Livestock Research for Rural Development 28 (10) 2016 Guide for preparation of papers LRRD Newsletter

Citation of this paper

Feed intake, digestibility and N retention in Mong Cai pigs fed ensiled cassava (Manihot esculenta Cranz) root and protein-rich foliages

Vanhnasin Phoneyaphon and T R Preston1

Department of Animal Science, Faculty of Agriculture and Forest Resource
Souphanouvong University, Luang Prabang Province, Lao PDR
Vanhnasin83@gmail.com
1 Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria (CIPAV),
Carrera 25 No 6-62 Cali, Colombia

Abstract

The aim of the study was to determine the effect of three sources of protein (soybean meal, taro foliage (Colocasia esculenta (L.) Schott) silage and cassava foliage silage) on feed intake, digestibility and N retention in Mong Cai pigs fed ensiled cassava root as source of energy. Four male Mong Cai pigs with average live weight of 12 kg were allotted at random to 4 diets within a 4*4 Latin square design.

Feed intake, apparent digestibility coefficients of DM and crude protein, and N retention, were higher when the protein supplement was soybean meal compared with ensiled taro foliage, which in turn was better than ensiled cassava foliage or a mixture of ensiled taro and ensiled cassava foliage.

Key words: Colocasia esculenta, leaves, petioles, taro


Introduction

Lon Mong Cai (Mong Cai pig) is an indigenous breed that originated from Quang Ninh province, in northern Vietnam. The breed is very well adapted to the harsh conditions in the region and is known for its early puberty, good litter size and maternal ability. The Mong Cai have been shown to perform better than Large White sows when the diet was based on forages (Nguyen Van Lai 1998; Hoang Nghia Duyet et al 2006).

Taro is well-adapted to the Vietnamese climate and can grow almost everywhere with minimal maintenance, under either dry-land or wet-land conditions (Toan and Preston 2010). The leaves are rich in vitamins, minerals and are a good source of thiamin, riboflavin, iron, phosphorus and zinc, vitamin B6, vitamin C, niacin, potassium, copper and manganese.

The foliage of Taro appears to have more potential than cassava as a protein source for pigs (Preston 2006). It was reported that Taro leaves are rich in protein (21-26% of DM) while the petioles are rich in soluble carbohydrates (Hang and Preston 2009; Rodríguez and Preston 2009; Hang and Kien 2012). However, the plant contains oxalic acid present as calcium salts which form small crystals in all parts of this plant, and when consumed cause irritation in the mouth and throat epithelium (Miller 1929). Normally, the Taro leaves are cooked with rice or rice bran and cassava roots, in order to reduce the concentration of calcium oxalate before feeding them to pigs. Recent research in Vietnam and Cambodia showed that the oxalate problem could be avoided by ensiling the leaves with molasses or combining them with the petioles (Hang and Preston 2010; Chhay Ty et al 2007; Giang et al 2011).

Cassava (Manihot esculenta, Crantz) is extensively cultivated throughout the tropics and subtropical regions due to its ability to grow in diverse soil conditions and with minimal management (Wanapat 2003; Wanapat et al 2006). The root is composed almost entirely of easily digestible carbohydrate. However, it contains cyanogenic glucosides which are changed to hydrocyanic acid (HCN) by the action of the laminarase enzyme when roots are crushed or sliced (Wanapat et al 1999). This feature of the cassava root can be a constraint to its utilization for human consumption and for livestock feeding. Sun drying the sliced root or ensiling it after grinding have been shown to reduce the levels of cyanide to tolerable levels and that ensiling was a less costly procedure than sun-drying (Loc et al 1997).

The cassava root has minimal levels of protein (<3% in DM), thus using it as the basal diet requires major supplementation with this nutrient source. However, cassava root also has minimal levels of fiber. Considered together, these two features of cassava roots (low protein and low fiber) offer the opportunity to use locally available protein-rich foliage that otherwise have limited potential for use in conventional pig diets because of their content of fiber (Preston 2006).

Incorporation of the leaves of the cassava plant in cassava root diets has been studied by Phuc et al (1995, 1996). DM and N digestibility and N retention were better when the leaves were ensiled rather than sun-dried, but these criteria were reduced linearly as the cassava leaves replaced soybean meal as the source of protein.

The purpose of the present study was to compare foliage from Taro and from cassava, preserved by ensiling, as replacement for soybean meal in a cassava root basal diet fed to growing Mong Cai pigs.


Material and methods

Location and duration

The experiment was conducted in the Technology and Research Center, Nong Lam University, Vietnam from May to July, 2015.

Treatments, experimental design and feeds

Four female of Mong Cai Pigs (initial weight 12 kg) were used to compare four treatments arranged in a 4*4 Latin Square with 10 days per period: 5 days for adaptation and 5 days for collection of feed refusals, feces and urine (Table 1).

The treatments were:

Table 1. Layout of the experiment

Period/Pigs

1

2

3

4

1

SBM

TS

CFS

TSCFS

2

TS

CFS

TSCFS

SBM

3

CFS

TSCFS

SBM

TS

4

TSCFS

SBM

TS

CFS

Animals and housing

Four male Mong Cai pigs with average live weight of 12 kg were housed individually in metabolism pens made from local materials and designed to separate feces and urine. They were bought from a pig farm in Nong Lam Province, Vietnam. They were vaccinated against swine fever and were treated against round worms with Ivermectin (1 ml/20kg LW), before starting the experiment. The pigs had free access to water through nipple drinkers.

Photo 1. Housing made from local materials Photo 2. Mong Cai pigs in individual pens
Feeds and feeding

Cassava roots were bought in the market, chopped and ground by machine into small pieces (1 mm length) and ensiled in sealed 30 liter plastic bags for 14 days before being fed to the pigs. Cassava foliage (leaves and petioles) (bitter variety) and Taro leaves and petioles were collected from plots in the Research and Technology Transfer Center in Nong Lam University. They were chopped into small pieces (1-2cm length) and packed tightly into 30 liter plastic bags which were sealed and stored for 14 days before feeding. Soybean meal was collected from a Feed Factory in Ho Chi Minh City.

The ingredients in each diet were mixed together according to the proportions shown in Table 2 taking account of the values for DM and crude protein in the diet ingredients (Table 3). The diets were offered twice daily at 6:30am and 4:30pm, the amount being based on an offer level of 40g DM/kg live weight, but with daily adjustments to avoid refusals. Water was supplied ad libitum.

Table 2. Composition of the diets (% as DM)

Ingredient

SBM

TS

CFS

TSCFS

Cassava root silage

77

35

53

44

Soybean meal

23




taro foliage silage


65


32

Cassava foliage silage



47

24

Total

100

100

100

100



Table 3. Chemical composition of the diet ingredients

Cassava root
silage (CRS)

Taro foliage
silage (TS)

Cassava foliage
silage (CFS)

Soybean
meal (SBM)

Dry matter,%

28.7

14.4

24.3

88.4

CP in the DM,%

3.00

17.8

23

46.1

CF %

3.5

13.2

16.8

8.02

NDF %

34.3

33.8

41.5

13.7

Ca %

1.6

10.3

25.1

0.7

P %

1.2

2.9

3.3

0.6

Oxalic acid, %

-

0.30

-

-

Sources: Hang (1998); Hang and Preston (2010); Inthapanya (2006).

Measurements and data collection

Live weight was recorded in the morning before feeding at the beginning and at the end of each period. Feed refusals, feces and urine were collected daily during the 5 days of the collection period, and stored in the refrigerator at (4°C). To prevent loss of N from the urine, 20ml of dilute sulphuric acid (10% concentrated sulphuric acid + 90% distilled water) were added daily to each urine collection bucket. At the end of each period, samples were mixed together and ground (feeds and feces) with a coffee grinder.

Chemical analysis

AOAC (1990) methods were followed for DM and N analyses of sub-samples of feeds offered and refused and of feces; and for N in urine.

Statistical analysis

The data were analyzed by the General Linear Model option in the ANOVA program of the Minitab (2000) software. Sources of variation in the model were: pigs, treatments, periods and error.


Results and discussion

DM intake, digestibility and N retention

DM intake was highest for the diet supplemented with soybean meal and lowest for diets supplemented with ensiled cassava foliage alone. Ensiled Taro foliage supported higher intakes than ensiled cassava foliage with intermediate values for the mixed silages of Taro and cassava foliages (Table 4; Figure 1).

Table 4. Mean values for intakes of DM by Mong Cai pigs fed ensiled cassava root supplemented with soybean meal, Taro foliage silage, cassava foliage silage or a combination of Taro and cassava foliage silages

SBM

TS

TSCFS

CFS

SEM

p

DM intake, g/day







ECR

347

145

178

207



SBM

104

-

-

-



TFS

-

265

84

-



CFS

-

-

134

176



Total

451 a

412 ab

402 ab

384 b

16.8

0.001

Intake, g/kg LW

35.0 a

33.6 b

31.8 c

30.9 d

0.179

0.001

Crude protein, % in DM

13.0

12.5

12.7

12.2



Figure 1. Effect of soybean meal, Taro foliage silage, cassava foliage silage and mixtures of the two silages on DM intake of Mong Cai pigs fed ensiled cassava root as the basal diet
Apparent digestibility coefficients and N retention

The apparent digestibility coefficients of DM and crude protein were highest for cassava root supplemented with soybean meal and lowest when ensiled cassava foliage was the only protein supplement; ensiled Taro foliage was better than ensiled cassava foliage with intermediate values for the mixed silages of Taro and cassava foliage (Table 5; Figures 2 and 3). Values for N retention followed the same pattern (Figures 4 and 5).

Table 5. Mean values for apparent digestibility and N balance by Mong Cai pigs fed ensiled cassava root supplemented with soybean meal, Taro silage, cassava foliage silage and combination of both forage silages

SBM

TF

TF-CF

CF

SEM

p

Apparent digestibility, %







Dry matter

73.0 a

64.4 b

60.3 c

61.2 c

0.30

<0.001

Crude protein

58.7 a

51.6 ab

51.2 ab

46.7 b

2.08

0.001

N balance, g/day

Intake

9.39 a

8.26 ab

8.19 ab

7.47 b

0.33

<0.001

Feces

1.46 b

1.72 ab

1.89 a

1.90 a

0.09

0.003

Urine

1.82 b

1.69 b

2.16 a

1.77 b

0.09

0.003

N retention

g/day

6.11 a

4.85 b

4.13 bc

3.80 c

0.19

<0.001

% of N intake

64.8 a

58.7 b

50.7 c

51.5 c

0.70

<0.001

% of N digested

76.9 a

74.1 a

65.6 c

68.7 b

0.79

<0.001

abc Means without common superscript are different at p < 0.05



Figure 2. Effect of soybean meal, Taro foliage silage, cassava foliage silage and mixtures of the two silages on DM digestibility by
Mong Cai pigs fed ensiled cassava root as the basal die
Figure 3. Effect of soybean meal, Taro foliage silage, cassava foliage silage and mixtures of the two silages on crude protein digestibility
by Mong Cai pigs fed ensiled cassava root as the basal diet




Figure 4. Effect of soybean meal, Taro foliage silage, cassava foliage silage and mixtures of the two silages on N retention by Mong
Cai pigs fed ensiled cassava root as the basal diet
Figure 5. Effect of soybean meal, Taro foliage silage, cassava foliage silage and mixtures of the two silages on N retention as percent of digested N by Mong Cai pigs fed ensiled cassava root as the basal diet

The results of this experiment indicate that silage made from the leaves and petioles of Taro is superior to ensiled cassava foliage (leaves and petioles) and only slightly inferior to soybean meal to provide all the protein needed to balance the energy in a basal diet of ensiled cassava root. These findings are in agreement with other reports that have demonstrated a positive role for ensiled Taro foliage as a protein source to supplement rice byproducts in diets for growth (Chay Ty et al 2007; Hang and Preston 2010; Manivanh and Preston 2011) and reproduction in pigs (Malavanh et al 2008) and growth in ducks (Giang and Preston 2011).


Conclusions


Acknowledgements

This research was done by the senior author as part of the requirements for the MSc degree in Animal Production "Improving Livelihood and Food Security of the people in Lower Mekong Basin through Climate Change Mitigation" in Cantho University, Vietnam. The authors would like to express sincere gratitude to the MEKARN II program, financed by Sida (Swedish International Development Agency) for supporting this research. We are also grateful to Le Thuy Binh Phuong and staff and of the Research and Technology Transfer Center, Nong Lam University, for providing infrastructure support.


References

AOAC 1990 Official methods of analysis. Association of Official Analytical Chemists, Arlington, Virginia, 15th edition, 1298 pp.

Chhay Ty, Borin K, Preston T R and MeaSokveasna 2007 Intake, digestibility and N retention by growing pigs fed ensiled or dried Taro (Colocasiaesculenta) leaves as the protein supplement in basal diets of rice bran/broken rice or rice bran/cassava root meal. Livestock Research for Rural Development.Volume 19, Article #137.Retrieved, from http://www.cipav.org.co/lrrd/lrrd19/9/chha19137.htm

Giang N T and Preston T R 2011 Taro (Colocacia esculenta) silage and water spinach as supplements to rice bran for growing pigs. Livestock Research for Rural Development.Volume 23, Article #45 Retrieved August 24, 2016, from http://www.lrrd.org/lrrd23/3/gian23045.htm

Hang D T 1998 Digestibility and nitrogen retention in fattening pigs fed different levels of ensiled cassava leaves as a protein source and ensiled cassava root as energy source. Livestock Research for Rural Development. Volume 10, Article #24. http://www.lrrd.org/lrrd10/3/hang1.htm

Hang D T and Kien N T 2012 Taro (Alocasia odora (C) Koch, Xanthosoma nigra (vell) Stellfeld and Colocasia esculenta (L) schott) in Central Vietnam: biomass yield, digestibility and nutritive value. Livestock Research for Rural Development. Volume 24, Article #222. http://www.lrrd.org/lrrd24/12/hang24222.htm

Hang D T and Preston T R 2009 Taro (Colocacia esculenta) leaves as a protein source for growing pigs in Central Viet Nam. Livestock Research for Rural Development. Volume 21, Article #164. http://www.lrrd.org/lrrd21/10/hang21164.htm

Hang D T and Preston T R 2010 Effect of processing Taro leaves on oxalate concentrations and using the ensiled leaves as a protein source in pig diets in central Vietnam.Livestock Research for Rural Development. Volume 22, Article #68. Retrieved August 24, 2016, from http://www.lrrd.org/lrrd22/4/hang22068.htm

Hang D T, Thanh Tra T T, Loc N T, Hai P V, Qui N D, Ngoc Linh H L and Ngoan L D 2014 Taro (Colocasia esculenta (L) Schott) and banana pseudo-stem as energy sources for pigs in Central Vietnam.Livestock Research for Rural Development. Volume 26, Article #109. Retrieved August 24, 2016, from http://www.lrrd.org/lrrd26/6/hang26109.html

Hoang Nghia Duyet, Truong Thi Thuan and Nguyen Duc Son 2006 the effect of sweet potato stem levels in the diet onproductivity of Mong Cai sows. Science & Technology Journal of Agriculture & Rural Development, No 6(2003), p.707, from: http://www.mekarn.org/proprf/duyet.htm.

Inthapanya S, Preston T R and Leng R A 2016 Ensiled brewers’ grains increased feed intake, digestibility and N retention in cattle fed ensiled cassava root, urea and rice straw with fresh cassava foliage or water spinach as main source of protein.Livestock Research for Rural Development. Volume 28, Article #20. Retrieved August 24, 2016, from http://www.lrrd.org/lrrd28/2/sang28020.htm.

Loc N T, Ogle B and Preston T R 1997 Cassava root silage for crossbred pigs under village conditions in Central Vietnam. Livestock Research for Rural Development. Volume 9, Article #14. http://www.lrrd.org/lrrd9/2/loc922.htm.

Malavanh C, Preston T R and Ogle B 2008 Effect of replacing soybean meal by a mixture of taro leaf silage and water spinach on reproduction and piglet performance in Mong Cai gilts.Livestock Research for Rural Development. Volume 20, supplement. Retrieved August 9, 2016, from http://www.lrrd.org/lrrd20/supplement/mala2.htm.

Manivanh N and Preston T R 2011 Taro (Colocacia esculenta) silage and rice bran as the basal diet for growing pigs; effects on intake, digestibility and N retention.Livestock Research for Rural Development. Volume 23, Article #55. Retrieved August 9, 2016, from http://www.lrrd.org/lrrd23/3/noup23055.htm

Miller C D 1929 Food Values of Breadfruit, Taro Leaves, Coconut and Sugar Cane. Bernice P. Bishop Museum. Bulletin 64. Honolulu, Hawai.

MINITAB 2000 Minitab reference Manual release 13.31. User’s guide to statistics. Minitab Inc, USA

Nguyen Van Lai 1998 On-farm comparison of Mong Cai and Large White pigs fed ensiled cassava root, rice bran and duckweed. Livestock Research for Rural Development (10) 3, from: http://www.lrrd.org/lrrd10/3/lai103.htm.

Phuc B H N, Ogle R B, Lindberg J E and Preston T R 1996 The nutritive value of sun-dried and ensiled cassava leaves for growing pigs. Livestock Research for Rural Development. Volume 8, Article #30. http://www.lrrd.org/lrrd8/3/phuc83.htm.

Preston T R 2006 Forages as protein sources for pigs in the tropics. In: Proceeding of a Workshop on forages for Pigs and Rabbits. http://mekarn.org/proprf/preston.htm

Rodríguez L and Preston T R 2009 A note on ensiling the foliage of New Cocoyam (Xanthosoma sagittifolium). Livestock Research for Rural Development. Volume 21, Article #183. http://www.lrrd.org/lrrd21/11/rodr21183.htm

Toan N H and Preston T R 2010 Taro as a local feed resource for pigs in small scale household condition. Livestock Research for Rural Development. Volume 22, Article #152. http://www.lrrd.org/lrrd22/8/toan22152.htm

Wanapat M 2003 Manipulation of cassava cultivation and utilization to improve protein to energy biomass for livestock feeding in the tropics. Asian-Australasian Journal of Animal Science, v.16, p.46-52.

Wanapat M, Pimpa O, Sripuek W, Puramongkol T, Petlum A, Boontao U, Wachirapakorn C, Sommart K and Brooker J D 1999 Cassava hay: an important on-farm feed for ruminants. In: Tannins in livestock and human nutrition. Proceedings.Adeleaide: CABI International, p.71-74.

Wanapat M, Promkot C and Wanapat S 2006 Effect of cassava-urea pellet as a protein source in concentrate on ruminal fermentation and Digestibility in Cattle. Asian-Australasian Journal of Animal Science, v.19, p.1004-1009.


Received 7 July 2016; Accepted 13 September 2016; Published 1 October 2016

Go to top