Effects of Gamma Irradiation Pretreatment and Exogenous Fibrolytic Enzyme Supplementation on the Ruminal Fermentation and Nutritional Value of Typha latifolia

Efficient bioconversion of lignocellulosic biomass into ruminant feed requires advanced strategies to enhance fiber degradation and ruminal fermentation efficiency. This study evaluates the synergistic effects of gamma irradiation (150 kGy) and exogenous fibrolytic enzyme (EFE) supplementation (4 µL/g dry matter) from Trichoderma longibrachiatum on the structural composition and ruminal fermentation of Typha latifolia. Gamma irradiation significantly reduced neutral detergent fiber (NDF) while increasing non-fiber carbohydrates (NFCs), reducing sugars (RS) and antioxidant activity. These modifications enhanced ruminal bacterial proliferation, suppressed ruminal protozoal populations, and improved ruminal fermentation efficiency by increasing gas production, dry matter degradability, and NDF degradability. Additionally, irradiation decreased ruminal NH3-N concentrations and branched-chain volatile fatty acids (VFAs) without affecting total VFA production and ruminal pH. While EFE alone accelerated only ruminal fermentation, its combination with irradiation further reduced NDF content, enriched NFC and RS, and enhanced fermentation efficiency. This dual treatment increased total VFA production, shifted fermentation pathways toward propionate synthesis, and reduced acetate and branched-chain VFA levels. It also stimulated ruminal bacterial populations without altering ruminal pH. These findings highlight gamma irradiation as an effective pretreatment to enhance EFE hydrolysis, offering a promising strategy to improve the nutritional value of low-quality forages to integrate into ruminant diets.