Fermented Mixed Feed Increased Egg Quality and Intestinal Health of Laying Ducks

This study investigated the effects of adding fermented mixed feed (FMF, composed of several unconventional protein feeds, such as brown rice, rice bran, rice bran meal, sunflower meal, cottonseed meal, and corn starch residue) into the diet of Longyan Shan-ma ducks on their egg quality and intestinal health. The ducks were randomly divided into two groups: one group served as the control and received a standard diet, while the other group received a diet in which 4% of the feed was substituted with FMF. Compared to unfermented feed, FMF had elevated lactic acid levels and reduced phytic acid and crude fiber, along with higher amounts of crude protein and a range of amino acids, including serine, histidine, arginine, alanine, valine, methionine, cysteine, isoleucine, and lysine. FMF significantly enhanced egg production and improved the overall egg quality, such as eggshell strength and thickness. It also enhanced total antioxidant capacity and glutathione peroxidase concentrations in serum while reducing serum urea nitrogen and interleukin-1β levels. Histological analysis showed that FMF supplementation improved the ileal villus height-to-crypt depth ratio. Microbiota analysis demonstrated that FMF had a significant impact on β-diversity by increasing Firmicutes , Actinobacteriota , and Desulfobacterota and decreasing Proteobacteria and Myxococcota at the phylum level. The abundance of Corynebacterium , Lactobacillus , and Gallicola was found to be elevated due to FMF at the genus level, whereas Kocuria , Rothia , Helicobacter , and Escherichia-Shigella were decreased. Additionally, diets supplemented with FMF resulted in higher intestinal valeric acid levels among ducks. Our findings indicate that incorporating FMF into laying duck diets can enhance production performance, egg quality, and gut health.