bs_bs_banner

Animal Science Journal (2015) 86, 842–848

doi: 10.1111/asj.12362

ORIGINAL ARTICLE Microbial population, chemical composition and silage fermentation of cassava residues Viengsakoun NAPASIRTH,1 Pattaya NAPASIRTH,2 Tue SULINTHONE,1 Kham PHOMMACHANH,1 and Yimin CAI3,4 1

Department of Livestock and Fisheries, Faculty of Agriculture (FOA), National University of Laos (NUOL), Vientiane, Lao People’s Democratic Republic; 2Faculty of Technology, Udon Thani Rajabhat University, Udon Thani, Thailand; 3Japan International Research Center for Agricultural Sciences and 4Japan National Institute of Livestock and Grassland Science, Tsukuba, Ibaraki, Japan

ABSTRACT In order to effectively use the cassava (Manihot esculenta Crantz) residues, including cassava leaves, peel and pulp for livestock diets, the chemical and microbiological composition, silage preparation and the effects of lactic acid bacteria (LAB) inoculants on silage fermentation of cassava residues were studied. These residues contained 104 to 105 LAB and yeasts, 103 to 104 coliform bacteria and 104 aerobic bacteria in colony forming units (cfu) on a fresh matter (FM) basis. The molds were consistently at or below the detectable level (102 cfu of FM) in three kinds of cassava residues. Dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) content of cassava residues were 17.50-30.95%, 1.30-16.41% and 25.40–52.90% on a DM basis, respectively. The silage treatments were designed as control silage without additive (CO) or with LAB inoculants Chikuso-1 (CH, Lactobacillus plantarum) and Snow Lacto (SN, Lactobacillus rhamnosus) at a rate of 5 mg/kg of FM basis. All silages were well preserved with a low pH (below 4.0) value and when cassava residues silage treated with inoculants CH and SN improved fermentation quality with a lower pH, butyric acid and higher lactic acid than control silage.

Key words: cassava residues, fermentation quality, silage.

INTRODUCTION The feedstuffs used in Lao People’s Democratic Republic (PDR) included by-products such as rice bran and distiller’s waste, planted feeds, mainly maize and cassava, and various green plant materials (Phengsavanh et al. 2010). Cassava or tapioca (Manihot esculenta Crantz) is an annual root crop grown widely in tropical and subtropical areas. It thrives on sandyloam soils of low organic matter content and under low rainfall and high temperatures. It is usually a cash crop cultivated by smallholder farmers within existing farming systems in many countries (Wanapat & Devendra 1999). Cassava production in Laos is developing rapidly due to the increasing demand for its multiple uses in the region, totally 1 060 880 tons per year in 43 973 ha with productivity 24.12 tons per ha (DOA 2012). Recently interest has been focused on foliage from cassava as an animal feed in Lao PDR (Phengvichith & Ledin 2007). Cassava pulp and peel are the solid waste product consequences of starch production. These pulp and peel contain a high starch © 2015 Japanese Society of Animal Science

level, causing an environmental problem with disposal. Therefore, the starch industry has attempted to eliminate or utilize it. The use of cassava industrial byproduct for animal feed ingredients is one of the alternatives to overcome this problem (Champawadee & Soychuta 2009). Using these byproducts as an animal feed has been proven economically viable, not only as a way of disposing of cassava residues, but also as a real alternative for feeding livestock in regions where cassava is the main crop. These byproducts, when properly utilized, can contribute to the development of better quality and more economical production of feed for livestock. Usually, cassava residues are easily perishable because of their high moisture content. Technologies

Correspondence: Yimin Cai, Japan National Institute of Livestock and Grassland Sciences, Tsukuba, Ibaraki, Japan. (Email: [email protected]) Received 16 June 2014; accepted for publication 16 October 2014.

CASSAVA RESIDUE SILAGE

to create good quality animal feed from cassava residues and to provide long-term storage of the resulting silage need to be developed. Usually, silage preparation and storage are considered to be the most effective techniques for fresh or wet crop byproduct resources (Russell & Wilson 1996; Ruppert et al. 2003; Pang et al. 2011). Silage is now a common preserved feed in many countries; the preservation of forage crops as silage depends on the production of sufficient acid to inhibit activity of undesirable microorganisms under anaerobic conditions. Epiphytic lactic acid bacteria (LAB) naturally present on forage crops, and are responsible for silage fermentation and also influence silage quality (Lin et al. 1992a). During silage fermentation, LAB converts sugar into lactic acid (Muck 1989). As a result, the pH is reduced, and the forage is preserved (Cai et al. 1999). However, from a silage fermentation point of view, to our knowledge, very little information is available on the silage preparation with cassava byproducts in Laos. In order to establish the animal feed production system to cover the shortage of animal feed in the dry season in tropic areas, the microbial population, chemical composition, silage preparation and the effects of LAB inoculants on silage fermentation of cassava residues were studied in Laos.

MATERIALS AND METHODS Microbiological analysis Cassava leaves (30 cm from the top) were collected from cassava fields around Vientiane capital randomly with cutting age of 6 months, while cassava peel and pulp (Fig. 1) were collected from a cassava starch factory (Indo China Group Co., Ltd, Vientiane capital, Lao PDR) on 27 November 2012. The microorganism composition of cassava leaves, peel and pulp were analyzed by using plate count method as described by Cai et al. (1999). Samples of cassava residue (10 g) were blended with 90 mL of sterilized water, and serially diluted from 10−1 to 10−5 in sterilized water. The number of LAB were measured by plate count on Lactobacilli de Man, Rogosa, Sharpe (MRS) agar (Difco

843

Laboratories, Inc., Detroit, MI, USA) incubated at 30°C for 48 h under anaerobic conditions (Anaerobic box; TEHER Hard Anaerobox, ANX-1; Hirosawa Ltd, Tokyo, Japan). Coliform bacteria were counted on blue light broth agar (Nissui Ltd, Tokyo, Japan), incubated at 30°C for 48 h; molds and yeasts were counted on potato dextrose agar (Nissui Ltd), incubated for 48 h at 30°C. Yeasts were distinguished from molds or bacteria by colony appearance and observation of cell morphology. Aerobic bacteria were distinguished by the colony shape and counted on nutrient agar (Nissui Ltd) incubated for 48 h at 30°C under aerobic conditions. Colonies were counted as viable numbers of microorganisms (cfu/g of fresh matter (FM)).

Silage preparation Cassava leaves were chopped into a length of 10 mm. On the other hand, the cassava peel and pulp were not chopped in this experiment and all silage treatments were prepared by using a small-scale method of silage fermentation (Cai et al. 1999). Treatments were designed as control silage (CO) without additive or with LAB inoculants, Chikuso-1 (CH, L. plantarum, Snow Brand Seed Co., Ltd, Sapporo, Japan) and Snow Lact L (SN, L. rhamnosus, Snow Brand Seed Co., Ltd). Silages were preserved at room temperature (25– 32°C) for 3, 5, 10, 30 and 60 days after fermentation. The experimental designed was a 3 × 3 factorial arrangement in a completely randomized design (cassava residues × additive treatment) with triple replicates per treatment.

Chemical and statistical analysis The samples of cassava residues and silages were dried in a forced air oven at 60°C for 48 h and after that ground to pass through a 1 mm screen. Dry matter (DM), crude protein (CP), ether extract (EE) and crude ash were analyzed according to methods 934.1, 976.05, 920.39 and 942.05, respectively, of AOAC (1990). The organic matter (OM) was calculated as the weight loss upon ashing. The neutral detergent fiber

Figure 1 Leaves, peel and pulp of cassava residues used in this experiment.

Animal Science Journal (2015) 86, 842–848

© 2015 Japanese Society of Animal Science

844 V. NAPASIRTH et al.

(NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were analyzed by the methods of Van Soest et al. (1991). Fermentation products of the silages were determined from cold water extracts. Wet silage (10 g) was homogenized with 90 mL of sterilized distilled water (Cai et al. 1999). The pH was measured with a glass electrode pH meter (MP230; Mettler Toledo, Greifensee, Switzerland), and ammonia-N concentration was determined by steam distillation of the filtrates (Cao et al. 2010). The organic acid contents were measured by high-performance liquid chromatography (HPLC) methods as described by Cai et al. (1999). Data on the chemical composition and fermentation products of the cassava residues of the 60-day silages were subjected to two-way analysis of variance (ANOVA) with sources of cassava residues and LAB additives as a two main factors, respectively. The differences between means were assessed by Tukey’s multiple comparison. The effect was considered significant when probability was less than 0.05. (Steel & Torrie 1980)

RESULTS Chemical composition and microbial population of cassava residues Chemical composition of cassava residues are shown in Table 1. DM content of cassava leaves, peel and pulp were 26.90, 30.95 and 17.50%, while their OM, CP, NDF content were 92.50, 16.41 and 52.90% for cassava leaves; 58.79, 1.30, and 36.51% for cassava peel; 98.20, 2.80 and 25.40% for cassava pulp on a DM basis, respectively. The counts of microorganisms in cassava leaves, peel and pulp are shown in Table 2. Overall, these residues

were 104 to 105 LAB and yeasts in colony forming units (cfu), 103 to 104 coliform bacteria and 104 aerobic bacteria. The mold was consistently at or below the detectable level (102 cfu of FM) in three kinds of cassava residues silages.

Fermentation quality of cassava residues silage treated with LAB inoculants Fermentation quality of cassava residues silage prepared with CH and SN inoculant are show in Figure 2 and Table 3. The pH values of cassava leaves and pulp silages were decreasing slowly from 3 to 60 day of ensiling. The pH values of peel silages decreased sharply after day 10 of fermentation, while the pH value was stable at days 30 and 60 of fermentation. At day 60 of fermentation, cassava residue, additive and their interaction (Cassava residue × Additive) did not influence contents of organic acid and ammonia-N. Overall, all silages were well preserved with a low pH below 4.0. Cassava leaves silage treated with inoculants CH and SN improved fermentation quality with a lower pH (P < 0.001) and tend to be of higher lactic acid content than that in control silage. However, the fermentation quality of peel and pulp silages were similar, their contents of lactic acid, acetic acid, butyric acid and ammonia-N were not significantly different between Control, CH and SN treatments. The lactic acid contents in leaves and pulp silage were higher (P < 0.001) than that of peel silage, but the contents of butyric acid in leaves and peel silages were lower (P < 0.001) than that of pulp silage. The leaves silage showed ammonia-N content at 4.36 g/kg of FM, which was higher (P < 0.001) than that in pulp and peel silages (3.16 to 3.35 g/kg of FM).

Table 1 Chemical composition of cassava residues

Item

DM (%)

Chemical composition OM

CP

EE

NDF

ADF

ADL

———————————–% of DM ————————————— Cassava leaves† Cassava peel Cassava pulp

26.90 ± 0.87 30.95 ± 2.08 17.50 ± 0.16

92.50 ± 0.15 58.79 ± 0.83 98.20 ± 0.03

16.41 ± 0.14 1.30 ± 0.01 2.80 ± 0.04

5.20 ± 0.06 0.22 ± 0.01 0.70 ± 0.02

52.90 ± 0.94 36.51 ± 0.62 25.40 ± 0.59

40.72 ± 0.32 22.46 ± 0.16 19.16 ± 0.67

10.23 ± 0.06 15.76 ± 0.72 12.80 ± 0.33

†Cutting age = 6 month. ADF, acid detergent fiber; ADL, acid detergent lignin; CP, crude protein; DM, dry matter; EE, ether extract; NDF, neutral detergent fiber; OM, organic matter.

Table 2 The counts of microorganisms in cassava leaves, peel and pulp

Items

Cassava leaves Cassava peel Cassava pulp

Microorganism (cfu/g of FM) Lactic acid bacteria

Coliform bacteria

Aerobic bacteria

Yeast

7.5 × 10 8.6 × 105 4.8 × 105

2.7 × 10 2.8 × 104 6.4 × 103

3.3 × 10 2.2 × 104 8.5 × 104

2.8 × 10 3.8 × 104 1.0 × 105

4

3

4

Mold 4

ND ND ND

cfu, colony forming unit; FM, fresh matter; ND, not detected.

© 2015 Japanese Society of Animal Science

Animal Science Journal (2015) 86, 842–848

CASSAVA RESIDUE SILAGE

845

Figure 2 pH value of cassava residue silage at 0, 3, 5, 10 and 30 days of ensiling. ab Mean with different superscript letters differ (P < 0.05).

Chemical composition of cassava residue silage Chemical composition of cassava residue silage prepared with CH and SN after 60 days of ensiling are shown in Table 4. The CH-inoculated silages increased (P < 0.001) OM content but decreased (P < 0.001) CP, EE and ADL contents; SN-inoculated silages increased (P < 0.001) EE, but decreased (P < 0.001) OM, CP and ADL contents; the interaction (Cassava residues × Additive) significantly influenced (P < 0.001) all the chemical composition. The highest OM (P < 0.001) content was found in cassava pulp, followed by leaves and peel. The CP contents of cassava leaves, peel and pulp were 14.88, 1.57 and 3.46% on a DM basis, their NDF content were 55.03, 35.36 and 25.71% on a DM basis. The ADF and ADL contents ranged from 17.41 to 34.53% and from 12.18 to Animal Science Journal (2015) 86, 842–848

14.14% on a DM basis, with the highest contents (P < 0.001) found in leaves and peel, respectively.

DISCUSSION Usually, LAB play an important role in silage fermentation, and LAB species, number and their characteristics have become a significant factor in predicting the adequacy of silage fermentation and in determining whether to apply LAB inoculant to silage preparation. The different species and the characteristics of epiphytic LAB might change and influence fermentation losses and silage quality (Lin et al. 1992b). LAB, aerobic bacteria, coliform bacteria and yeasts were mainly distributed in the cassava leaves, peel and pulp, and the LAB were the dominant counts of the microorganism population in three types of residue. This is a © 2015 Japanese Society of Animal Science

846 V. NAPASIRTH et al.

Table 3 Fermentation quality of cassava residues silage prepared with CH and SN after 60 day of ensiling

Items Cassava leaves Control CH† SN‡ Cassava peel Control CH SN Cassava pulp Control CH SN SEM§ Cassava residues mean Cassava leaves Cassava peel Cassava pulp Additive treatments mean Control CH SN Significant of main effects and interactions Cassava residues (Ca) Additive treatment (Ad) Ca × Ad

Moisture (%)

pH

Lactic acid (% of FM)

Acetic acid (% of FM)

Butyric acid (% of FM)

Ammonia-N (g/kg of FM)

73.52 73.87 73.51

3.97 3.54 3.54

0.62 1.19 1.27

0.13 0.05 0.17

0.01 0.01 0.01

0.50 0.40 0.41

70.25 68.10 69.69

3.48 3.40 3.48

0.50 0.71 0.51

0.33 0.49 0.34

0.01 0.01 0.01

0.35 0.32 0.34

82.25 82.74 83.04 0.22

3.07 3.06 3.08 0.05

1.16 1.15 1.25 0.10

0.44 0.32 0.39 0.06

0.33 0.27 0.26 0.04

0.33 0.28 0.34 0.01

69.40c 73.63b 82.70a

3.68a 3.45b 3.07c

1.03a 0.57b 1.03a

0.11b 0.39a 0.38a

0.01b 0.01b 0.29a

0.44a 0.34b 0.32b

75.34 74.90 75.41

3.50a 3.33b 3.36b

0.76 1.02 1.01

0.30 0.28 0.30

0.12 0.10 0.09

0.39 0.36 0.34

< 0.001 < 0.001 < 0.001

< 0.001 0.1370 0.1196

< 0.001 0.9399 0.1445

< 0.001 0.5374 0.6512

< 0.001 0.1124 0.4780

< 0.001 0.1709 < 0.001

†Lactobacillus plantarum (Chikuso-1; Snow Brand Seed Co. Ltd, Sapporo, Japan). ‡Lactobacillus rhamnosus (Snow Lact L; Snow Brand Seed Co. Ltd, Sapporo, Japan). §Stanrd error of the mean. abcMean within columns with different superscript letters differ (P < 0.05).

first report of the microbial compositions from these cassava residues in tropical areas. Among epiphytic LAB, lactobacilli (Rodhe 1990) are important promoters of lactic acid fermentation for a longer fermentation period. Many studies (Cai et al. 1998, 1999) have reported that the inoculation of forage with lactobacilli such as L. casei or L. plantarum has beneficial effects on promoting lactic acid fermentation and improving silage quality. The commercial inoculants used in this study were L. plantarum Chikuso-1 (CH) and L. ramnosus Snow Lact (SN); these strains could promote the propagation of LAB during fermentation, decrease pH, inhibit the growth of harmful bacteria, and improve silage quality. When LAB, especially lactobacilli, reaches at least 105 cfu/g of FM, silage can be well preserved. As shown in Table 2, the LAB counts with 104 to 105 cfu present in these cassava residues suggest that high-quality silage may be fermented well by these epiphytic LAB. In addition, at day 60 of fermentation, cassava residue silages were all well preserved with a low pH < 4.0. The factors involved in assessing fermentation quality, including the chemical composition and the physiological properties of epiphytic bacteria, the character of epiphytic LAB may be similar to commercial LAB from inoculants. During silage fermentation, the epiphytic LAB could produce sufficient lactic acid to reduce pH and inhibit the growth of other harmful bacteria; © 2015 Japanese Society of Animal Science

therefore, the resulting control silage was of good quality, similar to LAB inoculant-treated silages. The cassava pulp and peel had lower CP, NDF and ADF contents, the pulp had higher moisture, and the leaves had higher CP content than do some types of forage crops such as Guinea grass, Italian ryegrass and sorghum (Cai et al. 1999). Many starch byproducts, including cassava leaves, peel and pulp result from processing and manufacturing, but most are dumped into landfills or used as compost, which leads to wasted resources and possible environmental problems due to unsuitable disposal. Because of economic and environmental concerns, demand is increasing for efficient use of cassava byproducts (Cao et al. 2011). Not only could these byproducts be utilized as a source of nutrients for ruminants, but using them to replace imported commercial feedstuffs could save energy in transportation, and possibly reduce the environmental impact of burning them as waste or burying them in landfills. These cassava residues are easily perishable because of their high moisture content. In this experiment, we demonstrated that it is possible to make a good quality silage of cassava residue by using a smallscale experiment. However, cassava residues are produced in a large amount with a seasonal variation every year, and their chemical composition of leaves, peel and pulp are very different. Technologies to create good nutrient balance animal feed from cassava Animal Science Journal (2015) 86, 842–848

CASSAVA RESIDUE SILAGE

Table 4

847

Chemical composition of cassava residue silage prepared with CH and SN after 60 day of ensiling

Items

DM (%)

Chemical composition OM

CP

EE

NDF

ADF

ADL

——————–% of DM ——————— Cassava leaves Control CH† SN‡ Cassava peel Control CH SN Cassava pulp Control CH SN SEM Cassava residues mean Cassava leaves Cassava peel Cassava pulp Additive treatments mean Control CH SN Significant mean effects and interactions Cassava residues (Ca) Additive treatment (Ad) Ca × Ad

29.75 31.90 30.30

92.40 92.18 91.92

15.97 13.78 14.90

4.87 4.40 4.75

56.39 54.30 54.41

34.32 36.67 32.62

11.99 11.05 13.51

26.48 26.13 26.48

57.76 64.61 52.81

1.66 1.48 1.57

0.54 0.57 0.55

33.58 37.41 35.09

24.21 22.28 24.46

17.51 12.22 12.70

17.75 17.26 16.96 1.10

98.00 97.12 97.09 3.44

3.43 3.27 3.68 1.16

0.67 0.44 0.87 0.38

27.36 25.27 29.54 2.29

17.58 16.86 17.80 1.41

12.85 13.34 11.26 0.38

30.65a 26.36b 17.33c

92.17b 58.39c 97.40a

14.88a 1.57c 3.46b

4.67a 0.55c 0.66b

55.03a 35.36b 25.71c

34.53a 23.65b 17.41c

12.18b 14.14a 12.48b

24.66 25.10 24.58

82.72b 84.63a 80.61c

7.02a 6.17c 6.71b

2.02a 1.80c 2.06b

39.11 38.99 39.68

25.37 25.27 24.96

14.12a 12.49b 12.20b

< 0.001 0.1709 < 0.001

< 0.001 < 0.001 < 0.001

< 0.001 < 0.001 < 0.001

< 0.001 < 0.001 < 0.001

< 0.001 0.1125 < 0.001

< 0.001 0.3259 < 0.001

< 0.001 < 0.001 < 0.001

†Lactobacillus plantarum (Chikuso-1; Snow Brand Seed Co. Ltd, Sapporo, Japan). ‡Lactobacillus rhamnosus (Snow Lact L; Snow Brand Seed Co. Ltd, Sapporo, Japan). abcMean within columns with different superscript letters differ (P < 0.05). ADF, acid detergent fiber; ADL, acid detergent lignin; CP, crude protein; DM, dry matter; EE, ether extract; NDF, neutral detergent fiber; OM, organic matter.

residues and to provide long-term storage of the resulting silage need to be developed. Currently, there is an increasing practice to ensiling high-moisture by-product with available local dry feed resources as fermented total mixed ration (TMR) silage in a frecon bag. TMR silage also has high DM intake and digestibility in ruminants (Imai 2000). Therefore, preparation techniques of TMR with local available feed resources, and their utilization system between livestock farmers and food factory are necessary to develop our next research step. In the present study, the OM and NDF contents of cassava residue silages were not big changes from their materials prior to ensiling. These results showed that the cassava residue can be preserved well with a good quality by using silage fermentation technique. In this experiment, CP content of CH-inoculated silage is less than Control and SN; however, we cannot explain why the CH-inoculated silage decreased the CP content. We suspect that the cassava residues contained abundant microbes and the natural LAB may grow well during silage fermentation and more effectively inhibit clostridia than commercial inoculant. Therefore, the natural LAB may lead to inhibit decreased CP content in silage. Animal Science Journal (2015) 86, 842–848

The study suggests that cassava residues contained abundant LAB and nutritional contents. Based on the silage fermentation and chemical composition analysis, we have found that the cassava residues can be well prepared in silage and it has good potential as a feed source for livestock diets.

ACKNOWLEDGMENTS This work was supported by the project of Establishment of a Sustainable and Independent Farm Household Economy from in the Rural Areas of Indo-China from Japan International Research Center for Agricultural Sciences (JIRCAS). We thank the Indo-China Group Co., Ltd, Lao PDR for providing the cassava residues samples, Hideyuki Ohmori (National Institute of Livestock and Grassland Science) and Yang Cao (Heilongjiang Bayi Agricultural University) for their advice in silage quality and statistical analysis.

REFERENCES AOAC. 1990. Official Methods of Analysis, 15th edn. Association of Official Analytical Chemists, Washington, DC. Cai Y, Benno Y, Ogawa M, Kumai S. 1999. Effect of applying lactic acid bacteria isolated from forage crops on © 2015 Japanese Society of Animal Science

848 V. NAPASIRTH et al.

fermentation characteristics and aerobic deterioration of silage. Journal of Dairy Science 82, 520–526. Cai Y, Benno Y, Ogawa M, Ohmomo S, Kumai S, Nakase K. 1998. Influence of Lactobacillus spp. from an inoculants and of Weissella and Leuconostoc spp. from forage crops on silage. Applied and Environmental Microbiology 64, 2982– 2987. Cao Y, Cai Y, Hirakubo T, Fukui H, Mutsuyama H. 2011. Fermentation charecteristics and microorganism composition of total mixed ration silage with local food by-products in different seasons. Animal Science Journal 82, 259–266. Cao Y, Takahashi T, Horiguchi K, Yoshida N. 2010. Effect of adding lactic acid bacteria and molasses on fermentation quality and in vitro ruminal digestion of total mixed ration silage prepared with whole crop rice. Grassland Science 56, 19–25. Champawadee S, Soychuta S. 2009. Nutrient enrichment of cassava starch industry by-product using rumen microorganism as inoculums source. Pakistan Journal of Nutrition 8, 1380–1382. Department of Agriculture (DOA). 2012. Crop Statistic Year Book. Ministry of Agriculture and Forestry, Vientiane, Lao PDR. Imai A. 2000. Silage making and utilization of high moisture by-products. Japanese Journal of Grassland Science 47, 307– 310. Lin C, Bolsen KK, Brent BE, Fung D. 1992a. Epiphytic lactic acid bacteria succession during the pre-ensiling and ensiling periods of alfalfa and maize. Journal of Applied Bacteriology 73, 375–387. Lin C, Bolsen KK, Brent BE, Hart RA, Dickerson JT, Feyerherm AM, Aimutis WR. 1992b. Epiphytic microflora on alfalfa and whole-plant corn. Journal of Dairy Science 75, 2484–2493. Muck RE. 1989. Initial bacterial numbers on lucerne prior to ensiling. Grass and Forage Science 44, 19–25.

© 2015 Japanese Society of Animal Science

Pang H, Qin G, Tan Z, Li Z, Wang Y, Cai Y. 2011. Natural populations of lactic acid bacteria associated with silage fermentation as determined by phenotype, 16S ribosomal RNA and recA gene analysis. Systematic and Applied Microbiology 34, 235–241. Phengsavanh P, Ogle B, Stür W, Frankow-Lindberg BE, Lindberg JE. 2010. Feeding and performance of pigs in smallholder production systems in Northern Lao PDR. Tropical Animal Health and Production 42, 1627–1633. Phengvichith V, Ledin I. 2007. Effect of feeding different levels of wilted cassava foliage (Manihot esculenta, Crantz) on the performance of growing goats. Small Ruminant Research 71, 109–116. Rodhe H. 1990. A comparison of the contribution of various gases to the greenhouse effect. Science 248, 1217–1219. Ruppert LD, Drackley JK, Bremmer DR, Clark JH. 2003. Effects of tallow in diets based on corn silage or alfalfa silage on digestion and nutrient use by lactating dairy cows. Journal of Dairy Science 86, 593–609. Russell JB, Wilson DB. 1996. Why are ruminal cellulolytic bacteria unable to digest cellulose at low pH. Journal of Dairy Science 79, 1503–1509. Steel RGD, Torrie JH. 1980. Principles and Procedures of Statistics: A Biometerial Approach, 2nd edn. Mc Graw-Hill, New York, USA. Van Soest PJ, Robertson JB, Lewis BA. 1991. Methods for dietary fiber neutral detergent fiber and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74, 3583–3597. Wanapat M, Devendra C. 1999. Feeding and nutrition of dairy cattle and buffalo in Asia. In: Wanapat M (ed.), Proceedings of Feeding of Ruminants in the Tropics Based on Local Feed Resources, pp. 191–211. Khon Kaen Publishing Company Ltd, Khon Kaen, Thailand.

Animal Science Journal (2015) 86, 842–848

Microbial population, chemical composition and silage fermentation of cassava residues.

In order to effectively use the cassava (Manihot esculenta Crantz) residues, including cassava leaves, peel and pulp for livestock diets, the chemical...
559KB Sizes 0 Downloads 11 Views