Nutritional value evaluation of solid-state fermented sorghum fed to meat ducks and its effects on growth performance...

The objective of this study was to evaluate the effects of mixed-culture solid-state fermentation (SSF) with Bacillus subtilis and Candida utilis on the nutritional value of sorghum (SOR) and its application in Cherry Valley ducks. In Experiment 1, a substitution method was used to determine the AME and ileal amino acid digestibility of SOR and fermented sorghum (FS). The diets consisted of a corn-SBM basal diet and two experimental diets containing 70% basal diet mixed with 30% SOR or FS. Experiment 2 was a subsequent growth experiment using sorghum or FS diet. In Experiment 2, 320 ducks (14 days old) were randomly allocated to 3 groups: (1) control (CON) group, meat ducks fed a basal diet; (2) the SOR group, meat ducks fed a corn-soybean meal-based diet with 80% SOR replacing corn; and (3) the FS group, meat ducks fed a similar diet with 80% FS replacing corn. Fermentation of SOR, relative to unfermented SOR, increased CP and trichloroacetic acid-soluble protein while reducing neutral detergent fiber, tannin, and phytate acid (P < 0.05). Furthermore, scanning electron microscopy demonstrated pronounced structural deconstruction that improved nutrient availability. In the first experiment, compared with feeding SOR, feeding FS increased the utilization of ether extract and AME in meat ducks, as well as the digestibility of leucine, histidine, tyrosine, and cysteine in the ileum (P < 0.05). In the second experiment, ducks fed FS exhibited higher body weight and average daily gain and lower feed-to-gain ratio compared with SOR group (P < 0.05). Fermentation also enhanced jejunal and ileal morphology and digestive enzyme activities (P < 0.05). Besides, cecal butyrate concentrations were lower in the SOR group than those in the CON and FS groups (P < 0.05). In conclusion, solid-state fermentation enhanced the nutritional quality and structural properties of SOR. Dietary inclusion of FS as a replacement for corn improved nutrient utilization, growth performance, cecal fermentation characteristics, and intestinal development in meat ducks.