ABSTRACT
This experiment was conducted to study the genetic estimates for body weight and some economic important traits in Japanese quail from a foundation stock of 784 chicks, which were sexed at day 21. Selected birds of 50 sires and 150 dams based on body weight were used as parents G0 (Unselected generations) for the next generation. Data were collected over two consecutive hatches for G1 ( selected generation one) and G2 ( selected generation two) and records collected at day 35, 42, 49 and 56 from males and females to determine the effect of selection on age and body weight at sexual maturity; the trend of growth in body weight, body length, egg quality characteristics, egg production, carcass traits in generations, sex and age of Japanese quail; the effect of sex and age on breast meat quality of Japanese quail; the rate of genetic improvement in reproductive traits, body weight, egg traits, carcass traits, mineral and chemical composition of meat in Japanese quail and the genetic parameters (h2) based on individual selection for body weight at different ages, reproductive, egg production, minerals, chemicals, and carcass traits of Japanese quail. The results indicated that sexual maturity characteristics in female Japanese quail such as age at sexual maturity, body weight, egg weight, follicle size, oviduct weight, ovary weight, pectoral major weight and abdominal fat weight varied significantly (P with selection. Also in males body weight at day 35, age at sexual maturity, body weight, testicular weight, pectoral major weight and abdominal fat weight varied significantly (P with selection. Live body weight, body dimensions, carcass traits in males and females after selection increased between, age and sex at day 35, 42, 49 and 56 in both males and females birds. At day 56, carcass weight, % carcass weight, abdominal fat weight, % abdominal fat weight, breast weight, drumstick + thigh weight, % drumstick + thigh weight, back bone weight, % back bone weight and body length and body part lengths also improved with selection. Females
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had higher part weights than males (P Egg quality traits increased with generations and as birds advanced in age so also did the meat quality of Japanese quail affects both the males and females water holding capacity, cooking loss, lightness, chroma colour and as birds advances in age it affects the % drip loss of the meat, cooking loss, lightness and chroma colour significantly (P. It can be deduced from the result that there was genetic improvement in body weight, growth rate of shank length, sexual maturity in males and females traits, reproductive traits, egg traits, carcass weight, minerals and chemical composition in meat of Japanese quail. Japanese quail shows improvement in body weight, parts and dimension in both sexes, but females were heavier than males possibily because of their genetic make-up. Selection increase egg size with advances in age but decreases egg shell. The realized heritability for carcass weight, mineral composition and chemical composition ranged mostly between 0.38 to 0.08. However, the realized heritability estimates for body weight at day 35 and 42, egg quality traits, egg production traits were high, therefore, Breeders can select for those traits because of their genetic merits.
TABLE OF CONTENTS
Title Page …………………………………………………………………………………………………………………. i
Copyright Statement ………………………………………………………………………………………………… ii
Declaration……………………………………………………………………………………………………………… iii
Certification ……………………………………………………………………………………………………………. iv
Dedication ……………………………………………………………………………………………………………….. v
Acknowledgement …………………………………………………………………………………………………… vi
Table of Contents ………………………………………………………………………………………………….. viii
List of Tables ………………………………………………………………………………………………………… xiii
Abstract …………………………………………………………………………………………………………………. xv
CHAPTER ONE
1.0 INTRODUCTION…………………………………………………………………………………………. 1
1.2 Justification of study ……………………………………………………………………………………… 3
1.3 The Specific objectives …………………………………………………………………………………… 4
CHAPTER TWO
2.0 LITERATURE REVIEW ……………………………………………………………………………… 5
2.1 Japanese Quial ……………………………………………………………………………………………… 5
2.2 Sexual Maturity Characteristics of Female Japanese Quail …………………………….. 6
2.3 Sexual Mayurity Characteristics of Male Japanese Quail ……………………………….. 6
2.4 Carcass Traits of Japanese Quail …………………………………………………………………… 7
2.5 Bodyweight and Some Parts of Japanese Quail ………………………………………………. 8
2.6 Egg Weight and Yolk Characteristics of Japanese Quail ………………………………… 9
2.7 Egg Weight and Albumen Characteristics of Japanese Quail at Different Generations ……………………………………………………………………… 9
2.8 Egg Production and Weight Traits in Japanese Quail …………………………………… 10
2.9 Effect of Age and Sex on Live Body Weight and Carcass Traits in Japanese Quail ……………………………………………………………………………… 10
2.10 Slaughter Weight and Carcass Percentage Characteristics of Japanese Quail ……………………………………………………………………………………………. 10
2.11 Effect of Sex and Age on Carcass Weight and Some Internal Organs in Japanese Quail ……………………………………………………………………………. 11
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2.12 Slaughter Age and Sex on Carcass and Some Inedible Traits in Japanese Quail ………………………………………………………………………………. 12
2.13 Effect of Age and Sex on Carcass and Live Body Length at Different Generations of Japanese Quail. ……………………………………………………………………. 12
2.14 Effect of Age and Sex on Live Body Weight and Dimensions at Different Generations In Japanese Quail …………………………………………………………………….. 13
2.15 Effect of Age and Sex on Breast Meat Acidification in Japanese Quail ………….. 14
2.16 Effect of Age and Sex on Breast Meat Colour in Japanese Quail ………………….. 14
2.17 Rate of Genetic Improvement from Selection for Body Weight and Shank length ……………………………………………………………………. 16
2.18 Genetic Improvement of Male Sexual Reproductive Traits …………………………… 16
2.19 Genetic Improvement of Some Reproductive and Egg Traits in Japanese Quail. ………………………………………………………………………. 17
2.20 Genetic Improvement in Egg Quality Traits …………………………………………………. 18
2.21 Genetic Improvement of Body Weight at Different Ages of Growth ………………. 18
2.22 Response to Genetic Improvement of Carcass Weight at Different ages of ……….. Growth in Japanese Quail ……………………………………………………………………………. 19
2.23 Heritability Based on Individual Selection for Body Weight in Japanese Quail ……………………………………………………………………. 19
2.24 Heritability Estimates of Body Weight at Different Ages of Growth Japanese Quail……………………………………………………………………. 19
2.25 Heritability Estimates of Female Sexual Reproductive Traits ……………………….. 20
2.26 Heritability Estimates of Male Sexual Reproductive Traits …………………………… 21
2.27 Heritability Estimates of Egg Quality Traits in Japanese Quail …………………….. 21
2.28 Heritability for Egg Production in Japanese Quail ……………………………………….. 22
2.29 Heritability Estimates of Carcass Weight at Different Ages of Growth in Male Japanese Quail……………………………………………………….. 22
CHAPTER THREE
3.0 MATERIALS AND METHODS ………………………………………………………………….. 23
3.1 Experimental Site ………………………………………………………………………………………… 23
3.2 Mating Plan ………………………………………………………………………………………………… 23
3.3 Management of Fertile Egg ………………………………………………………………………….. 24
3.4 Incubation and Hatching of Fertile Eggs ………………………………………………………. 24
3.5 Experimental Birds and their Management ………………………………………………….. 24
3.6 Data collection …………………………………………………………………………………………….. 25
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3.6.1 Body Weight ………………………………………………………………………………………………… 25
3.6.2 Measurement of the Live Body Changes (g): ……………………………………………………. 25
3.6.3 Sexual Maturity …………………………………………………………………………………………….. 26
3.6.4 Live Body Length Measurement (cm): …………………………………………………………….. 28
3.6.5 Carcass Trait Measurement : ………………………………………………………………………….. 29
3.6.6 Body weight gain: …………………………………………………………………………………………. 30
3.6.7 Egg Production Traits: …………………………………………………………………………………… 31
3.6.8 Egg Quality Traits …………………………………………………………………………………………. 31
3.6.9 Reproduction Traits: ……………………………………………………………………………………… 32
3.6.10 Quail Meat Proximate Composition: ……………………………………………………………….. 33
3.6.11 Mineral Composition of Quail Meat ………………………………………………………………… 34
3.6.12 Rate and the Intensity of the Muscle Acidification during Post mortem: ………………. 34
3.7 Estimation of Genetic Parameters ………………………………………………………………… 36
CHAPTER FOUR
4.0 RESULTS …………………………………………………………………………………………………… 39
4.1 Sexual Maturity Characteristics of Japanese Quails ……………………………………… 39
4.1.1 Sexual maturity characteristics in females ………………………………………………………… 39
4.1.2 Sexual Maturity Characteristics in males …………………………………………………………. 39
4.2 Carcass Traits, Body length and Body Parts of Japanese Quail …………………….. 42
4.2.1 Carcass traits of Japanese quail by generations and sex ……………………………………… 42
4.2.2 BW56 Body length and some parts of Japanese quail ………………………………………… 42
4.3 Egg Characteristics of Japanese Quail. ………………………………………………………… 45
4.3.1 Egg weight, yolk and albumen characteristics of Japanese Quail. ……………………….. 45
4.3.2 Performance Characteristics of Quial Hens ………………………………………………………. 47
4.4 Carcass Traits as Influenced by Sex, Age and Generations in Japanese Quail. ……………………………………………………………………. 47
4.4.1 Carcass parts traits ………………………………………………………………………………………… 47
4.4.2 Carcass weight and some internal organs and inedible traits ………………………………. 50
4.4.3 Carcass and live body dimensions …………………………………………………………………… 50
4.5 Breast meat quality of Japanese quail by age and sex ………………………………………… 53
4.6 Response to Genetic Improvement in Traits of Japanese Quail……………………… 53
4.6.1 Response to Rate of genetic improvement for body weight and shank length inJapanese Quail ……………………………………………………….. 53
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4.6.2. The rate of improvement for growth rate in body weight and shank length in Japanese quail ………………………………………………………………………… 56
4.6.3. Estimated genetic improvement in female sexual reproductive traits of females …… 56
4.6.4 Estimated correlated correlated improvement in male sexual reproductive traits …… 59
4.6.5 Correlated improvement in some reproductive and egg traits in Japanese quail. ……. 59
4.6.6 Response to genetic Improvement in egg quality traits ………………………………………. 62
4.6.7 Genetic improvement of egg production at different ages in Japanese quail …………. 62
4. 6.8 Response to genetic improvement of body weight at different ages of growth………. 62
4.6.9 Changes genetic improvement of carcass weight for different ages of growth in Japanese quail ………………………………………………………………………………………………. 66
4.6.10 Response to Mineral composition improvement in meat of Japanese quail …………… 66
4.6.11 Response to chemical composition improvement for meat of Japanese quail ………… 66
4.7 Realized Heritability in Traits of Japanese Quail ………………………………………….. 70
4.7.1 Heritability estimate based on individual selection for body weight in Japanese quail. ………………………………………………………………………. 70
4.7.2 Heritability estimates of body weight at different ages of growth in Japanese quail ………………………………………………………………………………… 70
4.7.3 Heritability estimates of female sexual reproductive traits in female quail …….. 70
4.7.4 Heritability estimates of male sexual reproductive traits …………………………………….. 74
4.7.5 Heritability estimates of egg quality traits in Japanese quail ……………………………….. 74
4.7.6 Heritability for egg production in Japanese quail. ……………………………………………… 74
4.7.7 Heritability of carcass weight at different ages of growth in male Japanese quail … 78
4.7.8 Heritability estimates of mineral composition in meat of Japanese quail ……………… 78
4.7.9 Heritability estimates of chemical composition for meat of Japanese Quail ………….. 78
CHAPTER FIVE
5.1 Sexual Maturity Characteristics of Japanese Quail ………………………………………. 82
5.2 Effect of sex on bodyweight ………………………………………………………………………….. 83
5.3 Effect of Generation of Selection and Sex on body weight and Carcass Characteristics of Japanese Quails……………………………………………………………….. 85
5.4 Breast Meat Quality of Japanese Quail ………………………………………………………… 89
5.5 Realized heritability estimates for body weight …………………………………………….. 92
5.6 Heritability estimates for egg production and quality traits ………………………….. 94
5.7 Heritability Estimates for Carcass Weight ……………………………………………………. 95
5.8 Heritability Estimates for male and female reproductive traits ……………………… 95
CHAPTER ONE
1.0 INTRODUCTION
Japanese quail (Coturnix coturnix japonica) has become a pilot animal in the field of research. This is due to its fast growth rate, early sexual maturity, high rate of egg production, short generation interval, less feed and space requirement, easy maintenance, resistance to many avian diseases and potential source of meat and egg (Ajay-Kurma et al., 2000; Akpa et al., 2008). However, despite the numerous advantages over other poultry birds, its breeding programme has not been fully exploited in Nigeria. In order to establish a breeding programme, it is essential to estimate genetic parameters for improving traits that are of economic value. The scale of the genetic parameters could show the amount of improvement deriavable by selection.
Some estimates of genetic parameters for various traits of domestic Japanese quail have been reported by several workers (Kawahara and Saito, 1976; Toelle et al., 1991; Minvielle et al., 1999; 2000; Akpa et al., 2006; 2008). Knowledge of the heritability of traits is essential for understanding how individual characteristics change from one generation to another in response to selection (Falconer and Mackey, 1996). Studies of heritability have mostly focused on the estimation of genetic parameters for growth, especially under different selection environments (Anthony et al., 1996; Marks, 1996; Saatci et al., 2003). However selection rarely operates on only one trait at a time hence, if there is a genetic correlation between traits under selection, the overall response to selection will change according to the heritability of the traits examined, and strength and sign of the genetic covariance among them (Jensen et al., 2003).
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The Japanese quail is a sexually dimorphic bird with females having a larger body size than males, unlike other poultry species; and females require more time to reach sexual maturity than males (Reddish et al., 2002). The differences in growth pattern between the sexes are also a well- known phenomenon (Balcioglu et al., 2005; Sezer and Tarhan, 2005). Sexual dimorphism is believed to evolve under the pressure of natural sexual selection, which implies that genes controlling sexually dimorphic characteristics differ between females and males (Mignon-Grasteau et al., 2004). Therefore, it has been suggested that genetic parameters for male and female Japanese quails be estimated separately (Sefton and Siegel, 1974), otherwise, it would be assumed that genetic correlations between male and female traits are equal to one and variances of both traits are equal, which is not often the case. Variations in live body weights of Japanese quail at 35, 42, 49 and 63 days of age showed that females had heavier body weight than males (Kawahara and Saito, 1976; Caron and Minvielle, 1990; Baumgartner, 1994; Minvielle et al., 2000). Carcass weight, breast weight, breast percent and thigh weight are higher in females than males (Caron and Minvielle, 1990; Toelle et al., 1991; Minvielle et al., 1999; 2000). Males showed higher percentage of carcass weights than females (Caron and Minvielle, 1990; Minvielle, et al., 2000). Birds slaughtered at 63 days of age had higher carcass weight compared to those slaughtered at 46 days but breast weights and breast percentage were not affected (Vali et al., 2005).
Meat pH is one of the major contributing factors to poultry meat colour. Research conducted by Oguz et al. (2004) showed that animal model heritability estimate for pH in Japanese quail was 0.48. The authors equally indicated that the heritability of colour
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characteristics in Japanese quail, namely Brightness (I), Redness (a) and Yellowness (b), estimated from animal model was 0.23, 0.45 and 0.22, respectively. Variation in pH significantly affected the storage and processing quality of poultry meat by modifying its water holding capacity and properties (Kijowski and Niewiarowicz, 1978; Daum- Thunberg and Sales et al., 1997; Barbut, 1997). Low pH meat is characterized by low water-holding capacity and poor quality and is usually referred to as pale, soft and exudative (PSE) meat (Barbut, 1997; Kijowski and Niewiarowicz, 1978). High pH meat, known as dry, firm and dark (DFD), presents poor storage quality due to faster rate of off- odor production and accelerated microbial growth (Allen et al., 1997). Carcass composition of Japanese quail is known to be influenced by dietary protein (Kim and McGinnis, 1976; Annaka et al., 1993; Marks, 1993; Hussein et al.,1996; Hashiguchi et al., 1998). Lilburn and Mayer-Miller (1990) suggested that body fat and protein deposition increased and decreased, respectively by decreasing dietary protein level in broiler breeder hens. Kilkpinar and Oguz (1995) stated that feeding low protein diets increased carcass fat content and decreased carcass protein content in female quails.
1.2 Justification of study
The awareness on quail meat is beginning to gain the interest of quail producers in Nigeria, but most producers find it difficult to obtain superior quality parents to establish an outstanding breeding programme. This is a big set back to the quail industry and a challenge to Nigeria whose population is geometrically growing with low dietary protein intake. This research was therefore geared towards estimating genetic parameters for improving the carcass, meat traits and the scale of genetic parameters that will determine the amount of improvement necessary to predict response to selection.
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1.3 The Specific objectives
i. The effect of selection on age and body weight at sexual maturity in Japanese quail.
ii. Effect of generations, sex and age on growth of body weight, body length, egg quality characteristics, egg production and carcass weight in Japanese quail.
iii. The effect of sex and age on breast meat quality of Japanese quail.
iv. The rate of genetic improvement in reproductive traits, body weight, egg traits, carcass traits, mineral and chemical composition of meat in Japanese quail.
v. The heritability (h2) based on individual selection for body weight at different ages, egg production, mineral, chemical, and carcass traits of Japanese quail.
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