Livestock Research for Rural Development 15 (9) 2003

Citation of this paper

The use of ensiled cassava leaves in diets for growing pigs. 3. The effect of graded levels of palm oil on performance traits 

Chhayty, T R Preston, J Ly* and Keo Sath


University of Tropical Agriculture Foundation
Chamcar Daung, PO Box 2423, Phnom Penh 3, Cambodia

chhayty@utafoundation.org
regpreston@utafoundation.org
* Visiting researcher at UTA, Present address: Swine Research Institute,
PO Box 1, Punta Brava, La Habana, Cuba
jlyca@yahoo.com

 

 

Abstract

 

Sixteen Mong Cai*Large White female and castrate male pigs weighing on average 16 and 12 kg, respectively, were used in a 4*2 factorial arrangement to study the effect of graded levels of crude palm oil (0, 5, 10 and 15%) and sex (castrate male or female) on performance traits with a basal diet formulated with cassava leaf silage, fish meal and broken rice. The pigs were housed in individual pens and allotted at random to the four experimental diets. The feeding trial lasted for 16 weeks (112 days) and was analysed according to three periods (0-8; 9-16 and overall 0-16 weeks).

 

There was no significant interaction between treatment and sex. Voluntary DM intake tended to increase with level of palm oil and to be less for castrate male pigs than for females. Level of palm oil had no effect on daily live weight gain but tended to improve the feed conversion ratio.

 

There appear to be no advantages in terms of pig growth and feed conversion from adding up to 15% palm oil in a diet based on ensiled cassava leaves as the main protein source.

 

Key words: Crude palm oil, ensiled cassava leaves,  live weight,  pigs, sex
 


Introduction

In view of the predicted world shortage of cereal grains because of competing needs for the expanding human and livestock populations (Leng 2002), there is an urgent need for research to develop alternative feed resources especially for pigs and poultry. 

Cassava (Manihot esculenta Crantz) is a widely grown crop in the tropical regions of Africa, Latin American and Asia (Calpe 1992). The leaves are high in protein (Ravindran and Ravindran  1988) and are a readily available product at the time of harvesting the root. Several reports have shown that cassava leaf protein is rich in lysine but low in sulphur amino acids (Eggum 1970; Gomez and Valdivieso 1984).

Palm oil (Elaeis guineensis Jacq.), palm fruit and by-products of palm oil extraction have been shown to have a high feeding value for growing pigs, and can replace completely the cereal component of the diet (Ocampo et al 1990a,b; Ocampo 1994a,b).  An advantage of using vegetable oil as the energy source in pig diets is because it has a very high energy content and no fibre. This creates opportunities for using it as a supplement in diets in which the main source of protein is the leaf biomass from trees and shrubs (Preston and Murgueitio 1992). 

The aim of the present study therefore was to determine the effect of graded levels of palm oil on performance traits of pigs fed diets based on ensiled cassava leaves.  The feeding trial was a follow up to  earlier experiments on digestibility and N retention in pigs fed similar diets (Chhaty et al 2003a,b).


Material and methods

Location and climate

This experiment was carried out in the ecological farm of the University of Tropical Agriculture Foundation (UTA), located in Chamcar Daung, at the outskirts of Phnom Penh City, Cambodia, from 16 June to 3 October 2002. The temperature in the area was about 35 ºC in the middle of the day during the experiment.  

Experimental animals, treatments and design

Eight female and eight castrated male crossbred (Mong Cai*Large Wite) pigs with an average initial body weight of 16.0 kg (females) and 12.0 kg (males) were allocated to a 4*2 factorial arrangement to study the effects of level of supplementary crude palm oil (0, 5, 10 and 15%) and sex.  The pigs were housed in individual pens of 1.2m x 1.4m. The pens had a concrete floor with brick walls and were provided with feeders and drinking nipples. The pigs were vaccinated against Salmonella and Swine cholera disease. The pigs were adapted to the feeds and the housing for a 14 day period before starting the experiment. The pigs were allocated to 2 blocks according to sex and body weight. The nutritional treatments were applied at random within each block. 

Feeding and management

The diets were formulated to contain 16% crude protein (N*6.25) in dry basis, with cassava leaf silage as the main protein source and a low level of fish meal to compensate for the low methionine content of the cassava leaves (Table 1).


Table 1. Characteristics of the diets (percentage in DM, except for DM% which is on “as-fed” basis)

 

Ensiled cassava leaves

Refined palm oil, %

0

5

10

15

Ingredients,%

 

 

 

 

 

Ensiled cassava leaves

-

45.0

45.0

45.0

45.0

Refined palm oil

-

-

5.0

10.0

15.0

Fishmeal

-

3.0

4.0

5.0

6.0

Broken rice

-

50.0

44.0

38.0

32.0

Sugar palm syrup

-

0.5

0.5

0.5

0.5

Vitamins and minerals#

-

1.5

1.5

1.5

1.5

Analysis (%)

 

 

 

 

 

Dry matter

50.7

68.4

68.6

68.5

69.2

Ash

14.1

8.2

8.5

8.9

9.2

Organic matter

85.9

91.8

91.5

91.1

90.8

NDF

47.0

21.1

21.1

21.1

21.1

Crude fibre

35.3

15.9

15.9

15.9

15.9

NFE

11.7

52.1

46.4

40.6

34.8

Crude fat

14.3

7.6

13.0

18.4

23.7

Crude protein (Nx6.25)

24.5

16.1

16.2

16.3

16.4

GE, MJ/kg DM##

20.6

18.9

20.1

21.3

23.6

#According to NRC (1998) recommendations

## Calculated according to Nehring and Haenlein (1973). For further details, see text


Leaves were harvested from 4 to 5 month-old cassava plants grown for root production in farmers’ fields in Kandal province. The cassava leaves (after removing stems and petioles) were sun-dried for half a day before being chopped into small pieces and ensiled with 5% sugar palm syrup and stored in sealed plastic containers for 30 days before feeding. Crude palm oil was bought from the Palm oil plantation in Sihanouk Ville, Cambodia. Broken rice is a by-product of Cambodian rice mills and was available in the local market as was the fish meal and sugar palm syrup.

The supplements (crude palm oil, broken rice, mineral/vitamin premix, sugar palm and fish meal) were mixed together with the cassava leaf silage before feeding. The pens were cleaned every day after collecting the feed residue. The pigs were adapted to the diet and pen for two weeks and thereafter were fed the test diets divided in 3 meals daily.

Data collection and analyses

The pigs were weighed every week. Individual daily weight gains were calculated by the regression of live weight on time in days. Individual feed intake was recorded daily from weight of fresh material offered minus the residue collected the next morning. Feed conversion ratio was calculated from individual daily DM intake and live weight gain. Feed samples were taken weekly, dried and bulked prior to taking sub-samples for chemical analysis. The analytical methods were those described in Chhayty et al (2003a). 

Statistical analysis

Mean values for effects of supplementation on weight gain, feed intake and feed conversion were compared using the general linear model (GLM) option of the analysis of variance, determined with software of Minitab, release 12.2. The sources of variation in the ANOVA were the dietary treatments, sex and error.
 

Results

Health 
 

During the experiment the animals were generally in good health but feed intake decreased in the females when they reached 50kg of body weight due to occurrence of oestrous.

Daily feed intake

There was no effect of the level of palm oil on the daily feed intake during the 0-8 week period (Table 2). In the second period (9-16 weeks) feed refusals were observed in all treatments and feed intake, expressed on a live weight basis,  was reduced as the level of palm oil was increased. Females ate more DM per day than males but this difference was not apparent when intake was expressed as percent of live weight. The same was true of the differences between blocks.


Table 2.  Feed DM intake of female and male pigs fed graded level of palm oil and 45% of cassava leaf silage in diet DM 

 

 

Sex

Crude palm oil

Fem.

Male

SEM

Prob.

0

5

10

15

SEM

Prob.

0-8 weeks

 

 

 

 

 

 

Total, g/d

894

672

45.9

0.01

695

779

763

894

64.9

0.27

Cassava, g/d

335

246

24.7

0.04

266

320

256

322

34.9

0.45

% LW

4.2

4.2

0.11

0.76

4.29

4.41

3.91

4.09

0.15

0.21

9-16 weeks

 

 

 

 

 

 

 

 

 

 

Total, g/d

1387

1233

50.8

0.07

1231

1392

1240

1377

71.8

0.31

Cassava, g/d

499

448

24.6

0.19

460

527

447

460

34.8

0.42

 % LW

3.4

3.56

0.12

0.41

3.78

3.73

3.36

3.07

0.17

0.06

0-16 weeks

 

 

 

 

 

 

 

 

 

 

Total, g/d

1166

976

40.0

0.01

985

1113

1019

1164

56.7

0.19

Cassava,  g/d

431

359

19.5

0.04

375

436

363

407

27.5

0.31

% LW

3.82

3.89

0.09

0.67

4.06a

4.09a

3.64b

3.59b

0.13

0.05


Growth and feed conversion

There was a strong indication (P=0.09) that  the female pigs grew slightly faster than castrated males during the first 8 weeks, but this was not apparent over the overall 16 week period (Table 3).  Pigs receiving the 15% level of palm oil grew faster than those with 0, 5 or 10% oil during the first 8 weeks, and there was a tendency (P=0.11) to maintain this superiority over the overall 16 week period. There were no differences due to sex or oil supplementation in the 9 to 16 week period.  Growth rate was linearly related (R2=0.71) with DM feed intake (Figure 1).

 

Table 3.  Mean values for live weight gain of pigs fed graded levels of palm oil in a basal diet with 45% (in DM) of cassava leaf silage

 

Sex

Crude palm oil, % in diet DM

 

Female

Male

SEM

Prob.

0

5

10

15

SEM

Prob.

Live weight, kg

 

 

 

 

 

 

 

 

Initial

16.0

12.0

-

-

12.3

12.9

14.7

15.8

-

-

Final

53.2

46.2

 

 

42.8

50.1

48.6

57.1

 

 

Live weight gain, g/d

 

 

 

 

 

 

 

0-8 weeks

351

298

19.7

0.09

264c

334b

297bc

404a

27.9

0.03

9-16 weeks

362

363

26.6

0.97

328

389

353

379

37.6

0.67

0 – 16 weeks

367

352

22.1

0.64

312

376

340

409

31.2

0.22

abc Means within main effects without letter in common are different at P<0.05

 

Figure 1.  Relationship between live weight gain and feed intake of growing pigs fed a basal diet
of ensiled cassava leaves, broken rice and graded levels of palm oil



Males had better feed conversion than females in the 9-16 week period and overall from 0 to 16 weeks. There was no apparent effect of level of palm oil on this trait (Table 4). Pigs in block 2 had feed conversion ratio better than those in block 1 in the 0-8 weeks and overall  0-16 weeks periods.


Table 4. Mean values for feed DM conversion ratio in pigs fed graded levels of palm oil and ensiled cassava leaves as 45% of  diet DM

 

Sex

Crude palm oil, % in diet DM

Female

Male

SEM

Prob.

0

5

10

15

SEM

Prob.

0-8 weeks

2.6

2.3

0.15

0.18

2.7

2.31

2.5

2.2

0.20

0.46

9-16 weeks

3.8

3.4

0.11

0.02

3.8

3.6

3.5

3.7

0.15

0.62

0-16 weeks

3.2

2.8

0.14

0.04

3.2

3.0

2.9

2.8

0.17

0.56

 

Conversion of gross and digestible energy to live weight was calculated on the basis of the conversion indices proposed by Nehring  and Haenlein  (1973) and the digestibility data reported by Chhaty et al (2003a). These parameters were poorer in females compared with castrate males in periods 9 to16 and overall from 0 to 16 weeks (Table 5).  They were also poorer for the 15% oil level, compared with 0, 5 or 10% added oil,  in the 9 to 16 week period. From 0 to 8 weeks and overall from 0 to 16 weeks oil level had no effect on energy conversion. Differences between blocks for energy conversion reflected differences in DM conversion rates. 

 

Table 5. Mean values for gross and digestible energy conversion of pigs fed ensiled cassava leaves and crude palm oil

 

Sex

Crude palm oil

 Energy, MJ/ kg gain

Female

Male

SEM

Prob.

0

5

10

15

SEM

Prob.

0-8 weeks

 

 

 

 

 

 

 

 

 

 

GE

53.3

47.2

3.09

0.20

50.1

46.3

52.9

51.6

4.37

0.74

DE

39.0

34.6

2.24

0.19

37.2

34.2

38.0

37.8

3.17

0.81

9-16 weeks

 

 

 

 

 

 

 

 

 

 

GE

80.3

71.4

2.26

0.02

71.0

71.7

73.9

86.9

3.20

0.02

DE

58.8

52.3

1.65

0.02

52.7

53.0

53.1

63.6

2.34

0.02

0-16 weeks

 

 

 

 

 

 

 

 

 

 

GE

66.4

58.3

2.46

0.04

60.0

59.3

63.1

66.8

3.48

0.45

DE

48.7

42.7

2.23

0.04

44.5

43.8

45.3

49.0

2.53

0.51

 

Discussion

 

Increasing the digestibility energy content of pig diets through fat addition has been showed have a variety of effects on performance of pigs, including a decrease, no effect or an improvement (Allee et al 1976; Adams and Jensen 1984, 1987; Chiba et al 1985; Howard et al 1990; Brumm and Peo 1994).  Similarly,  in the study by Olayiwola Adeola and Bajjalieh (1997) weight gain was improved in pigs fed a high-oil maize compared with regular maize; yet in another study, Nordstrom et al (1972) reported that high-oil maize (6.7 to 8.7% ether extract) had no beneficial effect on weight gain compared with regular maize.   All these studies used basal diets of cereals. According to the study of Fetuga et al (1975), addition of crude palm oil from 2 to 10% in the diets had no significant effect on performance. Another study in Malaysia, using palm oil from 5 to 30%, showed no effect of level of oil, but the level of palm oil of 10% was superior to the cereal control and feed conversion was improved 17% (Devendra 1977).

 

The two recent reports on oil addition to forage-based diets indicated a reduction in digestibility when the basal diet was water spinach Prak Kea et al (2003), or ensiled casava leaves (Chhayty et al 2003a).  The implication from these findings is that the added energy from the oil is used inefficiently for tissue growth, according to the results of the present experiment and of Chhayty et al (2003a),  or that the high level of oil reduces the utilization of other dietary nutrients (Prak Kea et al 2003).  Neither of these explanations is supported by the work of Ocampo with high levels of palm oil (Ocampo et al 1994a), palm oil by-products (Ocampo et al 1990a,b)  or palm fruit (Ocampo 1994b).  Results in all these studies showed that the energy in the oil was used highly efficiently with better DM feed conversion in the diets containing palm oil, palm fruit or palm by-products, compared with control cereal-based diets. The major difference between the diets used by Ocampo and his colleagues and those in the present experiment (and the experiment of Prak Kea et al 2003) is that solvent extracted soya bean meal supplied the major part of the protein in the former case, while in the latter the protein was mainly from green plant tissue.

 

The results for the control diet (45% DM as ensiled cassava leaf silage, 50% broken rice and 3% fish meal) were encouraging from the point of view of DM conversion (3.2) even though the growth rate (from 12 to 43 kg) was rather low (312 g/day).



Conclusion

The results of the current study indicate that moderate growth rates (312 g/day) and acceptable feed DM conversion ratios (3.2) can be obtained in diets  for young growing pigs containing 45% of ensiled cassava leaves (DM basis), but that there are no benefits in performance to be gained  from adding palm oil to increase the energy density.

More research is needed to elucidate possible interactions between the high level of palm oil and the nature of the rest of the diet and especially the protein component in pig diets. 
 

Acknowledgments

The present experiment is part of a study on the use of ensiled cassava leaves and palm oil in pigs, supported by the MEKARN project financed by the SIDA-SAREC Agency, and was presented as partial requirement for the MSc degree at SLU, Uppsala, Sweden.  The authors express their gratitude to all the personal of the Ecological Farm, of the University of Tropical Agriculture Foundation, for help with the experiment, especially Mr. Keo Saeth for his assistance in taking care of the animals. Thanks are also expressed to Mr. Pok Samkol for analytical assistance in the laboratory of the Ecological Farm.


 

References

 

Adams K L and Jensen A H  1984 Comparative utilization of in seed fats and the respective extracted fats by the young pig. J. Anim. Sci. 59:1557

 

Adam K L and  Jensen H 1987 high-fat maize in diets for pigs and sows. Anim. Feed Sci. Technol. 17: 201

 

Allee G L,  Koch B A and Hines R H 1976 Effect of fat level and calorie protein ratio on performance of finishing pig. J. Anim. Sci. 42: 1349 (Abstr.)

 

Brumm M C and Peo Jr E R 1994 Effect of fat source in receiving diets and reduced natural temperature on commingled feeder pig performance. J. Anim. Sci. 72: 1522

 

Calpe C 1992 Root, tubers and plantains: recent trends in production trade and use. In: Machin F, Nyvild S (Ed.), Root, tuber, Plantains and Bananas in Animal Feeding. FAO Animal Production and Health Paper 95, pp. 11-25

 

Chiba L I,  Peo Jr E R, Lewis A J, Brumm M C, Fritschen R D and Crenshaw J D 1985 Effect of dietary fat on pig performance and dust levels in modified-open-front and environmentally regulated confinement buildings. J. Anim. Sci. 61: 763

 

Chhay Ty, Preston T R  and  Ly J 2003a: The use of ensiled cassava leaves in diets for growing pigs. 1.     The effect of graded levels of palm oil on N digestibility and N balance;  Livestock Research for Rural Development (15) 7 Retrieved, from http://www.cipav.org.co/lrrd/lrrd15/7/chha157.htm

 

Chhay Ty,  Preston T R and Ly J  2003b:  The use of ensiled cassava leaves in diets for growing pigs. 2. The influence of type of palm oil and cassava leaf maturity on digestibility and N balance for growing pigs.  Livestock Research for Rural Development (15) 8 Retrieved, from http://www.cipav.org.co/lrrd/lrrd15/8/chha158.htm

 

Devendra C 1977 Utilization of Feedingstuff from the oil palm. In: Proc. Symp. Feedingstuff for Livestock in South East Asia p 116-131

 

Eggum O L 1970 The protein quality of cassava leaves. Br. J. Nutr. 24, 761-769

 

Fetuga B L, Babatunde G M and Oyenuga U L 1975 The effect of varying the level of palm oil in a constant high protein diet on performance and carcass characteristics of the growing pig. Ef. Afr. Agric. Ror. J. 40: 264-270

Gomez G and Valdivieso M 1984 Cassava for animal feeding: effect of variety and plant age on production of leaves and roots. Anim. Feed Sci. Technol. 11 49-55

Howard K A, Forsyth D M  and  Cline T R 1990 The effect of an adaptation period to soybean oil additions in the diets of young pigs. J. Anim. Sci. 68:678

 

Leng R A 2002 Future direction of animal protein production in a fossil fuel hungry world.  Livestock Research for Rural Development  (14) 5: http://www.cipav.org.co/lrrd/lrrd14/5/leng145.htm

Nehring K and Haenlein G F W 1973 Feed evaluation and ration calculation based on net energy fat Journal of Animal Science 36: 949-964

Nordstrom J W,   Behrends B R,   Meade R J and Thompson E H 1972 Effect of feeding of high oil corn to growing-finishing swine. J. Anim. Sci. 35:357

NRC 1998 Nutrient Requirement of Swine. National Academic of Science Press. Washington DC

Ocampo A, Lozano E and Reyes E 1990a Utilizacion de la cachaza de palma africana como fuente de energia en el levante, desarrollo y ceba de cerdos. Livestock Research for Rural Development (2) 1: http://www.cipav.org.co/lrrd/lrrd2/1/ocampo.htm

Ocampo A, Castro C and Alfonso L 1990b Determinacion del nivel optimo de proteina al utilizar cachaza de palma africana como fuente de energia en raciones para cerdos de engorde. Livestock Research for Rural Development (2) 2: http://www.cipav.org.co/lrrd/lrrd2/2/ocampo.htm

Ocampo A 1994a Raw palm oil as the energy source in pig fattening diets and Azolla filiculoides as a substitute for soya bean meal. Livestock Research for Rural Development (6) 1: http://www.cipav.org.co/lrrd/lrrd6/1/ocampo2.htm

Ocampo A 1994b Efecto del nivel de pulidura de arroz en una dieta basada en el fruto entero de palma africana para el engorde de cerdos. Livestock Research for Rural Development  (6) 2: http://www.cipav.org.co/lrrd/lrrd6/2/ocampo.htm

Olayiwola Adeola and Bajjalieh N L  1997 Energy Concentration of High-Oil Corn Varieties for pigs, J. Anim. Sci. 1997. 75:430-436
 

Preston T R and Murgueitio E 1992 Strategy for sustainable livestock production in the tropics. Condrit Ltda, Cali Colombia pp 89

 

Prak Kea, Preston T R and Ly J 2003 Feed intake, digestibility and N retention of a diet of water spinach supplemented with palm oil and / or broken rice and dried fish for growing pigs.  Livestock Research for Rural Development (15) 8 http://www.cipav.org.co/lrrd/lrrd15/8/kea158.htm

Ravindran V and Ravindran G 1988 Changes in the nutritional composition of cassava (Manihot esculenta Crantz) leaves during maturity. Food Chemistry 27:299-239


Received 30 May 2003; Accepted 19 August 2003

 Go to top