In vitrofermentative characteristics of ruminant diets supplemented with fibrolytic enzymes and ranges of optimal endo-β-1,4-glucanase activity

Abstract

Effectiveness of fibrolytic enzymes supplementing a range of forage to concentrate (F:C) diets was assessed with goat (G) or cow (C) inoculum using the gas production (GP) technique. Four F:C diets were evaluated: forage (1:0), high forage (0.7:0.3), medium forage (0.5:0.5) and low forage (0.3:0.7) diets, supplemented or not with Promote(TM) (PRO) at 1 or 2 ml/kg dry matter (DM). The GP kinetic was different between F:C (1:0 < 0.7:0.3 < 0.5:0.5 < 0.3:0.7) and inoculum. Responses to enzyme were positively related to forage level and differed with inoculum. The neutral detergent fibre and acid detergent fibre degradation were depressed by the concentrate in the substrates fermented with C and were not altered or even enhanced in G sets. Results confirm that increasing starch proportion modified the pattern of microbial fermentation, while no influences were detected in the improvement of cell wall degradation with fibrolytic enzymes. Another in vitro experiment was conducted to investigate factors by which endo-beta-1,4-glucanase activity (EA) of PRO is compromised in a factorial design (3 x 4 x 3) for three pH (4.0, 5.5 and 6.5), four temperatures (30, 40, 50 and 70 degrees C) and three doses (1, 2 and 3 ml/kg DM of substrate). Maximum EA were obtained for pH 4.0, 50 degrees C and 3 ml/kg DM. Optimal conditions for PRO proved to be outside the normal ranges in ruminal environment.

Sustainability of ruminant agriculture in the new context: feeding strategies and features of animal adaptability into the necessary holistic approach

“…Cherney et al, 1991;Sewalt et al, 1997;Turner et al, 2001), lignolytic fungi (e.g. Akin et al, 1995;Mayer and Staples, 2002;Sun and Cheng, 2002) and exogenous enzymes (McAllister et al, 2001;Beauchemin et al, 2004;Gonzá lez-García et al, 2009b).…”