Anthelmintic activity of Carica pubescens aqueous seed extract and its effects on rumen fermentation and methane reduction in Indonesian thin-tailed sheep: An in vitro study

Background and aim: Seeds from Carica pubescens were observed to be abundant as waste. This waste contains active plant compounds whose utilization has not been studied in the livestock sector. This study was conducted to evaluate the potential of an aqueous seed extract of Carica pubescens (ASE) as an anthelmintic agent during rumen fermentation and methane reduction.

Materials and methods: Aqueous seed extract of Carica pubescens was prepared from C. pubescens cultivated in Wonosobo, Indonesia. Phytochemical analyses were performed to quantify the secondary metabolite content of ASE. In vitro adult worm mortality tests, scanning electron microscopy, and gas production tests were conducted to evaluate rumen characteristics, methane reduction, and the potential of ASE as an anthelmintic against Haemonchus contortus. Adult worms and ruminal fluid were collected from Indonesian thin-tailed sheep. Two-way analysis of variance followed by Tukey's test was performed using the Statistical Package for the Social Sciences^® 21.0 software to detect significant differences.

Results: In vitro study results showed that 1-5% ASE inhibited H. contortus after the 1^st h of incubation, and 5% ASE suppressed 100% of adult H. contortus worms in the 5^th h. Scanning electron microscopy analysis of ASE-treated worms ASE revealed damaged cuticle structures. ASE had no significant effect on pH, NH₃, volatile fatty acid, acetate, propionate, butyrate, acetate: propionate, or microbial protein in rumen fluid (p > 0.05). The in vitro feed fermentation results showed that ASE significantly affected methane reduction.

Conclusion: The inclusion of up to 5% ASE in sheep diets may serve as a potential alternative anthelmintic against H. contortus as well as a methane reduction agent, without deleterious effects on rumen fermentation.