Replacing a farm-mixed diet with a commercial complete feed increases laying rate and is associated with physiological and cecal microbial changes in late-laying local crossbred hens.

This study examined the response to replacing a farm-mixed diet with a commercial complete feed in late-laying local crossbred hens. A total of 60 hens, approximately 350 d of age, were assigned to a 2 × 2 factorial design with genetic background and diet as factors, with 15 individually housed hens per treatment combination. The trial lasted 42 d. Laying performance was recorded throughout the trial, and egg quality was assessed on d 21 and 42. Serum indices were measured in 4 hens per treatment combination at each sampling time; reproductive traits, hepatic gene expression, and cecal microbiota were assessed on d 42. The diets had similar metabolizable energy and crude protein concentrations but differed in other nutrients and ingredients. The complete feed increased laying rate during both periods (P < 0.01). On d 21, diet affected egg length-to-width ratio, albumen height, Haugh unit, and yolk color. On d 42, diet affected yolk color, and genetic background × diet interactions were detected for albumen height and Haugh unit (P < 0.05). The complete feed decreased serum malondialdehyde and increased total superoxide dismutase and glutathione peroxidase activities on d 21; catalase and total superoxide dismutase activities were higher on d 42 (P < 0.05). Serum anti-Müllerian hormone was lower with the complete feed at both times (P < 0.05), whereas large white follicle counts were higher (P < 0.05). Hepatic CAT, GPX1, and SOD1 expression showed genetic background × diet interactions (P < 0.05). Cecal community structure differed among treatment combinations (P = 0.001); taxon-level comparisons were exploratory. The design does not identify the individual dietary components responsible for these responses. Replacing the farm-mixed diet increased laying rate and was accompanied by selected physiological and microbial differences, although production-scale studies that measure feed intake and feed cost per egg are needed before this feeding strategy can be recommended.