Supplementing NSP enzymes in high concentrate diets can prevent foamy rumen bloat in goats

Ruminants fed high concentrate diets (HCD) are highly susceptible to foamy rumen bloat, but up to now the cause of rumen foam formation is unknown, making it difficult to prevent effectively. Exp. 1 of this study investigated the relationship between saccharide content in rumen fluid (RF) and foaming performance, and explored the effect of supplementing non-starch polysaccharides (NSP) enzymes to RF on foaming performance. The RF of 16 HCD-fed goats was used as experimental material to correlate RF viscosity, foaming performance, and saccharide content. Subsequently, the RF from 4 goats with severe rumen bloat was collected as experimental material, divided into 5 equal portions and randomly assigned to 5 treatment groups, namely adding 0, 100, 300, 500, and 700 mg/kg NSP enzymes to the RF. The viscosity and foaming performance of the RF, as well as the saccharide content, were determined for each treatment group. The results showed that polysaccharide was significantly and positively correlated with viscosity and foaming performance (P < 0.05). The supplementation of NSP enzymes notably decreased the polysaccharides content in RF and foaming performance (P < 0.05), with the best effect achieved by supplementing 500 mg/kg NSP enzymes. Exp. 2 further investigated the feasibility of supplementing NSP enzymes to HCD to prevent rumen bloat in goats. Twelve goats with rumen fistula were selected as experimental animals and were randomly assigned to 2 dietary treatment groups with 6 goats in each group, including CON (basal HCD) and E (basal HCD + 500 mg/kg NSP enzymes). The trial was conducted for 18d with a 6d sampling period. The rumen contents and RF were collected daily during the sampling period to determine rumen fermentation indexes, foaming performance and microbial structure and composition, and to determine nutrient digestibility in goat. The results showed that supplementation of NSP enzymes in HCD significantly reduced foaming performance in goat RF (P < 0.05), the effects on nutrient digestibility, rumen fermentation, and microbial composition were not significant (P > 0.05). In summary, polysaccharide is an important factor affecting the foaming performance of RF, and supplementation of NSP enzymes in HCD can prevent the occurrence of rumen bloat.