Làm giàu protein củ sắn bằng cách lên men với nấm men làm thức ăn cho lợn địa phương ở lào

HUE UNIVERSITY
UNIVERSITY OF AGRICULTURE AND FORESTRY

NOUPHONE MANIVANH

NUTRITIVE IMPROVEMENT OF CASSAVA ROOT AND
ITS UTILISATION IN TARO FOLIAGE AND BANANA
STEMS BASAL DIETS FOR LOCAL PIG PRODUCTION
IN SMALLHOLDERS IN LAO PDR

DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES

HUE, 2019


HUE UNIVERSITY
UNIVERSITY OF AGRICULTURE AND FORESTRY
NOUPHONE MANIVANH

NUTRITIVE IMPROVEMENT OF CASSAVA ROOT AND
ITS UTILISATION IN TARO FOLIAGE AND BANANA
STEMS BASAL DIETS FOR LOCAL PIG PRODUCTION
IN SMALLHOLDERS IN LAO PDR

SPECIALIZATION: ANIMAL SCIENCES
CODE: 9620105
DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES

SUPERVISORS
1: ASSOCIATE PROFESSOR DR. LE VAN AN
2: ASSOCIATE PROFESSOR DR. TRAN THI THU HONG

HUE, 2019


GUARANTEE
I hereby guarantee that scientific work in this thesis is mine. All results
described in this thesis are righteous and objective. They have been published in
Journal of Livestock Research for Rural Development (LRRD)

Hue University, 2019

Nouphone MANIVANH, PhD student

i


DEDICATION
To my parents, my husband (Phoneouthai Thiphavanh), my daughter (Southida
Thiphavanh) and my son (Kanlaya Thiphavanh)

ii


ACKNOWLEDGEMENTS
The research in this PhD thesis was conducted four experiments with supported
from Mekong Basin Animal Research Network (MEKARN II) project for funding this
thesis research and the scholarship for the PhD study.
I am grateful for the support from all of those people and institutions:
I would like to express my sincere gratitude to the Mekong Basin Animal
Research Network (MEKARN II) project for funding this theses research and the

scholarship for the PhD study.
I would like to thanks the Faculty of Agriculture and Forestry, Souphanouvong
University, Luagprabang province, Laos, for allowing me study leave and helping me
to carry out the experiments.
I would like to express my cordial and faithful gratitude to my main supervisors,
Associate Professor Dr. Le Van An and co-supervisor, Associate Professor Dr. Tran
Thi Thu Hong for their support, guidance, and valuable advice for writing paper.
I would like to express deeply gratitude to Professor Dr. Thomas Reg Preston
Director of the University of Tropical Agriculture (UTA) for his good discussion,
valuable advice and useful guidance during my studies and research project.
My sincere thanks to Professor Dr. Ewadle, International Coordinator
MEKARN II project; Dr. Vanthong Phengvichith, National Agriculture and Forestry
Researcher Institute (NAFRI), Lao PDR; Dr. Kieu Borin, MEKARN II regional
coordinator for their facilitation, help and support to the whole course. Professors,
lecturers and assistant lectures in Hue University of Agriculture and Forestry and
MEKARN II program, for giving me care and useful knowledge; Dr. Vongpasith
Chanthakhoun, Dean of Faculty of Agriculture and Forestry, Souphanouvong
University for his help and encouragement.
I am also grateful to my friends on the PhD course from Cambodia, Laos and
Vietnam for their good friendship and sharing
Lastly I would like to express special thanks to my husband (Phone outhai
Tiphavanh), my parents and all my brothers and sisters for their support,
encouragements and patience.
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ABSTRACTS
The study was aimed at improving protein content of cassava root (Manihot
esculenta Crantz) by solid-state fermentation with yeast (Saccharomyces cerevisiae),
urea and di-ammonium phosphate (DAP) additive and its utilization as protein source

in the diets of Moo Lath Pig in Laos. Four experiments were carried out with “two in
cassava root fermentation experiments, two experiments were conducted with Moo
Lath pig using taro silage (TS) replaced by protein-enriched cassava root (PECR) as
protein sources on growing trial and digestibility. In chapter 2, experiment 1. Cassava
root was fermented with yeast, urea and DAP in a solid-state fermentation to determine
the degree of conversion of crude to true protein; and experiment 2 the limiting factor
to the synthesis of true protein from crude protein in the fermentation of cassava root
could be the decrease in pH in the fermentation substrate preventing the hydrolysis of
urea to ammonia and thus decreasing the availability of nitrogen for growth of the
yeast. The following experiment to determine the degree of conversion of crude to true
protein, pH and ammonia. In experiment 1. The experiment was arranged as a 2*3*4
factorial in a completely randomized design (CRD). The treatments were: root
processing (steamed and not steamed); DAP: 0, 1 and 2% of the substrate DM. The
fermentation was over 14 days with samples taken for determination of true and crude
protein (CP) at 0, 3, 7 and 14 days. In experiment 2. A CRD was used with 2 treatments
arranged as a 2*9 factorial. The treatments were anaerobic and aerobic fermentation.
The substrate was cassava root 93.6% + DAP 2% + urea 1.4% + yeast 3% (DM basis).
True, crude protein, ammonia and pH were measured at 0 and 3h after preparing the
substrates and every 24h until end of day 7 (0, 3h, 1, 2, 3, 4, 5, 6 and 7 day).
Experiment 1 (chapter 2). The true protein (TP) in cassava root increased with a
curvilinear trend (R2 = 0.98) from 2.30 to 6.87% in DM as the fermentation time
increased from zero to 14 days; the ratio of true to crude protein increased from 24.6 to
63.7 over the same period. Increasing the proportion of DAP from zero to 2% of the
substrate DM increased the TP from 5.6 to 7.3% in DM after 14 days of fermentation.
Steaming the cassava root prior to fermentation improved slightly (p=0.67) the
conversion of crude to TP. Experiment 2 (chapter 2). The pH decreased with
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fermentation time, according to an almost linear trend, from 5.8 immediately after

mixing the substrate, to 5.47in 3h and to 3.43 after 7 days. The level of CP after mixing
the substrate and additives was 10.35% in DM and did not change over the 7 days of
fermentation. TP in the substrate increased from 2.37 to 6.97% in DM as the
fermentation time increased from zero to 7 days. There were no differences in all these
criteria as between the aerobic and anaerobic condition, other than a tendency for the
pH to fall slightly more quickly in the first 4 days in the anaerobic condition followed
by a slower rate of fall to reach almost the same final value after 7 days, as for the
aerobic condition. Experiment 3 (chapter 3). A growth trial was conducted with 12
Moo Lath pigs with average 14.8 ±1.89 kg initial live weight in a CRD, with three
replications of four treatments. The aim of the study was to determine the effect of
replacing TS with PECR in a basal diet of ensiled banana stem (BS). There were
positive responses in dry matter (DM) intake, live weight gain, feed conversion ratio, as
the percentage of PECR in the diet was increased (zero to 15% in DM ). It was
concluded that the replacing of taro foliage silage with PECR improved the quality of
the overall diet, which resulted in higher intake, growth rate, better feed conversion
ratio and economical efficiency. Experiment 4 (chapter 4). Four castrated male Moo
Lath pig, weighing on average 15 kg were allotted at random to 4 diets within a 4*4
Latin square design, to study effects on DM intake, digestibility and N retention of
levels of protein-enriched cassava root (PECR) as 0, 25, 50 and 75% in combination
with TS as 80, 55, 30 and 5% with constant levels of ensiled banana stem 20% (all on
DM basis). PECR at 25% in a diet led to increases in feed intake, diet digestibility and
N retention in native Moo Lath pigs and PECR could be the result of its superior
biological value compared with the protein in the taro foliage. These criteria declined
linearly when the proportions of PECR were increased to 50 and 75% of the diet DM.
Key words: banana pseudo-stem, di-ammonium phosphate, probiotic, solidstate fermentation, urea, yeast, crude protein, true protein, ammonia, pH, Moo Lath pig

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TABLE OF CONTENTS

GUARANTEE ................................................................................................................. i
DEDICATION ....................................................................................................... ii
ACKNOWLEDGEMENTS ................................................................................... iii
ABSTRACTS ....................................................................................................... iv
TABLE OF CONTENTS ....................................................................................... vi
LIST OF FIGURES ............................................................................................... xi
LIST OF PHOTO ................................................................................................ xiii
LIST OF TABLES .............................................................................................. xiii
LIST OF ABBREVIATIONS ............................................................................... xv
INTRODUCTION .................................................................................................. 1
1. PROBLEM STATEMENT ................................................................................. 1
2. OBJECTIVES ............................................................................................................. 1
3. HYPOTHESES ........................................................................................................... 3
4. SIGNIFICANCE/INNOVATION OF THE DISSERTATION.................................. 1
CHAPTER 1: LITERATURE REVIEW ........................................................................ 5
1. PIG PRODUCTION IN LAOS .................................................................................. 5
1.1. ROLE OF PIG PRODUCTION ........................................................................... 5
1.2. PIG POPULATION ............................................................................................. 6
1.3. PIG PRODUCTION SYSTEM IN LAOS ............................................................ 8
1.3.1. Commercial pig production .......................................................................... 8
1.3.2. Semi-commercial pig production ................................................................. 8
1.3.3. Smallholder pig production .......................................................................... 9
1.3.4. Main problems in smallholder pig production systems ............................ 11
1.3.5. Important points to improve smallholder pig production system ............. 11
1.4. LOCAL PIG BREEDS RAISED BY SMALLHOLDERS ................................ 12
1.4.1. Moo Lath .................................................................................................... 12
1.4.2. Moo Chid, Moo Markadon or Moo Boua................................................... 13
1.4.3. Moo Nonghad or Moo Hmong ................................................................... 14
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1.4.4. Moo Deng or Moo Berk ............................................................................. 14
2. REQUIREMENT OF PROTEIN AND AMINO ACID FOR GROWING PIGS .... 16
3. FEED STUFFS FOR PIG IN LAOS ........................................................................ 18
3.1. LOCAL FEED AVAILABLE FOR PIG ............................................................ 19
3.1.1. Taro (Colocasia esculenta) ......................................................................... 19
3.1.2. Cassava (Manihot esculenta Crantz) .......................................................... 22
3.1.3. Banana pseudo (Musa sapientum Linn) stems ........................................... 25
4. METHOD TO IMPROVE NUTRITIVE VALUE FOR FEED STUFF WITH LOW
PROTEIN CONTENT .................................................................................................. 26
4.1. SACCHAROMYCES CEREVISIAE (S. CEREVISIAE) .......................................... 26
4.2. SOLID-STATE FERMENTATION (SSF) ........................................................ 28
4.2.1. Application of solid-state fermentation ...................................................... 28
4.2.2. Advantage solid-state fermentation ............................................................ 28
4.2.3. Factors influencing solid-state fermentation .............................................. 29
4.2.4. Problem of solid-state fermentation............................................................ 29
4.2.5. Conditions necessary for fermentation ....................................................... 29
4.3. PROTEIN ENRICHMENT................................................................................ 30
5. UTILIZATION OF FORAGE-BASED DIET FOR PIGS ....................................... 32
5.1. EFFECT OF TARO FOLIAGE AS PROTEIN SOURCE ON FEED INTAKE
AND DIGESTIBILITY OF PIGS ............................................................................. 32
5.2. EFFECT OF TARO FOLIAGE AS PROTEIN SOURCE ON GROWING
PERFORMANCE OF PIGS ..................................................................................... 32
5.3. EFFECT OF TARO FOLIAGE REPLACING BANANA PSEUDO STEM ON
GROWTH AND DIGESTIBILITY OF PIGS .......................................................... 33
5.4. EFFECT OF ENSILED TARO FOLIAGE REPLACED BY PROTEINENRICHED CASSAVA ROOT ON GROWTH PERFORMANCE AND
DIGESTIBILITY ...................................................................................................... 34
REFERENCES ............................................................................................................. 35
CHAPTER 2 ................................................................................................................. 51
IMPROVING NUTRITIVE VALUE OF CASSAVA ROOTS ................................... 51

(Manihot esculenta Crantz) .......................................................................................... 51
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ABSTRACT ............................................................................................................. 51
INTRODUCTION .................................................................................................... 52
EXPERIMENT 1: ......................................................................................................... 53
MATERIALS AND METHODS .............................................................................. 53
Experimental design ............................................................................................. 53
Measurements ....................................................................................................... 55
Chemical analysis ................................................................................................. 55
Statistical analysis ................................................................................................. 55
RESULT AND DISCUSSION ................................................................................. 55
Changes in the mass of substrate during fermentation ......................................... 58
EXPERIMENT 2. ......................................................................................................... 60
MATERIALS AND METHODS .............................................................................. 60
Experimental design ............................................................................................. 60
Measurements ....................................................................................................... 61
Chemical analysis ................................................................................................. 61
Statistical analysis ................................................................................................. 61
RESULT AND DISCUSSION ................................................................................. 61
DISCUSSION ........................................................................................................... 64
CONCLUSIONS ...................................................................................................... 65
REFERENCES ......................................................................................................... 66
CHAPTER 3 ................................................................................................................. 69
REPLACING TARO (Colocasia esculenta) SILAGE BY PROTEIN-ENRICHED
CASSAVA ROOT IMPROVED THE NUTRITIVE VALUE OF A BANANA STEM
(Musa sapientum Linn) BASED DIET AND SUPPORTED BETTER GROWTH IN
MOO LATH PIG .......................................................................................................... 69
ABSTRACT ............................................................................................................. 69

INTRODUCTION .................................................................................................... 69
MATERIALS AND METHODS .............................................................................. 70
Experimental design ............................................................................................. 73
Data collection ...................................................................................................... 74
Chemical analysis ................................................................................................. 74
viii


Statistical analysis ................................................................................................. 74
RESULTS AND DISCUSSION ............................................................................... 74
DISCUSSION ........................................................................................................... 78
CONCLUSIONS ...................................................................................................... 79
REFERENCES ......................................................................................................... 79
CHAPTER 4 ................................................................................................................. 82
APPARENT DIGESTIBILITY AND N RETENTION IN GROWING MOO LATH
PIGS FED ENSILED TARO FOLIAGE (Colocasia esculenta) REPLACED BY
PROTEIN-ENRICHED CASSAVA ROOT (Manihot esculenta Crantz) ................... 82
ABSTRACT ............................................................................................................. 82
MATERIAL AND METHODS ................................................................................ 84
Experimental design ............................................................................................. 84
Measurements and data collection ........................................................................ 85
Statistical analysis ................................................................................................. 86
RESULTS AND DISCUSSION ............................................................................... 86
Chemical composition .......................................................................................... 86
Feed intake ............................................................................................................ 86
Apparent digestibility ........................................................................................... 88
Nitrogen balance ................................................................................................... 89
DISCUSSION ........................................................................................................... 90
CONCLUSIONS ...................................................................................................... 92
REFERENCES ......................................................................................................... 92

GENERAL DISCUSSION AND CONCLUSIONS .................................................... 95
1. GENERAL DISCUSSION ....................................................................................... 95
1.1. IMPROVING NUTRITIVE VALUE OF CASSAVA ROOT (MANIHOT
ESCULENTA CRANTZ) BY FERMENTATION WITH YEAST (SACCHAROMYCES
CEREVISIAE) UREA AND DI-AMMONIUM PHOSPHATE (DAP) ......................... 95

1.2. EFFECT OF THE USE OF PROTEIN ENRICHED OF CASSAVA ROOT
(MANIHOT ESCULENTA CRANTZ) ON INTAKE, DIGESTIBILITY, N BALANCE AND
GROWTH PERFORMANCE OF LOCAL PIG. ...................................................... 98
2. GENERAL CONCLUSIONS ................................................................................. 102
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3. IMPLICATION AND FURTHER RESEARCH.................................................... 103
3.1 IMPLICATION................................................................................................. 103
3.2. FURTHER RESEARCH.................................................................................. 104
REFERENCES ............................................................................................................. 95
PUBLISHCATION LIST ........................................................................................... 111

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LIST OF FIGURES
CHAPTER 1 .................................................................................................................... 5
Figure 1. Number of pigs in Laos from 2010-2016 ............................................. 7
Figure 2. Characteristic of pig in northern, central and southern in 2005-2015 .. 8
CHAPTER 2 .................................................................................................................. 51
EXPERIMENT 1: .......................................................................................................... 53
Figure 1. The level of crude and true protein after fermented 14 days ............. 57
Figure 2. Curvilinear response in the true and crude protein ratio with increasing

length of fermentation........................................................................................ 57
Figure 3. Effect of level of DAP on concentration of true protein after 14 days
of fermentation................................................................................................... 58
Figure 4. Changes in the mass of substrate during the fermentation ................. 59
Figure 5. Proportion of the original substrate fermented during different stages
of the fermentation ............................................................................................. 59
EXPERIMENT 2. .......................................................................................................... 60
Figure 1. Effect of fermentation time on pH of cassava root fermented with
yeast, urea and DAP, under anaerobic and aerobic condition ........................... 63
Figure 2. Effect of fermentation on true and crude protein content of cassava
root supplemented with urea, DAP and yeast .................................................... 63
Figure 3. Distribution of the nitrogen as urea, ammonia and true protein at the
beginning and after 7 days of fermentation ....................................................... 64
CHAPTER 3 .................................................................................................................. 69
Figure 1. Effect of supplementation with PECR on DM intake of pigs by
replacing taro silage and ensiled banana stem as a basal diet........................... 75
Figure 2. Relationship between live weight gain and PECR content of the diet 76
Figure 3. Relationship between feed conversion ratio and PECR content of the
diet ..................................................................................................................... 77
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CHAPTER 4 .................................................................................................................. 82
Figure 1. Mean values for DM intake by pigs fed diets in which taro silage was
replaced by PECR .............................................................................................. 87
Apparent digestibility............................................................................................. 88
Figure 2. Mean values for apparent digestibility of DM and crude protein in
pigsfed diets in which taro silage was replaced by PECR ................................. 88

xii

LIST OF PHOTO
CHAPTER 1: LITERATURE REVIEW ........................................................................ 5
Photo 1. Local pigs are allowed to scavenge freely all year round .................... 9
Photo 2. Local pigs in pen ................................................................................ 10
Photo 3. Feed stuffs available in farm condition .............................................. 11
Photo 4. Moo Lath ............................................................................................ 13
Photo 5. Moo Chid, Moo Markadon or Moo Boua .......................................... 14
Photo 6. Moo Nonghad or Moo Hmong ........................................................... 14
Photo 7. Moo Deng or Moo Berk ..................................................................... 15
CHAPTER 2 ................................................................................................................. 51
EXPERIMENT 1: ......................................................................................................... 53
Photo 1. The steaming of the cassava root ....................................................... 54
Photo 2. Aerobic fermentation of the cassava root .......................................... 54
CHAPTER 3 ................................................................................................................. 69
Photo 1. Wooden boards 30cm above the base of the barrel ............................ 71
Photo 2. The bamboo strips placed above the boards ....................................... 71
Photo 3. The steaming of the ............................................................................ 71
cassava root ....................................................................................................... 71
Photo 4. Mixing cassava root with urea, di-ammonium phosphate (DAP) and
yeast .................................................................................................................. 71
Photo 5. The mixed substrate was put in bamboo baskets covered with plastic
netting ............................................................................................................... 72
Photo 6. The protein-enriched cassava root ...................................................... 72
Photo 7. Taro (Colocasia esculenta) were chopped by hand ........................... 72
Photo 8. Taro (Colocasia esculenta) were wilted for 24h to reduce the moisture
.......................................................................................................................... 72
Photo 9. Taro silage in the plastic bag .............................................................. 72
Photo 10. Ensiled taro after 14 days ................................................................. 72

Photo 11. Banana stems were chopped by hand into small pieces ................... 73
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Photo 12. Ensiled banana stems in 200 liter PVC ............................................ 73
Photo 13. Housing made from local materials.................................................. 73
Photo 14. Moo Lath pig used in the experiment ............................................... 73

xiv


LIST OF TABLES
CHAPTER 1 .................................................................................................................... 5
Table 1. Number of meat consumption in 2017 of Lao PDR .............................. 6
Table 2. Statistic of livestock population in Laos (2010-2016)........................... 6
Table 3. Pig population in Laos (2005-2015) ...................................................... 7
Table 4. Classification of phenotype characteristics and reproductive
performance of native pigs produced under smallholder farm (SHPF)
conditions in Lao PDR....................................................................................... 15
Table 5. Dietary amino acid requirements of growing-finishing pigs (NRC
1998) .................................................................................................................. 17
Table 6. Chemical composition of taro (Colocasia esculenta) in DM basis ..... 20
Table 7. Planted area, yield and production of cassava root ............................. 23
Table 8. Proximate nutrient composition of Cassava root and leaves ............... 24
Table 9. Planted area, yield and production of banana ...................................... 25
CHAPTER 2 .................................................................................................................. 51
EXPERIMENT 1: .......................................................................................................... 53
Table 1. Composition of the substrates (DM basis) .......................................... 54
Table 2. Mean values for DM, OM, crude protein; true protein and ratio of
TP/CP at

different stages of the fermentations (% in DM) ............................ 56

Table 3. Effect of level of DAP on concentration of crude protein, true protein
and ratio of TP/CP

after 14 days of fermentation (% in DM) ....................... 58

Table 4. Changes in the mass of fresh (FM) and dry (DM) substrate during the
fermentation ....................................................................................................... 58
Table 5. Chemical composition (g/kg of DM)................................................... 59
EXPERIMENT 2. .......................................................................................................... 60
Table 1. Changes in pH, crude protein (CP), true protein (TP) and ammonia in
cassava root fermented with yeast, urea and DAP under aerobic or anaerobic
conditions ........................................................................................................... 62
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CHAPTER 3 .................................................................................................................. 69
Table 1. The chemical composition of feed ingredients (% in DM, except DM
which is on fresh basis)...................................................................................... 74
Table 2. Mean values for DM intake (g/day) by pigs fed taro silage (TS) and
ensiled banana stem (BT) supplemented with protein enriched cassava root
(PECR) ............................................................................................................... 75
Table 3. Mean values for live weight changes of growing pigs during the
experiment ......................................................................................................... 76
Table 4. Feed ingredient costs (LAK) ............................................................... 77
Table 5. Economic analysis of experimental treatments (LAK) ....................... 78
CHAPTER 4 .................................................................................................................. 82
Table 1. The chemical composition of feed ingredients (% in DM, except DM

which is on fresh basis)...................................................................................... 86
Table 2. Mean values of DM intake by pigs fed protein-enriched cassava root
(PECR) replacing taro silage with constant levels of ensiled banana stem ....... 87
Table 3. Apparent digestibility (%) of diets with PECR replacing ensiled taro
foliage with constant levels of ensiled banana stem .......................................... 88
Table 4. Mean values for N balance in pigs fed protein enriched cassava root
replacing taro silage with constant levels of ensiled banana stem..................... 89

xvi


LIST OF ABBREVIATIONS
AA

Amono acids

ADG

Average daily gain

ANOVA

Analysis of variance

ADF

Acid detergent fibre

AOAC

Association of Official Analytical Chemists

BS

Banana stem ensilage

BW

Body weight

Ca

Calcium

CF

Crude fibre

CSF

Classical swine fever

Cl

Chloride

CRD

Completely randomized design

Cm

Centimetre

CP

Crude protein

°C

Degree Celsius

DAP

Di-ammonium phosphate

DE

Digestible energy

DLF

Department of Livestock and Fisheries

DM

Dry matter

EAA

Essential amino acids

EE

Ether extract

EBS

Ensiled banana stem

FAO

Food and Agriculture Organization of the United Nation

FW

Fresh weight

FCR

Feed conversion ratio

g

Gram

GDP

Gross domestic product

h

Hour
xvii


ha

Hectare

HCN

Hydrocyanic acids

Kg

Kilogram

Lao PDR

Lao People’s democratic republic

LWG

Live weigh gain

LW

Live weigh

L

Liter

m

Meter

ME

Metabolisable energy

MAF

Ministry of Agriculture and Forestry

Mekarn

Mekong Basin Animal Research Network

N

Nitrogen

NRC

National Research Council

NAFES

National Agriculture and Forestry Extension Service

NAFRI

Institute National Agriculture and Forestry Research

NE

Net energy

NPN

None protein nitrogen

NFE

Nitrogen-free extract

F

Neutral detergent fibre

NST

Non steamed

NP

Non-protein

OM

Organic Matter

P

Phosphorus

PECR

Protein-enriched cassava root

PECP

Protein-enriched cassava pulp

pH

Power of/potential Hydrogen

Prob/p

Probability

RCBD

Randomised Complete Block Design

RDB

Rice distillers’ by-product

xviii


Sida/SAREC

Swedish international development agency-Dpartment for research
Cooperation

ST

Steamed

SEM

Standard error of the mean

TS

Taro silage

T

Ton

TCA

trichloracetic acid

TP

True protein

xix


INTRODUCTION
1. PROBLEM STATEMENT
Pig is one of the most important animals for smallholders in the uplands of Lao PDR
because it can be sold when cash is needed for buying rice and other food, for paying school
fees or if a household member is sick and needs medical attention and Pork used in traditional
ceremonies in households. Pigs can be confined in a small area, and can covert to meet a
variety of crop and kitchen wastes and give a rapid return on investment (Steinfeld, 1998).
About 75% of households in upland areas are raising pig in the country (FAO, 2017).
Overall, native pig around 85.1% under small holder system (DLF, 2017), they are hardy and
able to scavenge at least part of their feed requirements in free-range condition, Native pigs
are mainly raised in extensive low-input systems that take advantage of naturally occurring
feed (Kennard, 1996; FLSP, 2002). In most parts of Laos, agricultural by-products, such as
rice bran, and natural grasses are the main feeds for live stock (ILRI 2002). In Lao villages,
where most farmers are growing paddy rice for sale, the feed for pigs is based on rice bran,
which is fed together with a small amount of green feed. Thus rice bran is available in most
farm households but they cannot support full performance because of their poor nutritive
value. (ILRI, 2002; FLSP, 2002). Since feed accounts for about 50-60% of the variable costs
of production, feed quality is crucial to the success of pig farming operations. Major problems
that may result from low quality feeds are poor appetite, slow growth, high feed conversion
ratio, and low survival. These usually develop as a result of problems on quality of raw
materials, feed formulation, processing technology, storage, and feed manage. The main
problem is the supply of protein as soybean and fish meals are not available in rural areas and
expensive (Phengsavanh and Stür., 2006).

Cassava plantation is mainly for root production. The yields of root are variable
depending on soil fertility, management and irrigation system. Cassava root yields can be
from 10 to15 tonne/ha without inputs on eroded soils (Howeler, 1991). In Laos, cassava
(Manihot esculenta Crantz) known as ‘Man Ton’, it is currently the third most important crop
in Laos, after rice and maize for smallholder farmers in remote upland areas. Recently, the
crop has become an important cash crop for either domestic use or for export because it can
be used for food and feed as well as for industrial processing into starch (Ministry of
Agriculture and Forestry, 2013). Cassava has become a major crop in Lao PDR mainly
because of the export of starch that is extracted from the cassava root. There are five cassava
1


starch factories with a total planted area of 60,475 ha, giving an average yield of fresh roots of
27 tonnes/ha. Annual production is of the order of 1.6 million tonnes (Ministry of Agriculture
and Forestry, 2013). Cassava farms are needed not only for a major source of income for rural
households but also for use in pig diets as energy sources because of cassava root content high
levels of energy (75 to 85% of soluble carbohydrate) but low crude protein (2 to 3% CP). The
root is composed of highly digestible carbohydrate in the form of starch with little fiber (Kang
et al., 2015; Polyorach et al., 2013). Solid state fermentation of the cassava root is a promising
technology as this has the potential to raise the protein content to levels required to balance
the carbohydrate thus presenting the opportunity to make an almost complete feed for pigs
(Boonnop et al., 2009). Sengxayalth and Preston, (2017a) reported an increase in true protein
from 2 to 12% in dry matter (DM) of the cassava pulp. Agreement with Vanhnasin et al.,
(2016a) true protein increased from 2 to 7% in dry matter (DM) of the cassava root. Similar
findings were reported by Balagopalan et al., (1988) who developed a solid state fermentation
process for the protein enrichment of cassava flour and cassava starch factory wastes using
the fungus Trichoderma pseudokonigii rifai. Fermentation with yeast, bacteria has been
studied for reducing non-nutritional components, increasing the nutritive value of agroindustrial by-products (Okpako et al 2008; Aderemi et al 2007; Tran Thi Thu Hong and
Nguyen Van Ca 2013). Additional phosphate results in increased biomass growth of yeast and
bacteria (Papagianni et al 1999). Huu and Khammeng, (2014) reported that when replacing

maize with fermented cassava pulp containing 13% crude protein (DM basis), digestibility
and N retention were similar to the control diet. Protein enriched of cassava root (PECR)
could provide in pig diets up to 25 to 28% of the dietary protein in a diet based on cassava
pulp (or ensiled root), replacing ensiled taro foliage (Vanhnsin and Preston, 2016b) or
soybean meal (Sengxayalth and Preston, 2017b). It similar to the growth response in pigs
reported by Phuong et al., (2013) for cassava pulp enriched from 3 to 5.5% true protein using
the fungus Aspergillus niger.
The local feed used in smallholder systems for pigs include rice by-products, planted
feeds and various green plant materials (ILRI 2002). However, the local feed contain low
nutritive value. Women typically are the key persons in this effort, and, with traditional
practices, they spend 2 to 3 hours each day collecting and preparing feed for pigs (Australian
Center for International Agricultural Research 2010). Farmers have little knowledge on
optimizing use existing feed resources, the growth rate of the pig only 100 to 120 g/day if
depend on local feed staffs. In commercial complete feeds, the most common protein sources

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are fish meal and soybean meal. These feedstuffs provide high quality protein for pigs, but
they are imported and are expensive. Due to their high price, such protein sources cannot be
used by smallholder farmers (Phengsavanh et al., 2010). So, improving nutritive value of local
feed that is abundance in their area especially the application of microorganism fermentation
it is possible to improve the nutritive value of local feed and its utilization as diets for local
pigs in Laos, which helps in reducing feed cost and bringing economic benefits to the farmers
in rural area.

2. OBJECTIVES
The overall aim of this thesis was to improve nutritive value of cassava roots by
fermentation yeast (Saccharomyces cerevisiae), Urea and di-ammonium phosphate additive
and its utilization as protein source in the diets of Moo Lath pigs. Specific objectives were to:



To study nutritive value of casssava root by fermentation yeast (Saccharomyces
cerevisiae), Urea and Di-ammonium phosphate additive



To study the limiting factor to the synthesis of true protein from crude protein in the
fermentation of cassava root



To evaluate the use of protein-enriched cassava root as partial replacement of taro
silage in a ensiled banana stem - based diet fed to Moo Lath pigs

3. HYPOTHESES
•

Nutritive value of cassava root will be increased by fermentation with increase level of
di-ammonium phosphate with yeast, Urea and additive

•

The pH decreased with fermentation time could be limiting factor to the synthesis of
true protein from crude protein in the fermentation of cassava root

•

The protein-enriched cassava root as a partial replacement for taro silage in a diet will
be improve growth performance of Moo Lath pigs.

4. SIGNIFICANCE/INNOVATION OF THE DISSERTATION
The innovations of the thesis study are:
This thesis is the output from four experiments; of which two experiments focus on
the improving nutritive value of carbohydrate-rich (cassava root) feeds is by solid-state
fermentation Yeast (Saccharomyces cerevisiae), Urea and Di-ammonium phosphate (DAP)
additive and creating database on nutritive values, including chemical composition profile of
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protein-enriched cassava root (Manihot esculenta Crantz); one on growth performance and
other one on feed intake; digestibility and N balance in local pig (Moo Lath pig). The results
from experiments can help the people particularly rural farmers to understand more about the
utilization of locally available feed resources for improving pig performance. Despite the
abundance of cassava root in Laos, the application of microorganisms, particularly yeast
(Saccharomyces cerevisiae), to enhance its nutritional and economic values to feed livestock
and, consequently, increase farming profitability, and provide jobs for the masses is yet to
attract serious attention. Additionally, there is very minimal biotechnological application of
yeast (Saccharomyces cerevisiae) in the production of protein-enriched agro-industrial
products in Laos. This present study therefore aimed to assess the application of in yeast
(Saccharomyces cerevisiae) enriching protein content of cassava root by solid-state
fermentation. This process of solid-state fermentation provides a means of converting cassava
root into useful feed for the production of pig. High protein forages such as taro foliage can be
good sources protein in diets. One important local feed is banana pseudo-stem contain the
sugar. Feeding systems based on replacing taro (Colocasia esculenta) silage with
proteinenriched cassava root (PECR) improved the nutritive value of a banana stem (Musa
sapientum Linn) based diet and have a great potential for increasing pig productivity. The root
is composed of highly digestible carbohydrate in the form of starch with little fiber; the
foliage is rich in protein and nutritive value of banana stalk could be improved by treated with
indigenous microorganism. And utilizing effectively those feed resources for pigs as a main

protein sources (ensiled taro foliage and PECR) at small scale household in Laos. Main
findings were: Improving nutritive value of cassava roots by fermented with yeast, urea and
DAP and PECR can be provided at highest 25% in a diet of ensiled cassava root, ensiled taro
foliage and ensiled banana stem, led to increases in feed intake, diet digestibility and N
retention in native Moo Lath pigs. These criteria declined linearly when the proportions of
PECR were 50% and 75% of the diet DM.

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