The present study was conducted to evaluate the in vitro dry matter disappearance (IVDMD) and fermentation characteristics of 6 fibrous feedstuffs incubated with donkey cecal or colic microorganisms. The fibrous feeds were corn straw, wheat straw, peanut vine, peanut shell, wheat shell and wheat bran (WB), which are commonly applied in large-scale donkey farms in China. After 48 hours fermentation, the highest IVDMD occurred in WB, and the lowest occurred in peanut shell (P < .05) regardless what inoculum applied. The IVDMD was positively correlated with OM (R = 0.42, P < .01), CP (R = 0.76, P < .01) and EE (R = 0.56, P < .01), while it was negatively correlated with NDF (R = 0.75, P < .01) and ADF (R = 0.79, P < .01). In terms of volatile fatty acids (VFAs), the greatest net VFA production also occurred in WB (P < .05). The acetate and branched-chain volatile fatty acid proportions were greater in the colon culture fluids than in caecum (P < .05), but the propionate proportions were lower in colon than in caecum (P < .05). This resulted in an increase in the ratio of acetate to propionate in colon culture fluids. In summary, based on the highest IVDMD, net VFA production and CP content occurring with the lowest contents of both NDF and ADF, WB had the highest nutritive value compared to other fibrous substrates. The extent of feed degradation and fermentation depended mainly on the nature of the incubated feedstuffs. Nevertheless, further study is required to investigate these fibrous feeds on hindgut fermentation and in vivo nutrient digestibility.
Keywords: Caecum; Colon; In vitro fermentation technique; Volatile fatty acids.
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