Meta-analysis of effects of inoculation with homofermentative and facultative heterofermentative lactic acid bacteria on silage fermentation, aerobic stability, and the performance of dairy cows

Abstract

Forages are usually inoculated with homofermentative and facultative heterofermentative lactic acid bacteria (LAB) to enhance lactic acid fermentation of forages, but effects of such inoculants on silage quality and the performance of dairy cows are unclear. Therefore, we conducted a meta-analysis to examine the effects of LAB inoculation on silage quality and preservation and the performance of dairy cows. A second objective was to examine the factors affecting the response to silage inoculation with LAB. The studies that met the selection criteria included 130 articles that examined the effects of LAB inoculation on silage quality and 31 articles that investigated dairy cow performance responses. The magnitude of the effect (effect size) was evaluated using raw mean differences (RMD) between inoculated and uninoculated treatments. Heterogeneity was explored by meta-regression and subgroup analysis using forage type, LAB species, LAB application rate, and silo scale (laboratory or farm-scale) as covariates for the silage quality response and forage type, LAB species, diet type [total mixed ration (TMR) or non-TMR], and the level of milk yield of the control cows as covariates for the performance responses. Inoculation with LAB (≥10 cfu/g as fed) markedly increased silage fermentation and dry matter recovery in temperate and tropical grasses, alfalfa, and other legumes. However, inoculation did not improve the fermentation of corn, sorghum, or sugarcane silages. Inoculation with LAB reduced clostridia and mold growth, butyric acid production, and ammonia-nitrogen in all silages, but it had no effect on aerobic stability. Silage inoculation (≥10 cfu/g as fed) increased milk yield and the response had low heterogeneity. However, inoculation had no effect on diet digestibility and feed efficiency. Inoculation with LAB improved the fermentation of grass and legume silages and the performance of dairy cows but did not affect the fermentation of corn, sorghum, and sugar cane silages or the aerobic stability of any silage. Further research is needed to elucidate how silage inoculated with homofermentative and facultative heterofermentative LAB improves the performance of dairy cows.

A meta-analysis on the effectiveness of homofermentative and heterofermentative lactic acid bacteria for corn silage

“…Considering that commercial freeze-dried products may commonly contain up to 1-5 9 10 10 CFU per g, trying to achieve such a high rate may be technologically challenging in practice, as freezedried powders must be dissolved in water to be sprayed on the chopped fresh material. Additionally, a rate ≥10 7 CFU per g may be not economically viable in most cases (Oliveira et al 2017). As a result, the referenced reports were not considered for application rate of LAB.…”

“…Additionally, a rate ≥10 7 CFU per g may be not economically viable in most cases (Oliveira et al . ). As a result, the referenced reports were not considered for application rate of LAB.…”

Meta‐analysis of the effects of Lactobacillus plantarum and Lactobacillus buchneri on fermentation, chemical composition and aerobic stability of sugarcane silage

“…Lactobacillus plantarum is a facultative heterofermentative lactic acid bacteria (LAB) (Holzer, Mayrhuber, Danner, & Braun, 2003) that has been successfully used to improve fermentation of tropical and temperate grasses and alfalfa silage (Oliveira et al, 2017;Rabelo et al, 2016). Considering the positive results found from other crops, L. plantarum has been used to treat sugarcane silage, but the results have varied widely.…”

Effects of storage temperature and combined microbial inoculants on fermentation end products and microbial populations of Italian ryegrass (Lolium multiflorumLam.) silage

“…Based on this fact, the alternative should be experiments in silos with an addition of a combination of LAB strains. Moreover, in a meta-analysis conducted by Oliveira et al (2017), results showed that 67% of the studies involved inoculation of silage with only Lactobacillus plantarum, while few studies involved mixtures of LAB. Given this, more research is needed on effects of combined LAB strains on silage quality.…”