*2.1.3. Sugarcane silage*

WSC concentration and epiphytic bacteria populations found prior to ensiling in those crop, which commits the ensiling process [31]. In our survey, although homolactic inoculation consistently improved the fermentation parameters of tropical grass silages, a small effect was observed on the nutritive characteristics, and IVDMD was only slightly improved (+1.5%).

In some cases, adding homolactic inoculants reduced the aerobic stability of silages, because the lactic acid they produce is used as a growth substrate by yeasts that initiate spoilage [32]. However, unexpectedly the aerobic stability of tropical grass silages increased from 59.5 to 114 h when hoLAB were applied at ensiling, which is likely to be due to the greater production of acids and a lower pH, inhibiting the growth of aerobic microorganisms. But this is only a hypothesis and perhaps factors other than fermentation end products likely contributed to

DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; IVOMD, *in vitro* organic matter

**Table 5.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated grass silages

digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria.

Silages inoculated with both heterofermentative and homofermentative bacteria.

Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

(data are given in % of DM, unless otherwise stated).

increase the aerobic stability of grass silages treated with hoLAB.

16 Advances in Silage Production and Utilization

1

2

3

4

5

Number of means.

Standard deviation.

Data were summarized from a total of 50 studies, of which 21, 40, and 7 investigated the effect of hoLAB, heLAB, and a combination of both (mixed), respectively. Considering all treatments, the application rate of silage inoculants ranged from 2.5×104 to 2.5×1010 cfu/g of fresh forage.

The range of fermentation parameters, *in vitro* digestibility, and aerobic stability are given in **Table 7**.


yeast overgrowth and associated ethanol production, with reduced DM losses [35]. Moreover, the reduced DM losses involve a better preservation of WSC [35], which may lead an increased

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DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF,

**Table 7.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated sugarcane

In this regard, considering the overall mean, acetic acid was unaffected, but heLAB reduced the ethanol concentration by 28.9%, because the number of yeasts was reduced. Reductions in yeast growth were probably due to the slight drop in the lactic:acetic acid ratio, in addition to a 12.8% increase in the production of propionic acid, which also has antifungal properties [30]. *L. brevis*, *L. buchneri*, and *L. hilgardii* are the most common heLAB used in sugarcane silage by Brazilian studies, and they are capable in producing 1,2-propanediol anaerobically [36]. Thus, the greatest production of propionic acid is likely to be related to the conversion of 1,2 propanediol to equimolar portions of 1-propanol and propionic acid, a process driven by

neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble

carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria.

silages (data are given in % of DM, unless otherwise stated).

Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

IVDMD of sugarcane silages.

1

2

3

4

Number of means.

Standard deviation.

1 DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; IVOMD, *in vitro* organic matter digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria. 2 Silages inoculated with both heterofermentative and homofermentative bacteria.

**Table 6.** Summary of positive responses of silage inoculants on the fermentation patterns, nutritive value, and aerobic stability of grass silages (data are given in % of DM, unless otherwise stated).

Heterolactic inoculants have been used to increase the production of acetic acid in order to reduce aerobic deterioration [28]. For sugarcane silages, the use of heLAB was proposed to avoid yeast overgrowth and associated ethanol production, with reduced DM losses [35]. Moreover, the reduced DM losses involve a better preservation of WSC [35], which may lead an increased IVDMD of sugarcane silages.


1 DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria.

**Item1 Homofermentative LAB Mixed2**

**Mean Difference,**

**%** 

DMoven, % as fed 78 26.9 22.32 24.55 +10.0 10 20.0 20.90 21.94 +5.0 Ash 24 0.0 – – – 6 0.0 – – – CP 85 27.1 7.82 9.36 +19.7 10 10.0 6.16 6.20 +0.7 NDIN, % N 3 0.0 – – – 1 0.0 – – – ADIN, % N 15 0.0 – – – 1 0.0 – – – NDF 72 9.7 69.99 66.15 −5.5 10 10.0 77.08 64.98 −15.7 ADF 65 9.2 46.23 41.46 −10.3 10 20.0 52.37 50.87 −2.9 Hemicellulose 62 4.8 37.34 35.18 −5.8 10 0.0 – – – Cellulose 29 13.8 38.81 35.40 −8.8 8 0.0 – – – Lignin 29 13.8 5.90 5.20 −11.9 8 0.0 – – – IVDMD 27 18.5 58.17 64.08 +10.2 6 0.0 – – – IVOMD 3 66.7 57.25 60.50 +5.7 0 0.0 – – – Effluent, kg/t 20 0.0 – – – 6 16.7 68.50 48.20 −29.6 Gas losses 19 57.9 5.56 3.49 −37.3 6 0.0 – – – DM losses 31 25.8 14.60 9.52 −34.8 2 50.0 10.90 8.00 −26.6 WSC 3 33.3 1.82 2.58 +41.8 0 0.0 – – – Lactic acid 35 48.6 3.59 5.08 +41.7 1 0.0 – – – Acetic acid 28 53.6 1.16 0.74 −36.5 1 0.0 – – – Propionic acid 17 5.9 0.77 1.09 +41.6 0 0.0 – – – Butyric acid 24 37.5 0.05 0.03 −31.2 1 100.0 0.082 0.004 −95.1 Ethanol 4 0.0 – – – 0 0.0 – – – Lactic:acetic acid 28 46.4 5.30 10.97 +106.9 1 0.0 – – – pH 80 36.3 4.56 4.20 −8.0 12 0.0 – – –

**Untreated Inoculated Total Positive**

73 30.1 9.97 7.65 −23.3 9 0.0 – – –

LAB, log cfu/g 9 44.4 8.36 9.32 +11.4 1 0.0 – – – Yeasts, log cfu/g 9 11.1 5.83 2.06 −64.7 0 0.0 – – – Molds, log cfu/g 4 0.0 – – – 0 0.0 – – – Aerobic stability, h3 33.3 96.00 120.00 +25.0 1 0.0 – – –

DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; IVOMD, *in vitro* organic matter

**Table 6.** Summary of positive responses of silage inoculants on the fermentation patterns, nutritive value, and aerobic

Heterolactic inoculants have been used to increase the production of acetic acid in order to reduce aerobic deterioration [28]. For sugarcane silages, the use of heLAB was proposed to avoid

digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria.

Silages inoculated with both heterofermentative and homofermentative bacteria.

stability of grass silages (data are given in % of DM, unless otherwise stated).

**Number of treatments**

**responses, %**

**Mean Difference, %**

**Untreated Inoculated**

**Number of treatments**

18 Advances in Silage Production and Utilization

Ammonia-N, %

TN

1

2

**Total Positive**

**responses, %**

4 Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

**Table 7.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated sugarcane silages (data are given in % of DM, unless otherwise stated).

In this regard, considering the overall mean, acetic acid was unaffected, but heLAB reduced the ethanol concentration by 28.9%, because the number of yeasts was reduced. Reductions in yeast growth were probably due to the slight drop in the lactic:acetic acid ratio, in addition to a 12.8% increase in the production of propionic acid, which also has antifungal properties [30]. *L. brevis*, *L. buchneri*, and *L. hilgardii* are the most common heLAB used in sugarcane silage by Brazilian studies, and they are capable in producing 1,2-propanediol anaerobically [36]. Thus, the greatest production of propionic acid is likely to be related to the conversion of 1,2 propanediol to equimolar portions of 1-propanol and propionic acid, a process driven by

<sup>2</sup> Number of means.

<sup>3</sup> Standard deviation.

*Lactobacillus diolivorans*, assuming that this bacterium was present in ensiled forage [37, 38]. Moreover, heterolactic inoculation reduced gas and DM losses by 13.2% and 17.7%, respectively. Fermentative losses decreased because of the control of yeast growth. For each mole of glucose consumed, yeasts produce two moles of ethanol and CO2, leading to 49% of DM losses in the ethanolic pathway [6]. In addition, *L. buchneri* was the main bacterium used in sugarcane silage, and this bacterium is known for its lack of acetaldehyde dehydrogenase [39], which reduces ethanol production. Conversely, the enhanced aerobic stability caused by heterolactic inoculation did not occur based on the overall mean.

The ADIN content decreased 14.6% due to heterolactic inoculation, suggesting that the control of yeast activity reduced the temperature of the ensiled mass during fermentation. Despite the effects on the fiber fraction, heLAB reduced the NDF content by 4.5%, likely due to increased hydrolysis of hemicellulose during fermentation [6]. Indeed, a net disappearance of hemicellulose was observed in heLAB-treated sugarcane silages (**Figure 6**), and as a consequence, the IVDMD increased by 6% on average.

1

expected.

DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF,

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**Table 8.** Summary of positive responses of silage inoculants on the fermentation patterns, nutritive value, and aerobic

Homolactic inoculation had the greatest frequency of positive responses for effluent production and propionic acid, but there is no clear explanation for these results. Furthermore, the greatest difference of responses was observed for WSC, effluent production, and lactic acid. Commercial homolactic inoculants investigated in Brazilian studies were often composed of pediococci, streptococci, and lactobacilli. Thus, the inoculation of silages with pediococci and streptococci leads to the rapid production of lactic acid and great sugar-to-lactic acid conversion efficiency [6, 40]. Afterward, the more acid-tolerant lactobacilli continue producing lactic acid until stable fermentation is achieved [6]. Therefore, the greater production of lactic acid and preservation of WSC from homolactic inoculation in sugarcane silages is

Regarding heterolactic inoculation, the greatest frequency of positive responses was observed for ethanol, acetic acid, and DM losses. In addition, the greatest differences in responses were observed for aerobic stability and propionic acid. Second generation bacterial inoculants are expected to improve the aerobic stability of silages. As described earlier, the bacteria that composed the heLAB group used for sugarcane ensiling are able to convert lactic acid into acetic acid and 1,2-propanediol [25, 36, 41] when the primary fermentation is ended up. In turn, acetic

neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble

carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria.

stability of sugarcane silages (data are given in % of DM, unless otherwise stated).

**Figure 6.** Proportion of hemicellulose, cellulose, and lignin in sugarcane silages untreated or inoculated with homofermentative and heterofermentative LAB (as-is a NDF basis).

The main action of homolactic inoculation is related to the increased preservation of nutrients during fermentation via the production of lactic acid [6]. In this regard, lactic acid increased by 28.2% in sugarcane silages inoculated with hoLAB. In addition, there was greater preservation of residual WSC (+6.2%), a reduction in the concentration of acetic acid (−45.7%), and a decrease in DM losses (−3.6%). As a consequence, IVDMD improved by 8.6%. However, homolactic inoculation increased ethanol production by 55.5% once yeasts are able to use WSC to grow in anaerobic conditions [8]. Furthermore, homolactic inoculation reduced the aerobic stability of silages by 11.4 h.

The frequency and magnitude of positive responses found in sugarcane silages from homolactic and heterolactic inoculations are given in **Table 8**.

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*Lactobacillus diolivorans*, assuming that this bacterium was present in ensiled forage [37, 38]. Moreover, heterolactic inoculation reduced gas and DM losses by 13.2% and 17.7%, respectively. Fermentative losses decreased because of the control of yeast growth. For each mole of glucose consumed, yeasts produce two moles of ethanol and CO2, leading to 49% of DM losses in the ethanolic pathway [6]. In addition, *L. buchneri* was the main bacterium used in sugarcane silage, and this bacterium is known for its lack of acetaldehyde dehydrogenase [39], which reduces ethanol production. Conversely, the enhanced aerobic stability caused by heterolactic

The ADIN content decreased 14.6% due to heterolactic inoculation, suggesting that the control of yeast activity reduced the temperature of the ensiled mass during fermentation. Despite the effects on the fiber fraction, heLAB reduced the NDF content by 4.5%, likely due to increased hydrolysis of hemicellulose during fermentation [6]. Indeed, a net disappearance of hemicellulose was observed in heLAB-treated sugarcane silages (**Figure 6**), and as a consequence, the

**Figure 6.** Proportion of hemicellulose, cellulose, and lignin in sugarcane silages untreated or inoculated with homofer-

The main action of homolactic inoculation is related to the increased preservation of nutrients during fermentation via the production of lactic acid [6]. In this regard, lactic acid increased by 28.2% in sugarcane silages inoculated with hoLAB. In addition, there was greater preservation of residual WSC (+6.2%), a reduction in the concentration of acetic acid (−45.7%), and a decrease in DM losses (−3.6%). As a consequence, IVDMD improved by 8.6%. However, homolactic inoculation increased ethanol production by 55.5% once yeasts are able to use WSC to grow in anaerobic conditions [8]. Furthermore, homolactic inoculation reduced the aerobic

The frequency and magnitude of positive responses found in sugarcane silages from homo-

inoculation did not occur based on the overall mean.

IVDMD increased by 6% on average.

20 Advances in Silage Production and Utilization

mentative and heterofermentative LAB (as-is a NDF basis).

lactic and heterolactic inoculations are given in **Table 8**.

stability of silages by 11.4 h.

1 DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen; LAB, lactic-acid bacteria.

**Table 8.** Summary of positive responses of silage inoculants on the fermentation patterns, nutritive value, and aerobic stability of sugarcane silages (data are given in % of DM, unless otherwise stated).

Homolactic inoculation had the greatest frequency of positive responses for effluent production and propionic acid, but there is no clear explanation for these results. Furthermore, the greatest difference of responses was observed for WSC, effluent production, and lactic acid. Commercial homolactic inoculants investigated in Brazilian studies were often composed of pediococci, streptococci, and lactobacilli. Thus, the inoculation of silages with pediococci and streptococci leads to the rapid production of lactic acid and great sugar-to-lactic acid conversion efficiency [6, 40]. Afterward, the more acid-tolerant lactobacilli continue producing lactic acid until stable fermentation is achieved [6]. Therefore, the greater production of lactic acid and preservation of WSC from homolactic inoculation in sugarcane silages is expected.

Regarding heterolactic inoculation, the greatest frequency of positive responses was observed for ethanol, acetic acid, and DM losses. In addition, the greatest differences in responses were observed for aerobic stability and propionic acid. Second generation bacterial inoculants are expected to improve the aerobic stability of silages. As described earlier, the bacteria that composed the heLAB group used for sugarcane ensiling are able to convert lactic acid into acetic acid and 1,2-propanediol [25, 36, 41] when the primary fermentation is ended up. In turn, acetic acid has an antagonistic effect on the growth of yeasts [30], and reductions in ethanol production are expected.

*2.1.4. Alfalfa, sorghum, and high-moisture corn silages*

for alfalfa, sorghum, and HMC ranged from 1×105

cfu/g of fresh forage, respectively.

**Item1 Untreated Homofermentative LAB**

5×104

1

2

3

Number of means.

Standard deviation.

to 1×106

Data on alfalfa, sorghum, and HMC silages were summarized from 7, 10, and 10 studies, respectively. All studies comprising alfalfa and sorghum evaluated hoLAB only. For HMC silages, hoLAB, heLAB, and a combination between both (mixed) were investigated in six, three, and one study, respectively. Considering all treatments, the application rate of silage inoculant

DMoven, % as fed 25 30.58 30.89 4.48 19.80 42.33 35 28.44 26.31 4.17 21.70 42.29 Ash 5 5.25 4.20 1.55 3.79 8.77 5 4.88 3.76 1.60 3.27 8.53 CP 18 7.03 7.04 1.40 5.15 13.28 22 7.80 7.55 1.85 5.32 14.08 NDF 23 52.97 53.13 8.87 36.67 73.89 31 56.13 58.67 7.37 35.36 71.42 ADF 19 28.20 23.70 6.78 18.99 44.95 23 31.33 28.77 7.49 19.60 45.78 Hemicellulose 19 22.84 23.20 3.13 14.76 31.65 23 22.90 22.61 2.56 11.68 27.70 Cellulose 14 23.25 21.22 4.51 17.03 39.61 16 24.63 23.37 3.80 17.28 39.99 Lignin 14 3.93 3.42 1.47 1.96 8.34 16 4.58 3.84 2.03 1.99 9.32 IVDMD 16 58.39 59.02 2.54 46.38 62.88 22 59.46 59.77 1.51 55.00 61.75 DM losses 11 1.88 1.69 0.77 0.00 5.12 13 4.18 2.48 2.92 0.31 14.14 WSC 12 1.12 0.32 1.28 0.12 7.34 14 1.49 0.23 2.02 0.14 6.62 Lactic acid 8 5.69 5.20 1.12 3.95 8.54 10 5.80 6.06 1.32 3.90 7.65 Acetic acid 5 1.55 1.52 0.42 0.86 2.42 7 1.53 1.21 0.66 0.82 2.93 Lactic:acetic acid 5 4.38 3.82 1.17 2.89 7.14 7 5.35 3.79 2.50 2.50 8.33 pH 16 3.94 3.86 0.18 3.74 4.94 20 3.94 3.87 0.16 3.66 4.88 Ammonia-N, % TN 15 6.01 4.62 3.76 0.26 16.87 17 5.48 4.05 3.18 0.38 16.79

DM, dry matter; CP, crude protein; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM

**Table 10.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated sorghum

The range of fermentation parameters, *in vitro* digestibility, and aerobic stability in alfalfa, sorghum, and HMC silages are given in **Tables 9**, **10**, and **11**, respectively. Considering the

digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen.

silages (data are given in % of DM, unless otherwise stated).

to 9.9×105

Survey About the Use of Bacterial Inoculants in Brazil: Effects on Silage Quality and Animal Performance

**n2 Mean Median SD3 Min Max n Mean Median SD Min Max**

cfu/g, 9.99×104

to 8×105

http://dx.doi.org/10.5772/64472

cfu/g, and

23


1 DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen.

2 Number of means.

3 Standard deviation.

4 Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

**Table 9.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated alfalfa silages (data are given in % of DM, unless otherwise stated).

#### *2.1.4. Alfalfa, sorghum, and high-moisture corn silages*

acid has an antagonistic effect on the growth of yeasts [30], and reductions in ethanol produc-

DMoven, % as fed 7 41.26 51.29 14.46 14.64 56.20 11 33.39 23.49 15.60 14.81 62.64 Ash 4 11.51 12.47 1.99 7.60 13.49 4 10.54 11.64 1.76 7.02 11.85 CP 7 19.75 19.51 2.00 16.38 24.33 11 20.14 20.49 1.83 15.90 23.44 NDIN, % N 2 13.03 13.03 1.71 11.32 14.73 3 13.47 12.28 1.82 11.93 16.21 ADIN, % N 3 15.04 15.92 2.31 11.57 17.63 7 16.68 17.17 1.55 11.24 19.08 NDF 8 45.06 45.82 3.19 40.18 52.04 13 44.26 43.43 4.18 37.86 54.28 ADF 7 38.29 39.76 2.26 33.99 40.39 9 38.00 39.94 3.00 33.22 42.50 Hemicellulose 6 7.59 6.88 1.99 5.43 13.57 7 8.06 7.25 2.50 4.14 11.78 Cellulose 3 26.42 25.41 1.47 25.22 28.63 5 26.44 25.60 1.53 24.38 29.72 Lignin 4 12.20 11.51 2.16 9.25 16.52 9 13.29 12.71 3.12 8.84 18.87 IVDMD 3 68.92 66.50 5.92 62.46 77.81 7 67.98 65.13 6.22 60.21 75.57 DM losses 2 10.58 10.58 1.09 9.49 11.67 6 5.17 4.95 3.13 1.33 9.55 WSC 3 2.78 2.44 1.00 1.62 4.27 7 3.17 2.97 1.32 1.57 4.84 Lactic acid 3 4.92 4.45 2.82 1.16 9.15 7 7.17 5.62 4.00 0.95 13.83 Acetic acid 3 5.03 3.90 3.51 0.89 10.29 7 5.24 3.93 2.05 2.35 8.36 Propionic acid 3 0.14 0.14 0.10 0.00 0.29 7 0.20 0.10 0.15 0.00 0.41 Butyric acid 3 0.33 0.01 0.43 0.00 0.99 7 1.00 0.02 1.13 0.00 2.85 Total acids4 3 10.09 11.74 3.16 5.34 13.2 7 12.61 13.23 2.86 7.97 17.84 Ethanol 3 0.37 0.46 0.23 0.02 0.61 7 1.44 0.51 1.26 0.02 3.08 Lactic:acetic acid 3 2.46 2.40 1.61 0.11 4.87 7 2.26 3.02 1.59 0.12 4.57 Total acids:ethanol 3 89.78 25.29 88.5 21.5 223 7 79.97 32.91 103.67 3.20 442.83 pH 6 4.83 4.66 0.39 4.25 5.50 10 4.98 4.78 0.60 4.22 6.11 Ammonia-N, % TN 6 13.85 8.21 9.50 5.21 29.48 10 22.85 28.61 10.99 5.30 37.27 Maximum T, °C 3 26.85 27.00 1.70 24.30 29.25 7 27.21 27.33 1.18 23.78 28.63

DM, dry matter; CP, crude protein; NDIN, neutral detergent insoluble N; ADIN, acid detergent insoluble N; NDF,

**Table 9.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated alfalfa

neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble

Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

silages (data are given in % of DM, unless otherwise stated).

**n2 Mean Median SD3 Min Max n Mean Median SD Min Max**

**Item1 Untreated Homofermentative LAB**

tion are expected.

22 Advances in Silage Production and Utilization

1

2

3

4

carbohydrates; TN, total nitrogen.

Number of means.

Standard deviation.

Data on alfalfa, sorghum, and HMC silages were summarized from 7, 10, and 10 studies, respectively. All studies comprising alfalfa and sorghum evaluated hoLAB only. For HMC silages, hoLAB, heLAB, and a combination between both (mixed) were investigated in six, three, and one study, respectively. Considering all treatments, the application rate of silage inoculant for alfalfa, sorghum, and HMC ranged from 1×105 to 9.9×105 cfu/g, 9.99×104 to 8×105 cfu/g, and 5×104 to 1×106 cfu/g of fresh forage, respectively.


1 DM, dry matter; CP, crude protein; NDF, neutral detergent fiber; ADF, acid detergent fiber; IVDMD, *in vitro* DM digestibility; WSC, water-soluble carbohydrates; TN, total nitrogen.

2 Number of means.

3 Standard deviation.

**Table 10.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated sorghum silages (data are given in % of DM, unless otherwise stated).

The range of fermentation parameters, *in vitro* digestibility, and aerobic stability in alfalfa, sorghum, and HMC silages are given in **Tables 9**, **10**, and **11**, respectively. Considering the overall mean, there was a large difference in the DM content of alfalfa silages, with 33.4% in inoculated silage and 41.3% in untreated silage. Homolactic inoculation increased the concentration of lactic acid by 45.8% in alfalfa silage; however, the pH of silage did not decline, compared with untreated silage; this point may be a consequence of the greater moisture content found in hoLAB-inoculated silages.

Sorghum silages had few alterations on fermentation parameters due to homolactic inoculation. However, DM losses increased from 1.88 to 4.18% when silages were inoculated, when

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The inoculation of sorghum silages also increased the NDF content by 6%, but the ammonia-N concentration decreased by 8.8%. Positive responses from inoculation in sorghum silages occurred only for DM (+14.5%), CP (+15.2%), NDF (−8.5%), and IVDMD (+20.8%) at frequencies of 8.6, 4.6, 6.5, and 9.1%, respectively. Overall, the lack of positive results from inoculation is likely related to the suitable characteristics of sorghum for the ensiling process [45]. Similar to corn, sorghum plants also have good fermentation capability, considerable WSC and DM contents, and low buffer capacity. However, sorghum silages often have low aerobic stability because the suitable characteristics described earlier [13, 15]. Although aerobic deterioration can become a great problem under tropical conditions, there is not any study that assessed

DM, dry matter; CP, crude protein; EE, ether extract; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber;

**Table 12.** Summary of positive responses of silage inoculants on the fermentation patterns, nutritive value, and aerobic

It was not observed significant differences for lactic acid production and final pH by homolactic inoculation in HMC silages. As described earlier, hoLAB are used with the goal to increase lactic acid production and quickly reduce pH of the ensiled crop [6, 8]. In addition, there is an expected inhibition on the growth of undesirable microorganisms such as enterobacteria and clostridia [6, 8]. These effects likely help us to understand why DM losses decreased by 20.4% due to homolactic inoculation. Considering the overall mean, homolactic inoculation reduced

ADF, acid detergent fiber; TN, total nitrogen; LAB, lactic-acid bacteria.

stability of high-moisture corn silages (data are given in % of DM, unless otherwise stated).

compared with losses in untreated silage.

heLAB for sorghum silage in Brazil.

1

The hoLAB reduced DM losses by 51.1% in alfalfa silages. Conversely, homolactic inoculation increased the concentration of ammonia-N by 65%, and an increase from 0.37 to 1.44% in the ethanol concentration was also observed. The greater concentration of ammonia-N was unexpected, since lactic acid produced by hoLAB should be able to decrease proteolytic bacterial populations within the ensiled mass.

Considering the frequency of positive responses of inoculation, only the acetic acid concentration was affected, which was reduced by hoLAB in 14.3% (−35.95%) of the treatments. Usually, improvements on quality of alfalfa silages have been reported due to the homolactic inoculation [42, 43] most likely due to increases on the numbers of LAB, which is quite low in alfalfa [44]. Although the present survey does not contain data regarding number of LAB in alfalfa silages, homolactic inoculation improved the preservation of this crop.


1 DM, dry matter; CP, crude protein; EE, ether extract; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; TN, total nitrogen; LAB, lactic-acid bacteria.

2 Number of means.

3 Standard deviation.

4 Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

**Table 11.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated highmoisture corn silages (data are given in % of DM, unless otherwise stated).

Sorghum silages had few alterations on fermentation parameters due to homolactic inoculation. However, DM losses increased from 1.88 to 4.18% when silages were inoculated, when compared with losses in untreated silage.

overall mean, there was a large difference in the DM content of alfalfa silages, with 33.4% in inoculated silage and 41.3% in untreated silage. Homolactic inoculation increased the concentration of lactic acid by 45.8% in alfalfa silage; however, the pH of silage did not decline, compared with untreated silage; this point may be a consequence of the greater moisture

The hoLAB reduced DM losses by 51.1% in alfalfa silages. Conversely, homolactic inoculation increased the concentration of ammonia-N by 65%, and an increase from 0.37 to 1.44% in the ethanol concentration was also observed. The greater concentration of ammonia-N was unexpected, since lactic acid produced by hoLAB should be able to decrease proteolytic bacterial

Considering the frequency of positive responses of inoculation, only the acetic acid concentration was affected, which was reduced by hoLAB in 14.3% (−35.95%) of the treatments. Usually, improvements on quality of alfalfa silages have been reported due to the homolactic inoculation [42, 43] most likely due to increases on the numbers of LAB, which is quite low in alfalfa [44]. Although the present survey does not contain data regarding number of LAB in

DM, dry matter; CP, crude protein; EE, ether extract; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber;

**Table 11.** Range of fermentation patterns, nutritive value, and aerobic stability of untreated and inoculated high-

ADF, acid detergent fiber; TN, total nitrogen; LAB, lactic-acid bacteria.

Total acid content was calculated as the sum of lactic, acetic, and propionic acids.

moisture corn silages (data are given in % of DM, unless otherwise stated).

alfalfa silages, homolactic inoculation improved the preservation of this crop.

content found in hoLAB-inoculated silages.

24 Advances in Silage Production and Utilization

populations within the ensiled mass.

1

2

3

4

Number of means.

Standard deviation.

The inoculation of sorghum silages also increased the NDF content by 6%, but the ammonia-N concentration decreased by 8.8%. Positive responses from inoculation in sorghum silages occurred only for DM (+14.5%), CP (+15.2%), NDF (−8.5%), and IVDMD (+20.8%) at frequencies of 8.6, 4.6, 6.5, and 9.1%, respectively. Overall, the lack of positive results from inoculation is likely related to the suitable characteristics of sorghum for the ensiling process [45]. Similar to corn, sorghum plants also have good fermentation capability, considerable WSC and DM contents, and low buffer capacity. However, sorghum silages often have low aerobic stability because the suitable characteristics described earlier [13, 15]. Although aerobic deterioration can become a great problem under tropical conditions, there is not any study that assessed heLAB for sorghum silage in Brazil.


1 DM, dry matter; CP, crude protein; EE, ether extract; ADIN, acid detergent insoluble N; NDF, neutral detergent fiber; ADF, acid detergent fiber; TN, total nitrogen; LAB, lactic-acid bacteria.

**Table 12.** Summary of positive responses of silage inoculants on the fermentation patterns, nutritive value, and aerobic stability of high-moisture corn silages (data are given in % of DM, unless otherwise stated).

It was not observed significant differences for lactic acid production and final pH by homolactic inoculation in HMC silages. As described earlier, hoLAB are used with the goal to increase lactic acid production and quickly reduce pH of the ensiled crop [6, 8]. In addition, there is an expected inhibition on the growth of undesirable microorganisms such as enterobacteria and clostridia [6, 8]. These effects likely help us to understand why DM losses decreased by 20.4% due to homolactic inoculation. Considering the overall mean, homolactic inoculation reduced the aerobic stability by 6.9 h, compared with untreated silage. Homolactic inoculation can impair the aerobic stability of silages in some cases [32], because the lactic acid produced and the increased preservation of the forage crop can lead to an increase in the number of spoilage microorganisms, mainly yeasts.

In our survey, we found 42 studies that included feeding inoculated silages to animals in Brazil. In these studies, feed intake, digestibility, and/or growth performance were measured. Twenty of the 42 studies were conducted in cattle, 19 in sheep, 2 in pigs, and 1 in poultry. In this survey, we summarized data into two groups of silages: (1) untreated and (2) inoculated (regardless of the type of bacterial inoculant used). Only the performance of cattle and sheep fed corn, grass, and sugarcane silages were reported in this chapter, because there were a greater number of trials in these crops than others. Nevertheless, the number of studies is much lower than

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DM, dry matter; BW, body weight; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average

**Table 13.** Range of feed intake, digestibility, and growth performance of cattle and sheep fed untreated and inoculated

The inoculation of corn silage slightly depressed DM intake, feed efficiency, and average daily gain (ADG) of cattle (**Table 13**). Conversely, cattle fed inoculated corn silages had small increases in DM and OM digestibility, resulting in a higher intake of digestible DM (+0.16 kg/ day). Regarding the performance of sheep, the inoculation of corn silage increased DM intake by 7.2%, but the digestibility and intake of digestible nutrients were unaffected, in general. Data regarding ADG were not considered, because only one study measured this parameter and, as a prerequisite of this survey, all comparisons between treatments were made consid-

The inoculation of tropical grass silages reduced the DM intake (−0.14 kg/day) in cattle (**Table**

those reported in the international literature.

1

3

daily gain. 2

corn silages.

**14**).

Number of means.

Standard deviation.

ering a minimum of two studies.

Considering the overall mean, heterolactic inoculation of HMC silages increased the concentration of lactic and acetic acids by 106.5 and 92.7%, respectively. Due to the antifungal properties of acetic acid [30], the aerobic stability of HMC silages inoculated with heLAB increased by 102.5 h compared to untreated silage. Furthermore, heterolactic inoculation reduced the NDF content (−56%) and increased the CP content (+32%).

The frequency and difference of the positive responses found in HMC silages from homolactic and heterolactic inoculations are given in **Table 12**. Homolactic inoculation had the greatest frequency of positive responses for DM losses and LAB count. Furthermore, the greatest difference of responses was observed for DM losses and ADF content. Despite heterolactic inoculation, the greatest frequency of positive responses and the greatest magnitude of responses were observed for aerobic stability.

The fermentation of HMC silages is often restricted due to low moisture and fermentable sugar content, and the quantity of total acids produced is quite low [46]. Indeed, the data from this survey showed an increase in fermentation products in HMC silages treated with bacterial inoculants, and heLAB had the greatest impact on fermentation end products and aerobic stability.

Even without statistical analysis, the mean and median values for most variables were very similar, indicating that the data were normally distributed. Although the results of the current survey for all crops investigated are encouraging, some caution should be used when interpreting the data, because the inoculants, application rate, strains, and crops were not the same in each study and the conditions were highly variable. Moreover, the goal of this chapter was to conduct a survey that provides an exploratory picture of the silage trials carried out in Brazil, more than a proper comparison among treatments, which require analyses more specific.

#### **2.2. Animal performance**

Considerable efforts have been devoted to understand how silage inoculants affect animal performance, since such improvements are, in many cases, the principal economic justification for their use, in addition to improved nutrient recovery and enhanced aerobic stability already presented above.

Significant improvements on the performance of animals fed inoculated silages have been found in studies carried out in Europe and North America, although less frequently than studies regarding changes in fermentation caused by inoculation [47]. In a previous review concerning bacterial inoculants in Brazil (see [5]), there was not a definitive conclusion regarding the effect of inoculation on animal performance due to the low number of studies, but the authors suggested that the difference and frequency of responses should be similar to those observed in other countries (see [48]).

In our survey, we found 42 studies that included feeding inoculated silages to animals in Brazil. In these studies, feed intake, digestibility, and/or growth performance were measured. Twenty of the 42 studies were conducted in cattle, 19 in sheep, 2 in pigs, and 1 in poultry. In this survey, we summarized data into two groups of silages: (1) untreated and (2) inoculated (regardless of the type of bacterial inoculant used). Only the performance of cattle and sheep fed corn, grass, and sugarcane silages were reported in this chapter, because there were a greater number of trials in these crops than others. Nevertheless, the number of studies is much lower than those reported in the international literature.


1 DM, dry matter; BW, body weight; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average daily gain.

2 Number of means.

the aerobic stability by 6.9 h, compared with untreated silage. Homolactic inoculation can impair the aerobic stability of silages in some cases [32], because the lactic acid produced and the increased preservation of the forage crop can lead to an increase in the number of spoilage

Considering the overall mean, heterolactic inoculation of HMC silages increased the concentration of lactic and acetic acids by 106.5 and 92.7%, respectively. Due to the antifungal properties of acetic acid [30], the aerobic stability of HMC silages inoculated with heLAB increased by 102.5 h compared to untreated silage. Furthermore, heterolactic inoculation

The frequency and difference of the positive responses found in HMC silages from homolactic and heterolactic inoculations are given in **Table 12**. Homolactic inoculation had the greatest frequency of positive responses for DM losses and LAB count. Furthermore, the greatest difference of responses was observed for DM losses and ADF content. Despite heterolactic inoculation, the greatest frequency of positive responses and the greatest magnitude of

The fermentation of HMC silages is often restricted due to low moisture and fermentable sugar content, and the quantity of total acids produced is quite low [46]. Indeed, the data from this survey showed an increase in fermentation products in HMC silages treated with bacterial inoculants, and heLAB had the greatest impact on fermentation end products and aerobic

Even without statistical analysis, the mean and median values for most variables were very similar, indicating that the data were normally distributed. Although the results of the current survey for all crops investigated are encouraging, some caution should be used when interpreting the data, because the inoculants, application rate, strains, and crops were not the same in each study and the conditions were highly variable. Moreover, the goal of this chapter was to conduct a survey that provides an exploratory picture of the silage trials carried out in Brazil, more than a proper comparison among treatments, which require analyses more specific.

Considerable efforts have been devoted to understand how silage inoculants affect animal performance, since such improvements are, in many cases, the principal economic justification for their use, in addition to improved nutrient recovery and enhanced aerobic stability already

Significant improvements on the performance of animals fed inoculated silages have been found in studies carried out in Europe and North America, although less frequently than studies regarding changes in fermentation caused by inoculation [47]. In a previous review concerning bacterial inoculants in Brazil (see [5]), there was not a definitive conclusion regarding the effect of inoculation on animal performance due to the low number of studies, but the authors suggested that the difference and frequency of responses should be similar to

reduced the NDF content (−56%) and increased the CP content (+32%).

microorganisms, mainly yeasts.

26 Advances in Silage Production and Utilization

responses were observed for aerobic stability.

stability.

**2.2. Animal performance**

those observed in other countries (see [48]).

presented above.

3 Standard deviation.

**Table 13.** Range of feed intake, digestibility, and growth performance of cattle and sheep fed untreated and inoculated corn silages.

The inoculation of corn silage slightly depressed DM intake, feed efficiency, and average daily gain (ADG) of cattle (**Table 13**). Conversely, cattle fed inoculated corn silages had small increases in DM and OM digestibility, resulting in a higher intake of digestible DM (+0.16 kg/ day). Regarding the performance of sheep, the inoculation of corn silage increased DM intake by 7.2%, but the digestibility and intake of digestible nutrients were unaffected, in general. Data regarding ADG were not considered, because only one study measured this parameter and, as a prerequisite of this survey, all comparisons between treatments were made considering a minimum of two studies.

The inoculation of tropical grass silages reduced the DM intake (−0.14 kg/day) in cattle (**Table 14**).

However, cattle fed inoculated grass silages exhibited better feed efficiency than cattle fed untreated silage, whereas ADG was similar between treatments (**Table 14**). Digestibility of DM, OM, NDF, and CP was slightly affected by inoculation. Furthermore, sheep fed inoculated silages exhibited higher DM intake (+11.7%), whereas bacterial inoculants had little effect on silage digestibility.

ments in nutritive value of silages from bacterial inoculation may be strongly correlated with enhanced animal performance [47, 48]. However, the great frequency and difference of the responses might be associated with the low number of studies carried out that evaluated

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The frequency of positive responses observed in sheep consuming inoculated silages was greater than those found in cattle. Sheep fed corn silage had a great frequency of positive responses for inoculation concerning DM, OM, NDF, and CP intake (≥50%). The ADG also improved in 50% of treatments, an overall increase of 4%. For grass silage, the greater frequency of positive responses from inoculation was observed for digestibility (DM, NDF, and CP). Conversely, only the intake of digestible NDF and NDF digestibility had positive responses

DM, dry matter; BW, body weight; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average

**Table 15.** Range of feed intake, digestibility, and growth performance of cattle and sheep fed untreated and inoculated

The results found in Brazilian studies suggest a greater effect of inoculation when there is a positive response, compared to those from other countries. In Europe, a review of 14 studies reported increases in DM intake (+4.8%) and milk production (+4.6%) when animals were fed silage inoculated with *L. plantarum* strain MTD1 [49]. Similarly, a review of studies carried out between 1990 and 1995 reported that in 28, 53, and 47% of these studies, there were increases

in DM intake (+4.8%), ADG (+4.6%), and milk production (+4.6%), respectively [48].

animal performance in Brazil.

by inoculation in sugarcane silages.

1

3

daily gain. 2

Number of means.

Standard deviation.

sugarcane silages.

The inoculation of sugarcane silages negatively impacted DM intake in cattle (−0.56 kg/day), as well as the intake of digestible nutrients (**Table 15**). As consequence, the ADG of cattle fed inoculated silages was lower than cattle fed untreated silages (1.17 vs. 1.21 kg/day, respectively). Few measurements were made in sheep fed sugarcane silages, but positive responses from inoculation were observed on DM and NDF intake, which increased by 4.6 and 11.3%, respectively; however, inoculation reduced DM digestibility by 16.6%.


1 DM, dry matter; BW, body weight; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average daily gain.

2 Number of means.

3 Standard deviation.

**Table 14.** Range of feed intake, digestibility, and growth performance of cattle and sheep fed untreated and inoculated grass silages.

Overall means of this survey consistently appointed for a reduction in DM intake when cattle were fed inoculated corn, grass, and sugarcane silages. However, effects of silage inoculants on feed intake and growth performance are widely varied and likely are microorganisms and strains specific along with dose dependent.

We also calculated the frequency and difference of positive responses, in addition to the impact of bacterial inoculation in experiments with cattle and sheep (**Tables 16** and **17**). There was great frequency of positive responses of inoculation concerning DM and OM digestibility in cattle fed corn silage. Similarly, inoculation had a great impact on the performance of cattle fed sugarcane silage, with feed efficiency and ADG improving by 80%. The greater ADG observed in cattle fed sugarcane silage likely arises from a better preservation of WSC during fermentation leading to the improved nutritive value of inoculated silages. In this regard, improvements in nutritive value of silages from bacterial inoculation may be strongly correlated with enhanced animal performance [47, 48]. However, the great frequency and difference of the responses might be associated with the low number of studies carried out that evaluated animal performance in Brazil.

The frequency of positive responses observed in sheep consuming inoculated silages was greater than those found in cattle. Sheep fed corn silage had a great frequency of positive responses for inoculation concerning DM, OM, NDF, and CP intake (≥50%). The ADG also improved in 50% of treatments, an overall increase of 4%. For grass silage, the greater frequency of positive responses from inoculation was observed for digestibility (DM, NDF, and CP). Conversely, only the intake of digestible NDF and NDF digestibility had positive responses by inoculation in sugarcane silages.


1 DM, dry matter; BW, body weight; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average daily gain.

2 Number of means.

However, cattle fed inoculated grass silages exhibited better feed efficiency than cattle fed untreated silage, whereas ADG was similar between treatments (**Table 14**). Digestibility of DM, OM, NDF, and CP was slightly affected by inoculation. Furthermore, sheep fed inoculated silages exhibited higher DM intake (+11.7%), whereas bacterial inoculants had little effect on

The inoculation of sugarcane silages negatively impacted DM intake in cattle (−0.56 kg/day), as well as the intake of digestible nutrients (**Table 15**). As consequence, the ADG of cattle fed inoculated silages was lower than cattle fed untreated silages (1.17 vs. 1.21 kg/day, respectively). Few measurements were made in sheep fed sugarcane silages, but positive responses from inoculation were observed on DM and NDF intake, which increased by 4.6 and 11.3%,

DM, dry matter; BW, body weight; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average

**Table 14.** Range of feed intake, digestibility, and growth performance of cattle and sheep fed untreated and inoculated

Overall means of this survey consistently appointed for a reduction in DM intake when cattle were fed inoculated corn, grass, and sugarcane silages. However, effects of silage inoculants on feed intake and growth performance are widely varied and likely are microorganisms and

We also calculated the frequency and difference of positive responses, in addition to the impact of bacterial inoculation in experiments with cattle and sheep (**Tables 16** and **17**). There was great frequency of positive responses of inoculation concerning DM and OM digestibility in cattle fed corn silage. Similarly, inoculation had a great impact on the performance of cattle fed sugarcane silage, with feed efficiency and ADG improving by 80%. The greater ADG observed in cattle fed sugarcane silage likely arises from a better preservation of WSC during fermentation leading to the improved nutritive value of inoculated silages. In this regard, improve-

respectively; however, inoculation reduced DM digestibility by 16.6%.

silage digestibility.

28 Advances in Silage Production and Utilization

1

3

daily gain. 2

grass silages.

Number of means.

Standard deviation.

strains specific along with dose dependent.

3 Standard deviation.

**Table 15.** Range of feed intake, digestibility, and growth performance of cattle and sheep fed untreated and inoculated sugarcane silages.

The results found in Brazilian studies suggest a greater effect of inoculation when there is a positive response, compared to those from other countries. In Europe, a review of 14 studies reported increases in DM intake (+4.8%) and milk production (+4.6%) when animals were fed silage inoculated with *L. plantarum* strain MTD1 [49]. Similarly, a review of studies carried out between 1990 and 1995 reported that in 28, 53, and 47% of these studies, there were increases in DM intake (+4.8%), ADG (+4.6%), and milk production (+4.6%), respectively [48].


1 DM, dry matter; OM, organic matter; NDF, neutral detergent fiber; ADG, average daily gain.

**Table 16.** Summary of positive responses of silage inoculants on the performance of cattle fed corn and sugarcane silages in experiments carried out in Brazil.

The results of the current survey are encouraging regarding the impact of bacterial inoculants on animal performance in tropical conditions. However, although the mean and median values for most variables measuring animal performance were very similar (which may indicate normal distribution of the data), this occurred because of the lack and/or low number of studies evaluated. Therefore, some caution should be taken when interpreting this data, as well as the great frequency of positive responses found, which is likely attributed to the low number of studies evaluated.

1

body weight.

**3. Implications**

sugarcane silages in experiments carried out in Brazil.

DM, dry matter; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average daily gain; BW,

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A probiotic can be defined as a culture of live microbes, that when fed to the animals, benefi‐ cially affects the host by improving the properties of the native gut microflora [48]. Indeed, a recent study displayed greater microbial protein synthesis in lambs fed silage inoculated with *L. buchneri*, applied either alone or associated with *L. plantarum* in corn silage [51],

The data summarized from Brazilian studies displays a recent increase in interest from researchers addressing bacterial inoculants as an alternative to improve silage quality. But although the number of studies remains quite low compared with the international literature, data of this survey revealed some trends for improved fermentation and nutritive value

**Table 17.** Summary of positive responses of silage inoculants on the performance of sheep fed corn, grass, and

which is likely related to changes in the microbial community in the rumen.

regarding the group of bacterial inoculant used at ensiling and crop.

Regarding the factors responsible for enhancing animal performance, certainly improvements in DM digestion are closely linked to greater growth performance. In a review of the literature from 1985 to 1992, animal performance improved in 9 of 16 trials when inoculation improved DM digestion, but only 2 of 15 trials when digestion was not significantly affected [50].

In our survey, we did not observe a relationship between DM digestibility and growth performance, because the number of studies evaluated was quite low. However, there are other hypotheses related to the improvement of animal performance. The first suggests that improvements in silage quality could lead to increased animal performance. The second suggests that silage inoculants may provide a probiotic effect by inhibiting detrimental microorganisms in the silage and rumen, or by producing beneficial substances that may enhance the functioning of specific microbial populations in the rumen, leading to an increase in animal performance [47].


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1 DM, dry matter; OM, organic matter; NDF, neutral detergent fiber; CP, crude protein; ADG, average daily gain; BW, body weight.

**Table 17.** Summary of positive responses of silage inoculants on the performance of sheep fed corn, grass, and sugarcane silages in experiments carried out in Brazil.

A probiotic can be defined as a culture of live microbes, that when fed to the animals, benefi‐ cially affects the host by improving the properties of the native gut microflora [48]. Indeed, a recent study displayed greater microbial protein synthesis in lambs fed silage inoculated with *L. buchneri*, applied either alone or associated with *L. plantarum* in corn silage [51], which is likely related to changes in the microbial community in the rumen.
