Effects of Plant Extracts on in-Vitro Gas Production Kinetics and Ruminal Fermentation of Four Fibrous Feeds: Towards Sustainable Animal Diets

Abstract

This study was conducted to determine the effects of increasing doses of plant extracts of moringa, thyme, and rosemary on in-vitro gas production (IVGP) of four fibrous feeds (kikuyu grass, alfalfa hay, oat hay, and corn stover). The extracts were applied at doses of: 0 (control), 6 (low), 12 (medium), and 18 (high) ml/g dry matter (DM). IVGP was assessed using three fistulated goats and different incubation periods. At the end of incubation, dry matter degradability (DMd), gas yield (GY24), metabolizable energy (ME), short chain fatty acids (SCFA), and microbial crude protein (MCP) production were determined. The results showed that the increasing doses of the evaluated extracts had neither linear nor quadratic effect on gas production (GP) of all fibrous feeds (P 0.05). The addition of plant extracts increased GP at all incubation periods (P 0.05), being higher for thyme. Moringa, thyme, and rosemary extracts altered ruminal fermentation parameters, including ME, MCP, SCFA, the partitioning factor at 72 h of incubation (PF72), and DMd, being higher for thyme followed by rosemary and moringa. In conclusion, the addition of thyme extract increased GP, ME, MCP, SCFA, PF72, and DMd compared with rosemary and moringa plant extracts. However, additional in-vivo studies should be conducted to confirm these effects.