Effect of feeding processed cowpea (Vigna unguiculata) as replacement of toasted soy bean on egg production and quality of Koekoek (Potchefstroom koekoek) chicken

Kegne Yismaw, Getachew Genetu, Birhan Kassa, Zeleke Jember and Mehari Ayalew

Andassa Livestock Research Center, P O Box 27, Bahir Dar, Ethiopia
kegney2013@yahoo.com

Abstract

This feeding trial was conducted to evaluate the effect of replacing different levels of Toasted and de hulled cowpea (TSCP) for toasted soybean (TSB) on dry matter intake (DMI), egg laying performance and egg quality, substitution level of TCP for TSB on Koekoek chicken diet. One hundred thirty five (135) twenty two week old Koekoek chicken with average initial body weight of 1641.5 ± 23.9 were used for the experiment. Chicks were equally and randomly distributed in five dietary treatment groups in a completely randomized design and each treatment group contained 27 birds distributed in three replication pens with 9 birds in each replicate. Treatments were Iso-nitrogenous and Iso-caloric with the replacement of TCP for TSB with TCP0= 0% TCP and 20% TSB; TCP8= 7.8% TCP and 15% TSB; TCP16= 15.7% TSB and 10% TSB; TCP24= 23.5% TCP and 5% TSB; TCP32= 31.4% TCP and 0% TSB. Initial and final body weight, egg production, feed offered and refusal was recorded. Egg quality analysis was conducted three times, at 5% of egg lying, at 50% laying and at peak laying periods. Data were analyzed using GLM procedure with SAS computer software SAS 9. (2004). Significant difference between treatments means were separated with tukey test with 5% significance level. There was significant difference (P < 0.05) among treatment groups in daily feed intake per bird while, FCR was not significant (P >0.05) in treatment groups. There was no any significant difference in total egg production, hen day and hen housed egg production, external and internal egg quality of birds except albumen height in treatments. The total mortality percentage of birds was 2.96. The main reason for the mortality of chicks was unknown predator at nighttime. In general, the results indicated that TCP can substitute 100% for TSB with 31.4% level of inclusion without affecting the egg production performance, egg quality and body weight change of Koekoek chicken. Therefore, toasted and de-hulled cowpea can be used as a good alternative protein supplement in substitute of toasted soybean for commercial poultry feed production in the areas where cowpea is widely cultivated.

Keywords: egg performance, protein sources, substitution

Introduction

Animal production in general and poultry production in particular plays important socio-economic roles in developing countries (Alders 2004). Poultry production plays a major role in bridging the protein gap in developing countries where the average daily consumption is far below recommended standards (Onyimonyi et al 2009). However, the productivity of poultry in the tropics has been limited by inadequacy and subsequent high prices of the conventional protein and energy feed sources. Protein sources are restraining factors in poultry feed production especially in the tropics (Atawodi et al 2008). Considerably, in chicken production feed represents the major cost of poultry production which lies between 65 and 75% and especially, there has been overdependence on soybean meal as a source of protein due to lack of alternative source of protein in Ethiopia which has led to high production costs in the poultry industry (Adino et al 2018). As a result of using importable feed ingredients in poultry production, conventional poultry feeds remain to increase in price in the country over several years. Since, the use of non-exportable feed ingredients is able to secure to reduce the cost of production. To this regard, it is necessary to search for readily available local feedstuffs to replace imported protein sources during period of soybean shortage (Teguia et al 2007).

Amongst the potential sources of plant protein, grain legumes like cowpea could be good substitutes to soybean meal since they are known to have a comparable amino acid profile (Ugwu and Onyimonyi 2008). The cheapness of the most legumes seeds as plant protein sources compared to animals protein can encourage their utilization in feeding animals and poultry especially in developing tropical countries, in which the climatic condition are suitable for their growth and existence. Cowpea can be grown on a wide range of soil conditions even in marginal areas by poor resource farmers. It is an excellent and inexpensive source of protein, fatty acid, essential amino acid, vitamins and minerals (Fageria et al 1990). Recent works have revealed that cowpea has promising potential as feedstuff for poultry. Its incorporation in diets of poultry has reduced the cost/kg of feed and improved growth and other production parameters (Teguia et al 2007; Chakam et al 2008). A disadvantage of many grain legumes including cowpeas ( Vigna unguiculata ) to fed in raw form to poultry has a difficulty due to anti nutritional factors (ANFs), in particular protease inhibitors. Although most of these ANFs can be reduced by appropriate means such as heat treatment or enzyme additives as a result it improves protein utilization (Robinson and Singh 2001).

According to Shi et al (2012) soybean meal, as the primary and most dependable protein source for poultry feed, is becoming progressively overpriced; therefore, there is a need to look for alternative economical, easily available and quality protein sources. In this regard studies had not made in our country in feeding of cowpea with substitute of soybean for Koekoek layer chicken. Therefore, this study was conducted aimed with the following objectives.

Objective

To evaluate the effect of processed cow pea on egg production performance and quality of Koekoek chicken

chicken To determine the substitution level of processed cow pea for toasted soybean

Materials and methods

Research design and diet formulation

The research design was completely Randomized design (CRD). The experiment was conducted with of one hundred thirty five (135) female koekoek pullets at the start of egg lying (at 22 weeks age) with average initial body weight of birds was 1641.5±23.9 gram. birds were randomly distributed in five dietary treatment groups in consisted of 27 Koekoek layers and in three replication pens with 9 birds in each replica. The raw cowpea grain (kenkety 9333) cultivar was socked to water for 15 minutes and then after the grain was allowed to dry with sun light. It was toasted using metal plate by putting on the fire flame. The grain was grinding using electrical mill to make suitable for de-hulling and the hull was removed manually. The feed ingredients were purchased in nearby local market, Bahir Dar. Five nearly iso-nitrogenous and iso-caloric diets were formulated by substitution of TCP for TSB for Koekoek layers diets. The treatment diet contains; TCP0= 0% TCP and 20% TSB; TCP8= 7.8% TCP and 15% TSB; TCP16= 15.7% TSB and 10% TSB; TCP24= 23.5% TCP and 5% TSB; TCP32= 31.4% TCP and 0% TSB. The diet formulation for Koekoek layer chicken is shown in Table 1.

Chicken management and feed analysis

The study was conducted at Andassa Livestock Research Center in deep litter system for a total age of 45 weeks) for 23 weeks (part time production period with the pens of 1.5*2 meter wide. Whole units of the pens were cleaned and the concrete floor was bedded with well dried hay with 10 to 12 centimeter thickness. The house was disinfected with disinfectant using formalin before 5 days placement of birds. The daily weighted quantity of ration was given three times a day, Early in the morning, at mid-day and late in the afternoon. Clean and cool water was provided adlib. Representative feed samples were taken from each of the feed ingredients and samples were sent to Tokachi Nokyonen Agricultural cooperative at Co., Obihino. Hokkaido Japan for analysis. The feed samples were analyzed based on proximate analysis of poultry feeds, Association of Official Analytical Chemists recommended methods AOAC 1990, and determined the DM, CP, ME, TDN, NDF, ADF, ADL, EE and Crud ash. Metabolizable energy (ME) contents of feed ingredients were calculated based on NRC (1989). The CP content was analyzed using the N analyzer (Gerhardt Vapodest 50S) by Kjeldahl method, in which % CP is expressed as % N×6.25. The crude fat (EE) was analyzed using automatic crude-fat extractor (Gerhardt Soxtherm 416). Amino acid analysis was done using High Performance Liquid Chromatograph (HPLC) (Shimadzu Prominence). The crude ash was obtained by combustion / burning with the temperature of 550°C for greater than 2 hours. Minerals were analyzed using method of atomic absorption spectrometry using (Shimadzu AA-7000).

Data collection and analysis

The total feed offered and refusal in each morning was weighted and recorded with sensitive balance. Total and average daily feed intake/bird (g) and feed conversion ratio (FCR) was calculated. Initial body weight was recorded with sensitive balance 0.01g sensitivity. And total weight and daily gains (g) were calculated. Hen day rate of egg production (HDEP) was calculated with the following formula:

Average number of bird alive x Number of days in lay

Where: HDEP = hen-day rate of egg production.

A total of 586 fresh eggs were sampled and 117 eggs per treatment at 5% production, at 50% and at peak laying production periods were measured for internal and external egg quality measurements. Egg weight and shell weight was taken using electronic digital sensitive balance of 0.01(g) capacity. Egg length, width and shell thickness were measured using digital caliper (mm). Shell thickness measurement was taken by removing the thin membrane as the averages of readings at 3 different points, at the small and large end and at the middle part of the egg. Albumen and yolk heights were taken using tripod micrometer having an accuracy of 0.01mm on a table glass. Albumen height was taken as the averages of readings at 3 locations of the albumen. The yolk color was determined according to Roche yolk color fan (1-15). The percentage of shell, albumen, yolk and yolk albumen ratio were calculated as stated by (Kumari et al 2008). Individual Haugh unit score was calculated using the egg weight and albumen height for individual egg using the formula: Hu= 100 log (AH + 7.57-1.7 EW^0.37), where; Hu is Haugh unit, AH is thick albumen height in mm and EW is egg weight in gram (Haugh 1937). Data collected were subjected to ANOVA using the General linear model (GLM) procedure of SAS Computer software (SAS 9.0.). Tukey method was used for mean separation at significance level of 5%. The following linear model was used for the analysis of quantitative data; Yij = μ + αi + еij; Where; Yij = the observation in ith treatment, μ = the overall mean measurement across all treatments, αi = the effect of ith treatment and еij = the random error.

Results and discussion

Feed analysis

The CP and ME content of TCP showed in table 2 and 3 that obtained through chemical analysis was comparable with the report of (Embaye et al 2018) reported that 25.8% and 3307.4 kcal/kg respectively. Similarly, the CP result was supported by the finding of (Adino et al 2018) which was 26.3% while, the ME result was a bit higher than the current result (3562 kcal/kg) for cow pea at Dahina District, Ethiopia. However, the current finding of CP was higher than the reports of Ayana et al (2013) and (Khattab and Arntfield (2009). Variation in nutritive value of cowpea in different studies resulted in different factors such as cultivars, growing environment, methods of processing and post-harvest handling (Khattab and Arntfield 2009). Thus TCP was able to meet the CP, ME and amino acid requirements especially lysine and methionine of layer chicken.

Feed intake and Egg production performance of birds

Feed intake and egg production performance of birds is showed in table 4. Results revealed differences (P < 0.05) among treatment groups in daily feed intake, while difference was not observed (P >0.05) in FCR. Higher daily feed intake was observed on TCP8 and TCP16 to the control group (TCP0). The reason might be due to the presence of TCP and TSB nearly in equal amounts in the ration at TCP8 and TCP16 and this might be encouraged the daily feed intake of birds. Feed intake result was supported by the study of (Eljack et al 2010) reported that feeding of cowpea up to 30% has no significant effect in total and weekly feed intake on the broilers diet. Similarly, Chakam et al (2008) reported statistically similar result for the study of feeding cooked cowpea seeds to broilers up to 30% for total feed intake. However, the present result was not agreed with the study of (Mulwa et al 2017) reported that daily feed intake was significantly different in Kenbero chicks fed with 100% substitution of cowpea with soybean with 28% of inclusion diet. The FCR result was in line with the study of (Chakam et al 2008) reported that feeding of cow pea up to 30% has no statistical difference in weight gain and feed conversion ratio in broiler diet. Similarly, (Amaefule et al 2007) reported that feeding of toasted pigeon pea up to 30% inclusion level with 75% substitution of soy bean has no significant difference in feed conversion ratio (FCR) on black bovan Nera chicken. Even though the daily feed intake of birds significantly different at TCP8 and TCP16, FCR was similar between those treatments. This entails that, 100% TCP substitution with TSB did not affect the Daily feed intake and FCR of egg laying Koekoek chicken. Significant difference was not observed in total egg production and hen day egg production. This result was in line with the study of (Amaefule et al 2007) reported that feeding of toasted pigeon pea up to 30% inclusion level has not differ in hen day egg production and total egg mass on black bovans nera chicken. Similarly, (Maidala et al 2016) fed cowpea seeds 0%, 20%, 30%, 40% and 50% and noted that inclusion of cowpea up to 30% in to broiler diets has no negative effects on carcass yield and gut characteristic. Moreover, the values found in hen day egg production was supported by the study of (Dawud et al 2018) reported that, (55.5%) of hen day egg production for koekoek chicken. However, the hen day egg production of the present study was a bit lower than the finding of (SAARCAPI 2010) reported that 60.35 - 61.09 hen day egg production for Koekeok chicken. This variation might be resulted in environmental and management differences on the experimental birds.

Egg quality analysis

Variations were not observed between treatment groups in external and internal egg quality of birds except albumen height (Table 5). TCP16 was significantly lower to TCP32 in albumen height. But TCP16 was found similar result to the control and other treatment groups in albumen height.

The average egg weight in this study was ranged in 45.75-46.77 gram. The result was closer with the finding of (Lishan 2017) reported that 42.80 gram of average egg weight for Koekoek chicken. However, the egg weight result was a bit lower than that of the study of (Dawed et al 2018) reported 53g and (Dereje and Tesfaye 2018) reported that 50.8gram for Koekoek chicken. The result found in egg height and width was nearly similar with the report of Lishan (2017) reported that 49.62 and 38.24mm respectively for Koekoek chicken while, it was failed to agree with the result of (Dawed et al 2018) reported that 52.9 and 41.3mm for egg height and width for Koekoek chicken respectively. The shape index reported under this study falls within the normal range 72-76 (Altuntas and Sekeroglu 2007). Eggshell thickness also found in the recommended rage that is between 0.33 and 0.35 mm (Khan et al 2004). An eggshell thickness of at least 0.33 mm has been estimated to be necessary for the egg to have at least a 50% chance of withstanding normal handling conditions without breaking (Stadelman 1995). The shell weight result was ranged in 4.79- 4.84gram and the shell ratio value was 10.38-10.68 and nearly similar to the report of (Lishan 2017) which is 5.19gram and 12.08, respectively for koekoek chicken. The albumen weight, yolk weight, yolk color and yolk/albumen ratio result was in line with the result of (Dereje and Tesfaye 2018) reported that 26.13gm, 13.62gm, 3 and 56.86 respectively. Likewise, (Dawed et al 2018) reported similar results of 29.7, 56.2 and 30.0 for albumen weight, albumen ratio and yolk ratio respectively for koekoek chicken. Moreover, the yolk weight and albumen weight results were supported by the study of (Hunton 1987) that reports Egg yolk accounts for slightly over 30% of total egg weight and albumen represents the largest proportion of the egg being estimated to be 58.5% of the total egg. The albumen height was ranged in 2.76- 3.13mm. This result was failed to meet the recommendation of (Zeidler 2002) with albumen heights of 8 to 10 mm being considered superior interior quality of the egg. Similarly, the HU unit of the current study was failed to agree to the recommendation of (Coutts and Wilson 1990) suggested that, most of eggs leaving the farm should be between 75 and 85 HU. The deviation in albumen height and HU might be due to the absence of cooling room to store eggs until the periods when the egg quality test was made and due to high temperature of the season which the experiment was conducted. (Rajkumar et al 2009) reported that Age of the hen and season of the year can also affect Haugh unit values. Thus, the egg quality result showed that 100% substitution of TCP with TSB had not showed negative effect on external and internal egg quality of Koekoek chicken.

Mortality of birds

The total mortality percentage of birds in 22-45 weeks period was 3.70%. This result was closely comparable to the finding of (Dawed et al 2018) which was reported 3.56% of mortality for egg laying parent stock Koekoek chicken with the period of 17-60 weeks age at Debre Ziet ARC. However this result was showed lower mortality percentage to the report of (Dereje and Tesfaye 2018) recorded that 18.04% of mortality for male and female laying of Koekoek chicken in a period of 27-48 weeks age at Bako ARC. In the current study the main reason for mortality of birds was unknown predator at night time. The predator expected to be snake because of once a day snake was found and killed at night in the pen of birds.

Conclusion

• The results indicated that TCP could be replaced 100% of TSB with 31.4% level of inclusion without affecting the egg production performance and egg quality in the diet of egg laying Koekoek chicken.
  
  
•  Therefore toasted and de-hulled cowpea can be used as a good alternative protein supplement in substitute of toasted soybean for commercial poultry feed production in the areas where cowpea is widely cultivated.

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