Sea cucumber extract enhances glutathione-related antioxidant defense and reduces apoptosis in Eimeria papillata-infected mice.

Eimeria spp. are globally significant parasites infecting many vertebrate hosts and causing coccidiosis. The widespread use of anticoccidial drugs has led to increased parasite resistance, highlighting the need for alternative therapies. This study aimed to evaluate the anticoccidial, antioxidant, and anti-apoptotic effects of Holothuria polii extract (HpE) compared with the reference drug amprolium in mice experimentally infected with Eimeria papillata. Seven groups of mice were studied: a negative control; a group treated with HpE only (200 mg/kg); a positive control (infected untreated); and four infected groups treated with HpE at 100, 200, or 400 mg/kg, or amprolium 120 mg/kg. All infected groups were orally infected with 1 × 103 sporulated oocysts of E. papillata, and all treatments were administered by oral gavage. Initially, oocyst output was assessed in all HpE dose groups to identify the most effective concentration. Results revealed that HpE was found to contain 1.28 g of total phenolics (gallic acid equivalents) per 100 g and 0.05 g of total flavonoids (rutin equivalents) per gram dry weight. A statistically significant reduction in oocyst output was observed in the group treated with 200 mg/kg HpE and amprolium, reaching 63.533 × 104 ± 50.06 × 104 and 0.4312 × 104 ± 0.1280 × 104 oocysts, respectively. Owing to its significant anticoccidial activity alongside its favorable safety profile, the 200 mg/kg HpE dose was selected for subsequent detailed analyses. The 200 mg/kg HpE markedly enhanced the oxidative status, as evidenced by a significant increase in GSH levels (28.11 ± 3.65 ng/mg) and GPx activity (100.9 ± 10.94 U/mg) compared to the untreated group. Similarly, amprolium-treated animals showed a significant increase in both GSH (32.63 ± 179) and GPx (138.6 ± 5.40) compared to the untreated group. Also, it led to a reduction in caspase-3 expression and apoptotic cells in the jejunum and decreased the number of CD68-positive macrophages compared to the infected untreated controls. In conclusion, this study highlights the therapeutic potential of HpE in improving oxidative status, reducing apoptosis, and modulating the immune response during infection. Future studies should explore the underlying molecular mechanisms and evaluate the long-term protective effects of HpE in different infection models.