In vivo assessment of Chaetomorpha vieillardii ethanolic extract as a natural anthelmintic in sheep

Gastrointestinal nematodes (GIN) cause substantial losses in ruminants, including nutrient depletion, anemia, reduced productivity, and mortality. Nematodes' resistance to synthetic drugs has led to interest in alternative control strategies. This study aimed to evaluate the potential of Chaetomorpha vieillardii extract, a green macroalga, as a natural anthelmintic agent and to assess its effects on productivity, feed intake, and digestibility in thin-tailed sheep. Sixteen naturally infected thin-tailed sheep were randomly allocated into four groups: P0 (basal diet), P1 (P0 + C. vieillardii extract 10 mg/kg BW), P2 (P0 + C. vieillardii extract 20 mg/kg BW), and Palb (P0 + albendazole 5 mg/kg BW). Diets were composed of king grass (80 dry matter, DM) and wheat bran (20 DM), targeting 0–50 g/day weight gain. Treatments were conducted over 8 weeks, with a 2-week adaptation period. Counting fecal eggs per gram (EPG) for GIN was monitored weekly. The ethanol extract of C. vieillardii yielded 2.45 with bioactive contents: total flavonoids 117.9 mg EQ/g, phenolics 5.2 mg GAE/g, phloroglucinol-reactive phenolics 2.1 mg PGE/g, and saponins 218.8 mg SE/g. At 20 mg/kg BW, the extract significantly reduced GIN prevalence by 98.1 (P < 0.05). Hematological parameters remained stable, with a positive trend in red blood cell indices, and a significant increase in eosinophils in controls due to infection. Administration at 20 mg/kg body weight enhanced feed intake, nutrient digestibility, feed efficiency, and improved growth performance in sheep. This suggests that C. vieillardii has the potential to be further developed as a natural anthelmintic for sheep, while also enhancing their nutritional status. © 2025 Elsevier B.V.