IMPROVEMENT IN EGG PRODUCTION TRAITS IN THE LIGHT LOCAL CHICKEN ECOTYPE USING A SELECTION INDEX
IMPROVEMENT IN EGG PRODUCTION TRAITS IN THE LIGHT LOCAL CHICKEN ECOTYPE USING A SELECTION INDEX
To create the parent generation (G0) for this study, which aimed to enhance egg production qualities in the LLCE using a selection index, fifty hens and five cocks from a random mating population of light local chicken ecotype (LLCE) were mated and the viable eggs hatched.
The hens were observed for three short-term egg production features, namely Body Weight at First Egg (BWFE), Average Egg Weight (AEW), and Total Egg Number (TEN), for a period of 90 days following the first day of lay.
To estimate descriptive statistics and genetic parameters, respectively, the data were statistically analysed using Harvey's (1990) paternal half-sib model and SPSS (2001) on the basis of the collected data.
These tools were used to build the selection index. Selection for each of the three selection criteria—BWFE, AEW, and TEN—went well. G1 and G2 were created through the mating of chosen parents. Additionally estimated were selection differentials, selection intensities, and the genetic response to selection.
To track environmental changes and calculate the genetic changes brought on by selection, a control population that covered three generations (each generation had its own control population) was employed.
Over the course of the three generations of the study, there were substantial increases (P0.05) in BWFE, AEW, and TEN in the chosen populations. These significant increases (P0.05) were not seen in the control group. Heritability estimates ranged from moderate to high for all traits across all generations and populations. The index's heritability was likewise moderate.
These significant additive genetic variances, which are indicated by estimates of moderate to high heritability, suggest that these qualities were mostly passed down from parents to their children.
In all research populations, there were low to strong positive genetic and phenotypic associations between BWFE and AEW. For all generations and study populations, the genetic and phenotypic connection between BWFE and EN, as well as between AEW and EN, was moderate to strongly negative.
In the G2 of the chosen population, AEW and TEN showed a favourable genetic association. For BWFE, AEW, and TEN, relative cumulative selection differentials of 269.38g, 1.58g, and 3.88 eggs were found. Over the generations, selection response for characteristics grew in a fairly linear fashion.
For BWFE, AEW, and TEN, the realised response per generation was calculated to be 94.22g, 0.84g, and 4.85eggs, respectively.
It is clear that the Light Local Chicken Ecotype's selected birds performed better overall across the generations when BWFE, AEW, and TEN were simultaneously included in a selection index.
1.1 BACKGROUND OF THE STUDY
Two significant criticisms were raised in the report of the Fourth Food and Agriculture Organisation Expert Consultation on Animal Genetic Resources (1973) regarding the effort to enhance and preserve the indigenous chicken.
The first was whether local strains still had genes that helped the immensely superior foreign strains, given that the latter had undergone millennia of genetic testing. The second argument emphasised how time-consuming, expensive, and labor-intensive it would be to further screen the local chicken.
The local chicken is a repository of beneficial genes, according to the findings of recent studies utilising local chicken (Ikeobi and Peters, 1996; Ayorinde et al., 2001; Udeh and Omeje, 2001).
Second, molecular genetic methods make it quick and affordable to genetically modify the native chicken. In addition, third-world nations that built breeding projects based on the diluted native material through massive crossbreeding programmes failed.
Because of their ability to adapt to the environmental stress of the tropics, indigenous breeds have become important in overall food production systems, raising the awareness of livestock producers.
Despite the abundance of cattle and poultry in the country, the amount of animal protein consumed per capita each day is still below the minimum level advised by UN/FAO (Ayodele and Ajani, 1999).
This has been linked to limited animal output, which may be caused by genetic and/or environmental limitations. The aforementioned highlights the necessity of raising Nigeria's level of animal protein output.
The development of the poultry industry is more crucial since it offers a variety of benefits, such as a short generational gap and the generation of a high number of offspring because of its unusual reproductive characteristics (Ibe, 2001). Additionally, all cultures and religions largely approve the consumption of poultry flesh.
The evolution of agriculture and breeding initiatives over the past few decades has significantly altered the breeding pools of poultry in many nations. Due to performance improvements, the formation of breeding institutes has caused a noticeable supra-regional propagation of some chicken breeds.
As a result, the desired high performance breeds have expanded while the native breeds have steadily dwindled. For instance, new high yielding and quick-growing poultry breeds have been incorporated into the existing poultry production systems in Nigeria since the late 1950s in an effort to satisfy the need for increased production and profitability in intensive production systems to meet the rise in demand for animal protein by the populace (Obioha, 1992).
In addition, such introduction has prevented the native breeds regarded as “low producers” from being integrated into industrial-scale chicken production.
Nigeria has a lot of genetic resources for chickens. A sizable number of employees have recorded the morphological, physiological, behavioural, and production traits of the local chicken.
These were reviewed by Nwosu in 1990. Some significant genes of tropical relevance were found in Nigerian local chicken populations by Ibe (1990a, b).
The body weight of the native chicken found in the various ecological zones of the nation may now be the most distinctive characteristic for physical characterization (Olori and Soniaya 1992).
According to observations, the indigenous chicken in the guinea savanna and swampy rainforest regions are lighter than the chicken in the highlands and sudan savanna regions (Nwosu, 1979).
These variations in body weight can be used to generically classify the local chicken as either Light Ecotype, which has lighter weight, or Heavy Ecotype, which has heavier weight.
According to research on the local chicken conducted over the past 50 years (Hill, 1954; Oluyemi, 1979; Omeje and Nwosu, 1982; Nwosu, 1987; Udeh and Omeje, 2001), the local chicken in Nigeria possesses useful genetic traits that can be used in crossbreeding programmes to create chickens that are better suited for producing eggs and meat.
However, there are restrictions on the realisation of total heterosis in such crosses with the exotic due to the local chicken's lack of pedigree, selection, and segregation (Omeje, 1985), making it impossible to classify it as a purebred like the exotics.
In contrast to hybrids from similar lines, which exhibit entire heterosis, crossbreds from purebred parents exhibit heterosis to the extent that their gene frequencies differ (Pirchner, 1983).
Selective breeding is required to use the native chicken as a parent breed, resulting in strains of chicken that can adapt to the local environment and help Nigeria achieve its long-term goal of becoming self-sufficient in the supply of breeding stock for poultry and expanding its poultry industry.
Selective breeding among regional strains has been found to be beneficial (El-Issawi, 1975). Variation is the idea behind selective breeding.
Because allelic differences occur within a population of individuals, they can have an impact on the outcomes of quantitative traits including growth, egg production, and egg quality attributes.
1.1 STATEMENT OF THE PROBLEM
The majority of studies have focused on crossbreeding with exotic birds, not on choosing local chicken for meat or egg production. Oluyemi (1979) came to the conclusion that the local chicken is not a possible grill strain after seven generations of mass selection on the 12-week body weight of the local chicken.
Although studies pertaining to the development of the local chicken as a potential layer have shown appreciable improvement in egg production traits of the birds under improved management system (Hill and Modebe, 1961; Nwosu et al, 1979; Omeje, 1985; Tule, 2005),
the local chicken has been labelled a low producer with regards to egg production (40–80 eggs/bird/year under extensive management system). Nwosu and Omeje (1985) added that the local chicken has the genetic capacity to lay 128 eggs per bird per year.
It should be highlighted that these research' findings came from populations that were randomly bred. It's entirely likely that the neighbourhood chicken may do better if it underwent selection and had better management. The current selection study of the local chicken utilising a selection index approach is a result of this.
1.3.1 PURPOSE OF THE STUDY
The purpose of this research are to:
calculate genetic parameters for the Light Local Chicken Ecotype (LLCE), such as the heritability of body weight at first egg, egg size, and egg weight, as well as the genetic and phenotypic relationships between these variables;
Create a suitable selection index (I) for LLCE selection utilising body weight at first egg, short-term (90 days from first egg) egg production, and egg weight;
Analyse and summarise the three generations of selection's applications and responses.
1.4 JUSTIFICATION OF THE STUDY
Nigeria's poultry management practises have substantially improved over the past few decades, and production has increased quickly. However, many people and farms were forced to stop producing chicken meat and eggs due to the high cost of production inputs, such as feed and medications,
and the market's dominance by a small number of livestock contract firms. For these small-scale farmers, diversifying their agricultural output base and generating additional money through the efficient production of local chicken may be an option.
According to Akinwumi (1979), indigenous poultry stock made up 92% of Nigeria's poultry production. Similar reports, however, from Prawirokusmo's 1988 Asian survey indicated that the native variety of chicken contributed to roughly 40% of Indonesia's egg production and 30% of its meat production.
Local breeds of chicken may seem to produce less than highly specialised exotic ones, but they are much more productive in terms of using local resources and are longer-lasting. Due to their colour, flavour, and leanness, products from local poultry stocks are frequently favoured (Haitook et al., 2003; Horst, 1988).
Local chicken can survive with little care and nutrition, and they frequently have higher disease tolerance or resistance. Additionally, they are more resilient to significant variations in food and water availability as well as harsh, unpredictable, and extreme weather conditions.
A chance to assist emerging nations in providing food for their citizens is being lost by failing to produce locally adapted breeds for increased output.
According to Barker (1982), there are significant phenotypic and perhaps genetic variations among native/local breeds and varieties. He recommended that proper evaluation and documentation of these breeds on an appropriate selection technique created to give the farmer an ideal genotype be performed as part of the application of genetics towards enhancing these stocks.
This suggests that a breeding strategy that values the introduction and growth of pure breeds as well as selection within regional breeds is advantageous. The effectiveness of such a method in native Delish chicken was discussed by Ahmed and Hasnath in 1983.
Therefore, ongoing attempts to create pure lines for local meat and egg production may one day match or perhaps surpass the best now available in the nation.
There hasn't been a thorough analysis of genetic parameter estimates or variance components for variables related to egg production in Nigerian indigenous chickens. As a result, the few experimental breeding operations on this species mainly rely on projections from far-flung populations.
Understanding the genetic parameter estimations of the specific breed or population that needs to be improved is crucial for successful genetic improvement. Therefore, this research is essential to advancing the genetics of the Nigerian light local chicken ecotype.