Heterosis and reciprocal effects of growth performances in F1 crosses generations of Local x Hubbard chicken in the Western Highlands of Cameroon

T C Keambou, Y Manjeli, B Boukila*, S Mboumba*, T Mezui Mezui* and B A Hako Touko

Faculty of agronomy and Agricultural Sciences, University of Dschang - Cameroon
* National institute of agronomic sciences and biotechnologies, University of sciences and techniques of Masuku - Gabon
christike2002@yahoo.fr

Abstract

This study had as objective to contribute to the genetic improvement of the local chicken by direct and reciprocal crossings with an exotic standard strain. The experimental birds where the parental genotypes HH (pure Hubbard strain; 88), LL (pure local chicken; 58) and their reciprocal crossbreds HL (crossbreds Hubbard rooster x local hen; 36) and LH (crossbreds local rooster x Hubbard hen; 39).  It came out from the study that the effect of genotype was significant on all the parameters under study. The products of the crossings (F1) presented intermediate performances to those of their pure parents HH and LL.

The effect of the heterosis was in general weak and positive only in some cases. As related to food consumption and feed efficiency, negative heterosis revealed a lower consumption of the crossbreds and a better food conversion for the LH at the seventh week (-15.6% and -19.7%). The mean parents in general had some performances higher to those of their descendants, notably for growth and conformation traits, probably due to breeds used. The results obtained for LH in relation to HL are confirmed by the reciprocal effect analysis. It revealed that for all parameters, in general, notably the live weight (311.6 g), the DWG (19.3 g), the consumption index (-2.5) and the carcass yield (577.8g), the local rooster x exotic hen crossing was superior to the exotic rooster x local hen crossing. This crossing could, consequently, allow higher genetic gains in shorter time and therefore reach the objectives of the crossings more quickly. Crossings with Hubbard breed upgraded the local chicken by 6.8% and 80.6% of live weight respectively in HL and LH genotypes, and carcass percentages by 17.5% and 143.6% in the same genotypes as compared to the pure local parental genotype. The coefficient of variation for live weight at 7^th week of age was 13.8% in HL and 16.1%in LH, while the carcass yield varied by 17.3% and 7.4% respectively in HL and LH.

The local fowl could then be favourably used as sire breed in crossbreeding programs, but several crossing generations and selection will be needed for homogenization and stabilization of a LH genotype

Key words: exotic chicken, crossbreds, hybrid vigour, maternal effects, native chicken

Résumé

Cette étude avait pour objectif de contribuer à l’amélioration génétique de la poule locale par croisements directs et réciproques avec une souche standard exotique. Les animaux expérimentaux étaient des génotypes parentaux HH (souche hubbard pure ; 88), LL (poule locale pure ; 58) et leurs croisés réciproques HL (croisé coq Hubbard x femelle locale ; 36) et LH (croisé coq local x femelle Hubbard ; 39). Il en est ressorti que l’effet du génotype a été significatif sur l'ensemble des paramètres étudiés. Les produits des croisements (F1) présentent des performances intermédiaires à celles de leurs parents HH et LL.

L’effet de l’hétérosis a été dans son ensemble faible et positif seulement dans quelques cas. Quant à la consommation alimentaire et l'indice de consommation, l’hétérosis négative a traduit une consommation moindre des croisés et une meilleure conversion alimentaire pour les LH à la septième semaine (-15,6 % et -19,7 %). Les parents moyens dans l'ensemble ont eu des performances supérieures à celles de leurs descendants, notamment pour les performances de croissance et de conformation; le type de souches utilisées pour les croisements étant probablement la cause. Les résultats obtenus chez les LH par rapport au HL sont confirmés par l'analyse des effets réciproques. Elle a révélé que pour tous les paramètres en général, notamment le poids vif (311,6 g), le GMQ (19,3 g), l'indice de consommation (-2,5) et le rendement carcasse (577,8g), le croisement coq local x poule exotique est supérieur au croisement coq exotique x poule locale. Ce croisement permettrait donc d’avoir dans un bref délai les meilleurs gains génétiques et d’atteindre plus rapidement les objectifs des croisements. Les croisements avec la race Hubbard ont amélioré les performances de la poule locale de  6,8%  et 80,6%  du poids vif respectivement chez les génotypes HL  et LH,  et les proportions de la carcasse de 17,5% et 143,6% chez les mêmes génotypes comparativement au génotype parental de la poule locale en race pure. Le coefficient de variation du poids vif à la 7^ième semaine d’âge a été de 13,8% chez le croisé HL et 16,1% chez LH, alors que le rendement carcasse a varié de 17,3% et 7,4% chez la HL et LH respectivement.

La poule locale pourra donc être utilisée comme parent male dans les programmes de croisement, mais plusieurs générations de croisement et de sélection seront nécessaires pour homogénéiser et stabiliser le génotype LH.

Mots clés: croisés, effets maternels, poule exotique, poule locale, vigueur hybride

Introduction

Native chickens play an important role as household food supply in rural areas of developing countries (Kitalyi 1998, Zaman et al 2004) and recently have been raised in semi-intensive systems with more efficient output per bird (Saadey et al 2008).

The avian population in Cameroon is made of 70% of local chicken (Fotsa et al 2007), of small size having a low productivity and of about 24% of exotic breeds (Tchoumboue et al 2000, Fotsa and Manjeli 2001, Téleu Ngandeu and Ngatchou 2006, Fotsa et al 2007). The Hubbard bird is one of the most exploited exotic lines in Cameroon for semi-intensive and intensive poultry production, but ample evidences pointed that the environment is a limiting factor for the performance of commercial strains (Washburn 1985, Washburn et al 1992; El-Gendy and Washburn 1995). Generally, native chickens show much genetic variation unexploited yet (El-Gendy et al 2007) and the massive information generated by genome scanning and collaborated with the phenotypic information has brought the local breeds into valuable research (El-Gendy 2009). The exploitation of the good adaptive features of the local chicken would be more efficient through inter-mating with highly performance exotic breeds to exploit the phenomenon of heterosis.

The crossbreeding improves the heterozygosis of non additive genes causing the heterosis, which is important in the adverse environmental conditions. In fact, crossings constitute one of the tools for the exploitation of the genetic variation and the hybrid vigour by combination of the different important characteristics of each breed (Willham and Pollack 1985, Hanafi and Iraqi 2001) and for the exploitation of maternal genetic effects or sex-linked effects, associated to particular combinations between breeds or lines. The analysis of the combining aptitudes and the difference between the productive performances of crossbreds help in identifying the best possible combinations in the exploitation of hybrid vigour according to the desired objectives (Mekki et al 2005). The crossings between the adapted local chicken and exotic standard breeds would allow exploiting the rusticity of first and the productive performances of the later at a time in tropical environment to produce adapted and more productive genetic types.

This research aimed to contribute to the productivity improvement of the local chicken, to evaluate the heterosis and reciprocal or maternal effects on growth performances and carcass yield, to estimate the superiority of reciprocal crossbreds to the pure local parental stock and the variation coefficient of each parameter within a crossbred genotype that will help in identifying the most advantageous crossing pathway, to evaluate the carcass yield and the organs proportions of the crossbreds as compared to the pure parental breeds. 

Material and methods  

Site

The survey has been achieved at the Application and Research Farm of the University of Dschang (F.A.R-UDs) situated in the Western Highlands of Cameroon (5°20'-7°00 ' LN and 10°03'-12°00 ' LE. The climate there is of the sudano-guinean type modified by the altitude, the temperature range varied from 16 to 27°C and the relative humidity from 40% during the most dried months (January-February) and 100% for the most humid months (July-august). The rain falls, with an average of 2000 mm a year are distributed on one season starting from March to November (Hako et al 2009).

Animals

The parental stocks were constituted of an exotic Hubbard (HxH) chicken, the Cameroon local normal feathered chicken (LxL) and of their reciprocal crossings (HxL and LxH) with a sex-ratio of 1male/8females, for a total number of 4 roosters and 32 females per lodge. The lodges were all equipped of three constituted linear boxes, each of four 30x30x25 cm dimension nests. A semi automatic drinking trough of 6 litres and two metallic conical feeding troughs of 40 cm diameter to the base were placed in every lodge. The crossings were by natural mounting under natural photoperiod.

The eggs  

Following the crossbreeding design, eggs were collected, cleaned, classified and kept at room temperature during 7 days before incubation.  

The chicks 

The experimental birds where the parental genotypes HH (88), LL (58) and their reciprocal crossbreds HL (36) and LH (39) at the beginning of the experiment.  At hatching, the chicks were identified by rings placed at the left shank. The live weight and the body measurements were raised before their transfer to the chicken-coop according to the genetic groups. Lodges were provided with a deep litter of wood chip. The density was 8 chicks/m². At the fourth week, the rings were transferred from the shanks to the left wing. During the week, the food brought to every group was weighed and at the end of weeks, the live weight and the individual body measurements were collected and the leftover weighed. The animals had free access to food and water. The prophylaxis programme was the standard from that in use at the FAR-UDs. Breeders and chick feed composition is shown in table 1.

Traits measured, data collection and calculations

Data collected were feed consumption and weight on a weekly basis, which in turn allowed calculation of the daily weight gain and consumption index. Also, body measurements were recorded weekly and at the end of the experiment, a sample of six birds per genotype were slaughtered for carcass analysis. The heterosis effects for each parameter were calculated as follows:
 

H_AB (%) = [[(PF₁ - (P_A+P_B)/2] x100] / (P_A+P_B)/2

Where

H_AB (%) is the heterosis (in percentage of parental performances),

PF₁ is the mean performances of F₁ reciprocal crossbreds,

P_A is the mean performance of parents A,

P_B is the mean performance of parents B.

The reciprocal effects for each parameter were calculated as the difference between reciprocal F₁ performances:
 

RE = PF_{1 (HL)} – PF_{1 (LH)}

Where

RE is the reciprocal effect

PF_{1 (HL)} is the mean performance of the F₁ from a Hubbard rooster and local hen crossings,

PF_{1 (LH)} is the mean performance of the F₁ from a local rooster and Hubbard hen crossings.

Statistical analysis

The collected data were submitted to the one factor analysis of variance, the mean separation was made by the Duncan test when significant differences existed between them. The analysis was done using SPSS 12.0 software at 1% significance level.  The statistical model used was:
 

Y_ij = μ + g_i + e_ij;

Where:

Y_ij = performance of the j^th individual of the i^th genotype (j =1-6)

μ  = general mean of the parameter

g_i   = fixed effect of the genotype i (i=1- 4)

e_ij = residual error

Results   

The analysis of variance of the effect of genetic factor on the evolution of the growth parameters, conformation and carcass characteristics of the chicks is presented in tables 2 and 3. 

It comes from table 2 and 3 that the live weight, the evolution of the daily weight gain, tarsus diameter, wing length, carcass yield as well as the organs weight, calculated as chicks live weight percentage were highly influenced (P<0.01) by the genotype. The variability between the genetic groups indicates the differential development of every group with age. 

Heterosis and reciprocal effects

Table 4 presents the heterosis and reciprocal effects obtained between the LH and HL crosses at the seventh week for all parameters under study.

It appears from the analysis of table 4 that the food consumption presented a negative value of the heterosis what ever the crossbred genotype, indicating an advantage of the F₁ upon the mean parental performance. In other words, for this parameter, the LH and HL crossbreds consumed less food than the pure mean parents. 

For the other parameters the negative values of heterosis means the superiority of parents in relation to the F₁crossbreds. However, the -100% heterosis observed for mortality shows the hybrid vigour of the chicks crosses. Then the crossings of the exotic Hubbard strain to the local chicken produced better rustic chicks but with a low productivity. An economic evaluation is necessary to compare the effect of the complementarity in hybrid vigour and the one of the productivity. 

The reciprocal effect values (RE) obtained between the LH and HL crosses at the seventh week revealed that for the quasi - totality of the parameters, the LH crosses proved to be more proficient than their HL counterparts. Also, the use of the exotic breeds as mother and the local rooster as sire would provide maximum of advantages with regard to the studied characters. 

Coefficients of variation and upgraded rate of crossbreds as compared to local parental performances

Table 5 shows in percentages the superiority of reciprocal crossbreds to the pure local parental stock and the variation coefficients of each parameter within the crossbred genotype.

These results showed that crossing considerably upgraded the local chicken for the economic characters such as live weight (6.8% and 80.6% respectively for HL and LH) and carcass percentages (17.5% and 143.6% for HL and LH). Moreover, the consumption index has been reduced by 37.0% in LH but raised by 16.7% in HL. This had as consequence a variation in the daily weight gain (143.5% and -6.1% respectively in LH and HL). Considering the coefficients of variation, they were higher in LH for growth and conformation characters but lower for carcass characters, suggesting that selection or further crossings still to be performed to homogenize and stabilize the genotype.

Discussion   

The strongly negative heterosis effects obtained in this study with the mean reciprocal crossbreds could be attributed to the greater genetic distance between the tested breeds. These results are not in accordance with those of Mafeni et al (2005) who used as exotic birds the German Dahlem Red crossed to the Cameroon local chicken, but corroborate the results of works achieved by Fotsa and Manjeli (2001) that got in general, the parental aptitudes superior to those of the F1 for parameters such as the daily weight gain, food consumption and consumption index. As compared to our results (-53.2% for HL and -20.8% for LH), Fotsa (1985) reported a better heterosis for the growth (16.9%). However, considering each reciprocal crossings, the heterotic effects were higher in LH than in HL and confirm Liu et al (1995) according to whom heterosis is influenced by maternal effects. On the other hand, this difference in results would find their explanation in the exotic genetic type used. Fotsa (1985) used the Jupiter that is of small size whereas the Hubbard is a breed selected for meat production and therefore heavier. The weak or negative heterosis observed could be explained by the high difference of growth and conformation performances existing between the local chicken and the exotic breed. Indeed here the local chicken, by its conformation and size is naturally intended for laying aptitude, whereas the Hubbard is a meat breed. The higher the heterosis, the smaller the degree of genetic resemblance between parental populations (Willham and Pollack 1985), the magnitude of heterosis is then expected to be proportional to the degree of heterozygosity of crosses (Sheridan 1981). The performances of LH, although lower to those of the improving breed, let foretell an increase of the heterosis and therefore a reduction of the performance gap between the exotic breed and the local one during the subsequent generations (F2, F3…). The reciprocal or maternal effect computed gives an advantage to the cross between the local rooster and female Hubbard breed, similar results were obtained by Hanafi and Iraqi (2001) and Singh et al (1983). The difference between the two genetic types (LH and HL) could be explained, by the possible genotypic difference between LH and HL as transmitted either by the father's way or by the mother's way, but also, this difference could be linked to a possible difference of the combining aptitudes between males and females of the local and exotic breeds. Thus the use of local fowls could be recommended as sire breed in crossbreeding programs, contrarily to what was done in the “Opération Coq’’ program in the 1950’s in must African countries where exotic roosters were mated to local hens. Furthermore, it may be beneficial to view heterosis for economic trait as coefficients of variation, coefficient of determination and as deviations from parental means (Saadey et al 2008), since this approach may enhance improvements in performance as well as uniformity which is becoming increasingly important with greater mechanization in production and processing.

In the present study the coefficient of variation of live weight (16.1%) is lower than the 20.7% obtained by El-Gendy (2009) at similar age. This difference may be attributed to the genetic diversity among the breeds. Whatever the situation, these results suggest further efforts in the homogenization of the crossbreds, with special attention to the LH crossbred which demonstrated 80,62% superiority in live weight to the local pure breed, as compared to 6.8% recorded by HL. Segura et al (2004) reported a significant improvement in meat production of native Mexican breeds when crossed with commercial strains.

The coefficients of variation for growth, conformation and carcass parameters could be attributed to the effect of sex. In fact, Keambou et al (2007) reported a sex-linked variation in body measurement in local chicken from the Western Highlands of Cameroon. That sex effect increases with age (El-Gendy 2009). 

Conclusions    

• The analysis of the heterotic effect showed negative effects for the studied characters, suggesting the superiority of the mean parents in relation to the mean crossbred. However, it is observed a strong mortality in HH chicks whereas the local race proved to be more rustic. Live weight, daily weight gain, body measurements and carcass yield are highly influenced by the genotype. The LH and HL crossbreds consumed less food than the pure mean parents (HH and LL) while the later were superior to the F₁crossbreds for other growth parameters. The LH crossbreed is more proficient than his HL counterpart. Some economic studies are necessary for a better comparison of the results obtained. The use of exotic breed as dams and the local rooster as sire provided maximum advantages. 

  
  

• LxH crossings considerably upgraded the local chicken by 80.6% in live weight and 143.6%in carcass percentage and reduced the consumption index by 37.0%.The higher variation coefficient for growth and conformation characters suggested that further crossing generations (F2, F3...) and selection must be performed to homogenise and stabilize the LH genotype 

  
  

• Hence the use of local fowls could be recommended as sire breed in crossbreeding programs for the improvement of local chicken flock performances.

References  

El-Gendy E A 2009 A model for the genetic employment of chickens local to warm climate.1. Crossing with a fast growing strain and growth patterns of crossbreds. International Journal of Poultry Science 8(3) 299-306

El-Gendy E A and Washburn K W 1995 Genetic variation in body temperature and its response to short term acute heat stress in broilers. Poultry Science 74: 225-230.

El-Gendy E A, Nassar M K and Mostageer A 2007 Genotype-Environment interaction in relation to heat tolerance in chickens.2. Variation in juvenile growth of warm region’s oriented breeds. International Journal of Poultry Science 6: 322-328. http://scialert.net/pdfs/ijps/2007/322-328.pdf

Fotsa J C 1985 Consommation, croissance et indice de consommation de la progéniture des croisements race Jupiter et poules locales. Mémoire d'ingénieur agronome, ENSA de Yaoundé - Cameroun. 68p.

Fotsa J C, Bordas A, Rognon X, Tixier Boichard M, Poné K D and Manjeli Y 2007 Caractérisation des élevages et des poules locales et comparaison en station de leurs à celles d'une souche commerciale de type label au Cameroun. Journée de la recherche avicole 7:  414-417 http://www.journees-de-la-recherche.org/JRA/Contenu/Archives/7_JRA/genetique/G86-FOTSA%20version-def.pdf

Fotsa J C and Manjeli Y 2001 Analyse comparée des performances de croissance en claustration des poussins de souche locale, d'une lignée Jupiter et de leurs croisements F1. Annales des Sciences Agronomiques du Bénin 2 (2): 181-192.

Fotsa J C. Poné K D, Manjeli Y and Ngou Ngoupayou J D 2007 The state of Cameroon Rural Chickens: Production and development Perspectives for poverty alleviation. Ghana Journal of Animal Science, volumes 1 and 3 (1): 175-180

Hako Touko B A, Manjeli Y, Teguia A et Tchoumboue J 2009 Evaluation et prédiction de l’effet du type génétique sur l’évolution du poids vif de la poule locale camerounaise (Gallus domesticus). Livestock Research for Rural Development. Volume 21, Article #31. Retrieved March 11, 2009, from http://www.lrrd.org/lrrd21/3/hako21031.htm 

Hanafi M S and Iraqi M M 2001 Evaluation of purebreds, heterosis, combining abilities, maternal and sex-linked effects for some productive and reproductive traits in chickens. Second International Conference on Animal Production and Health in Semi-Arid Areas, 4-6 September, Organized by Faculty of Environmental Agricultural Sciences, Suez Canal University. El Arish-North Sinai, Egypt, pp: 545-555.

Keambou T C, Manjeli Y, Tchoumboue J, Teguia A et Iroume R N 2007 Caractérisation morphobiométrique des ressources génétiques de poules locales des hautes terres de l'ouest Cameroun. Livestock Research for Rural Development. Volume 19, Article #107. Retrieved August 10, 2007, from  http://www.lrrd.org/lrrd19/8/keam19107.htm

Kitalyi A J 1998 Village production systems in rural Africa. Household food security and gender issue, FAO http://www.fao.org/docrep/003/w8989e/w8989E00.HTM

Liu G, Dunnington E A and Siegel P B 1995 Growth related traits in body weight selected lines and their crosses reared under different nutritional regimes. British Poultry Science 36: 209-219

Mafeni M J, Horst P, Vershulst A and Pone K D 2005 Production performance and exploitation of heterosis in Cameroon indigenous and German Dahlem Red chickens and their crossbreds. Bulletin of Animal Health and Production in Africa 53: 266-272.

Mekki D M, Yousif I A, Abdel R M K, Wang J and Musa H H 2005 Growth Performance of Indigenous X Exotic Crosses of Chicken and Evaluation of General and Specific Combining Ability under Sudan Condition. International Journal of Poultry Science 4 (7): 468-471 http://scialert.net/pdfs/ijps/2005/468-471.pdf

Saadey S, Mekky A, Galal HIZ and Zein El-Dein A 2008 Diallel crossing analysis for body weight and egg production traits of two native Egyptian exotic chicken breeds. International Journal of Poultry Science 7 (1): 64-71 http://scialert.net/pdfs/ijps/2008/64-71.pdf

Segura-Correa J C, Sarmiento F L, Magana M I G and Santos-Ricalde R 2004 Productive performance of creole chicken and their crosses raised under semi-intensive management conditions in Yucatan, Mexico. British Poultry Science 45: 342-345.

Sheridan A K 1981 Crossbreeding and heterosis. Animal Breeding Abstracts 49:131-144.

Singh Y P, Singh R V, Chaudhary R P and Singh V 1983 Diallel crossing for estimation of GCA, SCA, heterosis and other genetic effects of various traits in White Leghorn. Indian Veterinary Journal 60: 384-389.

Tchoumboué J, Manjeli Y, Teguia A et Ewane N J 2000 Productivité et effets comparés de trois systèmes de conduite de l'élevage sur les performances de l'aviculture villageoise dans les Hautes Terres de l'Ouest Cameroun. Science Agronomique et Développement 2 (1) 6-14.

Teleu Ngandeu E et Ngatchou A 2006 Première évaluation du secteur avicole au Cameroun: structure et importance  du secteur avicole commercial et familiale pour une meilleure compréhension de l'enjeu de l'influenza aviaire. Project OSR/GLO/MUL, Emergency assistance for the control ant prevention of avian influenza, FAO, 48p.

Washburn K W 1985 Breeding of poultry in hot and cold environments. In: Yousef M K (editor), stress physiology in livestock, volume 3: poultry. CRC press Inc, Boca Raton, FI, USA.

Washburn K W, El-Gendy E and Eberhart D E 1992 Influence of body weight and response to a heat stress environment. In: proceedings of the 19^th World Poultry Congress. Amsterdam, pp: 53-56.

Willham R L and Pollack E 1985 Theory of heterosis, Journal of Dairy Science 68: 2411-2417  http://jds.fass.org/cgi/reprint/68/9/2411

Zaman M A, Sorensen P and Howlider M A R 2004 Egg production performances of a breed and three crossbreeds under scavenging system of management.  Livestock Research for Rural Development, 12(1).  http://www.lrrd.org/lrrd16/8/zama16060.htm

Received 2 May 2009; Accepted 13 November 2009; Published 1 January 2010

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