FERMENTATION AND MICROBIOLOGICAL CHARACTERISTICS OF MILLET SILAGE ACCORDING TO VARIETY, HARVEST STAGE AND SALT ADDITION

Abstract

In Niger, a Sahelian country facing significant climate variability, preserving millet residues through ensiling represents a promising solution to address seasonal forage shortages. The objective of this study was to assess the influence of variety (six genotypes), harvest  stage (flowering and maturity), and 1 % salt addition on the fermentation and microbiological quality of these silages. The results show that these three factors significantly influence key parameters. The harvest stage has the most pronounced effect. Flowering silages exhibit a lower pH and higher levels of acetic, propionic, and butyric acids, indicating more active fermentation but also an increased risk of clostridial growth. Variety particularly affects organic acid levels, with the Maywa variety generally producing more acetic, propionic, and butyric acids. Salt addition has a moderate but significant effect, reducing the overall pH and increasing acetic and propionic acid levels. Microbiological analyses revealed the consistent presence of lactic acid bacteria, butyric acid bacteria, and spoilage flora. The addition of salt tended to reduce the populations of butyric acid bacteria and spoilage flora, although not significantly. Significant correlations confirmed the expected links, notably the acidifying effect of lactic acid and the positive association between propionic and butyric acids. In conclusion, for quality silage in Niger, it is recommended to favor a harvest stage close to maturity to minimize undesirable fermentations, to select varieties such as Siaka Millet associated with a low pH, and to consider adding 1% salt as a simple additive to improve acidification and positively modulate the fermentation profile.