Effect of Lactobacillus plantarum on the chemical composition, fermentation characteristics, aerobic stability, and in vitro digestibility of corn silage in different periods of harvesting

There are various methods to decline the nutrient loss in corn silage. One of these ways is adding lactic acid producing bacteria to silage. Lactic acid-producing bacteria prevent the growth of undesirable bacteria in silage by rapidly reducing the pH, and as a result, the nutritional value of the silage is preserved. Therefore, this research carried out to investigate the effect of Lactobacillus plantarum on the chemical composition, fermentation characteristics and in vitro digestibility of corn silage using of gas production method in corn fodder cultivated in Bardsir city of Kerman province at different time of harvesting.

The sampling was done randomly from six corn fields being harvested in the first and last decade of September to November in Bardsir city. After determination of dry matter, samples were ensiled with and without Lactobacillus plantarum additive in mini silo with three replicates for two months. The silage effluent was measured after 72 hours and also on the 10th, 20th, 30th and 60th days of the experiment. After opening the silos, silage pH and aerobic stability along with dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent insoluble fiber (NDF), acid detergent insoluble fiber (ADF), water soluble carbohydrates (WSC), ammonia nitrogen (NH3-N) and lactic acid were measured. In vitro digestibility of corn silage was determined by gas production test and fermentation parameters including metabolizable energy (ME), short chain fatty acids (SCFA) and organic matter digestibility (OMD) were estimated based on produced gas and chemical composition of samples from standard formulas.

The findings of this research showed that the average percentage of DM in the samples harvested at different time had a significant difference. The average DM of silage in different time of harvesting was 19.4%. The addition of Lactobacillus plantarum to fodder corn had no significant effect on the concentration of lactic acid, NH3-N and chemical composition of corn silage, but the concentration of WSC in inoculated silages was lower than the control silage (P< 0.05). The pH of silage and the percentage of effluent were not affected by the inoculation (P> 0.05), however the aerobic stability in the silage with Lactobacillus plantarum was lower than the untreated silage (P<0.05). The cumulative gas produced after 24 and 48 hours, gas production potential (b), gas production constant rate (c) and fermentation parameters (ME, SCFA and OMD) were not significantly different among silage with and without inoculant.

The results of this study showed that the addition of Lactobacillus plantarum had no effect on the fermentation characteristics of corn silage produced in Bardsir city.