Influence of anaerobic rumen fungal inoculation on the fermentation and nutritive content of selected forage silages

Résumé

This study investigated the ability of isolated anaerobic fungi to facilitate silage fermentation characteristic and nutritive content. To achieve this, two fungal isolates out of fourteen obtained in our laboratory from sheep rumen content were selected as silage inoculants. Selection of the isolates was based on their ability to present the highest growth characteristics and they belong to the genus Orpinomyces, and Neocallimastix (as identified with microscope). The two fungi alongside the control (i.e. no fungi) were used to inoculate different silages prepared from four selected forages i.e. two tropical grasses (i.e. Andropogon gayanus- AG, Brachiaria decumbens- BD) and two temperate forages (i.e. Triticum aestivum- TA straw and Lolium perenne- LP) in order to examine their effect on fermentation (i.e. pH) and nutritive content of these silages over 14 and 28 days of inoculation, respectively. The anaerobic fungal inoculated silages showed significant (P < 0.05) improvement in quality than un-inoculated silages which was reflected in terms of increase in soluble fraction i.e. CP content; reduction in fibre content; increase in metabolites, increase in total antioxidant content (TAC); and reduction in pH with minimal nutrient loss. However, the rate of the anaerobic fungal improvement was influenced by the forages used for the silage and the length of inoculation. The highest and lowest increase in quality was recorded in LP and TA silages, respectively, while more extended inoculation time supported more quality improvement in the silages. The use of anaerobic fungi as inoculants improved AG, BD, TA and LP silages quality through facilitation of the fermentation characteristics (i.e. pH and nutritive content).