Effect of different dry matter and lactic acid bacterial inoculants on the fermentation, aerobic stability, and feed value of maize silage

This study was designed to investigate the effects of homofermentative and heterofermentative lactic acid bacterial (LAB) inoculants on fermentation, aerobic stability, and feed value of maize (Zea mays L.) silages harvested at different dry matter (DM) contents. The maize was harvested at four different maturity stages, namely milk stage (MS), dough stage (DoS), dent stage (DeS), and physiological maturity stage (PS), and at 26.3%, 31.4, 37.3 and 42.7 DM contents, respectively. Inoculants containing Lactobacillus plantarum (LP) as homofermentative LAB, Lactobacillus buchneri (LB) as heterofermentative LAB, and the 1:1 combination of these two inoculants (LP+LB) were applied at 1×106 cfu g-1. The experimental groups consisted of four maturity stages (MS, DoS, DeS, and PS) and four treatments (control (C), LP, LB, and LP+LB). Each trial material was ensiled into 1.5 L anaerobic jars in four replicates. On the 60th day of ensiling, the jars were opened, and chemical and microbiological analyzes of the silages were made. The aerobic stability test was applied to the silages opened at the end of the ensiling period for five days. The feed value of silages was determined by in vitro gas production technique. The effects of maturity stages on all parameters were significant (P<0.0001 to P=0.0003). While the impacts of the treatment groups on DM, ammonia nitrogen, acid detergent fiber, hemicellulose, organic matter digestibilities, and metabolizable energy contents were found to be insignificant (P>0.05), the effects on other parameters were found to be significant at different levels (P<0.0001 to P=0.02). Inoculants were effective on pH decrease in all stages; in particular, LP was more effective than LB and LP+LB. All inoculants increased lactic acid and acetic acid production compared to control. The highest lactic acid production was in LP-treated silages. While LB and LP+LB applications improved aerobic stability in all periods, LP application decreased aerobic stability at all stages. Keywords: Aerobic stability, feed value, heterofermentative, homofermentative, in vitro digestibility, inoculant, lactic acid bacteria, Lactobacillus buchneri, Lactobacillus plantarum, maize, silage, maturity, reproductive stages, additive, fermentation, Zea mays