Zhentao Lu, Ning Wang, Wenwen Ren, Yongbao Wu, Junting Cao, Yulong Feng, Yiwen Yang, Xuezhuang Wu, Zhiguo Wen
Maotai baijiu distillers' grains (MTDGS) are produced as a by-product of repeated solid-state fermentation and distillation, but their feeding value in duck diets remains poorly characterized. This study evaluated the effects of graded dietary inclusion of MTDGS on growth performance, carcass traits, plasma biochemical variables, intestinal responses, and jejunal microbiota in Pekin ducks. A total of 192 one-day-old male ducks were assigned to diets containing 0, 6, 12, or 18% MTDGS on an as-fed basis for 35 d (6 pens per treatment; 8 ducks per pen). Across the 35-d study, ADG and final BW were greater at 6% than in control ducks, whereas 12% showed intermediate responses (both P = 0.010). By contrast, 18% MTDGS reduced BW during d 1 to 14, resulted in the greatest overall feed conversion ratio (FCR), and increased abdominal fat yield relative to the control diet (P < 0.001). Dietary inclusion at 6% increased jejunal villus height and lipase activity, whereas 12% increased ZO-1 and Villin mRNA abundance. The 18% diet increased relative duodenal weight, and the 12 and 18% diets increased relative ileal weight; relative jejunal weight increased linearly with inclusion level. Most plasma biochemical variables were unaffected, although plasma uric acid was lower at 18% than at 0% MTDGS. In the targeted comparison of the control and 12% groups, microbial community composition differed without a corresponding change in alpha diversity. Acidaminococcaceae and Phascolarctobacterium were enriched, whereas Treponema and unidentified Clostridia were reduced. One exploratory PICRUSt2-inferred pathway also differed between the groups. Overall, responses to dietary MTDGS were dose dependent: 6% was associated with greater growth, 12% showed intermediate growth responses and favorable changes in selected intestinal endpoints, whereas 18% reduced feed efficiency and increased abdominal fat deposition.