Effects of adding different concentrations of Aspergillus Niger inoculant on the quality of mixed rice straw silage

Abstract

The objective of the current study was to determine the silage quality of mixed rice straw silage inoculated with different concentration of Aspergillus niger. For this purpose, four experimental treatments were carried out that were based on different concentrations of Aspergillus niger per kilogram of mixed silage (80% straw + 18 wheat bran + 2% sucrose). In treatment 1, 50 mL of Aspergillus niger + 150 mL of sterile water was inoculated on mix rice straw silage (50 MRS), in treatment two, 100 mL of Aspergillus niger + 100 mL of sterile water was inoculated on mix rice straw silage (100 MRS), in treatment three, 150 mL of Aspergillus niger + 50 mL of sterile water was added on mix rice straw silage (150 MRS), while in treatment four, 200 ml of Aspergillus niger inoculant was added on mix rice straw silage (200 MRS). In control group only 200 ml of sterile water was added on mix rice straw silage (0 MRS). In all experimental treatments, the concentration of Aspergillus niger was 5.68 × 106 CFU ·mL-1. After 30 days of ensiling, all the ensiled bags of silage were opened for chemical analysis. The results showed that experimental treatments significantly increased water-soluble carbohydrate contents, dry matter, lactic acid and acetic acid (P<0.05), and reduced the pH and NH3-N/TN contents of mixed silage(P<0.05). The concentration of 100 MRS, 150 MRS, and 200 MRS significantly reduced neutral detergent fiber, crude fiber, acid detergent fiber and acid detergent lignin content of mixed silage (P<0.05). Enzyme activity results explored that carboxymethylcellulase, manganese peroxidase, laccase and xylanase enzyme activity decreased as the time of fermentation time increased. Based on the current study, it could be recommended that 100 MRS could be used to ensile rice straw because it is as efficient as other experimental treatment and it could decrease the cost of ensiling