Black soldier fly protein–based microencapsulation of lemongrass oil improves rumen fermentation efficiency and mitigates methane production in vitro

Vet World Vol.19 January-2026 Article - 4

Research Article

Veterinary World, 19(1): 39-51

https://doi.org/10.14202/vetworld.2026.39-51

Maharach Matra¹, Chaichana Suriyapha², Gamonmas Dagaew³, Rittikeard Prachumchai⁴, Srisan Phupaboon⁵, Sukruthai Sommai⁶, Theerachai Haitook⁷, Sajee Kunhareang⁷, and Metha Wanapat⁸

1. Division of Animal Science, Department of Agricultural Technology, Faculty of Technology, Mahasarakham University, Maha Sarakham 44150, Thailand.

2. Animal Production Innovation and Management Division, Faculty of Natural Resources, Prince of Songkla University, Hat Yai Campus, Songkhla 90110, Thailand.

3. Nakhon Phanom Provincial Livestock Office, Department of Livestock Development, Nakhon Phanom 48000, Thailand.

4. Department of Agricultural Technology, Faculty of Science and Technology, Thammasat University, Pathum Thani 12120, Thailand.

5. Department of Biology, Faculty of Science, Mahasarakham University, Maha Sarakham 44150, Thailand.

6. Department of Animal Science, Faculty of Agricultural Technology, Buriram Rajabhat University, Buriram 31000, Thailand.

7. Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.

8. Tropical Feed Resources Research and Development Center, Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.

Background and Aim: Essential oils (EOs) are promising natural modifiers of rumen fermentation and methane production; however, their volatility and rapid degradation limit their effectiveness. Microencapsulation can shield bioactive compounds and allow controlled release. Insect-derived proteins, especially from black soldier fly (BSF; Hermetia illucens L.), offer a sustainable and functional wall material, yet their use for rumen-targeted delivery remains unexplored. This study aimed to assess the effects of microencapsulated-lemongrass oil (M-LEO) using BSF protein as a biopolymer wall on gas kinetics, nutrient degradability, rumen fermentation parameters, microbial populations, and methane output in vitro.

Materials and Methods: A completely randomized design was used with five dietary treatments containing M-LEO at 0, 2, 4, 6, and 8% of total dry matter (DM) substrate. In vitro rumen fermentation was performed using rumen fluid from Holstein-crossbred dairy cattle. Fermentation was measured at 12, 24, and 48 h for gas kinetics, in vitro dry matter degradability (IVDMD) and in vitro organic matter degradability (IVOMD), pH, ammonia-nitrogen (NH₃-N), volatile fatty acids (VFAs), methane production, and microbial populations quantified by real-time polymerase chain reaction.

Results: M-LEO showed high encapsulation efficiency (85.2%) and significant bioactive content. Supplementing with M-LEO notably improved gas production kinetics and nutrient degradability, with optimal effects at 6% of total DM. At this level, IVDMD and IVOMD increased by up to 11.5% and 10.5%, respectively. Total VFA and propionate concentrations rose significantly (p < 0.05), while acetate proportion and the acetate-to-propionate ratio decreased. Rumen pH and NH₃-N levels stayed within optimal ranges and were unaffected by treatment. Methane production was substantially reduced, with decreases of up to 48.8% at 48 h compared to the control. Additionally, M-LEO boosted populations of key cellulolytic bacteria (Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens) and Megasphaera elsdenii, while significantly suppressing methanogenic archaea (Methanobacteriales).

Conclusion: Microencapsulation of lemongrass oil with BSF protein effectively enhances rumen fermentation efficiency and significantly decreases methane emissions in vitro. This innovative insect-protein delivery system provides a sustainable and climate-friendly feed additive approach, deserving further validation in vivo.

Keywords: black soldier fly protein, climate-smart ruminant nutrition, essential oil microencapsulation, lemongrass oil, methane mitigation, rumen fermentation, sustainable feed additive, in vitro gas production.

How to cite this article: Matra M, Suriyapha C, Dagaew G, Prachumchai R, Phupaboon S, Sommai S, et al. Black soldier fly protein–based microencapsulation of lemongrass oil improves rumen fermentation efficiency and mitigates methane production in vitro. Vet World. 2026;19(1):39–51.

Received: 26-07-2025 Accepted: 26-11-2025 Published online: 06-01-2026

Corresponding author: Metha Wanapat and Sajee Kunhareang E-mail: metha@kku.ac.th and ksajee@kku.ac.th

DOI: 10.14202/vetworld.2026.39-51

Copyright: Matra, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.