The effect of cell wall degrading enzymes or formic acid on fermentation quality and on digestion of grass silage by cattle

Abstract

A first cut of timothy, treated with water (untreated), formic acid (FA), cellulase + lactic acid bacteria (CB), cellulase + hemicellulase (CH) or cellulase + hemicellulase + a ligninmodifying enzyme (CHL), was ensiled in pilotscale silos. Silages, except CB, were fed to four male cattle, each equipped with a rumen and duodenal cannula, in a digestibility tricil designed as a 4 x 4 Latin square. The animals were fed a diet of 400 g of concentrate and 600 g of silage at a level of 70 g DM kg " ' live weight (LW").All enzyme-treated silages were well-preserved with a more extensive fermentation than in FA silage. The quality of untreated silage was poorer as indicated by higher pH and ammonia-N content. The amount of effluent from enzyme-treated silages ranged from 116 to 127 g kg ~ '; for FA and untreated silages values were 101 g kg"' and 80 g kg"', respectively. Total DM losses from enzyme-treated silages were higher than from FA silage (P<0-Q5). No significant differences were noticed between silages in the apparent digestibility of organic matter (OM), neutral-detergent fibre (NDF), acid-detergent fibre (ADF) or nitrogen (N). The apparent digestibility of cellulose was higher with enzyme-treated silages than with FA silage (P<Q-Q5). The values for microbial N flow at the duodenum were 80-0, 91-9, 80-7 and 70-5 g N d ~', and for the efficiency of rumen microbial N synthesis 38-6, 47-6, 36-9 and 32-5 g N kg"' OM apparently digested in the rumen for untreated, FA, CH and CHL silages, respectively. In the rumen the molar proportion of propionate was higher (P<0-01) and that of butyrate lower (P<0-01) with enzyme-treated silages when compared with FA silage. The proportion of butyrate was also lower with untreated than with other silages (P < 0 • 01). The rumen residence time of NDF and ADF was longer (P<0-05) with enzyme-treated silages than with FA silage.

Quality of meadow grass silage inoculated with cellulolytic bacteria

“…The addition anaerobic Cclb, which degrade structural carbohydrates, also resulted in a decrease in silage pH to 3.90, commonly accepted as satisfactory (Honig, 1967;Renner, 1967;Gross, 1987) and comparable with (3.84-3.95) enzyme-treated silages (Jaakkola et al, 1991). A similar pH value (3.93) was obtained in silage IV, made with an addition of both Cfl and Cclb at KP/g of fresh herbage.…”

“…In silage III (10 6 Cclb/g fresh herbage) the content of cellulose, the substrate for cellulolytic enzymes, decreased in comparison with the control silage by 2.80 percent units. According to Jaakkola et al (1991) and Stokes (1992) the difference between a control grass silage and silages made with the addition of cell wall degrading enzymes used alone or together with lactic acid bacteria, remained within the range of 0.21-1.80 percent units. The degree of structural carbohydrate degradation in silages made with Cclb may also reflect the relatively high cellulolytic activity of Clostridium cellobioparum bacteria.…”

“…Obtaining high quality silages from such materials requires wilting the original herbage or adding easily fermenting sugars (Gross and Becl, 1969;Honig, 1967;Gross, 1987). It is, however, possible to obtain well-preserved silages even from high moisture grass Jaakkola et al, 1991) by adding plant cell wall degrading enzymes which improve conditions for lactic acid fermentation (Letherwood et al, 1963;Jacobs etal., 1991). There is no information about the use of cellulolytic bacteria as a source of cellulolytic enzymes.…”

Efeito da adição de Lactobacillus sp. na ensilagem de cana-de-açúcar

“…Em comparação aos carboidratos solúveis, os produtos finais da fermentação da silagem têm pouco ou nenhum efeito como fonte energética para os microrganismos do rúmen (Chamberlain, 1987). No entanto, deve-se considerar que o ácido lático presente na silagem aumenta a proporção molar de propionato no rúmen (Jaakkola et al, 1991), reduzindo a relação entre ácidos graxos voláteis lipogênicos e glicogênicos (Huhtanen et al, 1997). Deve-se considerar também que silagens com maiores concentrações de carboidratos residuais, em geral, apresentam menor estabilidade aeróbia, exceto quando há algum fator que aumenta sua estabilidade.…”

The effects of the forage preservation methods on fermentation parameters in ruminal fluid of fattening bulls

“…The extent of fermentation of WSC during ensilage into lactic acid and VFA can change the end-products of rumen fermentation. The majority of published reports indicate that propionate is the main end-product of lactate fermentation with grass silage-based diets (Jaakkola et al, 1991). Diets based on restrictively fermented grass silages which are high in water WSC and low in lactate, favour a rumen fermentation pattern rich in butyrate or acetate and low in propionate.…”