《动物营养学报》英文论文格式模板

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《动物营养学报》英文论文格式模板

Effects of Dietary Energy Level on Growth Performance and Carcass

Composition of

Wujin

Pigs

ZHANG Xi

ZHAO Su-mei

GE Chang-rong

LAI Hua

LI Chang-qiang

GAO Shi-zheng

?

(

Yunnan Key Laboratory of Animal Nutrition and Feed Science, Yunnan Agricultural University, Kunming

650201,

China

)

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Abstract:

(Objective)

The aim of the present study was to investigate the effects of dietary digestible energy levels on

growth performance and carcass composition in

Wujin

pigs, and to investigate the most suitable dietary energy density

for maximum growth potential and best carcass composition using the fuzzy comprehensive evaluation model.

(

Method)

The experimental approach was by single factor random allotment. Ninety pigs were randomly allotted into five groups

of 18, and fed diets containing 14.22, 13.60, 12.98, 12.36 and 11.74 MJ/kg of digestible energy.

(

Result)

Results showed

that the daily gain was reduced and the feed gain ratio increased gradually with reduction in dietary energy levels. No

significant differences were found in the groups at body weight of 15

～

30 kg (

P

>0.05). At the body weight of 60 and

100 kg, lean meat weight, lean meat ratio and loin eye area were increased, but fat weight, fat percentage and back fat

thickness were decreased with reduction in dietary energy levels. From the fitting curve, the most suitable dietary energy

levels for best growth performance at body weights of 15

～

30 kg, 30

～

60 kg and 60

～

100 kg were 14.01, 13.15 and

12.98

MJ/kg,

respectively.

Using

lean

meat

ratio,

back

fat

thickness

and

loin

eye

area

to

represent

the

carcass

composition, the optimal dietary energy densities were 11.13, 11.36 and 11.71 MJ/kg at 15

～

30 kg, 30

～

60 kg and 60

～

100 kg, respectively.

(

Conclusion)

Optimum dietary energy levels were 13.55, 12.81 and 13.20 MJ/kg for a combination

of

growth performance and carcass composition.

Key words:

Digestive energy; Growth performance; Carcass composition;

Wujin

pigs

Wujin

pigs is a typical Chinese local breed in

Yunnan

province and its feeding is based on the availability of natural

resources in the local area.

Wujin

pigs grows slowly and its body fat is high, but its meat is very good, especially in its

Date recerved:

2007-12-22

Financial support:

Key Project of Yunnan Natural Science Foundation (2005C0008Z)

Author

information:

ZHANG

Xi,

professor,

major

in

animal

nutrition

and

feed

science.

E-mail

:

zhangxi_km@

?

Corresponding author:

GAO Shi-zheng, professor, major in animal nutrition. E-mail: gaoszkm@

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content of intramuscular fat which is higher than that in other breeds of pigs. Traditionally, it is an ideal material for

producing the high quality

Xuanwei

ham in China

[1-2]

. Efforts have been made to hybridize this Chinese local pigs breed

with

foreign

breeds

to

improve

growth

performance

and

to

obtain

the

best

carcass

traits,

but

there

has

been

limited

research in the traditional feeding model. To improve the feeding model, therefore, it is necessary to investigate the most

suitable dietary energy levels for

Wujin

pigs, based on the Chinese Feeding Standard for Local Pigs

[3]

and NRC (1998)

[4]

.

This study used fitting curves and fuzzy comprehensive evaluation to investigate dietary energy levels for best growth

performance and carcass composition.

1 MATERIALS AND METHODS

1.1 Experimental design

The experiment was designed by single factor random allotment. Ninety

Wujin

pigs with an initial live weight of

(

15±?

1

.

51) kg were divided into 5 dietary treatment groups based on different dietary energy content and crude protein

content (18%, 16% and 14%) at three growing finishing stages (15

～

30 kg, 30

～

60 kg , and 60

～

90 kg body weight).

1.2 Pigs and Housing

All experimental procedures were approved by the

Yunnan

Agricultural University Committee on Laboratory Animal

Care.

Groups

of

six

pigs

were

housed

in

one

pen

with

a

half

slatted

floor

in

an

insulated

but

unheated

shed

at

the

research station of

Yunnan

Agricultural University. The pigs were fed twice daily at 08:00 and 15:30, respectively.

1.3 Diets

The five dietary energy densities were derived from recommendations of the

Chinese

Feeding Standard for Local

Breed Pigs

[3]

(group III, DE: 12.98 MJ/kg) and the United States NRC (1998)

[4]

(group I, DE: 14.22 MJ/kg). The other

groups completed the series with increments of 0.62 MJ/kg; i.e., the dietary energy levels of group

Ⅰ

to group

Ⅴ

were

14.22,

13.60,

12.98,

12.36

and

11.74

MJ/kg,

respectively.

Composition

and

calculated

nutrient

contents

of

the

experimental diets are presented in Table 1.

1.4 Growth performance

The

feed

intake

was

recorded

daily.

The

pigs

were

weighed

monthly,

and

at

the

beginning

and

the

end

of

the

experiment. The average daily gain and the feed gain ratio were calculated.

1.5 Carcass composition

Six pigs from each group were slaughtered at 30, 60 and 100 kg body weight. The pigs were fasted for 24 h before

being slaughtered and weighed. Different parts of the carcass were separated and measured including loin eye area, back

fat

thickness,

lean

meat

weight,

fat

weight,

bone

weight,

skin

weight

so

that

the

slaughter

percentage,

lean

meat

percentage, fat percentage, the ratio of lean meat to fat were calculated

[4]

.

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1.6

Calculations and statistics

1.6.1 Statistical analysis

Significant differences and regression analyses were conducted with SAS and EXCEL software.

1.6.2 Model of fuzzy comprehensive evaluation

????

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Table 1

Composition and nutrient levels of diets

(DM basis, %)

Items

Ingredients

Corn

Wheat bran

Soybean meal

Fish meal

Soybean oil

CaHPO

4

Limestone

Met

Lys

NaCl

Premix

1)

Total

Nutrient levels

2)

DM

DE (MJ/kg)

3)

CP

NDF

ADF

Ca

TP

AP

Lys

1)

15

～

30 kg

Ⅰ

63.19

7.00

18.61

6.00

2.96

0.10

0.85

-

-

0.30

1.00

100.00

88.39

14.22

18.69

9.22

3.54

0.58

0.98

0.27

0.66

Ⅱ

62.46

10.00

19.16

5.00

0.90

0.20

0.90

-

0.08

0.30

1.00

100.00

88.97

13.60

18.74

10.32

3.94

0.55

0.97

0.28

0.64

Ⅲ

57.32

17.93

17.38

5.00

-

0.05

1.00

-

0.03

0.30

1.00

100.00

88.86

12.98

18.73

12.69

4.74

0.55

0.96

0.29

0.64

88.31

12.36

18.77

15.55

5.73

0.54

0.96

0.27

0.65

88.13

11.74

18.79

18.56

6.77

0.54

0.98

0.29

0.65

Ⅳ

48.31

27.93

15.90

4.80

-

0.20

0.90

-

0.67

0.30

1.00

100.00

Ⅴ

39.49

38.35

14.23

4.60

-

0.15

0.94

-

0.94

0.30

1.00

100.00

Ⅰ

88.47

14.22

16.48

9.28

3.46

0.45

0.77

0.20

0.55

88.94

13.60

16.44

10.86

3.98

0.47

0.79

0.21

0.56

68.67

7.00

14.40

5.00

2.90

-

0.72

-

-

0.30

1.00

100.00

Ⅱ

66.80

12.00

12.98

5.00

1.11

-

0.81

-

-

0.30

1.00

100.00

30

～

60 kg

Ⅲ

62.50

19.00

11.36

5.00

0.03

-

0.81

-

-

0.30

1.00

100.00

88.89

12.98

16.42

12.97

4.70

0.46

0.79

0.21

0.54

88.47

12.36

16.44

15.82

5.67

0.45

0.78

0.20

0.55

88.85

11.74

16.52

19.70

7.03

0.44

0.77

0.21

0.55

Ⅳ

53.79

29.00

9.54

5.00

-

0.01

0.80

0.57

-

0.30

1.00

100.00

Ⅴ

43.22

42.00

8.48

4.00

0.08

-

0.89

-

0.04

0.30

1.00

100.00

Ⅰ

88.43

14.22

14.28

9.38

3.41

0.37

0.69

0.14

0.46

88.88

13.60

14.25

10.96

3.93

0.36

0.68

0.13

0.44

73.79

7.00

10.93

3.50

2.70

-

0.75

-

0.02

0.30

1.00

100.00

Ⅱ

71.84

12.00

9.56

3.50

1.01

-

0.75

-

0.04

0.30

1.00

100.00

60

～

100 kg

Ⅲ

66.44

20.00

7.80

3.50

0.16

-

0.75

-

0.05

0.30

1.00

100.00

88.62

12.98

14.25

13.33

4.74

0.35

0.69

0.14

0.46

88.76

12.36

14.27

15.46

5.47

0.36

0.68

0.13

0.45

88.77

11.74

14.32

19.77

6.96

0.37

0.69

0.13

0.46

Ⅳ

59.00

27.62

6.56

3.50

-

0.50

0.96

0.50

0.06

0.30

1.00

100.00

Ⅴ

48.40

42.00

4.59

2.80

-

-

0.81

-

0.10

0.30

1.00

100.00

Premix provided the following per kilogram of diet: VA 8 267 IU; VD 22 480 IU; VE 66 IU; menadionine (as menadionine pyrimidinol bisulfite complex) 6.2 mg; VB

1

(thiamine) 3.31 mg; VB

2

(riboflavin) 10 mg; VB

6

(pyridoxine) 3.31 mg; VB

12

45

μ

g; D-calcium pantothenic acid 37 mg; niacin 66 mg; D-biotin 331

μ

g; folic acid 2.5 mg; VC 83

μ

g. Zn 127 mg; Fe 127 mg; Mn 20 mg; Cu 12.7

mg; I 0.80 mg; Se 0.3 mg.

2)

3)

Calculated values.

The values of digestive energy were obtained and calculated from the digestive energy values of each feed ingredient in The Database of Chinese Feeds (2007).