ABSTRACT
A total of 140 day-old chicks generated from cross- breeding experiment to evaluate the effect of plumage modifying genes on growth and early lay characteristics of cross- bred egg type chicken. Three genetic groups consisting of Naked neck x Isa Brown pullets (Na x IB), Frizzle x Isa Brown pullets (F x IB) and Normal feather x Isa Brown pullets (N x IB) were used. The experimental design employed was Randomized Complete Block design (RCBD) with genetic group as a major factor of interest and batches as block. The result of the growth performance studies revealed that Frizzle hybrid chicken birds were significantly (p<0.05) highest in day –old weight when compared to their Naked neck and Normal feather counterparts. The weekly body weights (BW) at brooding phase were significantly (p<0.05) highest with Naked neck and Frizzle at week 1 and 3 over the Normal feather birds .The weekly body weight does not follow a definite pattern because Normal feather and Naked neck hybrids were significantly (p<0.05) highest at week 6 when compared to their Frizzle counterparts. At growers phase, Naked neck and Normal feather birds were significantly (p<0.05) highest in body weight (BW) over Frizzle hybrids. While for feed conversion ratios, Naked neck and Frizzle were highest when compared to Normal feather hybrids. At point of lay, Naked neck had significantly highest body weight (BW),highest in feed conversion ratios (FCRS), average daily feed intake both at growers phase and point of lay (ADFI). At laying phase, the Naked neck birds were significantly (p<0.05) highest in body weight at first egg, the 30 days of lay, weight gain at 60 days (BWG@60), feed conversion ratios (FCRS) and average daily feed intake(ADFI) over their counterparts. For egg production traits, Naked neck hybrids chickens was significantly (p<0.05) highest in egg number (ENO) over Frizzle and Normal feather hybrid chickens, hen-day egg production (HDEP %), Frizzle and Normal feather hybrid chickens were highest compared to their Naked neck hybrid chickens .Hen-house egg production (HHEP %), Naked neck and Normal feather hybrid chickens were highest when compared to their Frizzle counterparts. Egg quality traits, were better for Naked neck individuals as well as egg weight (EWT), egg length (EL), egg width (EWD) egg volume (EV) first egg to 60 days of egg lay , Frizzle hybrids had improved significantly age at first egg, egg shape index and egg specific gravity. Normal feather on the order hand was better in egg specific gravity at 30 and 60 days of egg lay and more efficient in feed conversion ratio when compared to those of Naked neck and their Frizzle hybrid counterparts. There was a clear evidence of maternal influence in the expression of growth and egg traits in which birds tended to follow more of the dam-origin effects. Generally, cross breeding resulted in offspring with improved growth, egg production and egg quality traits. It was therefore concluded that for rapid improvement of these traits in crossbred egg-type chickens, Naked neck should be considered for rapid growth, improvement of egg production and egg quality traits while Frizzle individuals should be considered for fast growth, early sexual maturity and egg production while gene frequency which is relative abundance of genotypes in population favoured the Frizzle individuals, resulting in more heterozygote Frizzle hybrid chickens being produced in the study.
TABLE OF CONTENTS
Title page i
Certification ii
Declaration iii
Dedication iv
Acknowledgments v
Table of Contents vi
List of Tables xi
List of Plates xiii
Abstract xiv
CHAPTER
1: INTRODUCTION 1
1.1 Background Information 1
1.2 Problem Statement 5
1.3 Objective
of the Study 6
1.4 Justification 6
CHAPTER 2: LITERATURE REVIEW 8
2.1 Usefulness of Poultry in Nigeria
2.2 Description of Local Chickens 8
2.2.1 Social behaviour of local chickens 9
2.2.2 Nesting and laying behavior 9
2.3 Naked Neck (Na) Gene 9
2.4 Frizzle Gene (Fr) Gene 12
2.5 Normal
Feather Chicken (Nf) 13
2.6 Exotic Breeds 18
2.7 Characteristics
of the local chicken and potentials for genetic improvement 19
2.8 Their
Performance 20
2.8.1 Effect of naked neck gene
on bird’s performance 20
2.8.2 Effect of naked neck gene
on egg production 20
2.8.3 Body weight and growth
rate 22
2.8.4 Effects of the gene on body
temperature of birds. 24
2.8.5 Growth trait effect on
genes 25
2.8.6 Effects of naked neck (na)
gene on sexual maturity 26
2.8.7 Effects
of frizzle gene on birds performance 27
2.8.8 Frizzle gene effect on egg
production 28
2.8.9 Effect of frizzle gene on
body temperature 28
2.8.10 Effect of frizzle (f) gen on sexual maturity, growth traits
and mortality 30
2.8.11 Acceptability of birds with mutant genes 32
2.8.12 The interaction between
naked neck (na) and frizzle (f)
genes 32
2.8.13 Thermoregulation and resistance
to heat stress
35
2.8.14 Frequency of frizzle and
naked neck genotypes in local poultry population`37
2.8.15 Some major genes and their
usefulness in poultry breeding 39
2.9 Plumage
Genes Reduction And Their Functions In Egg Production 40
2.10 Effects
of Some Main Genes On Quantitative Traits In Chicken 43
2.10.1 Crossbreeding as a tools for genetic improvement
of the indigenous fowls 46
2.11.1 Breed complementarity 47
2.11.1 Heterosis 47
2.11.2 Individual heterosis 48
2.11.2.1 Maternal heterosis 48
2.11.2.2 Paternal heterosis 48
2.11.2.3
Mating system or breeding method in poultry
49
2.12 Pen mating 49
2.12.1 Flock mating
49
2.12.2 Stud mating 50
2.12.3
Management of poultry : 50
2.13 Litter materials and management 50
2.13.1
Light management in poultry 50
2.13.2 Sanitation and hygiene
52
2.13.3
Brooding temperature:
53
2.13.4 Management ventilation : 53
2.13.5 Heat
stress management 54
2.13.6 Laying performance traits 56
2.14 Factors Affecting
Laying Performance of Pullets 56
2.14.1 Age at first egg 57
2.14.2 Hen-day
egg production percentage 57.
2.14.3 Egg
production of hen-day and hen-housed 57
2.14.4 Egg
quality traits 57
2.15 External
Eggs Quality Traits 58
2.15.1 Egg weight 59
2.15.1.1 Egg length 60
2.15.1.2 Egg width 60
2.15.1.3 Egg shape index 60
2.15.1.4 Egg
volume 61
2.15.1.5 Egg specific gravity 61
CHAPTER
3: MATERIALS AND METHODS 62
3.1 Location of the Study
62
3.2 Management
of Parent Stock 62
3.3 Mating Scheme and
Number of Eggs Produced for the Production of
Hybrid Chicks 63
3.4 Management
of Hybrid Chicks 63
3.5 Parameters
Measured 67
3.5.1 Growth
performance traits 67
3.5.2 Laying
performance traits 67
3.5.3 External
egg quality traits 68
3.5.4 Gene
frequency 69
3.5 Statistical
analysis and experimental design 69
CHAPTER 4: RESULTS AND DISCUSSION 71
4.1 Growth
Performance Traits 78
4.2 Laying Performance Traits 93
4.3 External Egg Quality Traits 99
4.4 Gene Frequency 111
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS 113
5.1 Conclusion 113
5.2 Recommendations
113
References
LIST OF TABLES
3.1 Mating Scheme and Number of Egg
Produced 63
3.2 Distribution and Number of Chicks
Hatched per Genetic Group 65
4.1: Effect
of Plumage Modifying Genes on the Body Weight (BW (g))
and Body Weight
Gain (BWG g) of Naked neck, Frizzle and Normal
Feathered Chickens
at Brooding Phase (0-6 weeks) 71
4.2:
Body Weight (BWg) and Body Weight
Gain (BWG) of Naked
neck, Frizzle and
Normal Feathered Hybrids at Growers Phase
(7-13 weeks of
age). 74
4.3:
Body Weight (BW g) and Body Weight
Gain (BWG g) of Naked
neck, Frizzle and
Normal Feathered Hybrids Pullets Point of Lay
(15-18weeks). 76
4.4:
Body Weight and Egg Production
Parameters for Naked neck, Frizzle and
Normal Feather
Hybrids chickens. 78
4.5:
Feed Conversion Ratio (FCR), Average
Daily Feed Intake (ADFI)
and Average Daily
Body Weight Gain (ADWG) for the three
Hybrids 0-6weeks
(brooding phase) 82
4.6: Feed Conversion ratio (FCR), average daily
Feed intake (ADFI)
and average daily
weight gain(ADWG)of Naked neck, Frizzle
and Normal feather
Hybrids 8-14weeks (growers phase). 85
4.7 Feed Conversion Ratio (FCR), Average
Daily Feed intake (ADFI)
And Average Daily
Weight Gain (ADWG) Pullet of Naked neck, Frizzle
and Normal Feather
Hybrids 16-20weeks. 87
4.8:
Feed Conversion Ratio (FCR), Average Daily Feed Intake (ADFI)
and Average Daily
Weight Gain(ADWG of Pullet Naked
neck, Frizzle
and Normal feather
Hybrids from first egg-60days. 90
4.9: Short Term Egg Number Production of Naked
neck, Frizzle and
Normal feather Hybrids Chicken 93
4.10: Short Term Hen-day Egg Production Characteristics
(HDEP %) of Naked
neck, Frizzle and Normal feather Hybrids
Chickens from 20-32weeks 95
4.11: Short Term Hen-house Egg Production
Characteristics (HHEP %) of Naked
neck, Frizzle and Normal feathered Hybrid
Chickens from 20-32 weeks. 97
4.12 Egg Weight (EWTg) of Naked neck, Frizzle
and Normal feather Hybrid
Chicken from first egg to 60 days of egg
lay. 99
4.13: Short Term Egg Length (EL mm) of Naked neck,
Frizzle and Normal
feathered Hybrid Chickens from First egg
to 60 days. 101
4.14: Short Term Egg width (EWD mm) of Naked
neck, Frizzle and Normal
feather Hybrid Chickens from First egg to
60 days. 103
4.15: Short Term Egg shape Index (ESI %) of Naked
neck, Frizzle and Normal
feathered Hybrids Chickens from First egg
to 60 days. 105
4.16: Short Term Egg Volume (EV cm3)
of Naked neck, Frizzle and Normal
feather Hybrids Chickens from First egg to
60 days. 107
4.17: Short Term Egg Specific Gravity (ESPGg\cm3) for Naked neck, Frizzle
and Normal feather Hybrids Chickens from
First egg to 60 days. 109
4.18: Genotype, frequency and actual percentage
of Naked neck and
Frizzle hybrids chickens. 111
LIST OF PLATES
1. Naked neck cock x Isa Brown Pullets
Parental Stock (Na x IB) 14
2. Frizzle cock x Isa
Brown Pullet Parental Stock (FR x IB) 14
3. Normal feather
cock x Isa Brown Pullets Parental Stock (NF x 1B) 15
4. Dominant Naked neck
Hybrids Chickens (Na x IB) 15
5. Recessive Naked
neck Hybrids Chicken (Na x IB) 16
6. Frizzle Dominant
Hybrid Chickens (FR x IB) 16
7 Frizzle Recessive Hybrid Chickens
(FR x IB) 17
8. Normal feather Hybrids Chickens (NF x IB) 17
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND INFORMATION
Poultry production is a major area of
animal production with significant contribution to human food needs and health. Poultry
products offer protein of high biological standards (Eshiette and Okere, 1990),
Nigeria is gifted with a number of poultry species which are native to the
country (Martins, 2016). Today’s commercial poultry breeds and strains derive
majorly from the non-descript native fowls of their countries of origin. Modern
breeds of eggs and meat-type chicken are product of conscious and consistent
selection and breeding of native stock over generation until highly productive
breeds were developed. Such breeding effort using selected lines with desirable
traits and crossbreeding them with other choice breeds or lines in planned
breeding programmes have continued in many poultry breeding centers and
research institutions of the world especially in the technologically advanced
countries. The results of such effort are the popular meat (broiler) and egg
(layer)-type chickens which have been developed and have continued to sustain
the commercial poultry industry worldwide (Nwachukwu, 2006).
The growing interest in family poultry
production demands that research be carried out on genetic improvement of the indigeneous
chickens especially those genotypes that are known to posses some productive
adaptability genes (Nwachukwu et al.,
2011).
The Nigeria native chicken manifests diversity
in morphological characteristics, and consists of various mongrel
characteristics sub-population of heterogeneous not yet grouped into breeds and
varieties. They do not contribute to their common ancestry and have no clear
plumage colours (Ajayi, 2010).Usually,they have small body and egg size compared to their
exotic counterparts (Nwosu and Omeje, 1985).They are hardy and normally adapt
favourably to the tropical environment (Ikeobi and Godwin, 1990).The chickens
are flightly in nature, resistance to some diseases and parasites and lay eggs
within relatively thick egg shell (Peterset
al.,2007).The indigenous poultry are
mostly based on domestic chicken (Gallus
domenticus).The genetically unimproved local chicken remain predominant in
African villages despite the introduction of exotic and cross-bred types (Martins,2016).
In Nigeria, indigenous chickens
were classified along genetic lines of feather and plumage colour such as
normal, frizzled feathered, body structure such asnaked neck, dwarf types and other
colour variants for instance black, white, brown, mottled etc. The rate
allocation of the normal feathered chicken was 91.8%, while that of frizzled
and naked neck were 5.2 and 3.0% correspondingly (Ajayi
and Agaviezor, 2009) .categorization has been on the basis of
location. Most of the organization by different agro ecological zones
considered mainly the normal feathered native chicken because they are well-known
whereas the naked neck and frizzled feathered birds are uncommon and becoming
endangered and the gene pool they represent may be lost if not characterized
and conserved (Ajayi, 2010). Nigerian native chickens can beclassified into
various genotypes or genetic groups that have special genes of direct and
indirect result on production and quantitative trait loci (Fayeye et al.,
2006). These genes called useful genes complexes, main genes (Ibe and Nwosu,
1999) or plumage reduction gene which include the naked-neck (Na) and Frizzle
(FR). They are connected with heat tolerance and possess productive
adaptability (Horst, 1988),
These genes are useful to hot tropical regions
because they allow the indigeneous chicken to adapt comfortably to the tropical
environment. Naked-neck (Na) and frizzle (f) genes comprises two types of major
genes found in the native fowl population. Naked-neck is caused by a single
autosomal gene, Na. The gene is incompletely dominant with Na/na chicken showed
separated tuft of feathers on the neutral side of the neck above the crop,
while the homozygous dominant chicken lack this tuft or reduced to pinfeathers
or small feathers (Somes, 1990). On the other hand, frizzlegene is caused by a
single incompletely dominant autosomal gene F restricted by an autosomal
recessive modifier, mf. In original homozygous frizzle chickens the rachise of
all feathers are tremendously reserved (Nwachukwu,(2006). Feather reduction
coverage increase heat dissipation, allowing a greater rate of irradiation of
body heat and a better thermoregulation (Eberhart
and Washburn, 1993).,This has been the subject of many studies both in
broilers and in layers (Bordas
and Mérat, 1984; Deeb
and Cahaner, 1999; Chen
et al., 2004, 2008;
Cahaner
et al., 2008; Azoulay
et al., 2011). The main studied
genes causing feathers mass reduction are the naked neck (NA),
the scaleless (sc), and the frizzle (FR) genes.
Naked neck birds have feathered body surface reduced by 20% if heterozygous and
40% if homozygous for the NA mutation (Bordas
et al.,-1978). Its adaptive
effect at high environmental temperatures has been broadly studied (Hanzl
and Somes, 1983; Mérat,
1986; Cahaner
et al, 1993; Deeb
and Cahaner, 1999; Chen
et al., 2004; N’dri et al., 2007), and the results are
unanimous that the NA mutation confers an improved thermo tolerance.
(Oxford journal, 2016).
The usefulness of these genes over
their normal feathered counterparts in a hot humid environment are in areas of
feed intake, growth rate, and weight gains which have been reported by (Hanzle
and Somas, 1983, Merat, 1990, Lout et
al., 1992, Cahaner et al., 1993).
The superiority of eggs, apart from determining their food value, market
attractiveness, or economic value (Singh and Kumar, 1994) is important in
poultry for their embryo development and successful hatching. The external and
internal qualities of eggs in both pullets have been reported by (Norstron and
Ousterhout, 1982) had significant effects on the hatchability of incubated and
fertile eggs, weight and development of the pullets’chickens. Egg quality can
be external or internal. The external qualities of an egg are based on the
size, shape, shell colour and texture of the eggs. Domestic chickens exist genetic
and phenotypic heterogeneity. The diversity, which comprises a valuable genetic
resource, informs the reason for incorporating the native chicken into breeding
programs aimed at producing an indigenous meat and egg type strains modified to
the tropical environment. Moreover, there is a main global drive on genetic
preservation and biodiversity as reflected in the efforts on development of
genome and data banks. Following this approach, the local chicken for instance naked
neck and frizzle which are tropically useful should be preserved from becoming
lost. More importantly, the use of management practices to improved the unfavourable
effects of heat stress on poultry in many cases are not economical, and
alternative approach of breeding layers lines with better heat tolerance has
been recommended. Genetic improvement of heat tolerance may therefore provide a
low-cost that is particularly attractive to developing countries with hot
climates like Nigeria (Oke, 2011).
Commercial hybrids that are layers
and broilers also abound in south-west Nigeria. The hybrids layers starts to
lay at about 18 to 20 weeks of age and peak production is achieved during the
first production cycle The average production rate of commercial pullets normally
remains close to 0.9 eggs per day (Kekeocha,1985). Production behaviors of
laying birds are generally governed by several factors: the climatic condition
that had been identified to affect the production behavior of laying hens
(Smith and Lecled, 1999). In an area where climate is hot and humid, egg
production is usually lower than in temperate zones. Production cycle of egg
are also being influenced by many other factors such as breed, mortality rate
,body weight, laying house lightening schedule, feed and culling (North and
Bell, 1990).
However, for maximum egg production and
better egg quality, there are six fundamental ways to maximize the laying
performance and minimizing the economy of production of chickens and these
include pre-placement of preparation, feed management, water management,
temperature management, health management, air quality and ventilation. In
modern poultry production system, these several ways are often subsumed as
sound management strategies.(Olowofeso et
al.,2011) Furthermore,superior exotic chickens produce a higher number of
eggs and more meat than the local chicken strains, but the greatest challenge
is the tropical climate. They are not adapted to unfavourable environmental
conditions, such as high temperature, disease and shortage of feed (Barua et
al., 1998; Ali et al., 2000; Islam and Nishibori, 2009). (Fassill-Bekele,
2010).The aim of this study, therefore was to determine the effect of plumage
modifying genes on growth rate and early lay characteristics of crossbred egg
typechicken.
1.2 STATEMENT OF THE
PROBLEM
The fact that Nigeria as a nation does not
have her own indigenous breed of chicken or any known foundation stock is a
challenge to poultry geneticists and breeders in the country as well as to the
Federal Government of Nigeria. This situation has its negative effects on the
people and the economy of the nation. For instance, an average Nigerian cannot
afford to eat an egg a day and cannot afford the cost of a kilogram of
processed chicken every week. The direct effect of this scenario is obvious
protein malnutrition especially in children. Secondly, the issue of its
scarcity in the village market, especially the naked neck and the frizzle
chicken is a problem because the villagers no longer rear them due to superstition.
For instance, some said that it is a taboo or forbidden in their religion while
others said that these birds are mainly for ritual purposes and for
mischief. Because of these reasons, a
large number of people do not rear it again. This is one of the serious
challenges facing poultry breeders today because the issue of purchasing them
at a large quantity is very difficult and also expensive.
A sure way of changing this situation and
satisfying the local poultry industry is to encourage poultry geneticists and
breeders in the nation’s animal research institutes and universities to
undertake guided and well-funded studies aimed at producing a highly productive
indigenous foundation stocks which will meet both local and international
standards. This in turn, will stimulate the local poultry industry producing
the much needed parent stock and commercial meat and egg-type chickens which
will fuel and sustain the nation’s poultry.
1.3 OBJECTIVES OF THE STUDY
1.
To determine the effect of
plumage modifying genes on the growth performance traits of hybrids of Naked neck, Frizzle and normal chicken.
2.
To evaluate the short-term egg
production and egg quality characteristics of the three hybrids chicken
produced.
3.
To determine the gene frequency
of the Naked neck and Frizzle genes.
1.4 JUSTIFICATION
In Nigeria, the
problem of acclimatization, disease and management procedure, high cost of
import of exotic stock and prices of their products which is often beyond the
reach of common man,is one of the challenges facing poultry production(Sola et al.,2009). Attempt to significantly
reduced heat stress problem in poultry through management practices or dietary
adjustment have not been successful (Ige et
al., 2012). Eberhart and Washburn (1993) reported a genetic basis to heat
resistance and suggested the need to breed birds with more natural tolerance to
heat stress.
Certain major genes have been found
potentially useful to the tropical environment .Among these major genes are the
feather distribution (Naked neck (NN) and Frizzle feather (FF) gene. Both genes
have been associated with increased tolerance (Horst, 1988). Genetic and
phenotypic heterogeneity have been observed to exist in the domestic chicken
(Oke, 2011; Martins, 2016).This diversity which constitutes important genetic
resource informs the reason for incorporating the local chicken into breeding
programmes aimed at producing indigenous meat and egg-type birds adapted to the tropical environment.
Consequently upon their thermoregulatory functions, the plumage reducing genes
have been found relevant in the tropics as, the naked neck genes have
been found to cause 30-40% reduction in feather coverage (Njenga, 2005). The
advantages of these genes over their normal feathered counterpart in humid
environment in terms of feed intake, growth rate (Cahaner, 1994) and weight
gain (Yalcin et al., 1997). Several
other researchers have reported on the effects of Frizzle and Naked neck on
growth rate, egg number, and fertility and hatchability traits in chicken. Egg
quality in chicken is influenced by several factors which may be genetic or
environmental (Peter’s et al., 2007,
Martins, 2016). In order to overcome this problem and to ensure high
productivity, crossbreeding of genetically divergent genotype for instance
local chicken cock and exotic egg type chicken strains will ensure improvement
of their thermoregulatory functions and production of good quality pullets
chicks that would introduce desired hybrid vigor which will be useful to
poultry breeders and farmers alike (Nwachukwu et al., 2011).
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