The Impact of Different Dietary Ratios of Soluble Carbohydrate-to-Neutral Detergent Fiber on Rumen Barrier Function and Inflammation in Dumont Lambs.

ABSTRACT

Appropriate soluble carbohydrate (SCHO)-to-NDF ratios in the diet are essential for rumen health. The effects of different SCHO-to-NDF ratios (1.0, 1.5, and 2.0) on rumen barrier function and inflammation in Dumont lambs (n = 18, 6 replicates per treatment) was investigated. The SCHONDF ratio was altered by replacing the forage (Leynus chinensis) with corn grain. With an increase in the proportion of SCHO, the final body weight (FBW), average daily gain (ADG), soluble carbohydrate intake (SCHOI), and LPS level increased; and the neutral detergent fiber intake (NDFI), ruminal papillae height, papillae area, and pH decreased (p < 0.05, plin < 0.05). The medium CHONDF group had increased claudin-1 mRNA (p < 0.05, plin = 0.005, pquad = 0.003) and protein (p < 0.05, pquad < 0.001) levels; the high CHONDF group had increased occludin mRNA and protein (p < 0.05, plin = 0.001) levels. The level of the anti-inflammatory cytokine IL-10 was significantly greater in the medium CHONDF group than in the high CHONDF group (p < 0.05, pquad < 0.001). With an increase in the ratio of SCHO, the mRNA level and concentration of the proinflammatory cytokines IL-1ß, IL-6, and TNF-α linearly increased (p < 0.05, plin < 0.05), and those in the high CHONDF group were significantly greater than those in the low CHONDF group. The levels of phosphorylated p65 (plin = 0.003), IκB-α (plin < 0.001), and JNK (plin = 0.001) increased linearly, and those in the high CHONDF group were significantly greater than those in the other two groups (p < 0.05). Therefore, when the SCHO-to-NDF ratio was increased to 1.5, the rumen epithelium was not affected, but when the ratio was increased to 2.0, NF-κB and MAPK were activated in the rumen epithelium, leading to impaired barrier function and inflammation. The suitable NFCNDF ratio for the short-term fattening of Dumont lambs was found to be 1.50.