Silage fermentation quality
The Fleig point in all silages was over 97.99, indicating that all TMR silages in the present experiment have very good quality fermentation (Denek and Can, 2006). This might be caused by the material that was used in this experiment. Wet type of food by-products including tofu waste and brewer grain contained LAB that contributed to produce organic acid and then depressing the pH value. Actually, Tanaka et al. (2001) reported that before fermentation tofu cake and brewer grain contained LAB 9 × 107 and 6.4 × 107 cfu/g,respectively. With these numbers, it
would be sufficient to produce lactic acid and lowering pH to achieve good fermentation quality because well preserved silage will be obtained when LAB level reaches 105 cfu/g (Cao et al., 2016).
Acetic acid in the COM and MIX treatment showed higher than that in CON treatment. LAB in COM additives were Lactococcus lactis that generally considered as homofermentative LAB (McDonald et al., 1991; Gallo et al., 2018) and Lactobacillus paracasei as well (Nkosi et al., 2010). However according to Gollomb and Marco (2015), L. lactis possesses an enzyme required for heterofermentative metabolism. It suggested that this microorganism contributes to the high acetic acid production in COM treatment. Acetic acid has been known increases the aerobic stability in silage (Danner et al., 2003) because it could inhibit the growth of acid-tolerant yeast (Gallo et al., 2018). Li et al. (2016) found that increasing in acetic acid can suppress fungal growth in silage inoculated with heterofermentative LAB. Other parameters in silage fermentation quality did not differ among the treatment. Again, this was because non-additive treatment also contained sufficient LAB for getting favorable fermentation.
Table 4.3. Fermentation quality and chemical composition of TMR ensilaged with fermented juice of epiphytic lactic acid bacteria Item Treatment P-value CON FJLB COM MIX Fermentation quality pH 4.58 ± 0.13 4.41 ± 0.13 4.25 ± 0.10 4.33 ± 0.10 0.303 Lactic acid (g/kg DM) 31.51 ± 3.40 37.43 ± 3.78 37.80 ± 4.36 40.15 ± 2 0.379 VFA(g/kg DM) Acetic acid 13.22 ± 2.88 b16.72 ± 0.78 ab21.46 ± 1.59 a24.22 ± 1.21 a 0.005 Propionic acid 0.89 ± 0.34 0.92 ± 0.270.96 ± 0.31 1.08 ± 0.36 0.976 Butyric acid 0.46 ± 0.09 0.27 ± 0.10 0.42 ± 0.15 0.1 ± 0.06 0.125 NH3-N(g/kg DM) 0.18 ± 0.01 0.15 ± 0.01 0.19 ± 0.02 0.18 ± 0.03 0.217 Fleig point 97.99 ± 5.55 106.23 ± 4.86 109.35 ± 3.03 108.52 ± 3.94 0.301 Chemical composition DM 38.0 ± 0.33 38.8 ± 0.44 37.1 ± 0.45 38.4 ± 0.35 0.055 CP (%DM) 12.5 ± 0.16 12.9 ± 0.28 13.2 ± 0.20 13.1 ± 0.31 0.227 aNDFom (%DM) 48.9 ± 1.08 47.6 ± 1.41 47.7 ± 0.74 46.9 ± 0.34 0.581 ADFom (%DM) 30.5 ± 0.80 30.4 ± 0.74 30.3 ± 0.57 30.0 ± 0.36 0.946 EE (%DM) 4.55 ± 0.16 4.73 ± 0.20 4.84 ± 0.08 4.82 ± 0.12 0.412 Crude Ash (%DM) 8.2 ± 0.27 8.3 ± 0.18 8.2 ± 0.21 8.3 ± 0.07 0.938 CON: control (no additive added), FJLB: fermented juice of epiphytic lactic acid bacteria additive, COM: Commercial silage additive, MIX: FJLB+COM, VFA: volatile fatty acid, NH3-N: ammonia-nitrogen, CP: crude protein, aNDFom: α-amylase neutral detergent fiber exclusive ash, ADFom: acid detergent fiber exclusive ash, EE: ether extract,DM: dry matter. The values with different superscript within the same row are significantly different at 5% level. Values are mean ± standard error.
Table 4.4. Effect of different silage additives in TMR silage prepared from agriculture by-product on in vivo nutrient digestibility and in vitro methane production Parameters CON FJLB COM MIX P-value In vivo nutrient digestibility (%) DMD 69.5 ± 1.68 67.4 ± 2.24 68.3 ± 3.13 67.4 ± 3.39 0.763 CPD 69.3 ±1.72 67.9 ± 2.09 71.8 ± 3.07 67.2 ± 3.52 0.925 aNDFom 66.1 ± 2.28 62.4 ± 2.92 61.3 ± 5.49 62.2 ± 4.09 0.568 ADF 64.5 ± 1.34 60.6 ± 2.67 61.1 ± 4.79 61.6 ± 3.03 0.473 In vitro CH4 production (mL/g DM) 22.1 ± 0.42 21.0 ± 0.58 20.6 ± 0.42 20.7 ± 0.46 0.151 DMD (%) 30.9 ± 1.87 33.2 ± 3.03 32.6 ± 3.62 33.0 ± 3.25 0.944 OMD (%) 24.8 ± 1.98 27.1 ± 3.37 26.6 ± 4.01 27.0 ± 3.5 0.956 CH4/DMD 72.0 ± 4.98 64.4 ± 4.49 65.4 ± 7.56 64.3 ± 6.56 0.768 CH4/OMD 98.6 ± 9.20 87.5 ± 8.97 91.6 ± 16.87 88.0 ± 11.97 0.910 DM: dry matter; DMD: dry matter digestibility; OMD: organic matter digestibility; Values are mean ± standard error
Table 4.5. Serum parameters of ewes fed TMR silage with different silage additive Values are mean ± standard error Parameters Treatment P-value CON FJLB COM MIX Glucose (mg/dL) 60.6 ± 2.40 57.4 ± 2.90 53.3 ± 3.19 55.0 ± 6.12 0.686 Cholesterol (mg/dL) 110.0 ± 11.24 102.4 ± 6.44 92.3 ± 26.38 90.4 ± 9.65 0.584 Triglyceride (mg/dL) 35.9 ± 8.53 28.9 ± 7.87 26.8 ± 9.34 25.5 ± 7.01 0.374 Total protein (g/dL) 6.0 ± 0.51 5.8 ± 0.35 5.3 ± 0.35 5.5 ± 0.59 0.564 Urea nitrogen (mg/dL) 20.2 ± 2.19 21.3 ± 3.28 17.9 ± 2.88 20.0 ± 2.64 0.459
Table 4.6. Effect of different silage additives in TMR silage prepared from agriculture by-product on energy utilization in ewes Parameters CON FJLB COM MIX P-value DMI (g/kg BW 0.75/day) 48.3 ± 3.25 45.9 ± 3.37 39.5 ± 5.19 44.2 ± 1.9 0.404 GE intake (MJ/kg BW 0.75/day) 0.9 ± 0.06 0.9 ± 0.06 0.8 ± 0.07 0.8 ± 0.04 0.415 FE (MJ/kg BW 0.75/day) 0.3 ± 0.03 0.3 ± 0.03 0.2 ± 0.04 0.2 ± 0.02 0.638 DE (MJ/ kg BW 0.75/day) 0.6 ± 0.03 0.6 ± 0.03 0.5 ± 0.04 0.6 ± 0.05 0.663 Energy digestibility (%) 71.6 ± 1.55 69.8 ± 1.85 70.5 ± 2.85 69.9 ± 3.21 0.897 UE (MJ/kg BW 0.75/day) 0.03 ± 0.003 0.03 ± 0.003 0.04 ± 0.014 0.03 ± 0.05 0.822 CH4 energy (MJ/100 MJ GEI) 8.1 ± 0.09 8.0 ± 0.11 8.0 ± 0.17 8.0 ± 0.19 0.912 CH4 energy (MJ/kg BW 0.75/day) 0.07 ± 0.004 0.07 ± 0.004 0.06 ± 0.005 0.07 ± 0.004 0.786 ME (MJ/BW 0.75/day) 0.5 ± 0.03 0.5 ± 0.02 0.4 ± 0.03 0.5 ± 0.05 0.490 Energy metabolizability (%) 59.4 ± 1.48 57.5 ± 1.68 57.0 ± 3.93 58.4 ± 3.45 0.880 DMI: dry matter intake; GE: gross energy; FE: fecal energy; DE: digestible energy; UE: urine energy; ME: metabolizable energy.
Digestibility and methane production
Some studies reported the effect of FJLB on nutrient digestibility in ruminant.
The application of FJLB improved CP digestibility of ruzigrass silage in cows (Bureenok et al., 2011). Yahaya et al. (2004) also reported in vitro DM and NDF digestibility were improved in tropical elephant grass. Similarly, fibrous component clearly improved in whole crop rice ensilaged with FJLB (Takahashi et al., 2005). In contrast, there were no improvement in nutrients digestibility in the present study. The similar result among the treatment on nutrient digestibility might be related to the similar quality of TMR silage as shown in Table 4.3. This result is in line with the previous reports that added FJLB as silage additive in Napier grass silage did not improve the nutrient digestibility (Bureenok et al., 2012) and in vitro DM digestibility of rice straw were not improved by the addition of LAB inoculant from incubated king grass extract (Santoso et al., 2014). Those different result suggested that different of material for preparing FJLB, the dose of FJLB and the materials of silage will affect the digestibility in both in vitro and in vivo assessment.
In vitro methane production did not differ among the treatment. There was limited information on the effect of FJLB application on ruminal methane production.
Cao et al. (2009a) reported that supplementation with lactic acid bacteria reduced the methane production per in vitro digestible DM on TMR silage prepared from whole crop rice, commercial concentrate, tofu cake, rice bran, and green tea. Similarly, in vitro ruminal methane production was decreased 8.6% by adding LAB (Lactobacillus plantarum Chikuso-1) in TMR with whole crop rice (Cao et al. 2010a). They suggest that the higher lactic acid in the fermented TMR is the key factor on producing ruminal propionic acid, then accordingly, lowered methane production (Cao et al.,
2012). In the present study, all silage has similar lactic acid concentration; thus, the methane production was not different among the treatments.
Blood parameters
The FJLB, COM and MIX treatment in the present study did not affect serum glucose, cholesterol, triglyceride, total protein and urea nitrogen. The absence of any effect of silage additive on blood parameters in the present study could be due to similar qualities of TMR silages that lead to similarities in nutrient digestibility and uptake.
The normal range of blood glucose value in sheep is considered 25-50 mg/dL at any time of day (Reid, 1950). However, Marcias-Cruz et al. (2014) reported that blood glucose level in ewe lamb were ranged 79-84 mg/dL. In the present study, the blood glucose level ranged 53.3-60.6 mg/dL. Although, low and high levels of blood glucose suggest energy deficiency of animals, the present result indicated that the energy supply was sufficient to meet the ewe’s requirements.
The total cholesterol was not affected by the silage additives. In general, normal value of blood cholesterol is 52-76 mg/dL (Kaneko et al., 1983). The values of blood cholesterol in the present study (90.4-110.0 mg/dL) were higher than normal range. This high level of cholesterol in the present study might be due to the high content of EE (4.55-4.82% DM) in the TMR silage. An increase in the plasma cholesterol level is necessary to support the transport of large circulating quantities of PUFA and total lipids (Rufino et al., 2018). Thus, this relatively high EE in the present study contributes to the metabolism of EE metabolites (Cônsolo et al., 2017).
Serum total protein were also not affected by the treatments. The normal value of serum total protein value in ruminant is 6.0-7.9 g/dL (Kaneko et al., 1983). The
serum total protein in the silage additive treatments were slightly lower than the normal value. The lower in serum total protein reflects a fast rate of ruminal degradation of crude protein, and decreased quantities of protein available to absorb in the small intestine lead to low protein absorption into blood (Przemyslaw et al., 2015). The higher rumen degradable protein may attribute to higher N losses in the urine then lead to decrease in N retention (Singh et al., 2015). It suggested that TMR silage in this study has more degradable protein in the rumen and less protein absorption the digestion tract afterwards. However, this relatively low total protein is not negative for animal health.
Serum urea nitrogen in present study were ranged 17.9-20.2 mg/dL. There were no silage additive effects on serum urea nitrogen. Blood urea nitrogen concentration were closely related to dietary CP concentration (Koike et al., 2010;
Aliyu et al., 2012). Specifically, degradable protein produces excess levels of urea in the rumen. In the present study, tofu waste in the TMR silage includes relatively high level of degradable protein. This might lead to the higher serum urea nitrogen.
Although appropriate serum urea nitrogen level is not known in ewes, Ferguson et al.
(1993) reported that under 20 mg/dl in serum urea nitrogen did not have negative effect on reproduction of dairy cows.
Regarding the blood parameters result, the energy supply was sufficient to meet the ewe’s requirements. However, there might be no positive effect on nitrogen retention.
Energy balance
GE intake was similar in ewes fed TMR silage with different silage additive.
This result might be caused by the similar quality of TMR silage in all treatment and suggests that all silage has similar palatability. The FE loss was not different in all
silage additive treatment. These similar values of FE loss were likely due to similar DMI because FE loss is associated with DMI (Hales et al., 2015). Accordingly, the DE and the proportion of DE to GE were not different among the treatments. This is because similar chemical composition in all TMR silages led to have a similar rumen degradation and nutrient absorption in the intestinal tract.
Methane emission in ruminants is greatly affected by crude fiber content in DM intake. Due to no statistical difference in aNDFom and NDFom intake, the methane emissions did not different among the treatments. This result was in accordance with the result of in vitro methane production in the previous section.
Predicted energy losses as methane in this study was 0.08 of GE intake, and this value agreed with the value of predicted methane in Adesogan et al. (1998) that often quoted for feeds at maintenance. An in vivo study by Chuntrakort et al. (2014) in cattle fed rice straw based diet contained cassava chip and soybean meal found the methane emissions was 0.102 of GE intake. Whereas in finishing beef cattle offered maize silage was 0.073-0.084 of GE intake (Mc Geough et al., 2010). This result implied that TMR silage prepared from agriculture by-products does not have any adverse effect on methane emission.
In conclusion, TMR silage prepared from agricultural by-product and wet food by-product is an available way to make good quality of silage. FJLB did not affect effectively on TMR that contained original lactic acid bacteria. From the results of blood parameters and energy utilization in the present study, it can be concluded that TMR silage prepared from agriculture by-products with FJLB has no negative effect on animal health, methane emission and energy utilization. The FJLB did not improve methane emission and energy utilization in sheep.