Feeding value of velvet beans (Mucuna utilis) for laying hens

C D Tuleun, S N Carew * and I Ajiji *

Department of Animal Nutrition
*Department of Animal Production,University of Agriculture Makurdi, PMB 2373, Makurdi, Benue State, Nigeria
tuleundoo@yahoo.com

Abstract

A feeding trial was conducted to determine the effects of inclusion in the diet of raw, boiled and toasted mucuna beans (Mucuna utilis) on the performance of laying hens. The birds used were 34-week old Isa-Brown® hens. Four diets were formulated, such that diet 1 (control) contained no mucuna beans while diets 2, 3 and 4 contained 20% of raw, boiled and toasted mucuna beans, respectively. Each diet was fed to three groups of 10 birds.

Feed intake and body weight gain differed significantly among treatments. Birds on the raw mucuna bean diet were significantly (P<0.05) smaller than those on the other diets. The birds on the control and toasted mucuna diets had significantly (P<0.05) higher hen-day and hen-housed egg production than those on raw and boiled mucuna bean diet. Feed/gain ratio was, however, significantly (P<0.05) better for birds fed boiled mucuna beans, followed by those fed the toasted beans, while it was the same for birds fed the control and raw mucuna bean diets. External and internal egg quality indices were not significantly altered by the treatments.

Raw mucuna bean was shown to impair the performance of layers. This was partially reversed by boiling the beans, while toasting the mucuna beans completely reversed all the deleterious effects of the raw beans.

Keywords: egg production, Mucuna utilis, velvet bean

Introduction

The average Nigerian does not consume enough protein of animal origin, and animal protein is more efficient than plant protein in providing the amino acids necessary for tissue development, repair and function (FAO 1994).  Poultry production has great potential for improving the animal protein intake of the populace. However, the availability of high quality poultry feed is constrained by the phenomenal rise in the cost of the major conventional feed ingredients, due, mostly, to competition from direct consumption of these materials by human beings. This competition between humans and livestock for available cereal and legume grains makes it difficult to formulate balanced and economical feeds for livestock (Aduku and Olukosi 1990; Ezeagu et al 2003; Emenalom 2004). There is, therefore, a continual need to focus on the exploitation of lesser-known or non-traditional plant resources that are not subject to competition between man and livestock.

Mucuna utilis (velvet bean), a tropical legume, is little known and has a low human preference for food, but has a high potential as an energy/protein source in livestock feed (Emenalom and Nwachukwu 2006). It is comparable to soybean in terms of amino acid and mineral profile (Siddhuraju et al 1996; Iyayi and Taiwo 2003). However, the use of velvet beans as a source of protein for monogastrics is limited by the presence of antinutritional factors like trypsin inhibitors, haemagglutinins, phytic acids, hydrocyanic acid and tannins (Emiola et al 2003; Siddhuraju et al 1996). Heat treatment is frequently used to improve the utilization of the nutrients in legumes by animals. Boiling is a more conventional method of detoxification, but toasting is also practiced, and has advantages when drying is a problem. Hence these two methods of detoxification have been adopted in this study.

The objective of the study is to evaluate the performance of laying hens fed mucuna beans processed by various methods.

Materials and methods 

The mucuna beans used in this study were procured from International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. The beans were divided into three batches. One batch received no heat treatment (raw meal). The second portion was introduced into boiling water and cooked for 60 minutes, as described by Kaankuka et al (1995). The third portion was subjected to toasting, a process which involved mixing the bean seeds with sand in a frying pan and heating. The mixture was stirred continuously until the seeds were crispy and acquired the characteristic aroma of toasted beans. The raw and processed beans were milled with a hammer mill and stored in sealed jute bags until required for use.

Four iso-nitrogenous diets were formulated using soyabeans for the control diet, and raw, boiled and toasted mucuna beans, at the rate of 200g/kg, for the raw, boiled and toasted diets, respectively (Table 1).

The proximate composition of raw and processed beans was determined by standard methods (AOAC 1995). Calcium and phosphorus contents were determined by wet digestion followed by atomic absorption spectrophotometry. Gross energy was determined using a bomb calorimeter (AOAC 1995).

One hundred and twenty, 34-week old, Isa-brown birds were divided into twelve groups of 10 birds each, with uniform mean live weight. Three groups of hens were randomly allocated to each of four treatments (control, raw mucuna, boiled mucuna and toasted mucuna beans). All the birds were housed on deep litter and subjected to standard egg production management practices.

Egg quality analysis was carried out fortnightly on five percent of all eggs laid. Individual eggs were labelled and weighed using an electronic balance. Weight, external and internal egg quality parameters were measured as described by Ayanwale and Gado (2001) and Iyayi and Taiwo (2003).

Data collected were subjected to ANOVA using the completely randomised design (Steel and Torrie1980). Where significant differences were indicated, treatment means were compared using Duncan’s New Multiple Range Test, as outlined by Obi (2002).

Results and discussion 

Table 2 shows the results of chemical analysis carried out on the various types of mucuna bean meal that were used in formulating the diets.

Data from Aduku (1993) for boiled, full fat, soyabeans has been included in the table for comparative purposes. It can be seen that the major difference between soyabeans and mucuna beans is in fat and carbohydrate content. Soyabean contains much more fat, while mucuna is superior in carbohydrate content.

It could be speculated that some of the differences in chemical composition between the various types of mucuna bean are due to losses in cooking water. For example, boiled mucuna is the lowest in crude protein and ether extracts, but the highest in crude fibre.

Table 3 shows that the presence of raw mucuna beans in the diet reduced feed intake significantly (P<0.05).

The marked reduction in feed intake in the group fed the raw mucuna bean diet could be due to the presence of appetite depressant(s). Emiola et al (2003) have made a similar observation.

Heat treatment resulted in improvements in feed intake, the average daily feed intake of birds on the toasted mucuna diet comparing favourably with that of birds on the control diet. Several investigators (Ologhobo et al 1993; Kaankuka et al 1995; Kaankuka 1998; Emenalom and Udedibie 1998; Olomu 1995) have reported that the nutritive value of legume seeds was improved when they were subjected to cooking. This is attributed to increase in the palatability of the diet and higher protein digestion and better availability of resultant amino acids.

One of the classes of antinutritional factors frequently found in leguminous seeds is tannins. These polymeric phenols are strongly proteophillic, and are capable of binding and precipitating (denaturing) large amounts of proteins, which is one of the mechanisms by which they are thought to inhibit digestive enzymes. Extrapolating on this fact, Essig (1985) observed that tannins may bind to the proteins of the bucal mucosa, thus attenuating taste and lowering palatability and, thus, feed intake. Carew et al (2003^a) carried this argument further, reasoning that tannins may also bind to proteins of the ileal epithelium, thus disrupting digestive and absorptive processes in the intestine. This will account for the remarkable increase in the loss, through the faeces, of proteins and amino acids that is associated with the feeding of raw legume seeds (Scott et al 1982; Kaankuka 1998).

The inclusion of mucuna bean meal in the diets of the hens resulted in significant variations in body weight gain over the study period (Table 3). The values were 18.0, 6.65, 9.76 and 14.1% for control, raw, boiled and toasted mucuna bean diets respectively. Afolabi et al (1985) and Olaboro et al (1991) have reported similar, adverse effects of raw mucuna on weight gain in broiler chickens. Body weight gain improved as a result of boiling the mucuna, and the difference in body weight gain between the toasted mucuna diet and the control diet was not significant, suggesting that heat treatment is an effective antidote, and that toasting converts mucuna to an ingredient that is equivalent to properly processed soybean. This observation is in agreement with reports by Ukachukwu (2002), who showed that toasting mucuna beans improved the growth rate of broiler chicks, bringing them to par with that of the control diet.

The most remarkable effect of mucuna in the feed of the hens was on egg production. Hen-day egg laying rates were 34.8, 59.0, 73.9 and 84.5% for birds fed the control diet, raw mucuna, boiled mucuna and toasted mucuna respectively. These figures show clearly the ameliorative effects of heat treatment on the toxicity of raw mucuna. There was no significant (P<0.05) difference between birds fed the control diet and toasted mucuna, while all other treatment groupings were significantly different from each other. Mortality was nil or very low for all treatments, so hen-housed egg production values were near identical to hen-day values. Earlier findings by Iyayi and Taiwo (2003) and Carew et al (2003^b) on the adverse effects of feeding raw mucuna beans in poultry diets follow the pattern of these findings, as does that of Olaboro et al (1991), who showed that autoclaving mucuna fed to broiler chicks improved their growth rate dramatically. All these findings demonstrate that the major antinutrient(s) in mucuna is (are) heat labile.

The efficiency of feed conversion, in terms of g of feed per g of egg, showed significant differences (P<0.05) between toasted and the raw and/or cooked diets. The values of efficiency of feed conversion for the toasted mucuna bean diet was significantly (P<0.05) better than for the control diet. A similar observation was reported by Udedibie et al (1994) for toasted or urea treated jack bean meals. Lack of mortality of among the hens fed the toasted mucuna confirms that this method of processing was very effective in removing or detoxifying antinutritional factors contained in mucuna.

Data for external and internal egg quality are presented in Table 4. There were no significant (P>0.05) effects of type of diet on egg size as estimated by egg weight, length and width. Likewise yolk and albumen indices, as well as the Haugh units were not significantly altered by feeding the raw or processed mucuna bean diets.

The results of this trial have shown that performance was impaired when raw mucuna beans was fed to laying hens. Both boiling and toasting proved effective remedies for the toxic factors responsible for this effect, and toasting appears to be the better method of processing mucuna beans, giving results that are comparable to that of soybeans.

References 

Aduku A O 1993 Tropical Foodstuff Analysis Tables. Department of Animal Science, Ahmadu Bello University, Zaria, Nigeria

Aduku A O and Olukosi J O 1990 Rabbit management in the tropics. Living Books Series, GU publications, Abuja FCT Nigeria

Afolabi O A, Oshuntogun B A, Adewusi S R, Fopowo O O, Ayorinde F O, Grisson F E and Oke O L 1985 Preliminary nutritional and chemical evaluation of raw seeds from mucuna solanica; an under-utilized food source. Journal of Agriculture and Food Chemistry 33: 122-124

AOAC 1995 . Official Methods of Analysis. (16^th Edition) Association of Official Analytical Chemists Washington, D.C.

Ayanwale B A and Gado Y 2001 Effects of commercial diets on egg quality characteristics. Nigerian Journal of Animal Production 28:202-206

Carew S N, Ega R A I and Tion M A 2003^a The feed value of  Albizzia lebbeck seeds in broiler diets. Nigerian Food Journal 21:147-150

Carew L B, Hardy D, Weis J, Alsters F, Mischler S A, Gernat A and Zakrzewska F I 2003^b Heating raw velvet beans (Mucuna pruriens) reverses some anti-nutritional effects on organ growth, blood chemistry, and organ histology in growing chickens. Tropical and Subtropical Agroecosystems 1: 267-275

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

Emenalon 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 Nwachukwu I C 2006 Effect of calcium hydroxide soaked and cooked velvet beans (Mucuna pruriens) on the performance of finisher broilers. Nigerian Journal of Animal Production 33(1):53-57

Emiola I A, Ologhobo A D, Akinlade J, Adedeji O S and Bamigbade O M 2003 Effects of inclusion of differently processed mucuna  seed meal on performance characteristics of broilers. Tropical Animal Production Investigation 6:13-21

Essig B H 1985 Anti Nutritional Factors. In: Clover Science and Technology. N L Taylor (editor). American Agronomic Society. New York      

Ezeagu I E, Maziya-Dixon B and Tarawali G 2003 Seed characteristics, nutrient and anti-nutrient composition of 12 mucuna accessions from Nigeria. Tropical and Subtropical Agroecosystems 1:129-139

FAO 1994 The state of food and agriculture. FAO Agricultural Series No. 27. FAO/UN, Rome http://www.fao.org/docrep/t4450e/T4450E00.htm

Kaankuka F G 1998 Effects of cooking time on the levels of anti-nutritional factors and nutritive value of full fat soybeans for pigs. PhD thesis, Department of Animal Science, Ahmadu Bello University, Zaria

Kaankuka F G, Balogun T F and Tegbe T S B 1995 Effects of duration of cooking of full-fat soya beans on proximate analysis, level of anti-nutritional factors and digestibility by weanling pigs.  Animal Feed Science Technology 62:229-237

Iyayi E A and Taiwo V O 2003 The effects of diets incorporating mucuna (Mucuna pruriens) seed meal on the performance of laying hens and broilers. Tropical and sub-tropical Agroecosystems 1(2-3): 239-246

Obi I I 2002 Statistical methods of detecting differences between treatment means and research methodology issues in laboratory and field experiments. (2^nd Edition) Ap. Express Publication. Ltd. Nsukka-Nigeria

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

Ologhobo A D, Apata D F and Oyejide A 1993 Utilization of raw jackbean (Canavalia ensiformis) and jackbean fractions in diets of broiler chicks. British Poultry Science 34:323-337

Olomu J M 1995 Monogastric Animal Nutrition. Jachem Publishers, Benin City

Scott M L, Nesheim, M C and Young R J 1982 Nutrition of the chicken. M L Scott and Associates, New York

Siddhuraju 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 Agricultural and Food Chemistry 44:2636-2641

Steel R G D and Torrie J H 1980 Principles and Procedures of Statistics. A Biometrical Approach. 2^nd edition, McGraw-Hill book Co., New York. 195p

Udedibe A B I, Esonu B O, Obaji C N and Durunna C S 1994 Dry urea treatment prior to toasting as a method of improving the nutritive value of jackbean (Canavalia ensiformis) for broilers. Animal Food Science and Technology 48:335-345

Received 12 November 2007; Accepted 10 January 2008; Published 1 May 2008

Go to top