To continue on the topic of the microbial community within the digestive tract and the relation to health and performance of broiler chickens, as discussed in last month’s article (Brown et al., 2022 a), not only alpha-diversity, but also beta-diversity of ceca microbiota may be affected by graded levels of the soy anti-nutritional galacto-oligosaccharides (GOS) stachyose and raffinose.

Beta-diversity is an analysis used to quantify the similarity between different microbiome populations (Su, 2021). In the field of animal science, the beta diversity tells us how similar the microbiome is within a group of animals fed the same diet under the same environmental conditions. However, in contrast to alpha-diversity, which is considered positive for animal health and performance, greater beta-diversity is related to reduced broiler performance (Stanley et al., 2016).

In a study previously presented at PSA 2022 (Brown et al., 2022 b) further investigations revealed a dose-dependent effect of added anti-nutritional GOS on beta-diversity of ceca microbiota of broiler chickens. Beta diversity analysis of the replicated dietary treatments showed that the differences between samples from the same dietary treatment were small in chicks fed a GOS-free diet or only 0.9% GOS, while a greater variation in ceca microbiota composition was observed in chicks fed 1.9%, 2.7% and 3.6% soy anti-nutritional GOS (Figure 1). In addition, GOS-free and 0.9% GOS groups showed distinct clusters when compared to the other three groups. Thus, these findings indicate greater sample variation within dietary treatment with increased levels of GOS. Or put in other words, the homogeneity of microbiome composition within a group of animals was decreased with increased levels of soy anti-nutritional GOS. In the same study, a linear response of increasing levels of GOS was observed on FCR (the higher the content of GOS in the diet, the poorer the FCR of the chickens), corroborating the findings of Stanley et al. (2016).

In conclusion, dietary anti-nutritional GOS levels does seem to also affect microbial beta-diversity, which is suggested to be negatively correlated with animal performance. This further emphasizes the importance of knowing the content of soy GOS in your starter diet.