Effect of fermentation on pH, microbial profile and proximate composition of compound feed of growing-finishing pig

The study was to evaluate the effect of fermentation of compound pig feed on pH, microbial profile and proximate composition. A standard grower-finisher ration was prepared following NRC (2012) [14] standard incorporating conventional ingredients. Two probiotic cultures, namely Lactobacillus acidophilus and Enterococcus facium, were used separately as inoculum for fermentation process. After 48 hours of fermentation of 1st batch of liquid compound feed (Feed: water: 1:2), half of the amount was replaced with new liquid compound feed for fermentation again for 48 hrs. This back-slopping process was continued for seven times. Samples of fermented feeds were collected after completion of each cycle of fermentation. Fermented feed samples were analysed for pH and microbial profile [Lactic acid bacteria, E. coli and Salmonella] and proximate principles (AOAC 2012) [3]. The pH of the fermented feed was variable from 1st to 7th cycles of back slopping, but without any significant difference (p>0.05) and varied from 4.28-4.45 and 4.31-4.43 respectively for fermentation with Lactobacillus acidophilus and Enterococcus facium. The dry matter contents of fermented feeds ranged from 20.66-28.93% and 22.72-28.08%, respectively. Comparatively increasing trend was observed for crude protein (%) from 1st to 7th cycle for both Lactobacillus acidophilus and Enterococcus facium inoculation, and reverse was recorded for ether extract (%). Other proximate principles were variable without any significant difference (p>0.05). The numbers of Lactic acid bacteria in fermented feed with Lactobacillus acidophilus and Enterococcus facium decreased from 1st to 7th cycle (average 8.69 to 7.30 CFU log10/ml and 8.78 to 6.47 CFU log10/ml, respectively). The E. coli count decreased as the fermentation cycle progressed. Salmonella was not detected in any samples of fermented feeds. The baseline information of the present study may be utilised while deciding feeding strategy for pigs comparing with convention ways of feeding of dry and liquid feed for better performance and profit.