Effects of Genotype and Microbial Inoculants on Fermentation Quality, In Vitro Digestibility, and Feeding Value of Wheat Silage

This study evaluates the effect of homofermentative and heterofermentative inoculants used independently or in combination on the quality of fermentation, chemical composition, fiber digestion, and nutritional value of silage made from four wheat varieties (Bayraktar 2000, Kızıltan 91, Bezostaja 1, and Tosun bey). Four treatments were applied within each variety: an untreated control group; a homofermentative inoculant (HMF group; Lactiplantibacillus plantarum, formerly Lactobacillus plantarum, and Enterococcus faecium, applied at 1.0 × 105 cfu/g fresh weight); a heterofermentative inoculant (HTF group; Lentilactobacillus buchneri, formerly Lactobacillus buchneri, applied at 5.0 × 104 cfu/g fresh weight); and their combination (HMF+HTF; group 1.5 × 105 cfu/g fresh weight). The whole-crop wheat silage collected at the dough stage was allowed to ferment for 120 days using a 4 × 2 × 2 factorial design having four replications. Statistically significant differences between varieties and inoculation treatments were seen in most of the recorded characteristics (p < 0.001), demonstrating that inoculant responses were significantly impacted by genotype. In Kızıltan 91, dry matter (DM) did not differ significantly among treatments (p > 0.05). In Bayraktar 2000, DM was reduced only by HTF applied alone (36.56% vs. 43.23% in the control), while HMF and HMF+HTF did not differ from the control. In Bezostaja 1, both HTF and HMF+HTF decreased DM relative to the control, whereas HMF alone had no effect. In Tosun bey, all LAB treatments increased DM relative to the control, with the homofermentative inoculant producing the greatest increase. Homofermentative inoculants demonstrated improved fermentation characteristics by lowering silage pH and ammonia-nitrogen concentrations and enhancing physical traits, while Heterofermentative inoculants reduced butyrate accumulation and raised acetic acid concentration, which reached 3.50 g/kg DM in Kızıltan 91 during combined inoculation. According to genotype, the application of inoculants varied the amount of fiber and digestibility. In vitro dry matter and organic matter digestibility, net energy of lactation, total digestible nutrient, and relative feed value (RFV) were frequently reduced by the combination HMF+HTF treatment. In Bayraktar 2000, RFV was found to have decreased the most, from 166.79 to 106.51. Conversely, Bezostaja 1 showed comparatively constant levels of energy content and digestibility regardless of the treatment, suggesting greater adaptability to the effects of microbial inoculants. In general, wheat genotype was the main factor influencing the nutritional value and quality of silage, and varietal characteristics had a significant impact on the efficacy of microbial inoculation. These results show how essential it is to choose inoculant methods according to variety in order to maximize fermentation quality and maintain feeding value in the production of wheat silage.