Effects of dietary trace mineral sources on production parameters and intestinal microbiota in broiler breeder hens

Trace minerals are essential for maintaining physiological functions in poultry, including antioxidant defense, immune regulation, and reproductive performance. However, the bioavailability of conventional inorganic trace elements is relatively low, and their effects on gut microbiota and reproductive physiology in broiler breeder hens remain insufficiently understood. This study investigated the effects of inorganic trace elements (ITE), methionine hydroxyl analog chelated trace minerals (MTE), and proteinate trace minerals (PTE) on performance, egg quality, antioxidant status, immune responses, reproductive hormones, and cecal microbiota. A total of 432 Hubbard female broiler breeders (50 weeks old) were randomly assigned to 3 treatments with 6 replicates of 24 birds each for 56 days. No significant differences were observed in laying performance or egg quality among treatments (P > 0.05). However, dietary organic trace minerals significantly increased the activities of total superoxide dismutase (T-SOD) and catalase (CAT) and reduced malondialdehyde (MDA) concentrations in plasma and eggs (P < 0.05). MTE and PTE also increased plasma estradiol (E2), progesterone (PROG), and follicle-stimulating hormone (FSH), while PTE elevated plasma IgA and IgM levels (P < 0.05). No significant differences were observed in α-diversity indices of the cecal microbiota (P > 0.05). However, β-diversity analysis showed distinct clustering among treatments. LEfSe analysis identified differential microbial taxa, with the PTE group showing higher relative abundances of Lactobacillus and Enterococcus, while the ITE group exhibited higher relative abundance of Bacteroides. Overall, dietary organic trace minerals, particularly proteinate trace minerals, improved antioxidant status, immune function, hormonal profiles, and intestinal microbial structure in female broiler breeders, suggesting their potential advantages over inorganic trace mineral supplementation.