Effect of concentration of phenolic compounds of two sorghum varieties on fermentation of sorghum with lactic acid bacteria for inclusion in poultry diets

Abstract

Wet feeding beneficially affects feed intake and growth rates of poultry in hot climates (Forbes 2003). Fermenting liquid feeds for pigs has been shown to reduce microbial contamination of the feed (Beal et al., 2002) and this could be an added advantage in hot climates. The most desired property of fermented feed is a high lactic acid concentration produced by lactic acid bacteria (LAB) as the fermenting organisms. This high lactic acid concentration resulting in a low pH is responsible for the antimicrobial activity of fermented feeds. This activity is important for food and environmental safety. Grain sorghum is widely used as a food and animal feed cereal in many parts of Africa, Asia and the semi-arid tropics world-wide. It is recognised that differences in the colour of sorghum varieties are due mainly to their concentration of polyphenol compounds mainly tannins. These compounds have some antimicrobial properties and may affect the activity of lactic acid bacteria used to ferment liquid feeds. Little is known about the lactic acid fermentation of sorghum grain for fermented feeds in monogastric nutrition. The present study was designed to compare the fermentation of red and white sorghum with LAB for inclusion as a component of poultry diets.