Performance of Pullet chicks fed graded levels of Raw Bambarra groundnut (Vigna subterranean (L.) Verdc) offal diets as replacement for Soybean meal and Maize

K U Amaefule and F M Osuagwu

College of Animal Science and Animal Health, Michael Okpara University of Agriculture, 
Umudike, PMB 7267 Umuahia, Abia State, Nigeria
amakelvin@yahoo.com

Abstract

One hundred and eighty day-old Lohmann brown pullet chicks were used to evaluate the effect of replacing soybean meal and maize with Bambarra groundnut offal (BGO) in pullet chick diets. The experiments were in a completely randomized design (CRD) with six treatments, each replicated three times, with nine pullets per replicate. The inclusion levels of BGO in the diets were 0, 5, 10, 15, 20 and 25%. Parameters measured were daily weight gain, final live weight at 8^th weeks, daily feed and protein intake, feed conversion ratio, protein efficiency ratio, mortality and feed cost.

The result showed that the performance of chicks fed diet containing 5% BGO did not differ significantly (P>0.05) from that of the control. Pullets fed 10, 15, 20 and 25% BGO diets showed no significant differences (P>0.05) in their daily weight gain and final live weight. Pullets fed 20% BGO diet had significantly lower feed intake than others. The inclusion of Bambara groundnut offal in the diets significantly (P<0.05) reduced the cost per kg of feed.

The conclusion was that the BGO could be a valuable feedstuff in pullet chick diets which could be included up to 5% of the pullet diet.

Keywords: Bambarra groundnut offal, diets, performance, pullet chicks.

Introduction

Increased egg production in Nigeria is being hampered by high cost of feed, which constitutes about 70-80% of the total cost of egg production (Acamovic 2001). Soybean meal and maize used as the main plant protein and energy sources in poultry feed has continued to increase in price mainly due to increased demand and high cost of industrial processing activity.

Bambarra groundnut (Vigna subterranean (L.) Verdc)is a legume grown mainly in the Middle Belt and Enugu State of Nigeria (Doku and Karikari 1971). Bambarra seeds have been reported to contain 24% CP, 6.60 and 1.30% lysine and methionine, respectively (Poulter 1981; Temple and Aliyu 1994). The seeds are normally milled and sieved several times to obtain the flour locally called okpa, which is a nutritive human food. The offal, which is available throughout the year and cheap, has no industrial or other uses as at now. The offal contains 21.16% CP, 5.29% CF and 12.44 MJ/ kg gross energy (Amaefule and Iroanya 2004).

Onwudike and Eguakun (1994) had reported that raw Bambarra groundnut seeds did not support weight gain of broiler chicks but gave a negative protein efficiency value. This was attributed to the presence of trypsin inhibitor, haemagglutinin, tannic acid, phytic acid and oxalate present in the raw seeds (Onwudike and Eguakun 1992; Apata and Ologhobo 1997). However, the proximate composition and nutrient quality of the offal is expected to be affected by the processing method used when preparing the flour for human food. Scientific information on the feeding of Bambarra groundnut offal to poultry has been with pullet growers (Onyimonyi and Onukwufor 2003) and broilers (Amaefule and Iroanya 2004). There is dearth of information in available literature regarding the performance of pullet chicks fed Bambarra groundnut offal from day-old.

The objective of this study was, therefore, to determine the performance of pullet chicks fed graded levels of raw Bambarra groundnut offal as a replacement for soybean meal and maize in the diets.

Materials and Methods

This study was conducted at the Poultry Unit of Teaching and Research Farm of Michael Okpara University of Agriculture Umudike, Abia State. One hundred and eighty day-old Lohmann brown chicks were used. The experimental diets were formulated in such a way that there was a stepwise replacement of soybean meal and maize with Bambarra groundnut offal. The composition of the experimental diets is shown in Table 1.

Management of Birds

The day-old chicks were brooded using kerosene stoves under metal hovers and electric bulbs as source of light in a deep-litter house. The house was the tropical type with dwarf walls. Both sides were open and covered with wire gauze. Feed and water were provided ad libitum. Health management practices included the administration Newcastle disease vaccine ⁱ/o at day old, infectious bursal disease (Gumboro) vaccine on the 7^th, 21^st and 35^th day, Newcastle disease vaccine (Lasota) on the 14^th, 28^th and 42^nd day, and coccidiostat on the 2^nd, 4^th, 6^th and 8^th weeks. Antibiotics and vitamin mineral supplements were administered during the period of brooding. The experiment lasted 9 weeks.

Experimental Design and Parameters measured

The experimental design was completely randomized design (CRD). The birds were randomly allotted to six treatment diets each containing 0, 5, 10, 15, 20 and 25% BGO. There were 27 birds in each treatment. Each treatment was replicated three times with 9 birds per replicate. Parameters measured were weight gain, feed intake, feed conversion ratio (FCR) and feed cost. Initial live weights of the pullets were determined by weighing them in groups at day-old and individually after 4 weeks of age. The total weight of birds in each replicate was divided with the total number of birds to arrive at the average live weight of birds. Weight gain was determined by subtracting initial live weight from final live weight. Daily feed intake was determined by subtracting the quantity leftover from the quantity given each day. The weighing of birds and feed was done using a top loading (20 kg capacity, Goat Brand^R) weighing scale. Weighing of birds took place in the morning hours (7.00 - 8.00 am) each week. Feed conversion ratio was determined as feed intake divided by weight gain. Protein efficiency ratio was calculated as weight gain divided by protein intake, while cost per kg weight gain was calculated as FCR x cost/kg feed.

Chemical and Statistical Analyses

The proximate composition of the feed was determined according to methods of AOAC (1990) with the Kjeldhal for crude protein, Soxhlet extractor for ether extract and Muffle Furnace for ash. The data collected were subjected to analysis of variance (ANOVA) as described by Steel and Torrie (1980). Differences between treatment means were separated using Duncan's New Multiple Range Test (Duncan 1955).

Results and Discussion

The effect of bambarra groundnut offal (BGO) diets on the performance of pullet chicks was significant (P<0.05) for all the parameters measured, except percent mortality. However, there were no significant (P>0.05) differences between the pullet chicks fed control (0% BGO) and 5% Bambarra groundnut offal (BGO) diets in all the parameters measured (Table 2). 

This could be attributed to the similarities in the nutrient composition of the two diets (Table 1) and suggests that the inclusion of 5% BGO, which replaced 11.11% soybean meal and 14.93% maize in the pullet chick diet, was so low to have affected the performance of the birds. Pullets fed 10% BGO diet had daily weight gain and final live weight that were significantly (P<0.05) higher than those of pullets fed 15, 20 and 25% BGO diets. Values of these two parameters for pullet chicks fed 10, 15, 20 and 25% BGO diets were significantly lower (P<0.05) than the values of pullets fed 5% BGO and control diets. The higher live weight gain and final live weight of pullet chicks fed 5% BGO and control diets could be attributed to higher CP and ME of the diets (Table 1). It could be observed that the CP and ME content of the diets were decreasing with increasing levels of BGO in the diets. Crude fibre content was also increasing, which could have negatively affected the performance of the chicks.

Although, the BGO diets met the lysine, methionine and other nutrient requirements of the pullet chicks (National Research Council 1994), increasing levels of BGO may have adversely affected nutrient utilization probably due to the presence of antinutritional substances (Onwudike and Eguakun 1992; Apata and Ologhobo 1997). The poorer live weight gain and final live weight (8^th weeks) of pullet chicks fed 10, 15, 20 and 25% BGO diets, when compared to those fed 5% BGO and control diets, could also be attributed to imbalance between the first limiting amino acid and the background level of other amino acids (Morris 2004), since the amino acid profile of bambarra groundnut offal was unknown, but assumed from those of the seeds.

The consumption of 20% BGO diet was significantly lower (P<0.05) than those of the control and other BGO diets. This may have been due to diet composition (Acamovic 2001) rather than nutrient deficiency (National Research Council 1994). The feed conversion ratio (FCR) of pullets fed 10, 15 and 25% BGO diets did not significantly differ (P>0.05) from each other, but were significantly higher (P<0.05) than that of pullets fed 5% BGO diet. Protein intake followed the same pattern as feed intake, while protein efficiency ratio (PER) followed the pattern of FCR.

The cost per kg of the diets significantly (P<0.05) decreased with increase in the level of BGO in the diets from 0 to 25% (Table 3).

This caused a significant (P<0.05) decrease in the total feed cost of the pullets. The cost reductions were 6.81, 13.9, 20.0, 36.85 and 28.70% for 5, 10, 15, 20 and 25% BGO diets, respectively. The cost per kg of feed obtained resulted from the lower cost per kg of Bambarra groundnut offal (N18.0) compared to N88.0 for soybean meal and N40.0 for maize. The observed trend in total feed cost resulted from the cost per kg diet and the feed intake pattern of the pullets fed the various treatment diets. The feed cost per kg weight gain of the pullets fed 20% BGO diet was not significantly different (P>0.05) from that of pullets fed 25% diet but was significantly lower (P<0.05) than those of pullets fed control and other BGO diets. This was directly related to the daily weight gain and daily feed cost of the pullets.

Conclusion

The results of this study showed that BGO could be a valuable feedstuff for pullet chicks at 5% inclusion level, which could replace part of soybean meal and maize in the diets. Higher levels of BGO could be included in the pullet chick diet if reduced feed cost is desired at the expense of improved performance.

Acknowledgement

The authors are grateful to Mr Charles Nwaokoro and the entire staff of the Poultry Unit, Michael Okpara University of Agriculture, Umudike for their assistance throughout the duration of the study.

References

Acamovic T 2001 Commercial application of enzyme technology for poultry production. World's Poultry Science Journal. 57: 225-242.

Amaefule K U and Iroanya C O 2004 Replacement of soybean meal and maize offal with bambara groundnut offal in broiler diets. Nigerian Agricultural Journal. 35: 133-142.

A O A C 1990 Official methods of Analysis. Association of Official Analytical Chemists, Washington DC USA.

Apata D F and Ologhobo A D 1997 Trypsin inhibitor and other anti-nutritional factors in tropical legume seeds. Tropical Science. 37: 52 - 59.

Doku E V and Karikari S K 1971 Bambarra groundnut. Economic Botany. 25: 225- 262.

Duncan D B 1955 Multiple Range and Multiple F-tests. A Biometric Approach. 11: 1- 42.

Morris T R 2004 Nutrition of chicks and layers. World's Poultry Science Journal. 60: 5-18.

National Research Council 1994 Nutrient Requirements of Poultry, 9^th Revised Edition. National Academy Press, Washington DC, USA.

Onwudike O C and Eguakun A 1992 Effect of heat treatment on the composition, trypsin inhibitory activity, metabolizable energy level and mineral bioavailability of Bambara groundnut meal with Poultry. In Proceedings XIX World's Poultry Congress, Amsterdam, the Netherlands 20-24 September, 1992. 508 - 513.

Onwudike O C and Eguakun A 1994 Nutritional Evaluation of Raw and Heat-Treated Bambara groundnut meals for Starter Broilers birds. Journal of Agricultural Technology. 2: 38-46.

Onyimonyi A E and Onukwufor J O 2003 Effects of Toasted Bambarra groundnut (Voandzeia subterranea (L) Thouras) waste (TBW) on Performance of growing pullets. Proceedings of the 28^th Annual Conference of the Nigerian Society for Animal Production, 28: 237-239.

Poulter N H 1981 Properties of some protein fractions from Bambara groundnut (Voandzeia subterranea (L) Thouras). Journal of Science of Food and Agriculture. 32: 44 - 50.

Steel R G and Torrie J A 1980 Principles and Procedures of Statistic: A Biometrical Approach. 2^nd Edition, McGraw Hill Books, New York.

Temple V J and Aliyu R 1994 Proximate Composition of the Cream Coloured decorticated Seeds of Bambara groundnut (Voandzeia subterranea (L) Thouras). BioScience Research Communication. 6: 51 - 54.