The effects of Lactobacillus plantarum and Propionibacterium acidipropionici on corn silage fermentation, ruminal degradability and nutrient digestibility in sheep.

Abstract

Summary The chemical composition, in situ ruminal degradability coefficients of dry matter (DM), and nutrient digestibility in sheep were evaluated for corn silage (CS) treated (fresh weight basis) with different levels of commercial bacterial inoculant (I) as follows: (1) untreated CS (control); (2) CS + I at half of the recommended level; (3) CS + I at the recommended level (3 × 10 10 colony forming units per g of fresh forage) and (4) CS + I at two-fold recommended level. The inoculants (Lallemand, France) consisted of Lactobacillus plantarum and Propionibacterium acidipropionici. Whole- plant corn was ensiled for 60 days in plastic polyethylene bags. Also, three laboratory silos (70 g capacity) for each treatment were sampled on days 2, 3, 4 and 60 to study the pH changes. The silages underwent rapid fermentation and were well- preserved. The pH value decreased to 4.0 on day 2 and was the lowest for treatment 2 on day 60 after ensiling compared with other treatments. Treatment 2 had higher (P<0.05) contents of crude protein (CP), residual water soluble carbohydrates (WSC), lactic acid, acetic acid, propionic acid, and total acids, but lower (P<0.05) butyric acid than treatment 3, and also higher acetic and lower butyric acid levels than other treatments. No traces of ethanol were detected in any of the silages. The acid detergent fiber (ADF) content of treatments 1 and 4 was lower (P<0.05) than others. Only ether extract (EE) digestibility was affected by these treatments which was higher for treatments 1 and 4 (P<0.05). The DM recovery for treatment 1 was lower than others. Effective DM degradability was slightly higher for treatment 4 and fraction a was significantly (P<0.05) lower for treatments 1 and 3 compared with treatment 4. The results indicated that application of this inoculant at half of the recommended level was more effective to enhance the aerobic stability of silages due to higher acetic and propionic acid production which have antimycotyic properties. The decreased cost associated with this level of inoculant might be economical for farmers in warm climates as to encourage its use as an additive for silage making.