Early-life supplementation with mannan-rich fraction to regulate rumen microbiota, gut health, immunity, and growth performance in dairy goat kids.

Enhancing gastrointestinal health, immunity, and digestion are key factors to support dairy goat kid performance. Several additives have been studied in relation to these actions. This study investigated the impact of mannan-rich fraction (MRF) inclusion in goat milk on the growth performance, gut health, rumen fermentation, and microbial profiles of Xinong Saanen dairy goat kids. A total of 80 kids aged 14 d and 4.72 ± 0.33 kg BW were randomly assigned into 2 groups: control and MRF (1 g/d MRF mixed into milk). Each group consisted of 40 kids with 10 kids per pen. All kids were given milk individually and fed a starter diet by pen, with the trial lasting 10 wk. Body weight and blood samples were collected on the seventh day at 2, 6, 10 and 12 wk of age, and feed intake was determined daily. From the first to seventh day at 12 wk of age, fecal samples were collected from 4 kids in each group to analyze nutrient digestibility. On the seventh day of 12 wk of age, 4 kids from each group were slaughtered for evaluation of rumen fermentation, rumen microbiota, and gut morphology. The results indicated that MRF supplementation led to greater overall BW, overall starter DMI, and overall ADG, along with a lower overall diarrhea rate. However, no difference in overall feed efficiency and apparent digestibility of nutrients was observed. Furthermore, MRF supplementation resulted in increased ileal villus height; higher RNA expression of claudin-1 and occludin in the duodenum; higher expression of ZO-1, JAM-2, and occludin in the jejunum; and higher expression of claudin-1, JAM-2, and occludin in the ileum. Additionally, the concentrations of overall IgA, overall IgM, and overall IgG were higher in the MRF group. The concentrations of ruminal acetate and total volatile fatty acid were higher with MRF supplementation (P < 0.05). Meanwhile, supplementation with MRF resulted in higher abundance of Bacteroidetes and Succinivibrio and lower abundance of Firmicutes and Succiniclasticum in the rumen. Overall, the growth performance, gut health, immunity, and ruminal microbial structure of dairy goat kids benefited from MRF supplementation.