 |
| Figure 1. pH values of the silages |
| Livestock Research for Rural Development 23 (7) 2011 | Notes to Authors | LRRD Newsletter | Citation of this paper |
This experiment was conducted to study the effect of Effective Microorganisms (EM) on the anti-nutritional factors of wet processed coffee pulp silages. Eight treatment silages were produced by ensiling chopped grass hay in combination with 10, 20, 30 and 100% of wet processed coffee pulp with and without the use of EM as biological inoculants.
The best silages were prepared by ensiling chopped grass hay in combination with 30 and 100% of wet processed coffee pulp with the use of EM as inoculants, as measured by visual appraisal and pH value. The ether extract (EE) and crude protein (CP) content of the pure pulp tended to decrease as a result of dilution with chopped grass hay indicating the potential feed value of coffee pulp compared to the grass hay. There was significant improvement in the total ash, EE and CP content and significant decrease (P<0.05) in cell wall (NDF, ADF and hemicelluloses) components of pure coffee pulp ensiled with the use of EM as biological inoculant’s. The results obtained also showed that there was significant reduction (P<0.05) in the anti-nutritional factors (lignin, caffeine and condensed tannin) and improvement in in-vitro dry matter digestibility of pure coffee pulp ensiled with the use of EM as inoculants’. In summary, the results of this study seems to indicate that there was improvement in the overall nutritive value of wet processed coffee pulp as a result of using EM as a biological inoculants’ as measured by silage quality, chemical composition and in-vitro dry matter digestibility. However, animal evaluation of the effect of EM on the nutritive value of coffee by-products seems to be the future direction of research.
Key words: Anti-nutritional factors, biological inoculants, ensiling, grass hay
One of the major constraints to animal production in Ethiopia is inadequate nutrition. Animals are normally fed on natural pasture and crop residues of low feeding value. Efficient utilization of agricultural and agro-industrial by-products for animal feeding could improve the nutritional status (Solomon 1991). Coffee is an agricultural crop of significant economic importance in Ethiopia. About 600,000 hectares of the country’s agricultural land is planted to coffee and mean national annual coffee production is estimated at 350,000 tons (Alemayehu et al 2007). At present, large quantities of the by-product accumulate at the production site provoking disposal and environmental problems. Thus, the use of coffee pulp as animal feed has significant economic and environmental implication in Ethiopia. Unfortunately low feed intake, protein digestibility and nitrogen retention are the major factors limiting the use of coffee pulp as animal feed (Bressani 1987). Wet processed coffee pulp is high in moisture content which leads to conservation constraints. Ensiling either on its own or in combination with other locally available feed resources seems to be the best way of preservation and improvement in nutritive value of wet processed coffee pulp (Pandey et al 2000). It was reported that silages treated with microbial inoculants exhibited improvement in chemical composition (Gordon 1989; Steen et al 1989 and Anderson, 1989), indicating that Effective Micro-organisms (EM) could better be used as biological inoculant’s to ensile wet processed coffee pulp.
The EM is a product characterized by a mix of aerobic and anaerobic microorganisms consisting of three major groups: i.e. photosynthetic bacteria, lactobacillus bacteria and yeasts and/or fungi (Higa and Wididana 2007). The EM technology is found to be useful in a wide variety of fields. Studies conducted in Asia (Chantsawang and Watcharangkul 1999) and in Belarus (Konoplya and Higa 2000) reported the successful use of EM in poultry feeding. EM was reported to be successfully used for increasing productivity in integrated animal units and poultry farms in South Africa (Hanekon et al., 2001, Safalaoh and Smith, 2001) and in swine and fish farms in Austria (Konoplya and Higa 2000). The objective of this research work was to study the effect of using EM as biological ensiling inoculants’ on the anti- nutritional factors of wet processed coffee pulp.
Wet processed coffee pulps were collected from Gomma Wereda coffee processing station located at 370 km southwest of Addis Ababa and transported to Jimma University College of Agriculture and Veterinary Medicine (JUCAVM). Soon after transportation the wet pulp was sun dried to reduce the moisture content in order to facilitate handling processes. Adequate quantities of grass hay (natural pasture of mixed grass species dominated by Pennisetum clandestinum harvested at late stage of heading) obtained from JUCAVM hay-barn were chopped using manually operated chopper. The chopped grass-hay was ensiled in combinations with 10, 20, 30 and 100% of the sun-dried coffee pulp on weight basis (Table1) with and without the addition of EM (eight treatment silages shown in table 1) using airtight plastic containers (barrels) for a period of 30 days. The EM used as biological inoculants was prepared by thoroughly mixing one liter of EM solution, one liter of molasses and 18 liters of chlorine free water. The silage materials were thoroughly mixed, packed, sealed and made airtight during the ensiling process.
|
Table 1. Composition of the treatment silages |
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|
|
Treatment |
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|
|
CP10 |
CP20 |
CP30 |
CP100 |
CP10 |
CP20 |
CP30 |
CP100 |
|
EM |
Treated |
Treated |
Treated |
Treated |
- |
- |
- |
- |
|
Coffee pulp, % |
10 |
20 |
30 |
100 |
10 |
20 |
30 |
100 |
|
Chopped hay, % |
90 |
80 |
70 |
- |
90 |
80 |
70 |
- |
All the silages were evaluated for quality on the basis of visual appraisal (color and smell) and pH value. The pH values of the treatment silages were determined by potentiometer measurement (pH meter) of the extract (Playne and McDonald 1996). Visual appraisal and laboratory chemical analysis were followed by in-vitro dry matter digestibility (IVDMD) determination. Representative samples of one kg was taken from each of the silages. These were dried in an oven at 65 °C for 72 hours. The dried materials were ground to pass through 1 mm sieve in a Wiley mill and stored in polyethylene bags until required for chemical analysis and in-vitro dry matter digestibility determination (AOAC 1990).
One gram dried and ground sample taken from each treatment silages were used for the determination of IVDMD according to procedures of Tilley and Terry (1963). The rumen fluid was obtained from a cannulated steer fed on a roughage diet. DM residue was determined after 96 hours of digestion, followed by ashing of the residue to determine IVDMD.
The data collected were subjected to analysis of variance according to General Linear Model (GLM) procedures (SAS Institute 2000). Least Significant Difference (LSD) procedures were followed to separate the means when the F value showed significant differences.
|
Table 2. pH values, chemical composition and IVDMD of the treatment silages according to level of coffee pulp and inclusion of EM |
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|
|
With EM |
|
Without EM |
|
|
|
|
||||||
|
CP, % |
10 |
20 |
30 |
100 |
|
10 |
20 |
30 |
100 |
SE |
EM |
CoP |
EM*CoP |
|
pH |
4.60d |
4.49 d |
4.49 d |
3.9 e |
|
5.18bc |
5.01c |
5.48ab |
4.33 d |
0.09 |
<.001 |
<.001 |
0.067 |
|
DM |
87.6c |
87.0cd |
84.8ef |
80.3g |
|
89.2 b |
87.3c |
85.9de |
84.0f |
0.46 |
0.007 |
<.001 |
0.029 |
|
Ash |
13.3 a |
13.6 a |
13.5 a |
13.5 a |
10.8bc |
10.1c |
11.3b |
10.5c |
0.25 |
<.001 |
0.216 |
0.121 |
|
|
CP |
12.8 b |
12.9 b |
13.4 ab |
14.0 a |
10.7d |
10.9cd |
11.5 c |
11.5c |
0.26 |
<.001 |
0.016 |
0.759 |
|
|
EE |
2.3 cd |
2.7 c |
3.8b |
4.4 a |
|
2.0 d |
2.4 cd |
2.4 cd |
3.5 b |
0.2 |
0.001 |
<.001 |
0.014 |
|
NDF |
51.5 d |
46.1 f |
43.8 g |
39.7h |
|
59.0 a |
57.0 b |
55.2 c |
49.0e |
0.49 |
<.001 |
<.001 |
0.02 |
|
ADF |
42.5 c |
38.5e |
35.7 f |
33.1 g |
|
46.7a |
45.2 ab |
44.0 bc |
40.3d |
0.56 |
<.001 |
<.001 |
0.037 |
|
H-cellul. |
9.1 c |
7.6 d |
8.1 cd |
6.5e |
|
12.3 a |
11.7 ba |
11.3 b |
8.6 c |
0.29 |
<.001 |
<.001 |
0.046 |
|
Lignin |
8.9 bc |
7.5cd |
7.1d |
5.3.e |
|
10.5 a |
9.8 ba |
8.8 bc |
6.8 d |
0.45 |
0.006 |
0.002 |
0.836 |
|
Caffeine |
0.10 ef |
0.12e |
0.19 d |
0.67 b |
|
0.18d |
0.26c |
0.27c |
0.82 a |
0.01 |
0.05 |
0.96 |
0.004 |
|
CT |
0.22 c |
0.25 c |
0.24 c |
0.42 b |
|
0.34 b |
0.35 b |
0.36 b |
0.5a |
0.03 |
0.009 |
0.001 |
0.314 |
|
IVDMD |
77.1 a |
76.4 a |
78.1 a |
64.1 c |
|
60.6 cd |
62.0 cd |
57.1 d |
42.6 e |
1.8 |
<.001 |
<.001 |
0.213 |
|
Data expressed as % DM basis except pH and DM. |
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Coupled with a chemical analysis, factors such as color, odor and general appearance provide a good indication of the expected overall nutritive value of silage materials (http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/for4909, 2008). The results of the visual appraisal (smell and color) showed that good quality silages were produced by ensiling 20% coffee pulp + 80% grass hay (CP20), 30% coffee pulp + 70% grass hay (CP30) and 100% coffee pulp (CP100) with the use of EM as biological inoculant. These results are in agreement with those of Solomon (1991) who reported that the appearance and color of wet processed coffee pulp silages are characteristic of silage having developed adequate anaerobic fermentation. According to Solomon (1991) there was a change in color of the coffee pulp from brown to black when the silages were exposed to air attributed to enzymatic browning reactions.
According to Table 2 and Figure 1, the pH values recorded from all the treatment silages ranged between 3.9 and 5.5. The mean pH value of the silage treatments produced by ensiling coffee pulp and coffee pulp in combination with chopped grass hay with the use of EM as biological inoculant was significantly lower (P < 0.01) than those ensiled without the use of EM as biological inoculant. The range of pH values obtained from the treatment silages containing EM (3.9-4.6) was lower and narrower than the pH range obtained from the treatment silages without EM (4.3-5.5), showing that the use of EM as biological inoculant in silage preparation facilitates the fermentation of fibrous feed materials such as coffee pulp. It is accepted that a pH value of 4.5 is an indicator for the occurrence of adequate anaerobic fermentation during silage preparation (Mannetje 1999). Low pH values (< 4.5) are believed to increase chemical hydrolysis of the ensiled fibrous polysaccharides (Bolsen 1996; McDonald et al 1991). According to the results of this study, pH values of 3.9 and 4.3 were recorded from pure wet processed coffee (100%) pulp ensiled with or without the use of EM as biological inoculants, respectively. The pH value (3.9) obtained by ensiling pure coffee pulp with the addition of EM as biological inoculants was found to be below the acidity limits (4.2) of good silage (Solomon 1991; McDonald et al 1991; Mannetje 1999).
|
| Figure 1. pH values of the silages |
As shown in Table 2, the DM content of the silages followed the same trend as the pH values. The lower DM content of the silages containing EM as biological inoculant might be attributed to the better utilization of the ensiled materials by the fermenting micro-organisms due to the addition of EM.
Chemical composition and IVDMD of the treatment silages are shown in Table 2. There was no difference between the CP10, CP20, CP30 and CP100 silages without the addition of EM as biological inoculant in percentage composition of total ash. However, there was an increase in total ash as a result of using EM as biological inoculant (P< 0.05). This could be attributed to the presence of molasses, rich in minerals (Rojas et al 2003).
The crude protein content of CP10, CP20,CP30 and CP100 silages without the addition of EM ranged between 10 and 12%, the values of which is in agreement to that reported from pure wet processed coffee pulp silages by Solomon (1991) and Rojas et al (2002). On the contrary, crude protein of CP10, CP20, CP30 and CP100 silages with the addition of EM ranged between 12 and 14% indicating an improvement in the crude protein content of wet processed coffee pulp as a result of using EM as biological inoculant (P< 0.001). The highest crude protein (13-14%) was obtained from CP30 and CP100 treatment silages with the addition of EM. The improvement in crude protein of the treatment silages produced with the use of EM as biological inoculants could be attributed to the bacterial growth and a decrease in the concentration of cellulose. Similar results were reported by Tauk (1986) and Rojas et al (2003) who reported increased protein content from wet coffee pulp silage resulting from adequate bacterial growth and microbial protein synthesis during the anaerobic fermentation.
As shown in Table 2, the percentage composition of ether extract (EE) of the treatment silages tended to increase with increased proportion of coffee pulp and EE content of 3.45% was recorded from CP100 with out the use of EM as biological inoculants. Significantly higher (P<0.05) percentage composition of EE (4.4%) was recorded from CP100 ensiled with the addition of EM as biological inoculant indicating improvement of 27% in percentage composition of EE as a result of using EM as biological inoculants in ensiling coffee pulp. The increase in EE content could again be attributed to increased microbial population resulting from the addition of EM which eventually resulted in higher fat contents of CP100 treatment silage. The result of this study agree with that of Ramirez et al (1999) and Rojas et al (2003), who reported that microbes usually utilized the water-soluble carbohydrate as energy source and synthesize fat from other precursor molecules.
As shown in Table 2; there was reduction in the cell wall component (NDF, ADF and cellulose) of the treatment silages with increased proportion of coffee pulp indicating that the chopped grass hay is higher in cell wall components than that of the wet processed coffee pulp. There was further reduction in percentage composition of NDF, ADF and cellulose of the treatment silages with the use of EM as biological inoculant. According to Table 2, the NDF and ADF percentage composition of CP100 treatment silage decreased by 19 and 18% respectively as a result of addition of EM as biological inoculant. It is reported that the molasses in the EM might have increased the number of aerobic bacteria, including the lactic acid bacteria which in turn increased the rate of degradation of NDF and ADF components of the coffee pulp ensiled with the use of EM as biological inoculant (Bolsen et al 1996). Similar trends have been observed in the percentage composition of hemicellulose of the silages.
According to the result of this study CP100 silage without EM had 8.56% of hemicellulose, the value of which is higher than that reported elsewhere (Solomon 1991). In contrast CP100 treatment silage with EM had 6.54% hemicelluloses indicating the decrease of the percent composition of hemicelluloses by 24% as a result of addition of EM as biological inoculant. The lower hemicellulose content of wet coffee pulp ensiled with the use of EM as biological inoculants could be attributed to the increased chemical hydrolysis of hemicelluloses by lactic acid bacteria which might have used hemicellulose as source of lactate and acetate produced during the fermentation processes (Jester 1995).
Referring to Table 2, the percentage composition of lignin of CP100 without EM as biological inoculant was 6.78%, the value of which was reduced to 5.26% for CP100 treatment silage with the addition of EM as biological inoculants. Lignin is resistant to both mammalian and microbial enzymatic degradation and renders the other cell wall components of feed materials, particularly cellulose and hemicelluloses indigestible based on degree of lignification. The percentage composition of lignin of wet processed coffee pulp silage (CP100) was reduced by 22.4% as a result of using EM as biological inoculant which could be attributed to a partial degradation of lignin. In this study, it was expected that the Bacillus sp. which is found in EM solution had the ability to utilize extensively the cellulose and lignin component of coffee pulp (Amato 1999). The yeast component of EM also seems to have enhanced the cellulolitic activity of anaerobic bacteria species found in the EM solution. Yeasts are excellent consumers of oxygen and might have enhanced the cellulolytic activity of anaerobic bacteria species found in EM to utilize feeds with high structural components (Maurya 1993).
There was significant reduction in caffeine content of wet coffee pulp as a result of dilution of coffee pulp by chopped grass hay. Moreover. there was significant decrease in percent composition of caffeine of wet processed coffee pulp as a result of addition of EM as biological inoculant. Three factors appear to be important in relation to caffeine and its effects observed in various animals: the relatively high concentration of nitrogen in caffeine; its known effect of stimulating increased activities and its diuretic effect (Bressani 1979).
As shown in Table 2, CP100 treatment silage without EM as biological inoculant’s had 0.5% condensed tannins whereas; CP100 with the addition of EM as biological inoculants had 0.42% condensed tannins. Condensed tannins bind proteins as well as cell wall components and negatively affect protein digestibility. The reduction in tannin content of the EM-treatment silage is attributed to the use of EM as biological inoculant. According to Menezes et al (1994) a strain of Lactobacillus plantarum was found to degrade up to 90% of the tannin present in coffee pulp. Lactobacillus plantarum, which is one of the major microorganisms in EM, is also reported to have produced an enzyme tannase, capable of degrading tannin (Osawa et al 2000; Vaquero et al 2004). Bacillus sp. founds in EM are also reported to be capable of degrading tannin (Rojas et al 2003) whereas Penicillium curtosum, and Pleurotus sp. found in EM solution are reported to have capacity of degrading both caffeine and tannins (Aquiahuatl et al 1988).
One of the principal factors used to determine the nutritive value of feed is the quantity the animals consume when they have free access. The limitation to the use of coffee pulp as animal feed is the reluctance of animals to eat it when it is supplied as the main feed ingredient. It is generally agreed that low feed intake, protein digestibility and nitrogen retention are the major factors limiting the use of coffee pulp as animal feed (Murillo 1979). The low intake of pulp is due to its low palatability and probably to adverse effects on digestion and metabolism.
The IVDMD of the silages is shown in Table 2 and Figure 2. According to the results of this study the IVDMD of 42.6% for the CP100 silage without EM. is lower than the minimum recommended degradability (50%) for poor quality roughages (Aramble and Tung 1987); whereas the IVDMD of 64% recorded for CP100 silage with the use of EM indicated that the IVDMD of wet processed coffee pulp was improved by 50% as a result of the addition of EM. The improvement in in-vitro DM digestibility of coffee pulp ensiled with the use of EM might be attributed to the reduction in tannin concentration (McSeweeney et al 2001).
 |
| Figure 2. IVDMD of the treatment silages |
There was a reduction in the fibrous component and anti-nutritional factors of wet processed coffee pulp ensiled with the use of EM. Reduction in the anti-nutritional factors of wet processed coffee pulp in turn resulted in significant improvement in IVDMD. The overall results of this study showed that ensiling of wet coffee pulp in combination with other locally available feed resource with the use of EM as biological inoculant is appealing in coffee growing areas of Ethiopia. However, there is an urgent need for animal evaluation of the resulting silages.
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Received 29 April 2011; Accepted 13 May 2011; Published 1 July 2011