Prefermented cereals containing fungal gamma-linolenic acid and their effect on rumen metabolism in vitro

Abstract

The application of Thamnidium elegans fungal strain CCF 1456 (TE) for effective utilization of various agroindustrial materials creates new perspectives for animal cereal diets enriched with microbial γ-linolenic acid (GLA). Diets consisting of lucerne hay (LH) plus prefermented cereals (wheat bran/spent malt grains, WB+TE or WB+TE enriched with sunflower oil, WB+SO+TE in the first experiment and ground maize grains, GC+TE in the second experiment) were used in the artificial rumen. We examined their effect on the rumen fermentation pattern and lipid metabolism. The diet affected the results of degradability of dry matter, organic matter, neutral detergent fibre and acid detergent fibre of LH+WB diets (P < 0.05 and P < 0.01). The GLA daily output of prefermented diet substrates LH+WB+TE and LH+WB+SO+TE, or LH+GC+TE was higher compared to the non-prefermented LH+WB or LH+GC, respectively (P < 0.05 and P < 0.01). Daily outputs of trans11 oleic (TVA) of the LH+GC+TE diet were higher versus the non-prefermented LH+GC (P < 0.01). The biohydrogenation of fatty acids (C18:1 cis9 oleic, C18:2 linoleic, C18:3n-3 alpha-linolenic, C18:3n-6 GLA and total FA) of prefermented cereal diets was not influenced. Cereal diets containing microbial GLA might positively enhance GLA daily outputs in the RUSITEC effluent, but they are not effective enough to decrease the biohydrogenation of unsaturated fatty acids.