Effects of Designed Herbal Formula on Growth Performance, Blood Indices, Organ Traits, and Cecum Microbiology in Broilers

The objective of this study was to investigate the effect of the designed herbal formula (DHF) on growth performance, blood indices, organ traits, and cecum microbiology in broilers. A total of 96 male broilers of 1 d were selected and randomly assigned to two groups with six replicates of eight broilers each. The control (CON) and the basal diet containing 1.0% DHF (Astragali radix, Atractylodes macrocephala Koidz., Isatis tinctoria Linnaeus, and Citri reticulatae pericarpium, 2:1:1:2) were fed separately. The experiment was conducted for 35 days. The results showed that the DHF diet increased body weight and decreased the feed conversion ratio (FCR) (p < 0.05). At 21 days, the spleen, thymus, lymphocytes, and thrombocytes were increased (p < 0.05), and pancreas, duodenum, heterophils, and mean corpuscular hemoglobin (MCH) were decreased (p < 0.05). At 35 days, the heart, pancreas, white blood cell, heterophils, hemoglobin, MCH and mean corpuscular hemoglobin concentration (MCHC) were decreased, while lymphocytes and middle cells were increased (p < 0.05). The results of microbial diversity analysis showed that the DHF diet decreased the microbial diversity of the cecum. Firmicutes and Bacteroidetes were the dominant phyla, where the DHF diet increased the relative abundances of Bacteroides uniformis, Bacteroides vulgatus, and Faecalibacterium prausnitzii, and then decreased the relative abundance of Shigella sonnei. In conclusion, DHF played a positive role in improving the growth performance, immune performance, and relative abundance of Bacteroides uniformis, Bacteroides vulgatus, and Faecalibacterium prausnitzii in cecum microbiology in broilers, and has the potential to be used as a novel feed additive.