Study on the chemical and microbial composition and probiotic characteristics of dominant lactic acid bacteria in fermented poultry slaughterhouse waste

This study aimed to evaluate the quality of fermented poultry slaughterhouse waste and isolate and identify the probiotic bacteria present in it. Poultry slaughterhouse waste samples supplemented with 5% starter culture and 0.2% propionic acid received one of four experimental treatments, which consisted of further supplementation with: (1) 10% molasses (M10); (2) 15% molasses (M15); (3) 10% molasses with 200 ppm butylated hydroxytoluene (MB10); and (4) 15% molasses with 200 ppm butylated hydroxytoluene (MB15). All experimental treatments (silages) were fermented for 6 days with sampling before fermentation (day 1) and at the end of days 3 and 6. The pH of the silages decreased during the fermentation as it was lower on days 3 and 6 than day 1 (P < 0.05). On day 6 of the experiment, the number of lactic acid bacteria in MB15 was significantly (P < 0.05) higher than in MB10. The percentage of non-protein nitrogen increased (P < 0.05) on days 3 and 6 of fermentation. The amount of malondialdehyde indicated that the peroxidation ratio decreased (P < 0.05) with increasing the fermentation time. Among the 23 lactic acid bacteria detected in MB15, nine isolates (39.1%) belonged to the species Lactobacillus plantarum, ten (43.5%) belonged to the species Lactobacillus rhamnosus, and four (43.5%) belonged to the species Lactobacillus fermentum. The isolates LPL9, LRH25, and LFE26 were identified as the strain of L. plantarum, L. ramnosus, and L. fermentum, respectively, that demonstrated the best characteristics for use as a probiotic. The results of this experiment indicated that the fermentation is an advisable method for reusing the nutrients of poultry slaughterhouse waste and producing a probiotic supplement.