Xác định nhu cầu lysine tiêu hóa hồi tràng tiêu chuẩn và tỉ lệ tối ưu giữa axit amin chứa lưu huỳnh với lysine cho lợn (pietrain x duroc) x (landrace x yorkshire) giai đoạn 10 – 20 kg và 30 – 50 kg tt tiếng anh

HUE UNIVERSITY
UNIVERSITY OF AGRICULTURE AND FORESTRY

DAO THI BINH AN

ESTIMATION OF THE STANDARDIZED ILEAL DIGESTIBLE
LYSINE REQUIREMENT AND OPTIMAL SULPHUR
AMINO ACIDS TO LYSINE RATIO FOR HYBRID PIGS
[(PIETRAIN x DUROC) x (LANDRACE x YORKSHIRE)]
FROM 10 – 20 KG AND 30 – 50 KG

Specialization: Animal Sciences
Code: 9.62.01.05

SUMMARY OF PHD THESIS IN AGRICULTURAL SCIENCE

HUE - 2019

1


This work was completed at:

Hue University of Agriculture and Forestry, Hue University

Science instructor:
1. Assoc.Prof. Dr. Ho Trung Thong
2. Prof. Dr. Vu Chi Cuong

Reviewer 1: ………………………………………………………………………………………………
Reviewer 2: ……………………………………………………..………………………………………..

Reviewer 3: ……………………………………………………..………………………………………..

The thesis was defended at the Council of thesis assessment of Hue University:
Council held at: 4 Le Loi street, Hue City, Thua Thien Hue province, at…….. on ……/
……./2019

Theses can be further referred at:
1. National Library
2. Center for Information and Library of Hue University of Agriculture and Forestry, Hue
University

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INTRODUCTION
1. Background
Lysine (Lys) is generally the first limiting amino acid (AA) in practical pig diets, and
consequently, its requirement has been most extensively studied (Ball et al., 2007). There is
considerable variation in the reported Lys requirements which may be due to differences in the lean
gain potential of the pig genetics used. The ability of protein accumulation and lean meat
accumulation are different among pig breeds, and also different during the growth stages in the same
pig breed. The advances in nutrition and feed industry had played an important part in making a
sufficient of Lys requirement in the dietary for the range of growth stages of pigs. In case of lack of
adjustment to the effect of increase leanness on the pig’s lysine needs, dietary lysine deficiency may
occur, then limiting the development of pig genetic potential. Therefore, it is necessary to adjust lysine
in the dietary to ensure maximum growth in pigs. Along with Lys requirement in the pig dietary, sulfur
amino acid (SAA) (methionine and cysteine) is considered as the second or third limiting amino acid
in the pig diets. However, up to now, there is a lack of studies that focused on the standardized ileal
digestible sulfur amino acid (SID SAA) in comparison with standardized ileal digestible Lys (SID
Lys), and also the results in those studies were varied. In Vietnam, previous studies of AA requirement

for pigs were often focused on the needs of Lys, not considering the optimal proportions of others AA
to Lys, and often expressed in total AA level. In addition, the subjects of these studies were pure pig
breeds, domestic pig breeds and hybrid pig breeds between foreign breeds and domestic breeds. The
commercial pigs with 3 and 4 foreign breeds have not been studied yet. The conducting studies to
determine the requirements for ileum digestible AA for exotic breeds in Vietnam is necessary.
Therefore, the study “Estimation of standardized ileal digestible lysine requirement and optional sulfur
amino acids to lysine ratio for hybrid pigs [(Pietrain x Duroc) x (Landrace x Yorkshire)] from 10-20 kg
and 30-50 kg” were conducted.

2. OBJECTIVES
- Determining the SID Lys requirements for commercial pigs [(Pietrain × Duroc) × (Landrace
× Yorkshire)] in the periods 10-20kg and 30-50kg.
- Determining the optional ratio of SID SAA Lys to SID Lys of commercial pigs [(Pietrain ×
Duroc) × (Landrace × Yorkshire)] 10-20kg and 30-50kg periods.

3. SCIENTIFIC AND PRACTICE MEANING
- The study results of this thesis have contributed to data on the SID Lys requirements and the
optional ratio of SID SAA:Lys for pigs [(Pietrain x Duroc) x (Landrace x Yorkshire)] 10-20kg and 3050kg periods in husbandry condition in Vietnam;
- The results of this study would provide information to the optimal formulation in the feed
manufacturers, especially in the feed industry.

4. NEW CONTRIBUTION OF THESIS
- This was the first time in Vietnam, the SID Lys requirement of fourth breed commercial
hybrid pigs [(Pietrain × Duroc) × (Landrace × Yorkshire)] 10-20kg and 30-50kg periods was
determined.

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- This was the first time to identify the optimal SID SAA:Lys ratio for fourth breed

commercial hybrid pigs [(Pietrain × Duroc) × (Landrace × Yorkshire)] of 10-20kg and 30-50kg
periods.
- The results of this study have contributed to the database to build optimal diets for
commercial pigs which could be based on the balancing lysine with non-necessary amino acids at SID
as well as other nutrients in the formula.

5. THESIS STRUCTURE
The thesis consisted of 91 pages and 5 chapters. Chapter 1: Introduction (04 pages), chapter 2:
Literature review (26 pages), chapter 3: Materials and methodology (19 pages), chapter 4: Results and
discussion (24 pages), chapter 5: Conclusion and recommendations (2 pages). The thesis also included
30 tables, 15 diagrams and 147 references (25 Vietnameses)

CHAPTER 1: LITERATURE REVIEW
1.1. Overview of research on the SID AA requirement for the pig in the world
Nowadays, feed evaluation is based on the digestibility percentage of nutrients that there have
been used in numerous countries. Formulating diets that are based on feed digestibility will
demonstrate a higher accuracy than the total nutrient composition. The AA requirement for the pig was
studied for each AA and also for each growth stage of the pigs.
The standardized ileal digestible lysine requirements for pigs
In recent years, numerous researches have been done to determine the SID Lys requirement
for pigs. For example, at the growth stage of 12-24kg. Yi et al. (2006) reported that the requirement of
SID Lys was 1.32%. Ken et al. (2008) showed that using SID Lys at 1.30% or 19g/kg weight gain was
necessary for the optimal growth rate of pigs of 12-27kg period. In the case of a correlation between
SID Lys and dietary energy, that SID Lys was 3.81g/Mcal ME. Pigs from 11-19kg, the use of SID Lys
at 1.35% ensured optimal pig growth (Kendall et al., 2008). Meanwhile, NRC (2012) recommends
SID Lys requirements for the pig at 11-25kg was 1.23%, which was lower than the above studies. The
difference in the results of determining Lys requirements in growth pigs may be due to numerous
causes, including the establishment of a diet which based on the total AA instead of SID AA (Stein et
al., 2007b), statistical analysis methodology (Robbins et al., 2006), gender (Baker, 1986), or genotype
(Schneider et al., 2010).

NRC (2012) recommended that SID Lys for growth pig of 25-50kg period was 0.98%. Based
on broken-line regression, Li et al., (2012) found that ratio between SID Lys and ME at 3.0; 2.43; and
2.2 were the best for growth performance at 29-47kg, 54-76kg and 84-109kg periods, respectively.
Bergstrom et al., (2010) conducted four experiments with castrated boars and females (balance mixed
sex) to estimate the Lys requirement for different growth stages (PIC TR4 x 1050), the variety from
37-129kg. The results showed that the ratio between SID Lys and ME at 2.69; 2.35; 2.09 and 1.79
g/Mcal ME were the best for growth performance and highest rate income per feed cost (Bergstrom et
al., 2010). In addition, Shelton et al., (2009) [126] also reported that SID Lys requirements for gilts
(55-80kg) were 20g.
Percentage of sulfur amino acids to SID Lys

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Sulfur amino acid (methionine and cysteine) is considered as the second or third limiting AA
in the pig diets. Numerous studies have been done in these years to determine the requirement for total
SAA, methionine and cysteine requirement for pigs. Typically, methionine is accounted for 50% in
total SAA (according to the NRC, 48% by volume); however, the recent studies showed that
methionine might be accounted for a higher percentage (55% by weight or 50% by molecular weight)
in comparison with cysteine. Dean et al., (2007) found that the total requirement of SAA for the piglets
of 6-12kg was 10.1% g/kg weight gain or 54% Lys. Gaines et al., (2005) reported that the rate of total
SAA to Lys was 57-61%, which depending on the monitoring criteria and the stopping assessment
method of 8-26kg pigs. Yi et al., (2006) found that average optimal SAA: Lys ratio for an average
daily gain (ADG) of 12-24kg pigs to be 58%. In other studies, Schneider et al., (2-10) showed that the
total SAA: Lys ratio to the pig from 10-20kg was ranging from 57% to 60%. In addition, Gaines et al.,
(2004a, b) who done two independent experiments on pigs at 29-45kg and 45-68kg periods found that
the optimal SAA: Lys ratio at those stages were 60%. Similarly, Lawrence et al., (2005) also reported
that the optimal SAA: Lys ratio was 60% for pigs from the 30-60kg period. In a recent study of
Capozzalo et al., (2017), supplemented with E.coli strains with the high requirement of SAA in the
diets to assess their influence on SID SAA:Lys ratio. The results showed of that the SID SAA:Lys

ratio was no significant difference between diets with/without supplimentation E.coli.

1.2. Overview of research on the SID AA requirement for the pig in Vietnam
In Vietnam, the information on the AA requirement as well as SID Lys for major pig breeds in
Vietnam is still limited. Studies on AA requirement often focused on Lys requirement and usually
represented as total AA. Numerous studies on total lysine requirements, total methionine, total
cysteine, and total. Threonine were conducted on the domestic pig breeds, exotic breeds and the hybrid
between them. Recently, there was a study on SID Lys in pigs at the growth to finishing commercial 4
blood pig breeds, not on the piglets. This study was calculated the non-substituted AA based on the
reference public in the world. Currently, there has been no announcement about the digestible AA
requirement in piglets in Vietnam. In the current feed pig database, there is also no information on the
SID AA. That leads to a mission that determines the SID AA requirement for main pig breeds in
husbandry conditions in Vietnam is extremely necessary.

Chapter II: MATERIALS AND METHODS
2.1. Materials
A total of 400 crossbred pigs [(Pietrain x Duroc) x (Landrace x Yorkshire)] (abbreviation PiDu
x LY).
Materials used to mix diets include corn, broken rice, rice bran, soya bean meal, full-fat soya,
protein concentrate, whey powder, palm oil, corn starch, DCP 19% (Dicalcium phosphate), limestone,
mineral‐vitamin premix, salt, and crystalline amino acids.

2.2. Location and time
The experiment was conducted from February 2015 to December 2015 at the Center for
Animal Research and Practice under the Hue University of Agriculture and Forestry – Hue University.

2.3. Subjects

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- Estimation of SID lysine requirement for 10 – 20 kg pigs
- Estimation of SID lysine requirement for 30 – 50 kg pigs
- Estimation of optimal SID SAA:Lys ratio for 10–20 kg pigs
- Estimation of optimal SID SAA:Lys ratio for 30–50 kg pigs

2.4. Methodology
2.4.1. Estimation of SID Lys requirement for 10–20 kg pigs
A total of 108 crossbred pigs (PiDu x LY; balanced mixed sex) with an average initial BW of
11,8 kg were used in this experiment. They were allotted to one of six treatments on the basis of initial
BW with six replicate pens per treatment and three pigs per pen. Six diets were obtained by
supplementing graded levels of L‐Lysine. HCl to create six dietary levels of SID Lys (0.90%, 0.10%,
1.10%, 1.20%, 1.30% and 1.40%). The experimental diets were formulated based on corn, broken rice,
soya bean meal, full‐fat soya bean, soy protein concentrate and whey powder using analysed
ingredient AA contents and published SID coefficients to meet or exceed minimum AA requirement
(‘AMINODat 4.0 Platinum’ 2012; NRC 2012). Net energy (NE) in 6 diets is the same (10,4 MJ/kg).
Table 2.1. Ingredients composition of experimental diets of SID Lys requirement
for 10–20 kg pigs (as-fed)
Feed ingredients (%)
Corn
Soya bean meal
Full fat soya
Broken rice
Soy protein concentrate
Whey powder
Palm oil
Corn starch
DCP 19%
Limestone
Mineral‐vitamin premix *

Salt
DL-Methionine
L-Threonine
L-Tryptophan
L-Valine
L-Lysine.HCl
Total

0,9
Trial 1
52.69
15.00
5.12
8.00
7.26
5.00
2.94
1.00
0.86
0.55
0.30
0.52
0.28
0.24
0.09
0.14
100

1,0
Trial 2

52.69
15.00
5.12
8.00
7.26
5.00
2.94
0.872
0.86
0.55
0.30
0.52
0.28
0.24
0.09
0.14
0.128
100

SID Lys, %
1,1
1,2
Trial 3
Trial 4
52.69
52.69
15.00
15.00
5.12
5.12

8.00
8.00
7.26
7.26
5.00
5.00
2.94
2.94
0.744
0.615
0.86
0.86
0.55
0.55
0.30
0.30
0.52
0.52
0.28
0.28
0.24
0.24
0.09
0.09
0.14
0.14
0.256
0.385
100
100

1,3
Trial 5
52.69
15.00
5.12
8.00
7.26
5.00
2.94
0.487
0.86
0.55
0.30
0.52
0.28
0.24
0.09
0.14
0.513
100

1,4
Trial 6
52.69
15.00
5.12
8.00
7.26
5.00

2.94
0.231
0.86
0.55
0.30
0.52
0.28
0.24
0.09
0.14
0.641
100

*1 kg Pre-Starter 500 (lợn con – 20kg) contains 11.000.000 IU vitamin A; 1.500.000 IU vitamin D3; 40.000 mg
vitamin E; 2.000 mg vitamin K3; 2.4000 mg vitamin B1; 4.000 mg vitamin B2; 27.000 mg vitamin B3; 13.500 mg vitamin
B5; 4.000 mg vitamin B6; 1.700 mg vitamin B9; 35.000 mcg vitamin B12; 140.000 mcg biotin, 31.000 mg Fe; 20.000 mg Cu;
92.500 mg Zn; 40.000 mg Mn; 400 mg I; 420 mg Co; 225 mg Se; 120.000 mcg Cr.

Chemical analyses such as AA concentration, crude protein (CP) and dry matter (DM) were
performed at the Laboratory of Evonik Singapore. Crude fiber (CF), crude ash and ether extract (EE)
were analysed according to AOAC (1990) at Central Laboratory, Faculty of Animal Sciences, College
of Agriculture and Forestry - Hue University.

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Table 2.2. Nutrient composition of experimental diets of SID lysine requirement
for 10–20 kg pigs (% DM)
Nutrient
composition, %

NE (MJ/kg)
CP, %
SID Lys, %
SID Met, %
SID M+C, %
SID Thr, %
SID Trp, %
SID Ile, %
SID Val, %
SID Leu, %
SID Arg, %
SID, Phe, %
SID His, %
Calcium, %
Avail P, %
Sodium, %

0,9
10.40
19.08
0.90
0.53
0.79
0.83
0.29
0.68
0.90
1.33
1.17
0.79

0.45
0.70
0.35
0.25

SID Lys, %
1,1
1,2
10.40
10.40
19.08
19.08
1.10
1.20
0.53
0.53
0.79
0.79
0.83
0.83
0.29
0.29
0.68
0.68
0.90
0.90
1.33
1.33
1.17
1.17

0.79
0.79
0.45
0.45
0.70
0.70
0.35
0.35
0.25
0.25

1,0
10.40
19.08
1.00
0.53
0.79
0.83
0.29
0.68
0.90
1.33
1.17
0.79
0.45
0.70
0.35
0.25

1,3

10.40
19.08
1.30
0.53
0.79
0.83
0.29
0.68
0.90
1.33
1.17
0.79
0.45
0.70
0.35
0.25

1,4
10.40
19.08
1.40
0.53
0.79
0.83
0.29
0.68
0.90
1.33
1.17
0.79

0.45
0.70
0.35
0.25

The feed was provided with semi-ad libitum and free-drinking water. Pigs were weighed at the
beginning and at 7 days, 14 days and the end of the experiment at 21 days to calculate the daily weight
(ADG) by the week and by the entire experiment period. Feed was weighed daily to calculate intake
(FI) and weight gain/feed (G: F) by the week of the experiment and by the entire time of the
experiment. At the end of the experiment, 12 pigs (male: female ratio was 1: 1) for each treatment
were selected for blood sampling and analysis of plasma urea nitrogen (PUN) content.

2.4.2. Estimation of SID Lys requirement for 30–50 kg pigs
A total of 72 crossbred pigs (PiDu x LY; balanced mixed sex) with an average initial BW of
28,85 kg were used in this experiment. They were allotted to one of six treatments on the basis of
initial BW with six replicate pens per treatment and two pigs (one barrow and one gilt) per pen. Six
diets were obtained by supplementing graded levels of L‐Lysine. HCl to create six dietary levels of
SID Lys (0.70%, 0.80%, 0.90%, 1.00%, 1.10% and 1.20%). In the diets with SID Lys levels from
0.7% to 1.00%, the feed ingredients were kept constantly and the only change is Lys content by adding
L‐Lysine∙HCl. To avoid imbalance in AA patterns and keep the ideal AA pattern in all diets, there was
a small change in the feed compositions in the diets with SID Lys contents of 1.10% and 1.20%. The
experimental diets were formulated based on corn, broken rice, soya bean meal, full‐fat soya bean and
whey powder using analysed ingredient AA contents and published SID coefficients to meet or exceed
minimum amino acids requirement (‘AMINODat 4.0 Platinum’ 2012; NRC 2012). Net energy (NE) in
6 diets is the same in level 10,2 MJ/kg in all diets.

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Table 2.3. Ingredients composition of experimental diets of SID Lys requirement

for 30–50 kg pigs (as-fed)
Feed ingredients (%)
Corn
Soya bean meal
Corn starch
Rice bran
Palm oil
Dicalcium phosphate 19%
Limestone
Mineral‐vitamin premix*
Salt
DL-Methionine
L-Threonine
L-Tryptophan
L-Valine
L-Lysine.HCl
Total

0,7
Trial 1
65.69
21.44
1.00
9.00
1.13
0.74
0.30
0.22
0.19
0.18

0.05
0.06
100

0,8
Trial 2
65.69
21.44
0.872
9.00
1.13
0.74
0.30
0.22
0.19
0.18
0.05
0.06
0.128
100

SID Lys, %
0,9
1,0
Trial 3
Trial 4
65.69
65.69
21.44
21.44

0.744
0.615
9.00
9.00
1.13
1.13
0.74
0.74
0.30
0.30
0.22
0.22
0.19
0.19
0.18
0.18
0.05
0.05
0.06
0.06
0.256
0.385
100
100

1,1
Trial 5
69.12
27.3
0.487

1.15
0.69
0.30
0.22
0.18
0.14
0.04
0.03
0.340
100

1,2
Trial 6
65.67
30.43
0.231
0.50
1.13
0.68
0.30
0.22
0.21
0.17
0.04
0.04
0.380
100

*1 kg Pre-Starter 500 (20 – 40kg) contains 9.000.000 IU vitamin A; 1.300.000 IU vitamin D3; 33.000 mg vitamin
E; 2.000 mg vitamin K3; 2.4000 mg vitamin B1; 3.000 mg vitamin B2; 25.000 mg vitamin B3; 12.000 mg vitamin B5; 3.300

mg vitamin B6; 1.500 mg vitamin B9; 35.000 mcg vitamin B12; 125.000 mcg biotin, 31.000 mg Fe; 30.000 mg Cu; 92.500
mg Zn; 31.000 mg Mn; 460 mg I; 420 mg Co; 180 mg Se; 120.000 mcg Cr.

Table 2.4. Nutrient composition of experimental diets of SID Lys requirement
for 30–50 kg pigs (% DM)
Nutrient
composition, %
NE (MJ/kg)
CP, %
SID Lys, %
SID Met, %
SID M+C, %
SID Thr, %
SID Trp, %
SID Ile, %
SID Val, %
SID Leu, %
SID Arg, %
SID, Phe, %
SID His, %
Calcium, %
Avail P, %
Sodium, %

0,7%
10.23
16.07
0.70
0.41
0.64

0.67
0.21
0.55
0.70
1.16
0.95
0.66
0.38
0.66
0.31
0.10

SID Lys, %
0,9%
1,0%
10.23
10.23
16.07
16.07
0.90
1.00
0.41
0.41
0.64
0.64
0.67
0.67
0.21
0.21
0.55

0.55
0.70
0.70
1.16
1.16
0.95
0.95
0.66
0.66
0.38
0.38
0.66
0.66
0.31
0.31
0.10
0.10

0,8%
10.23
16.07
0.80
0.41
0.64
0.67
0.21
0.55
0.70
1.16
0.95

0.66
0.38
0.66
0.31
0.10

8

1,1%
10.20
18.35
1.10
0.42
0.68
0.71
0.22
0.64
0.75
1.32
1.10
0.77
0.44
0.66
0.31
0.10

1,2%
10.20
19.66
1.20

0.47
0.74
0.78
0.24
0.69
0.81
1.39
1.19
0.83
0.46
0.66
0.31
0.10


The feed was provided with semi-ad libitum and free-drinking water. Pigs were weighed at the
beginning and at 7 days, 14 days, 21 days and the end of the experiment at 28 days to calculate the
daily weight (ADG) by the week and by the entire experiment period. Feed was weighed daily to
calculate intake (FI) and weight gain / feed (G: F) by the week of the experiment and by the entire
time of the experiment. At the end of the experiment, 12 pigs (male: female ratio was 1: 1) for each
treatment were selected for blood sampling and analysis of plasma urea nitrogen content.

2.4.3. Estimation of optimal SID SAA:Lys ratio for 10–20 kg pigs
A total of 108 crossbred pigs with an average initial BW of 11,88 kg were used in the
experiment. They were allotted to one of six treatments on the basis of initial BW with six replicate
pens per treatment and three pigs per pen (balanced mixed sex). The diets 1–5 with 1.13% SID Lys
was set to be second limiting AA. These diets contained five graded levels of SID SAA: Lys ratios
(50%, 55%, 60%, 65%, and 70%) by supplementing graded levels of DL ‐Met. Diet 6 was formulated
to be adequate in all AA (1.25% SID Lys) (table 2.5). The diet formulation was followed by the
approach published by Warnants et al. (2003). To avoid imbalances amongst amino acids with the

increases of dietary SID Met+Cys, there were small changes in the ratios of corn and soya bean meal
and some crystalline amino acids of the last diet. The experimental diets were formulated based on
corn, broken rice, soya bean meal, full-fat soy and soy protein concentrate using analysed ingredient
AA contents and published SID coefficients to meet or exceed minimum amino acids requirement
(‘AMINODat 5.0 Platinum’ 2016; NRC 2012). Net energy (NE) in 6 diets is the same in level 10,3
MJ/kg in all diets.
Table 2.5. Ingredient composition of experimental diets of optimal SID SAA:Lys ratio
for 10–20 kg pigs (as-fed)
Feed ingredients (%)
Corn
Broken rice
Soya bean meal
Full fat soya
Soy protein concentrate
Whey powder
Corn starch
DCP 19%
Limestone
Mineral‐vitamin premix *
Salt
DL-Methionine
L-Threonine
L-Tryptophan
L-Valine
L-Lysine HCl
Total

Trial 1
29.69
27.67

15.00
3.06
15.76
5.00
1.00
1.50
0.44
0.30
0.51
0.00
0.03
0.01
0.00
0.03
100

Trial 2
29.69
27.67
15.00
3.06
15.76
5.00
1.00
1.50
0.44
0.30
0.51
0.058
0.03

0.01
0.00
0.03
100

Trial 3
29.69
27.67
15.00
3.06
15.76
5.00
1.00
1.50
0.44
0.30
0.51
0.116
0.03
0.01
0.00
0.03
100

Trial 4
29.69
27.67
15.00
3.06
15.76

5.00
1.00
1.50
0.44
0.30
0.51
0.175
0.03
0.01
0.00
0.03
100

Trial 5
29.69
27.67
15.00
3.06
15.76
5.00
1.00
1.50
0.44
0.30
0.51
0.233
0.03
0.01
0.00
0.03

100

Trial 6
34.03
25.00
15.00
11.28
5.00
5.00
0.71
1.69
0.32
0.30
0.50
0.29
0.23
0.09
0.12
0.44
100

*1 kg Pre-Starter 500 (lợn con – 20kg) contains 11.000.000 IU vitamin A; 1.500.000 IU vitamin D3; 40.000 mg
vitamin E; 2.000 mg vitamin K3; 2.4000 mg vitamin B1; 4.000 mg vitamin B2; 27.000 mg vitamin B3; 13.500 mg vitamin
B5; 4.000 mg vitamin B6; 1.700 mg vitamin B9; 35.000 mcg vitamin B12; 140.000 mcg biotin, 31.000 mg Fe; 20.000 mg Cu;
92.500 mg Zn; 40.000 mg Mn; 400 mg I; 420 mg Co; 225 mg Se; 120.000 mcg Cr.

9


Table 2.6. Nutrient composition of experimental diets of optimal SID SAA:Lys ratio

for 10–20 kg pigs (% DM)
Nutrient
composition, %
NE (MJ/kg)
CP, %
SID Lys, %
SID Met, %
SID M+C, %
SID Thr, %
SID Trp, %
SID Ile, %
SID Val, %
SID Leu, %
SID Arg, %
SID Phe, %
SID His, %
Calcium, %
Avail P, %
Sodium, %
Ratio to SID Lys, %
SID Met, %
SID M+C, %
SID Thr, %
SID Trp, %
SID Ile, %
SID Val, %
SID Leu, %
SID Arg, %
SID, Phe, %
SID His, %

50
10.5
23.04
1.13
0.29
0.56
0.73
0.25
0.83
0.90
1.53
1.45
0.97
0.52
0.70
0.35
0.25

55
10.5
23.04
1.13
0.34
0.62
0.73
0.25
0.83
0.90
1.53

1.45
0.97
0.52
0.70
0.35
0.25

SID SAA:Lys, %
60
65
10.5
10.5
23.04
23.04
1.13
1.13
0.39
0.44
0.68
0.73
0.73
0.73
0.25
0.25
0.83
0.83
0.90
0.90
1.53
1.53

1.45
1.45
0.97
0.97
0.52
0.52
0.70
0.70
0.35
0.35
0.25
0.25

0.26
0.50
0.65
0.22
0.73
0.80
1.35
1.28
0.86
0.46

0.30
0.55
0.65
0.22
0.73
0.80

1.35
1.28
0.86
0.46

0.35
0.60
0.65
0.22
0.73
0.80
1.35
1.28
0.86
0.46

0.39
0.65
0.65
0.22
0.73
0.80
1.35
1.28
0.86
0.46

70
10.5
23.04

1.13
0.49
0.79
0.73
0.25
0.83
0.90
1.53
1.45
0.97
0.52
0.70
0.35
0.25

62
10.5
24.82
1.25
0.48
0.77
0.81
0.28
0.89
0.95
1.36
1.22
1.03
0.55
0.70

0.35
0.25

0.43
0.70
0.65
0.22
0.73
0.80
1.35
1.28
0.86
0.46

0.38
0.62
0.65
0.22
0.71
0.76
1..09
0.98
0.82
0.44

The feed was provided with semi-ad libitum and free-drinking water. Pigs were weighed at the
beginning and at 7 days, 14 days and the end of the experiment at 21 days to calculate the daily weight
(ADG) by the week and by the entire experiment period. Feed was weighed daily to calculate intake
(FI) and weight gain / feed (G: F) by the week of the experiment and by the entire time of the
experiment. At the end of the experiment, 12 pigs (male: female ratio was 1: 1) for each treatment

were selected for blood sampling and analysis of plasma urea nitrogen content.

2.4.4. Estimation of optimal SID SAA:Lys ratio for 30–50 kg pigs
A total of 72 crossbred pigs with an average initial BW of 32.9 kg were used in the experiment.
They were allotted to one of six treatments on the basis of initial BW with six replicate pens per
treatment and two pigs (one barrow and one gilt) per pen. The diets 1–5 with 1.0% SID Lys was set to
be second limiting amino acid. These diets contained five graded levels of SID SAA: Lys ratios (50%,

10


55%, 60%, 65%, and 70%) by supplementing graded levels of DL‐Met. Diet 6 was formulated to be
adequate in all AA (1.11% SID Lys) (table 2.7). The diet formulation was followed by the approach
published by Warnants et al. (2003). To avoid imbalances amongst amino acids with the increases of
dietary SID Met+Cys, there were small changes in the ratios of corn and soya bean meal and some
crystalline amino acids of the last diet. The experimental diets were formulated based on corn, soya
bean meal and rice bran using analysed ingredient AA contents and published SID coefficients to meet
or exceed minimum amino acids requirement (‘AMINODat 5.0 Platinum’ 2016; NRC 2012). Net
energy (NE) in 6 diets is the same in level 10,3 MJ/kg in all diets.
Table 2.7. Ingredient composition of experimental diets of optimal SID SAA:Lys ratio
for 30–50 kg pigs (as-fed)
Feed ingredients (%)
50
57.08
12.00
26.64
0.23
1.00
1.51
0.54

0.30
0.44
0.00
0.08
0.02
0.16
0.00
100

Corn
Rice bran
Soya bean meal
Palm oil
Corn starch
DCP 19%
Limestone
Vitamin mineral premix*
Salt
DL Methionine
L-Threonine
L-Tryptophan
L-Lysine HCl
L-Valine
Total

55
57.08
12.00
26.64
0.23

0.95
1.51
0.54
0.30
0.44
0.00
0.08
0.02
0.16
0.00
100

SID SAA to Lys, %
60
65
57.08
57.08
12.00
12.00
26.64
26.64
0.23
0.23
0.90
0.85
1.51
1.51
0.54
0.54
0.30

0.30
0.44
0.44
0.00
0.00
0.08
0.08
0.02
0.02
0.16
0.16
0.00
0.00
100
100

70
57.08
12.00
26.64
0.23
0.80
1.51
0.54
0.30
0.44
0.00
0.08
0.02
0.16

0.00
100

64
58,87
12.00
25.52
0.00
0.00
1.51
0.55
0.30
0.44
0.22
0.17
0.04
0.34
0.04
100

*1 kg Pre-Starter 500 (20 – 40kg) contains 9.000.000 IU vitamin A; 1.300.000 IU vitamin D3; 33.000 mg vitamin
E; 2.000 mg vitamin K3; 2.4000 mg vitamin B1; 3.000 mg vitamin B2; 25.000 mg vitamin B3; 12.000 mg vitamin B5; 3.300
mg vitamin B6; 1.500 mg vitamin B9; 35.000 mcg vitamin B12; 125.000 mcg biotin, 31.000 mg Fe; 30.000 mg Cu; 92.500
mg Zn; 31.000 mg Mn; 460 mg I; 420 mg Co; 180 mg Se; 120.000 mcg Cr.

Table 2.8. Nutrient composition of experimental diets of optimal SID SAA:Lys ratio
for 30–50 kg pigs (% DM)
Nutrient
composition, %
NE (MJ/kg)

CP, %
SID Lys, %
SID Met, %
SID M+C, %
SID Thr, %
SID Trp, %
SID Ile, %
SID Val, %
SID Leu, %

50
10.25
19.00
1.00
0.25
0.50
0.67
0.21
0.68
0.76
1.40

55
10.25
19.00
1.00
0.30
0.55
0.67
0.21

0.68
0.76
1.40

SID SAA:Lys, %
60
65
10.25
10.25
19.00
19.00
1.00
1.00
0.35
0.40
0.60
0.65
0.67
0.67
0.21
0.21
0.68
0.68
0.76
0.76
1.40
1.40

11

70
10.25
19.00
1.00
0.45
0.70
0.67
0.21
0.68
0.76
1.40

64
10.25
19.00
1.11
0.47
0.71
0.74
0.23
0.66
0.78
1.38


SID Arg, %
SID Phe, %
SID His, %
Calcium, %
Avail P, %

Sodium, %
Ratio to SID Lys, %
SID Met, %
SID M+C, %
SID Thr, %
SID Trp, %
SID Ile, %
SID Val, %
SID Leu, %
SID Arg, %
SID, Phe, %
SID His, %

1.16
0.81
0.44
0.70
0.31
0.19

1.16
0.81
0.44
0.70
0.31
0.19

1.16
0.81
0.44

0.70
0.31
0.19

1.16
0.81
0.44
0.70
0.31
0.19

1.16
0.81
0.44
0.70
0.31
0.19

1.13
0.79
0.43
0.70
0.31
0.19

25
50
67
21
68

76
140
116
81
44

30
55
67
21
68
76
140
116
81
44

35
60
67
21
68
76
140
116
81
44

40
65

67
21
68
76
140
116
81
44

45
70
67
21
68
76
140
116
81
44

42
64
67
21
59
70
124
102
71
39

The feed was provided with semi-ad libitum and free-drinking water. Pigs were weighed at the
beginning and at 7 days, 14 days and the end of the experiment at 21 days to calculate the daily weight
(ADG) by the week and by the entire experiment period. Feed was weighed daily to calculate intake
(FI) and weight gain / feed (G: F) by the week of the experiment and by the entire time of the
experiment. At the end of the experiment, 12 pigs (male: female ratio was 1: 1) for each treatment
were selected for blood sampling and analysis of plasma urea nitrogen content.
2.5. Statistical analysis
All data were analysed by ANOVA using the GLM procedure (SAS Inst. Inc., Cary, NC) with
initial BW (covariate) and dietary treatment as sources of variation. To estimate Lys requirement, ADG
and G:F (overall treatment means) data were analysed by curvilinear‐plateau models. For the PUN
data were analysed by linear broken‐line models (Robbins et al., 2006).

CHAPTER 3: RESULTS AND DISCUSSIONS
3.1. Estimation of SID Lys requirement for 10-20 kg pigs
The effects of increasing SID Lys on growth performance and PUN concentration of 10-20 kg
pigs were represented in table 3.1. The final body weight of pigs was significantly different between
experiments (P<0.0001). During the overall experimental period, increasing dietary SID Lys linearly
increased ADG and G: F ratio, whereas Feed intake was not affected (P>0.01). The FCR was
improved with the linear increase (P<0.0001) with increasing SID Lys concentration in the range from
0.9% to 1.4%. ADG, and FCR, and G: F ratio was the best achievement at a proportion of SID Lys of
1.3%. Furthermore, increasing the SID Lys in the diets led to change the density of PUN. The PUN
concentration linearly decreased when increasing the SID Lys in the diets (P < 0.0001) and the PUN
was lowest at 1.3% SID Lys concentration in the diet (Table 3.1).
Table 3.1. Estimation of SID Lys requirement for 10-20 kg pigs

12


Initial

p-value

SID Lys for 10-20 kg Pigs (%)
SEM

Analyzed values

0.87

0.98

1.04

1.18

1.25

1.42

Calculated values

0.9

1.0

1.1

1.2

1.3

1.4

BW, kg

11.8

11.8

11.8

11.8

11.8

d

cd

bc

abc

11.8

a

Anova

Lin

Quad

0.17

1.000

0.898

0.966

ab

0.08

0.0002

<0.0001

0.121

BW7, kg

13.6

13.8

13.9

14.0

14.1

14.1

BW14, kg

16.6d

17.0c

17.4b

17.6ab

17.9a

17.8a

0.12

<0.0001 <0.0001

0.006

BW21, kg

d

c

b

a

a

a

0.15

<0.0001 <0.0001

0.004

6.69

0.382 <0.0001 <0.0001

0.247
0.116

20.6

PUN (mg/100ml)

a

21.1

a

21.7

b

22.3

22.6

b

6.54

c

22.5

c

11.81

10.84

9.05

8.70

ADG

263d

285cd

305bc

317ab

339a

332ab

9.24

ADFI

469

475

471

478

480

477

19.38

0.998

0.708

0.915

FCR

1.789a

1.669ab

1.541bc

1.444c

0.06

0.001

<0.0001

0.123

c

bc

ab

a

0.03

0.002

<0.0001

0.189

10.85 <0.0001 <0.0001

0.009

33.36

0.984

Week 1 (Day 0 – 7)

G:F

1.513bc 1.416c

0.562

0.604

0.656

0.666

ADG

424d

457c

498b

ADFI

800

ab

a

0.712

0.696

522ab

533a

534a

790

785

<0.0001 <0.0001

Week 2 (Day 8 – 14)
809
a

FCR

1.891

b

G:F

790

1.769

0.531

0.570

ADG

576c

ADFI

FCR

a

b

b

1.589

a

b

1.506

a

784
b

1.472

a

0.994

0.584

b

0.06

<0.0001 <0.0001

0.032

a

0.02

<0.0001 <0.0001

0.067

1.469

0.633

0.668

0.683

0.685

598bc

627b

669a

675a

672a

13.68 <0.0001 <0.0001

0.094

1122

1104

1080

1063

1018

1038

37.04

0.766

1.953a

1.849ab

1.723bc

1.587cd 1.509d

1.542d

0.05

<0.0001 <0.0001

0.070

d

cd

bc

a

Week 3 (Day 15 – 21)

G:F

ab

a

0.368

0.033

0.514

0.544

0.581

0.633

0.668

0.651

0.02

<0.0001 <0.0001

0.157

ADG

421d

447c

477b

503a

516a

513a

7.17

<0.0001 <0.0001

0.003

ADFI

797

777

761

Overall (day 0 – 21)
796
a

780
a

FCR

1.895

1.781

G:F

0.529c

0.564c

b

bc

1.475

766
c

1.636

1.542

0.612b

0.651ab 0.681a

26.49

0.898

0.234

0.909

1.494

c

0.04

<0.0001 <0.0001

0.014

0.672a

0.02

<0.0001 <0.0001

0.055

Notes: a,b,c,d: Means sharing a different superscript in a row differ significantly (p < 0.05); ADG: averagea daily gain
(g/head/day), ADFI: Average daily feed intake (g/head/day). FCR: Feed conversion ratio (Kg/Kg).

Based on the overall ADG and G: F ratio, the SID Lys requirement was estimated at 1.36 and
1.38%, respectively, using the curvilinear-plateau model (Figure 1 and figure 2). The two-slope
broken-line estimated the optimum Lys to be 1.28 % for PUN (Figure 3).On overage of all criteria, the
SID Lys requirement for the pigs of this period was 1.34%.

13

Figure 3.1. The correlation between SID Lys in

Figure 3.2. The correlation between SID Lys in

the diet with ADG

the diet with G:F ratio

Numerous previous studies evaluated the Lys requirement for 10-20kg pigs. Kahindi (2014)
found that the SID Lys requirement for 7-16 kg [Duroc x (Yorkshire x Landrace) pigs to maximize
ADG and G: F was 1.32%. Urynek and Buraczewska (2003) reported that the SID Lys requirement for
maximum nitrogen and ADG was 0.85 g AID Lys/MJ ME, using for 13-20kg pigs. Yi et al., (2006)
showed that the TID Lys was at least 1.3% to maximum ADG and G: F ratio. This finding was in
agreement with the results observed by Kendall et al., (2008) who reported that the TID Lys
requirement for 11-27kg pigs was 1.3% to maximize the growth performance. Meanwhile, Htoo and
Morales (2010) reported that the SID Lys requirement for 10-20kg PIC pigs (GP1050) was 1.38%,
which was higher than the above studies’ results. However, this result was higher than the
recommendation of NRC (20152) for 11-25kg pigs. NRC (2012) recommended that for this stage was
1.23%. It could be explant that the exotic pig breeds with fast growth performance and high rate of
lean meat require the higher protein proportion in the diet in comparison with the suggestion of NRC
(2012).
In this study, feed intake was not affected by the SID Lys in the diet. This study was in
agreement with the results in other previous studies which reported that using amino acid added in the
diet to increase the Lys in the diets (Urynek, and Buraczewska, 2003; Kendall et al., 2008).

Figure 3.3. The correlation between SID Lys in the diet with PUN
Plasma urea nitrogen has been often used as a response criterion for determining amino acid
requirements since PUN can be used as an indicator of protein utilization efficiency. When there is an
excess amino acid, PUN is known to increase because excess amino acid cannot be stored, and
therefore, they are degraded with the production of urea. If there is a decrease in PUN, it would

indicate either an increase in nitrogen utilization efficiency or a decrease in protein breakdown [45].
Using the overall results of this experiment, the two-slope linear broken-line analysis estimated the

14


optimum SID Lys requirement for 10-20kg pigs to minimize PUN was 1.28%. PUN concentration in
pigs of 10-20kg decreased from 11.8 mg/100ml to 6.54 g/100ml with increasing of SID Lys in the diets
from 0.9% to 1.3%.

3.2. Estimation of SID Lys requirement for 30-50 kg pigs
As can be seen in table 3.2, the final body weight was increased linearly (P<0.001) by
increasing the dietary SID Lys level. During the overall experimental period, increasing dietary SID
Lys linearly increased (p < 0.001) ADG and G: F ratio, whereas feed intake was not affected (p > 0.10,
table 3.2). The best ADG and G: F ratio were achieved at a proportion of SID Lys at 1.04%. The result
also showed that the PUN concentration decreased quadratically (p = 0.001) as dietary SID Lys level
increased, and the PUN concentration was the lowest at a dietary SID Lys of 1.04%.
Table 3.2. Effects of increasing SID Lys on growth performance and PUN concentration of 30-50
kg pigs
Initial
Analyzed values

SID Lys for 30-50 kg growing pigs (%)
0.71

Calculated values

0.7

Initial BW, kg

28.8
b

0.82

0.91

1.04

1.12

1.22
Anova

Lin

Quad

0.9

28.9

28.9

28.8

28.9

28.8

0.269

1

0.98

0.99

a

a

a

40.2

a

0.339

0.01

0

0.19

39.2

39.6

39.9

1.1

P-value

0.8

ab

1.0

SEM

40.2

1.2

BW14, kg

38.4

BW28, kg

49.5c

50.9bc

51.8ab

52.4ab

53.0a

53.1a

0.591

0

PUN (mg/100ml)

8.97a

8.73ab

8.15bc

8.04c

8.14bc

8.77ab

0.22

Week 1 (day 0-14)
ADG, g
ADFI, g

FCR

682b
1448
2.126a

739ab
1508
2.041ab

766a
1452
1.900bc

790a
1433
1.822c

809a
1526
1.886bc

812a
1547
1.905bc

G:F

0.471c

0.491bc

0.529ab

0.552a

0.531ab

ADG, g

795b

834ab

877ab

896a

ADFI, g

1842

1894

1784

FCR

2.319a

2.267a

G:F

0.433b

ADG, g

0.01

<0.000
1
0.128

0.001

24.203
48.951
0.052

0.01
0.47
0

0
0.21
0

0.19
0.38

0.01

0.529ab

0.015

0.01

0

0.01

915a

916a

27.046

0.02

0

0.26

1720

1833

1833

79.655

0.74

0.39

2.0367b

1.921b

2.002b

1.998b

0.063

0

0.442b

0.492a

0.525a

0.502a

0.504a

0.015

0

0.66
<0.000
1
0

739c

787bc

821ab

842ab

862a

864a

21.148

0

ADFI, g

1645

1701

1618

1577

1679

1690

59.111

FCR

2.227a

2.161a

1.972b

1.872b

1.946b

1.952b

0.046

G:F

0.450b

0.463b

0.509a

0.536a

0.515a

0.515a

0.012

0.66
<0.000
1
<0.000
1

0.15

Week 2 (day 15-28)

0.02
0.03

Overall (day 0-28)
<0.000
1
0.81
<0.000
1

<0.000
1

0.15
0.35
0
0.01

Notes: a,b,c,d: Means sharing a different superscript in a row differ significantly (p < 0.05);

Based on overall ADG and G:F, the SID Lys requirements were estimated at 1.23% and
1.10%, respectively, using the curvilinear – plateau model (Figure 3.4,3.5). The two-slope broken-line

15


estimated the optimum Lys to be 0.98% for PUN (Figure 3.6). On average of all criterias, the SID Lys
requirement for the pig of this period was 1.10%.

Figure 3.4: The correlation between SID Lys

Figure 3.5: The correlation between SID Lys

requirement and ADG

requirement and G:F

Numerous previous studies estimation of the optimal Lys requirements for 30-50kg pigs
aiming to provide opportunities for cost-effective gains, efficient growth performance, and
environmental benefits. Mathai and Stein (2014) reported that estimation of the optimum proportion of

SID Lys requirement to maximize ADG and G: F was 1.08% and 1.10%, respectively, for 25-50kg
growing pigs. These findings were in agreement with the results observed by Landero et al., (2016)
who reported that increasing dietary SID Lys quadratically (p <0.01) increased ADG and G: F, with
the maximum response estimated at 1.04% SID Lys for 25-50kg pigs. Thus the results in these
experiments indicated that the SID Lys requirement for 30-50kg growing pigs was slightly greater than
recommendations of 0.98% reported by NRC (2012). Moreover, Pigs fed the low CP diet containing
0.90% SID Lys had reduced weight gain compared with pigs fed the diets containing 1.02% SID Lys,
indicating that the low CP diet containing 0.9% SID Lys was deficient in Lys (Zhang et al., 2012).
Based on these findings, it was assumed that a diet with 1.0% SID Lys could be used in the subsequent
experiment to determine the optimum SID sulfur amino acids to Lys ratio. Possibly, in this study, the
balances among amino acids in the diets with high SID Lys contents (1.1% and 1.2% SID Lys diets)
by slight ingredient changes could be a reason for better ADG, G: F and lower PUN and as a
consequence high estimates of SID Lys requirement.

Figure 3.6: The correlation between SID Lys requirement and PUN
Coma et al., (1995) reported that there was a decrease in PUN, it would indicate either an
increase in nitrogen utilization efficiency or a decrease in protein breakdown. Using the overall results
of this experiment, the two-slope linear broken-line analysis estimated the optimum SID Lys
requirement for 49.5 – 53.1 kg pigs to minimize PUN from 8.97 mg/100ml to 8.04 mg/100ml (p <
0.05) was 10.37%. Based on all the above criteria, the SID Lys requirement for 30-50kg four-breeds

16


PiDu x LS pigs was 1.01%.

3.3. Estimation of optimal SID sulfur amino acid:Lys ratio for 10-20kg pigs.
The final body weight of pig was increased linearly and quadratically (p<0.0001) by increasing
dietary SID SAA: Lys level. During the overall experimental period, increasing dietary SID SAA: Lys
level, there was the linear and quadratic increase in ADG (p<0.0001) and G: F (p<0.0001). Whereas, FI

was not affected. In the meanwhile, FCR was a linear and quadratic achievement. FCR was decreased
from 1.95 kg to 1.51kg by increasing SID SAA: Lys from 52% to 60%. In this experiment, PUN
concentration decreased quadratically (p < 0.0001) as dietary SID SAA: Lys level increased, and the
PUN concentration was the lowest at a dietary SID SAA: Lys of 60%.
Table 3.3. Effects of increasing SID SAA:Lys ratio on growth performance and PUN
concentration of 10-20 kg pigs
Initial
Corrected
values
Calculated
values

SID SAA:Lys (%)
52
50

BW, kg
11.88
BW7, kg
13.83c
BW14, kg
16.82c
BW21, kg
20.59c
PUN
14.25ab
(mg/100ml)
Week 1 (day 0-7)
ADG, g
278c

ADFI, g
497
FCR
1.791a
G:F
0.559c
Week 2 (day 8-14)
ADG, g
428c
ADFI, g
835
FCR
1.951a
G:F
0.513b
Week 3 (day 15-21)
ADG, g
538c
ADFI, g
1094
FCR
2.035a
G:F
0.492c
Overall (day 0-21)
ADG, g
415c
ADFI, g
809
FCR

1.951a
G:F
0.513c

SEM

P-value

55

60

65

70

62

11.88
14.02b
17.47b
21.67b

11.88
14.22a
18.07a
22.68a

11.89
14.18ab

17.97a
22.52a

11.88
14.16ab
17.94a
22.41a

11.88
14.19ab
18.01a
22.56a

0.06
0.06
0.10
0.12

1.000
0.0003
<.0001
<.0001

0.968
0.0001
<.0001
<.0001

0.973
0.006

<.0001
<.0001

Comp
are
diet 4
vs
diet 6
0.971
0.856
0.797
0.819

13.31c

12.73c

13.53bc

14.83a

12.79c

0.287

<0.0001

0.138

<0.0001

0.076

306b
483
1.584b
0.632b

333a
470
1.411c
0.716a

328ab
471
1.443bc
0.701ab

326ab
471
1.444bc
0.699ab

330ab
471
1.426c
0.703ab

8.40
17.29

0.05
0.02

0.0003
0.836
<0.0001
0.0002

0.000
0.245
<0.0001
<.0001

0.006
0.514
0.001
0.008

0.854
0.978
0.799
0.973

493b
818
1.658b
0.621a

550a
823

1.498b
0.670a

542a
832
1.529b
0.660a

539a
828
1.537b
0.653a

545a
823
1.514b
0.663a

10.36
37.85
0.07
0.03

<.0001
1.000
0.000
0.001

<.0001
0.997

<0.0001
0.001

<.0001
0.846
0.003
0.005

0.855
0.870
0.875
0.954

600b
1058
1.765b
0.570b

659a
1039
1.574c
0.639a

650a
1038
1.596c
0.629a

639a
1046

1.639c
0.611ab

650a
1032
1.588c
0.630a

10.38
27.36
0.04
0.02

<.0001
0.629
<0.0001
<.0001

<.0001
0.187
<0.0001
<.0001

<.0001
0.305
<0.0001
<.0001

0.970
0.892

0.903
0.972

466b
786
1.684b
0.598b

514a
777
1.511c
0.664a

507a
780
1.539c
0.653a

501a
781
1.560c
0.642a

508a
776
1.526c
0.656a

5.80
22.07

0.04
0.02

<.0001
0.904
<0.0001
<.0001

<.0001
0.391
<0.0001
<.0001

<.0001
0.481
<0.0001
<.0001

0.842
0.878
0.807
0.890

57

60

66

69

64
Anova

Lin

Quad

Notes: a,b,c,d: Means sharing a different superscript in a row differ significantly (p < 0.05); ADG: averagea daily gain
(g/head/day), ADFI: Average daily feed intake (g/head/day). FCR: Feed conversion ratio (Kg/Kg),; Lin: linear; Quad:
quadratic)

Using the curvilinear – plateau model, the SID SAA: Lys requirements for ADG and G: F was
63.1% and 62.5%, respectively. The two – slope broken-line estimated the optimum SID SAA: Lys to be
62.9% to minimize the PUN. On average of all criteria, the SID SAA: Lys requirement for 10-20 kg
growing pigs was 62.8%.

17


Figure 3.7: Effects of SID SAA: Lys to ADG

Figure 3.8: Effects of SID SAA: Lys to G:F

NRC (1998, 2012) recommended that the SAA: Lys were 58% and 55%, respectively, for 1125kg pigs. However, other studies reported that 55% of SID SAA: Lys in the diet was not enough to
maximize the growth performance of pigs in different weights. Kongkeaw et al., (2013) concluded that
the optimum SID SAA: Lys for 7-25 kg growing pigs was 64%. The optimal proportion of SID SAA:
Lys for growing pigs from 8-19 kg period and 8-26 kg period were 59% and 60%, respectively
(Gaines et al., 2005). Yi et al., (2006) published that 58% of SID SAA: Lys in the diet provided
opportunities for cost-effective gains, efficient growth performance. Kahindin (2014) reported that the

7-16 kg growing pigs were to maximize growth performance when being fed the dietary with 60%
proportion of SID SAA: Lys. In that study, if only based on ADG criteria, the SID SAA: Lys was 61%.
Thus, the finding of SID SAA:Lys in this study was in agreement with the study of Kongkeaw et al.,
(2013), Gaines et al., (2005), and Kahindi (2014), and higher than recommendation of NRC (2012) for
11-25kg growing pigs (62.8% vs 55%).

Figure 3.9. Effects of SID SAA:Lys to PUN for 10-20 kg growing pigs.
The concentration of PUN has been used as response criteria for the determination of AA
requirements. Reduced PUN is indicative of a reduced need for the determination of excess AA. In
these experiments, the optimal proportion of SID SAA: Lys in the dietary to minimize the PUN was
62.9% for 10-20kg growing pigs.

3.4. Estimation of optimal SID sulfur amino acid:Lys ratio for 30 – 50 kg pigs
The analyzed Met+Cys contents were slightly higher than the calculated values. The corrected
SID SAA:Lys (corrected after diet analysis) in the diets were 52%, 59%, 63%, 68%, 75%, and 60%

18


(table 3.4). All data presented hereafter will refer to the corrected SID Lys or SID SAA: Lys as SID
Lys or SID SAA: Lys. The ADG, G: F, and FRC improved linearly and quadratically (P ≤ 0.001) as the
SID SAA: Lys level increased. FI was not affected by experiment treatments. In this study, increasing
dietary SID SAA supply quadratically decreased PUN (p < 0.05) and the lowest PUN concentration
was achieved at a proportion of SID SAA: Lys of 63%. Diet 6 was the same as diet 5 with an
exception that diet 6 contained a higher Lys content. The ADG and G: F of pigs fed diet 6 were
numerically higher compared with diet 5, but it was not different indicating the dietary Lys effect was
not different (p > 0.05). FRC was the lowest when pigs fed the dietary with 63% of SID SAA: Lys.
Based on these data, these findings suggested that the optimal proportion of SID SAA to Lys for 30 to
50 kg pigs was at 63% to maximize ADG, G: F and minimize PUN.
Table 3.4 Effects of increasing SID SAA:Lys ratio on growth performance and PUN

concentration of 30 – 50 kg pigs
Initial
Corrected
values
Calculated
values

SID SAA:Lys (%)

SEM
Anova

Lin

Quad

1
0.007
0.001
<0.0001

0.99
0.006
0.001
<0.0001

0.99
0.012
0.002
<0.0001

So
sánh
KP5
và
KP6
0.977
0.618
0.592
0.235

0.012

0.115

0.003

0.002

16.01
28.97
0.04
0.01

0.0075
0.883
0.063
0.075

0.005

0.329
0.035
0.037

0.013
0.431
0.05
0.066

0.537
0.987
0.461
0.539

842ab
1694
2.013b
0.497a

22.03
34.63
0.04
0.01

0.141
0.998
0.028
0.03

0.049

0.982
0.01
0.013

0.074
0.804
0.045
0.041

0.707
0.946
0.689
0.68

872ab
1803
2.076ab
0.485ab

896ab
1810
2.025b
0.495a

25.03
55.86
0.06
0.01

0.177

0.98
0.071
0.088

0.103
0.502
0.019
0.021

0.043
0.853
0.055
0.067

0.489
0.93
0.568
0.629

824ab
1687
2.048bc
0.488ab

841a
1691
2.011c
0.497a

9.81

25.23
0.03
0.01

<0.0001
0.99
<0.0001
<0.0001

<0.0001
0.893
<0.0001
0.0001

<0.0001
0.575
0.001
0.0001

0.241
0.926
0.32
0.324

52

59

63

68

75

60

50

55

60

65

70

64

32.9
38.16bc
43.84b
49.93b

32.9
38.56a
44.53a
50.86a

33
38.39ab

44.24ab
50.51ab

32.9
38.34ab
44.16ab
50.23ab

33
38.42a
44.29ab
50.59a

11.57b

11.18b

11.30b

12.58a

11.23b

745bc
1555
2.091ab
0.479ab

798a
1580

1.981b
0.506a

780ab
1575
2.022b
0.495ab

770ab
1568
2.043ab
0.492ab

785ab
1567
1.998b
0.501a

810ab
1707
2.113ab
0.474ab

855a
1692
1.982b
0.506a

836ab
1687

2.024b
0.495a

830ab
1691
2.038b
0.491a

868ab
1840
2.123ab
0.472ab

907a
1846
2.039b
0.493a

894ab
1801
2.012b
0.499a

807b
1701
2.106b
0.475b

853a
1706

2.000c
0.501a

837ab
1688
2.017c
0.496a

BW, kg
33
BW7, kg
37.91c
BW14, kg
43.31c
BW21, kg
49.04c
PUN
11.71b
(mg/100ml)
Week 1 (day 0-7)
ADG, g
710c
ADFI, g
1533
FCR
2.157a
G:F
0.465b
Week 2 (day 8-14)
ADG, g

772b
ADFI, g
1682
FCR
2.184a
G:F
0.459b
Week 3 (day 15-21)
ADG, g
818b
ADFI, g
1844
FCR
2.263a
G:F
0.444b
Overall (day 0-21)
ADG, g
767c
ADFI, g
1686
FCR
2.200a
G:F
0.455c

P-value

0.405
0.12

0.17
0.21

Notes: a,b,c,d: Means sharing a different superscript in a row differ significantly (p < 0.05); ADG: averagea daily gain
(g/head/day), ADFI: Average daily feed intake (g/head/day). FCR: Feed conversion ratio (Kg/Kg),; Lin: linear; Quad:
quadratic)

The estimation of the optimum proportion of SID SAA to Lys was affected by the statistical
models used. The curvilinear‐plateau analysis estimated the optimum SID Met+Cys: Lys ratio to be
65.5% and 66.7% to maximize ADG and G: F, respectively, while the broken‐line model estimated

19


63% and 63.9%. The two‐slope broken‐ line estimated the optimum Lys to be 66.8% for PUN. On
average of all criteria, optimal SID SAA: Lys ratio for growing pigs of this study was 65.2%. The
optimal proportion of SID SAA to Lys of 65.2% was obtained which was higher than the NRC (2012)
recommendation of 56% for 25–50 kg pigs. Estimates in this study were possibly partly affected by
the balances amongst amino acids in the last diet with 64% SID Met+Cys: Lys by slight ingredient
change. These estimates were similar to the results of Zhang et al. (2015) finding an optimal SID
SAA: Lys ratio was 62.3% for 25–50 kg pigs. The result from this study was also in agreement with
some other recent findings. For example, Gaines et al. (2004) found that the optimal TID SAA: Lys
ratio of 29–45 kg pigs were 59.7% and 61.1% for ADG and G: F respectively. Yi et al. (2005) also
published that the average optimal TID SAA: Lys ratio of approximately 61% for both 28–49 kg PIC
gilts and barrows.

The two‐slope linear broken‐line model estimated the optimum of SID SAA: Lys ratio to
minimize PUN was 66.8% for 30–50 kg pigs of this study. Similarly, Zhang et al. (2015), using the
curvilinear‐plateau model, reported an optimum SID SAA: Lys of 61.5% for serum urea N of 25–50
kg pigs.

CHAPTER 4: CONCLUSION AND RECOMMENDATION
4.1. CONCLUSION
The optimum proportion of SID Lys for 10-20 kg commercial [(Pietrain x Duroc) x (Landrace
x Yorkshire)] pigs to maximize the ADG and G: F were1.36% and 1.38%, respectively. The lowest
PUN concentration was achieved at a proportion of SID Lys of 1.28%. On average of all criteria, the
SID Lys requirement for the pigs of this period was 1.34%.

20


To optimize ADG, G: F and minimize PUN, the requirement of SID Lys in the dietary was
1.23%, 1.1%, and 0.98%, respectively, for 30-50 kg pigs. On average of all criteria, the SID Lys
requirement for 30-50kg pigs was 1.1%.
The optimum SID (Met+Cys): Lys ratio to maximize growth performance, G: F and minimize
FRC and PUN were 63.1%, 62.5%, and 62.9%, using for 10-20 kg commercial [(Pietrain x Duroc) x
(Landrace x Yorkshire)] pigs. On average of all criteria, the SID Met+Cys: Lys for the pigs in this
period was 62.8%.
The estimation of the optimum proportion of SID SAA to Lys was affected by the statistical
models used. The curvilinear‐plateau analysis estimated the optimum SID Met+Cys: Lys ratio to be
65.5% and 66.7%, while the broken‐line model estimated 63% and 63.9%. The two‐slope broken‐ line
estimated the optimum Lys to be 66.8% for PUN. On average of all criteria, optimal SID SAA: Lys
ratio for growing pigs of this period was 65.2%.

4.2. RECOMMENDATION
The results of SID Lys, SID SAA:Lys in this study should be used to formulate diets as well as
to determine the ideal model for formulation dietary for 10-20 kg and 30-50kg commercial [(Pietrain x
Duroc) x (Landrace x Yorkshire)] pigs to maximize the growth performance, G:F, protein
accumulation and minimize nitrogen excretion into the environment through urine.
Update research results to the amino acid requirement database for commercial pigs in

Vietnam.
Continuing extensive research the estimation of SID Lys, SID SAA: Lys for other growth
stages of commercial [(Pietrain x Duroc) x (Landrace x Yorkshire)] pigs.

THESIS RELATED ANNOUNCED RESEARCH WORKS
1.

Thi Binh An Dao, Trung Thong Ho, Xuan Quang Trinh, John Khun Kyaw Htoo, Eloisa Crenna,

Chi Cuong Vu, Quang Linh Nguyen (2016). The SID Lys requirement for 10-20kg commercial
[(Pietrain x Duroc) x (Landrace x Yorkshire)] pigs. Journal of Animal Science and Technology, 210;
18-25.
2.

Thi Binh An Dao, Trung Thong Ho (2018). Estimation of the standardized ileal digestible lysine

requirement for 30-50kg commercial [(Pietrain x Duroc) x (Landrace x Yorkshire)] pigs. Hue
University Journal of Science, 127 (3B). DOI: />3. Trung Thong Ho, John Khun Kyaw Htoo, Thi Binh An Dao, Maria Eloisa Carpenna, Nu Anh Thu
Le, Chi Cuong Vu, Quang Linh Nguyen (2018). Estimation of the standardized ileal digestible lysine
requirement and optimal sulfur amino acids to lysine ratio for 30 – 50 kg pigs. Journal of Animal
Physiology and Animal Nutrition, 2018; 1-11. Doi: 10.1111/JPN.13029

21