Fermentation Quality and Additives: A Case of Rice Straw Silage

Table 5

Effects of silage additives on fermentation and possible improvement in animal performance.

Effect(s) of silage additive	Results and possible effects on animal performance	Reason(s) for effect(s)	Reference
Lower pH	Inhibition of undesirable microbes; improved protein preservation and nitrogen metabolism	Dominance of homofermentative lactic acid bacteria	[9]
Inhibition of fermentation, for example, high levels of acid addition or other fermentation inhibitors	Improved intake due to reduction in overall fermentation of end-products and reduced acidity	Inhibition of microbial growth	[26]
High lactic acid: VFA ratio and low acetic acid concentration	Low acetate may result in increased DM intake and improved rumen microbial fermentation and palatability	Dominance of homofermentative lactic acid bacteria	[11]
High propionate concentration	Improved aerobic stability leading to less spoilage; better feed intake and less mycotoxin formation	Direct addition or microbial production	[27]
Low butyric acid	Improved feed intake	Lower pH which leads to inhibition of Clostridia	[28]
Low ammonia N, free amino acids, and amine concentrations	Improved nitrogen metabolism and feed intake	Dominance of homofermentative lactic acid bacteria causing rapid drop in pH and inhibition of plant proteases	[29]
High concentrations of peptides	Possible stimulation of microbial protein production	Rapid drop in pH and dominance of homofermentative lactic acid bacteria	[30]
Low concentrations of ethanol	Improved aerobic stability and possible improvement in feed intake	Inhibition of yeasts which are primarily responsible for aerobic spoilage	[9]
Low fiber contents	Improved nutrient utilization	Partial digestion of fiber by enzymes	[29]
Increased water soluble carbohydrates	Low aerobic stability and feed intake	Partial digestion of fiber by enzymes	[31]
Improved nutrient digestion, for example, fiber or starch	Change in physical or chemical structure of fiber, better nutrient/energy utilization, faster rate of digestion, and improved feed intake	Partial digestion of fiber by enzymes and unknown effects of lactic acid bacteria	[32]
Improved aerobic stability (less heating and moulding)	No mycotoxins; improved nutrient intake	Inhibition of yeasts which are primarily responsible for aerobic spoilage	[30]
Increase in lactic acid bacteria	Probiotic effect or other unknown effects (e.g., bacteriocins) resulting in improved feed intake or conversion	Addition of inoculants	[11]