Effect of velvet bean (Mucuna pruriens) seeds cooked in maize-cob ash solution on the performance of broiler starter chickens

O O Emenalom, V C Orji and N C Ogbonna

Department of Animal Science and Technology, Federal University of Technology, Owerri,
P.M.B. 1526, Owerri, Imo State-Nigeria
emenalom2000@yahoo.com       oemenalo@futo.edu.ng

Abstract

A 28-day feeding trial was conducted to determine the effect of whole and cracked velvet bean seeds cooked in maize-cob ash solution on the performance of broiler chicks. Whole and cracked velvet bean seeds were separately soaked in water for 48 hours, cooked for one hour in maize-cob ash solution, sun-dried and then ground into meals. The meals were then incorporated into broiler starter diets at 25 and 30% dietary levels respectively and fed from 0 to 28 days of age. The control diet contained no velvet bean meal.

At 25 and 30% dietary levels, cracked velvet bean meal supported broiler performance comparable to the control. Birds fed 30% whole velvet bean (WVB) meal had a significantly depressed growth; grew 84.22% of control but feed intake and feed to gain ratio were unaffected.

Cooking in maize-cob ash solution improved the nutritive value of velvet bean seeds, allowing for 25 and 30% dietary inclusion levels for whole and cracked seeds respectively.

Keywords: Broilers, maize-cob-ash, performance, velvet bean

Introduction

Velvet bean (Mucuna pruriens) contains several anti-nutritional factors (Siddhuraju et al 1996) which though reduced by heat treatment (Udedibie and Carlini 1998) are not completely inactivated. These anti-nutritional factors which include: trypsin inhibitors, lectins, phytates, phenols, cyanogenic glycosides, α-amylase inhibitors, tannins and L-3-4 dihydroxyphenylalanine (L-Dopa), among others, affect its acceptability and utilization by humans and animals.

To overcome these anti-nutritional factors, various heat processing methods have been used for its detoxification ( Siddhuraju et al 1996;Udedibie and Carlini 1998; Berhe 2001). Velvet bean seeds are high in L-Dopa and except for L-Dopa, all the anti-nutritional factors detected in the seeds are heat labile (Mary Josephine and Janardhanan 1992). It has however been observed that cooking in alkaline or acid solution was effective in reducing the L-Dopa content of Mucuna pruriens (Wanjekeche 2001).

Earlier studies (Harms et al 1961;Olaboro et al 1991; Emenalom and Udedibie 1998; Carmen et al 1999; Esonu 2001) have shown that raw Mucuna pruriens is toxic to broilers. Processing the bean by heat treatments (Emenalom and Udedibie 1998; Carmen et al 1999; Esonu 2001; Udedibie et al 2001; Emenalom 2004; Emenalom et al 2005), only gave indication of partial detoxification hence its dietary inclusion level could not exceed 25%. However,Mucuna pruriens seeds cooked in alkaline or acid solution has not been tried on the performance of broilers. The trial herein reported was therefore designed to examine the performance of broiler chicks fed diets containing whole or cracked Mucuna pruriens seeds cooked in maize-cob ash solution.

Materials and Methods

Mucuna pruriens seeds used for this study were harvested from the teaching and Research farm of the Federal University of Technology Owerri, located in the rainforest zone of Nigeria (5^o 29'N and 7^o 02'E) and at an elevation of 90.m. The environment has an annual rainfall of 2641 mm, temperature from 27 to 30.5^oC and relative humidity of 86.6%.

The Mucuna pruriens seeds were divided into two batches. One batch was soaked in water for 48 hours while the second batch was cracked into pieces of 2-4 parts per seed using a hammer mill adjusted plate electric grinding machine. The cracked seeds were then soaked in water for 48 hours. Both samples were rinsed with fresh water, cooked for an hour at 100^oC (timed from start of boiling) in maize cob ash solution (in 1:150 dilution with water), sun dried and ground into meals.

The whole velvet bean (WVB) and cracked velvet bean (CVB) meals were incorporated into broilers starter (0-28 days) diets at 25 and 30% for each meal respectively. The control contained no velvet bean meal (Table 1).

Each diet was fed to 50 Anak broilers in a completely randomised design (CRD) replicated 5 times. Each replicate contained 10 birds. The birds were housed in concrete floored pens covered with wood shaving as the litter material and measured 3m x 3m in length and width respectively. The birds were weighed at the beginning of the experiment and weekly thereafter. Feed intake (pen basis) was measured daily.

The data collected were subjected to analysis of variance (Snedecor and Cochran 1967). Where the analysis of variance indicated significant treatment effects, the means were compared using Duncan's New Multiply Range Test as outlined by Obi (1990)

Results

The data on the performance of the young broiler chicks fed on the five experimental diets are shown in Table 2.

The growth rates of birds fed on 25% WVB, 25% CVB and 30% CVB diets were similar to the control.. Birds fed 30%WVB had a lower growth rate. Feed intake and feed to gain ratio did not differ among treatments.

Discussion

It was a major objective of the experiment to investigate whether the beneficial effect of cooking in local alkaline solution in reducing the L-Dopa content of velvet bean (Wanjekeche 2001) could also improve its nutritive value for broiler chicks. There have been studies in which soaking and cooking in water have been used as treatments to improve the nutritional value of Mucuna pruriens for monogastrics in general and poultry in particular and results have been inconsistent. This lack of consistency on the performance of birds fed processed velvet bean diets may be attributed to the processing methods used. The methods do not seem to be good enough to remove the anti-nutritional factors in the seeds. For example, poor performances at 20 and 30% dietary inclusion levels of processed velvet bean in broilers were observed by Udedibie et al (2001) using soaked and cooked velvet bean and Emenalom (2002) using cracked soaked and cooked velvet beans diets,m respectively. In the present experiment, cooking was done in maize-cob-ash solution, whereas in the above mentioned experiments cooking was done in water. The addition of velvet bean meals so processed significantly improved the performance of the broilers contrary to earlier reports. These effects on performance were seen in both the processing methods and dietary inclusion levels.

The growth rate recorded by the 30%WVB group was better than that earlier reported in literature for velvet beans cooked in water. For example, Emenalom (2004) observed growth rates of 81.9, 87.5 and 43.9% (relative to the control) in broiler chicks fed 20% water-soaked and cooked, calcium hydroxide soaked and cooked, and calcium hydroxide soaked velvet bean meals, respectively. Emenalom (2002) had earlier observed growth rates of 83.3% (relative to the control) in broilers fed 30% cracked soaked and cooked velvet bean meal. Therefore, the improved growth rates of 84.2 and 95.2% (relative to the control) elicited in the present study for 30% whole and cracked velvet bean diets respectively, might be ascribed in part to the method of processing.

Velvet bean has been reported to contain toxic substances, which affect the performance of non-ruminant animals (Mary Josephine and Janardhanan 1992, Udedibie and Carlini 1998). Attempts aimed at reducing these toxic substances have shown no more than partial detoxification when fed to broilers (Emenalom and Udedibie1998; Carmen et al 1999, Udedibie et al 2001, Emenalom 2002, Emenalom 2004). Some authors have blamed the toxicity of velvet bean on the L-Dopa content (Pieris et al 1980, Afolabi et al 1985, Mary Josephine and Janardhanan 1992). If that is the case cooking in maize-cob ash solution as reported by Wanjekeche (2001) may have reduced the L-Dopa content of the seed hence the improved performance at the highest dietary level contrary to earlier reports.
 

Conclusions

• Cooking in maize cob ash solution is a an effective method of improving the nutritive value of velvet bean for broilers.

• Up to 30% CVB or 25% WVB could be incorporated into broiler starter diets without any adverse effect.

• Exploitation of these processing methods through practice could therefore form the starting point in the use of this long neglected tropical legume in non-ruminant animal nutrition.

Acknowledgements

The authors are grateful to the International Foundation for Science (IFS), Sweden for financing the research.

References

Afolabi O A, Oshuntogun B A, Adewesi S R, Fapojuwo O O, Ayorinde F O, Grissom F E and Oke O L 1985 Preliminary nutritional and chemical evaluation of raw seeds from Mucuna solanei. Journal of Agriculture and Food chemistry. 33: 122-124.

Berhe T 2001 Mucuna: Restoring the soil nutrients. In: feeding the future. News letter of the Sasakawa African Association. Issue 16:pp.5.

Carmen J del, Gernat A G, Myhrman R and Careal LB 1999 Evaluation of raw and heated velvet beans (Mucuna pruriens) as feed ingredients for broilers. Poultry science 78:866- 872.

Emenalom O O 2002 Evaluation of the seed of Mucuna pruriens (velvet bean) as feed ingredient in poultry and pig diets. Ph.D Thesis. Federal university of Technology Owerri- Nigeria.

Enenalom O O 2004 Comparative performance of broiler chicks fed diets containing differently processed Mucuna pruriens seed meals. Nigerian Journal of Animal Production 31 (1) 12 -16.

Emenalom O O and Udedibie ABI 1998 Effect of dietary raw, cooked and toasted Mucuna pruriens seed (Velvet bean) on the performance of finisher broilers. Nigerian Journal of Animal Production 25 (2): 115 -119

Emenalom O O, Udedibie A B I, Esonu B O and Etuk E B 2005 Evaluation of processed velvet bean (Mucuna pruriens) as a fed ingredient in starter diets for broilers. Journal of Poultry Science .42 ( 4) (inpress)

Esonu B O 2001 Comparative evaluation of raw and urea/toasted velvet bean (Mucuna pruriens) for broiler chicks. Nigerian Journal of Animal Production 28 (1) : 40 -44

Harms R I Simpson C F and Waldroup P W 1961 Influence of feeding various levels of velvet beans to chicks and laying hen, Journal of Nutrition 75:127-161

Mary Josephine R and Janardhanan K 1992 Studies on chemical composition and antinutritional factors in three germplasm seed materials of the tribal pulse, Mucuna pruriens (L) DC. Food chemistry 43: 1 13-18.

Obi I U 1990 Statistical methods of detecting differences between treatment means. 2^nd edition. Snaap Press, Enugu, Nigeria.

Olaboro G, Okot M W, Mugerwa J S and Latshawa J D 1991 Growth depressing factors in velvet bean fed to broiler chicks East African Agriculture and Forestry Journal 57(2):103-110.

Pieris N, Jansz E R and Dharmadasa H M 1980 Studies on Mucuna species of Sri-Lanka. Journal National Science council . Sri-Lanka 8:35-40

Siddhuaraju P, Vijayakumari K and Janardhanan K 1996 Chemical composition and protein quality of the little known legume, velvet bean (Mucuna pruriens) (L) DC. Journal of Agriculture and Food Chemistry. 44:2636-2641

Snedecor G W and Cochran W G 1967 Statistical methods. The lowa state university Ames. Lowa. 6^th edition.

Udedibie A B I and Carlini C R 1998 Brazilian Mucuna pruriens seeds (velvet bean) lack haemagglutinating activity. Journal of Agricultural Food Chemistry 46(4):1450-1452.

Udedibie A B I, Emenalom O O and Obikaonu H O 2001 Comparative evaluation of Nigerian and Brazilian Mucuna pruriens (velvet beans) s feed ingredients in broiler diets International Journal of Agriculture and Rural Development 2:9-13

Wanjekeche E 2001 Evaluation of processing methods of Mucuna for food in Kenya In: Mucuna news. Bulletin of CIEPCA .Fourth issue. pp.2.