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The use of cassava broiler diets in Côte d'Ivoire: Effects on growth performance and feed costs


Materials and methods
Results and discussion
Acknowledgment
References

Y.O. Tiémoko

In recent years, poultry farming has increased throughout the world, especially in developing countries. According to the projections for the year 2000, overall world production of poultry will increase twofold, while the increase in developing countries alone will be threefold. Although poultry farming supplies the populations in large urban centres with animal proteins, it should be acknowledged that this form of farming is very expensive and depends mainly on imported inputs. This form of rearing essentially requires chicks from selected stocks and whole feeds made from raw materials which are mainly imported.

There is a pressing need to explore the use of local foodstuffs, hitherto underexploited by poultry farmers in order to reduce feed costs and the dependence of local production on imports. Among the many products which could be used to develop feed for poultry, Cassava is of special importance.

Cassava has a high production potential and can adapt to different types of soils. It is an energy source which could take the place of maize or other cereals used far feeding poultry in tropical Africa. Cassava roots can be used to make flour with an energy value of more than 3000 kcal of metabolizable energy per kg (Müller and Chou 1974, Stevenson and Jackson 1983, Kirchgessner 1985). Cassava tuberous roots have not always been properly used because of their high linamarin content. Linamarin is a cyanogenic glucoside which releases highly toxic cyanide (HCN) during hydrolysis at the time of digestion (Scott et al. 1976, Stevenson and Jackson 1983, Preston 1987).

Cyanide is believed to be responsible for many of the poor results obtained when using Cassava to feed livestock although only little accurate information on the effective incidence of the HCN rate on the performance of animals is available (Gomez 1985). Experiments conducted using Cassava flour have given somewhat contradictory results. Müller and Chou (1974) and Stevenson and Jackson (1983) report that a rate of up to 50 percent of Cassava in the diet by no means impaired the growth performance of poultry, whereas Longe and Oluyemi (1977) as well as Willie and Kinabo (1980) observed a linear decrease in the weight of poultry resulting from the increase in the quantity of Cassava included in the ration. Gomez (1985) showed that diets including more than 10 to 20 percent of Cassava varieties with low or high HCN contents gave similar results.

The aim of this paper is to briefly the effects of incorporating cassava flour as a substitute for maize in broiler diets by closely observing the growth performance of the animals. The socioeconomic constraints which hamper the use of cassava as food for livestock, i.e. the opportunity cost of cassava for human nutrition, will also be discussed.

Materials and methods

Five hundred one-day old chicks obtained from the industrial cross of broilers (improved stock) were reared in a henhouse on the ground until they were 7 weeks old. During the first 29 days, the birds were given a conventional diet of 2900 kcal/kg with 22% protein. During the experimental phase ranging from the 29th to the 49th day, four isoenergetic and isoproteinaceous diets including 0%, 10%, 20% and 30% cassava were given in replacement of maize (table 1). A fifth diet included a commercial product. The daily feed consumption, live weight and mortality rate of the birds were recorded for each treatment.

Table 1. Composition of the experimental rations

Raw materials

Percentage of cassava in the ration

0%

10%

20%

30%

Ingredients






Maize

60

50

40

32


Cassava flour

0

10

20

30


Rice flour

12

14

13

10


Cottonseed cake

7

8

7

6


Soybean cake

6

7

7

7


Fish flour

9

9

11

13


Wheat middling

4

0

0

0


Premixa

2

2

2

2

Nutrientsb


Energy (kcal ME/kg}

2992

2995

2989

2989


Protein (%)

19.08

19.10

18.96

18.90


Lysine (%)

1.02

1.03

1.07

1.12


Methionine (%)

0.40

0.40

0.42

0 43


Methionine + cystine (%)

0.71

0.70

0.70

0.71


Calcium (%)

1.00

1.00

1.12

1.26


Available phosphorus (%)

0.56

0.57

0.61

0.66


Cellulose(%)

3.80

3.70

3.60

3.40

Notes: a One kg of Premix provides phosphorus 2. la, calcium 3.4g, sodium 1.54g, magnesium 0.25g, manganese 120mg, zinc 80mg, iron 48mg, copper 0.4mg, cobalt 0.2mg, flavomycine 2mg, vit. A 10000 IU, vit. D 31000 IU, vit. E 10mg, vit. B1, 1.6mg, vit. B2 3.2mg, vit. B6 2.4mg, vit. B12 8mg, folic acid 0.6mg, pantothenic acid 14mg, choline 80mg, vit. K3 2mg
b Data based on INRA (1984)

A simulated study was carried out to determine the advantage of cassava over maize, that the incorporation of cassava in the diet had no adverse effect on the growth performance of animals. The simulation determined the price limit for cassava to remain competitive with that of maize in a minimum cost diet for broilers.

Results and discussion

The incorporation of cassava flour in poultry diet at rates ranging from 10% to 30% did not affect the final weight or the gain in weight (P > 0.05) of the chickens (table 2). If the rate exceeded 10%, however, the feed consumption index increased, resulting in a decrease in the nutritional efficiency of the diet. The simulated economic study enabled us to calculate the "interest" price of cassava as a feed for broilers. Considering that the price of maize was 70 CFA/kg and taking into account the prices and nutritional values of other available raw materials, the minimum cost price for cassava-based diet was calculated at 52.73 CFA/kg. If cassava is sold below this price, the minimum cost diet including 51.5% cassava and maize (at 70 CFA/kg) was rejected. However, when cassava exceeded this top price, maize was a more economical energy source (table 3).

Table 2. Effect of cassava on the growth performance of broilers

 

Percentage of cassava in ration

Commercial check

0%

1 0%

20%

30%

Live weight at 49 days old (g)

1657a

1617a

1610a

1623a

1656a

Weight gain (29-49 days)

977a

936a

930a

943a

976a

Food consumption (29-49 days)

2471

2361

2615

2789

2618

Consumption index (29-49 days)

2.53a

2.52a

2.81a

2.96a

2.68a

Note: The mean values on the same row followed by the same letter are not significantly different (P > 0.05)

The weight gain performance observed during this experiment corroborated the results obtained by Chou et al. (1974), and Stevenson and Jackson (1983), but contradicted those of Longe and Oluyemi (1977) as well as Wyllie and Kinabo (1980), who observed a negative correlation between the rate of cassava in the diet and the growth of broilers.

The rate of incorporation of cassava seemed to adversely affect the shelf life of the feed when served in the form of flour, whereas the use of pellets containing up to 50% (Stevenson and Jackson 1983) and 58% cassava (Mailer and Chou 1974) did not affect the consumption index of broilers and resulted in a better storage capacity of the cassava-based diets. The use of flour was not satisfactory in terms of storage efficiency, especially when the incorporation rate of the product exceeded 10% (Müller and Chou 1974, Yeong et al. 1978, Wyllie and Kinabo 1980).

Table 3. Effect of cassava price fluctuations on the composition of a growth ration

Raw material

Ration cost

50 CFA/kg

52 CFA/kg

53 CFA/kg

% ingredient

Maize

0.0

0.0

43.5

Cassava

51.5

51.5

0.0

Cottonseed cake

10.0

10.0

10.0

Fish flour

12.0

12.0

12.0

Soybean cake

8.4

8.4

2.3

Wheat middling

11.5

11.5

24.0

Salt (NaCl)

0.2

0.2

0.2

Palm oil

4.2

4.2

4.0

DL Methionine

0.2

0.2

0.0

Premix

2.0

23.0

2.0


Cost (CFA/kg)

87.8

88.8

89.2

Note: The growth ration was a 3000 keel metabolizable energy per kg, 19% protein diet

The apparent heterogeneity of the results obtained on cassava was due to the great variability of the energy value of the product. The quality of cassava is very heterogeneous and its energy value varies considerably with the proportion of cellulose and silica it contains (INRA 1984). Müller and Chou (1974) showed that the use of cassava in the form of pellets improved its nutritional efficiency since starch and cellulose were better absorbed. Moreover, these authors observed that by subjecting the pellets to heat treatment during preparation certain growth inhibitors contained in cassava were destroyed. Longe and Oluyemi (1977) have shown that the age of broilers affected their digestion of the starch present in cassava, and digestion seemed to improve with age.

There is considerable literature on the use of cassava for animal feeding (Gomez 1985). However, only little information is available on the economic advantage resulting from its use. This is surprising because economic considerations are of paramount importance, since cereals can be replaced by cassava only if the nutritionally equivalent mixture of cassava with proteinaceous foodstuffs is cheaper than feed prepared with cereals (Müller and Chou 1974). The previous study showed that under the economic conditions described above the price of cassava must not exceed 75 percent of that of maize used as a reference, if it is to compete successfully with maize. If market prices of cassava in Côte d'Ivoire are considered, this condition is rarely met. The price paid for cassava is generally high and often greater than the price of maize. Under present market conditions, it seems that the opportunity cost of cassava for human consumption exceeds its value for animal feeding. This illustrates the major role of cassava in the nutrition of the rural populations of Africa where this tuber crop provides over 200 million people with 50 percent of their calorific needs (Hahn 1985). In southeast Asia and Latin America where cassava is widely produced, consumption is rather low (24 and 35 kg/pers/year respectively), whereas in Africa it reaches 102 kg and can even go up to 300 kg or more in certain countries of Central Africa (Truman 1985).

There is no doubt that cassava can replace cereals as an energy source for animal feeding in Africa. However, cassava is still a subsistence crop rather than a competitive commercial commodity because of the limited size of farms, the poor productivity of the crop (an average of 6.5 tons/ha), and the lack of facilities for efficient processing and distribution.

Acknowledgment

I thank Dr Odi Diambra of ENSA in Abidjan for his collaboration in the study of price variations of cassava in Côte d'Ivoire.

References

Chou, K.C., Z. Müller, and K.C. Nah. 1974. High levels of tapioca-meal in poultry rations. Indian Journal of Animal Sciences 44: 697-702.

Gomez, G. 1985. Le manioc, le cyanure et la nutrition animale. Pages 117- 122 in La toxicité du manioc et la thyroide: recherche et questions de santé publique: compte rendu d'un collogue tenu du 31 mai au 2 juin 1982 a Ottawa, Canada. Ottawa: CRDI 1985.

Hahn, S.K. 1985. La recherche pour abolir les obstacles a la production et a l'utilisation du manioc en Afrique. Pages 99-109 in La toxicité du manioc et la thyroide: recherche et questions de santé publique: compte rendu d'un collogue tenu du 31 mai au 2 juin 1982 a Ottawa, Canada. Ottawa: CRDI 1985.

INRA (Institut National de Recherches Agronomiques). 1984. L'alimentation des animaux monogastriques: porcs, lapins, volailles. INRA, Paris.

Kirchgessner, M. 1985. Tierernährung: Leitfaden für Studium, Beratung und Praxis. 6. verb. Auflage, DLG-verlag, Frankfurt (Main).

Müller, Z., and K.C. Chou. 1974. Le manioc: produit de remplacement des céréales dans les rations du bétail et de la volaille. Rev. Mon. Zoot. 12: 19-24.

Longe, O. G.L. and J.A. Oluyemi. 1977. Comparative use of cassava, maize and guinea corn as the major dietary source of carbohydrates for chicks. Journal of the Association for the Advancement of Agricultural Sciences in Africa 4: 47-52.

Preston, T.R 1987. Porcs et volailles sous les tropiques. CTA. Wageningen, Pays teas, 27p.

Scott, M.L., M.C. Nesheim, and R.J. Young. 1976. Nutrition of the chicken. M.L. Scott and Associates, Ithaca, New York. 555 pp.

Stevenson, M.H., and N. Jackson. 1983. The nutritional value of dried cassava root meal in broiler diets. Journal of the Science of Food and Agriculture 34: 13611367.

Truman,P. 1985. Revue de la consommation et de la production du manioc. Pages 87-93 in La toxicité du manioc et la thyroide: recherche et questions de santé publique: compte rendu d'un colloque tenu du 31 mai au 2 juin 1982 a Ottawa, Canada. Ottawa: CRDI 1985.

Wyllie, D., and A. Kinabo. 1980. Cassava or maize meal for broiler and the effect of supplementation with methionine and sulphate In cassava-based diets. Tropical Animal Production 5: 182-190.

Yeong, S.W., C. Devendra, M.N. Dhia Udin, and RH. Booth. 1978. The effect of cassava chip quality on their use In poultry feeds. Malaysian Research Bulletin 6: 180- 185.


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