traits of feed efficiency and feeding behavior up to 180 d of age. First, we quantified the phenotypic variance explained by the host genetics and the gut microbiota using fecal samples collected at 2-time points: 140 and 180 d. Second, we evaluated whether the microbiota at 140 d could serve as an early predictor of phenotypes measured at 180 d. Identifying accurate early predictors may serve as a valuable tool to support future strategies aimed at reducing testing duration in the nucleus of selection. Our results indicate that microbiota accounts for a low to moderate proportion of total phenotypic variance and improves model fit for feed efficiency traits when included. Furthermore, the inclusion of microbiota data at 140 d improved the prediction of feed efficiency traits at 180 d but did not improve predictions for feeding behavior. This study provides valuable insights into variance component estimation for feed efficiency and feeding behavior traits in Iberian pigs fed with automatic feeders and highlights new opportunities to explore the role of microbiota in feed efficiency.