RESUMO
This study aimed to evaluate the effects of natural extracts from nine medicinal herbs (SMA) on the growth performance, immunity, and intestinal integrity of broilers experimentally infected with Eimeria tenella. A total of 252 one-day-old broiler chicks were divided into 7 groups with 3 replicates per group and 12 broilers per cage. The groups were uninfected-untreated blank control group (BC), infected-untreated negative control group (NC), SMA treatment groups, Chinese medicine positive control group (CM), and chemical drug positive control group (CD). The SMA groups were infected and fed a basal diet supplemented with 0.6 (SMA-L), 0.8 (SMA-M), and 1.0 (SMA-H) g/kg SMA. The CM and CD groups were infected and fed a basal diet supplemented with 15 g/kg Jiqiuchong San and 0.2 g/kg Diclazuril, respectively. Results showed that feeding SMA could significantly reduce the number of oocysts in infected chickens, especially 1.0 g/kg SMA, which exhibited moderate anticoccidial efficacy. When infected with E. tenella, the supplementation of 1.0 g/kg SMA increased the renal index; restored the hepatic, splenic, and bursal indexes to BC levels; increased the levels of immunoglobulin A (IgA), IgM, and IgY; and reduced the contents of tumor necrosis factor (TNF-α), interferon-γ (IFN-γ), interleukin-6 (IL-6), and IL-10 of the infected chickens. Moreover, treatment with 1.0 g/kg SMA alleviated the pathological changes in cecal tissue and increased the contents of zonula occludens-1 (ZO-1), occludin, claudin-1, and mucoprotein 2 (mucin-2) in cecal tissues of E. tenella-infected chickens. We found that 1.0 g/kg SMA reduced the number of oocysts, improved immunity, and alleviated intestinal barrier damage, which could improve the growth performance of infected chickens. Thus, SMA proved to be an effective natural extract against E. tenella and has the potential to be used as an efficient anticoccidial drug or additive.
