Curculigo orchioides Polysaccharide Promotes the Growth and Development of Wenchang Chickens via the PI3K/Akt/mTOR Signaling Pathway

Previous studies have demonstrated that polysaccharides used as feed additives can promote poultry growth. This study evaluated the effects of different doses of <i>Curculigo orchioides</i> Polysaccharide (COP) on growth performance, antioxidant capacity, immune function, intestinal health and related mechanisms in 1 to 35 days old Wenchang female chicks. A total of 120 female Wenchang chickens (1 day old) were assigned to three treatment groups, with 5 replicates per group and 8 chickens per replicate. The Wenchang chickens were fed a basal diet (control) supplemented with either a low dose of <i>Curculigo orchioides</i> Polysaccharide (400 mg/kg) or a high dose (800 mg/kg) for 5 weeks. Purified COP is composed of mannose (68.97%), glucose (24.38%), galactose (6.34%), and arabinose (0.32%). Results showed that high-dose COP supplementation significantly increased Wenchang chicken body weight (<i>p</i> < 0.05) and feed intake (<i>p</i> < 0.05); reduced feed conversion ratio (<i>p</i> < 0.05); increased small intestinal villus height and tight junction protein expression levels; enhanced muscle fiber cross-sectional area (<i>p</i> < 0.05); improved total antioxidant capacity (<i>p</i> < 0.01); decreased serum malondialdehyde levels (<i>p</i> < 0.01), tumor necrosis factor-α (<i>p</i> < 0.0001), and pro-inflammatory cytokine interleukin-6 levels (<i>p</i> < 0.05); and elevated antibody titers against Newcastle disease virus at 21, 28, and 35 days (<i>p</i> < 0.01). It also elevated the protein phosphorylation levels of the PI3K/Akt/mTOR pathway (<i>p</i> < 0.0001) and enriched beneficial gut microbiota that may mediate this pathway activation. Analysis of the cecal microbiota in Wenchang female chicks revealed that the high-dose COP group enriched Oscillospira and Lactobacillus. In conclusion, high-dose COP improves growth performance and antioxidant capacity of Wenchang chicks, enhances immunity against NDV, enriches beneficial gut microbiota, and promotes growth by activating the PI3K/Akt/mTOR pathway.