Influence of breast milk microbiota on the composition of the early intestinal microbial community in goat kids: a study of composition and correlations

Colonization of gut microbes in young ruminants plays a fundamental role in their lifelong health. Although the relationship between breast milk (BM) and the gut microbiota of young animals has been reported, its specific impact on goats has yet to be thoroughly explored. Therefore, this study aimed to comprehensively reveal the influence of breast milk feeding on the development of intestinal microorganisms in goat kids and the interactions between breast milk microbiome and fecal microbiome. The results showed that there was a significant difference in the richness of breast milk microbiota between the BMD1, BMD7, and BMD14 groups (<i>P</i> < 0.05). At the genus level, the bacterial microbiota in breast milk across different days of age was predominantly composed of <i>Pseudomonas</i>, <i>Asticcacaulis</i>, <i>Mannheimia</i>, <i>Sphingomonas</i>, and <i>Staphylococcus</i>. In contrast, the fecal microbiota of goat kids was primarily dominated by <i>Escherichia-Shigella</i>, <i>Butyricicoccus</i>, <i>Bacteroides</i>, <i>Lactobacillus</i>, and <i>Limosilactobacillus</i>. Significant correlations (<i>P</i> < 0.05) were observed between the microbial communities of breast milk and the fecal microbiota of goat kids. Specifically, <i>Delftia</i> in breast milk was positively correlated with <i>Limosilactobacillus</i> and <i>Lactobacillus</i> and negatively correlated with <i>Lachnoclostridium</i> in the rectal feces of goat kids, and <i>Lactobacillus</i> in breast milk was positively correlated with <i>Ruminococcus_gnavus_group</i>. These results suggest that the structure of the breast milk microbiota may influence the colonization of the intestinal microbiota in goat kids, especially for some probiotic genera such as <i>Lactobacillus</i>. In conclusion, this study elucidates the dynamic changes in breast milk microbiota and the shifts in goat kid fecal microbiota following breast milk feeding, as well as the correlations between them. These findings provide a scientific foundation for enhancing goat kid growth, development, and health through early microbiota modulation in practical production.IMPORTANCEThe gastrointestinal (GI) microbiota has a profound effect on host health, especially in resisting pathogen colonization and promoting intestinal function (T. Zhong, Y. Wang, X. Wang, A. Freitas-de-Melo, et al., Front Microbiol 13:1020657, 2022, https://doi.org/10.3389/fmicb.2022.1020657). The results show that the stability of rumen microbial communities and their associated functions in lambs is not achieved until they reach at least 20 days of age (B. Brooks, B. A. Firek, C. S. Miller, I. Sharon, et al., Microbiome 2, 2014, https://doi.org/10.1186/2049-2618-2-1). From a nutritional perspective, young animals, such as lambs, can be considered non-ruminants (Y. Li, L. Ren, Y. Wang, J. Li, et al., Nutrients, 14, 2022, https://doi.org/10.1017/S1751731119003148). The gut is not only a key organ for digestion and absorption of nutrients, but also plays a variety of important roles in maintaining overall health. Thus, udder feeding may have a significant effect on the construction of the gut microbiota in lambs until 20 days of age. Although the relationship between breast milk (BM) and the gut microbiota of young animals has been reported, its specific impact on goats has yet to be thoroughly explored. Therefore, this study aimed to comprehensively reveal the influence of breast milk feeding on the development of intestinal microorganisms in goat kids and the interaction relationships between breast milk microbiome and fecal microbiome.