Randombred Control Line Research Articles

Egg production curves and their prediction through mathematical models in a random-bred broiler breeder control population

Six mathematical models, namely, Logistic, MMF, Polynomial Fit, Rational Function, Sinusoidal Fit and Quadratic fit were selected and fitted to the weekly hen housed egg production from 19 to 52 weeks of age of two generations of a random-bred broiler breeder control line. The efficiency or reliability of the models was obtained by the coefficients of determination (R2) as per the Least

Comparison of Muscle Fiber and Meat Quality Characteristics in Different Japanese Quail Lines.

The aim of this study was to compare the growth performance, fiber characteristics of the pectoralis major muscle, and meat quality characteristics in the heavy weight (HW) and random bred control (RBC) quail lines and genders. The HW male exhibited more than two times greater body (245.7 vs 96.1 g, p<0.05) and pectoralis major muscle (PMW; 37.1 vs 11.1 g, p<0.05) weights compared to the RBC female. This growth performance in the HW line was associated with a greater muscle fiber area (1,502 vs 663.0 μm2, p<0.001) compared to the RBC line. Greater muscle mass of the HW male was accompanied by a higher percentage of type IIB fiber compared to the HW female (64.0% vs 51.0%, p<0.05). However, muscle fiber hyperplasia (increase in fiber number) has had a somewhat limited effect on PMW between the two lines. On the other hand, the HW line harboring a higher proportion of type IIB fiber showed rapid pH decline at the early postmortem period (6.23 vs 6.41, p<0.05) and lighter meat surface (53.5 vs 47.3, p<0.05) compared to the RBC line harboring a lower proportion of type IIB fiber. There were no significant differences observed in the measurement of water-holding capacity including drip loss (2.74% vs 3.07%, p>0.05) and cooking loss (21.9% vs 20.4%, p>0.05) between the HW and RBC lines. Therefore, the HW quail line developed by selection from the RBC quail, was slightly different in the meat quality characteristics compared to the RBC line, and a marked difference was found in growth performance between the two quail lines.

Temperature effect on proliferation and differentiation of satellite cells from turkeys with different growth rates

Poultry selected for growth have an inefficient thermoregulatory system and are more sensitive to temperature extremes. Satellite cells are precursors to skeletal muscle and mediate all posthatch muscle growth. Their physiological functions are affected by temperature. The objective of the current study was to determine how temperature affects satellite cells isolated from the pectoralis major (p. major) muscle (breast muscle) of turkeys selected for increased 16 wk body weight (F line) in comparison to a randombred control line (RBC2) from which the F line originated. Pectoralis major muscle satellite cells were thermally challenged by culturing between 33°C and 43°C to analyze the effects of cold and heat on proliferation and differentiation as compared to control temperature of 38°C. Expression levels of myogenic regulatory factors: myogenic differentiation factor 1 (MYOD1) and myogenin (MYOG) were quantified by quantitative polymerase chain reaction (qPCR). At all sampling times, proliferation increased at a linear rate across temperature in both the RBC2 and F lines. Differentiation also increased at a linear rate across temperature from 33 to 41°C at all sampling times in both the F and RBC2 lines. Satellite cells isolated from F line turkeys were more sensitive to both hot and cold temperatures as proliferation and differentiation increased to a greater extent across temperature (33 to 43°C) when compared with the RBC2 line. Expression of MYOD1 and MYOG increased as temperatures increased from 33 to 41°C at all sampling times in both the F and RBC2 lines. These results demonstrate that satellite cell function is sensitive to both cold and hot temperatures and p. major muscle satellite cells from F line turkeys are more sensitive to temperature extremes than RBC2 satellite cells.

Effect of Growth Selection on Adipogenic Gene Expression During the Development of the Turkey Breast Muscle

The effect of growth selection in turkeys was studied for its effect on the expression of adipogenic genes in the pectoralis major (p. major) muscle both in vivo and in vitro in a random bred control line (RBC2) and a subline F selected long-term from the RBC2 for only increased 16-wk body weight. The expression of the adipogenic transcription factors peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding protein α (C/EBPα) and stearoyl-CoA desaturase (SCD) were measured in p. major muscle tissue isolated from 18 and 24 d old embryos and 1 and 16-wk old RBC2 and F line turkeys and in vitro with adult myoblasts (satellite cells) isolated from RBC2 and F line turkey p. major muscle tissue during proliferation and differentiation. Both in vivo and in vitro, the F line expressed significantly higher levels of PPARγ, C/EBPα and SCD. The data from the current study provides novel information about the effect of growth selection in turkeys on the potential of fat formation in vivo in the p. major muscle and the possible transdifferentiation of myogenic satellite cells to an adipogenic lineage.

Muscle hypertrophy in heavy weight Japanese quail line: Delayed muscle maturation and continued muscle growth with prolonged upregulation of myogenic regulatory factors

The objective of this study was to compare the temporal expression of myosin heavy chain (MyHC) isoforms, Pax7, and myogenic regulatory factors (MRF) between heavy weight (HW) and random bred control (RBC) Japanese quail lines during muscle development to better understand the mechanisms leading to increased skeletal muscle mass in the HW quail line selected for a greater BW at 4 wk of age separated from RBC quail. Expression of neonatal MyHC isoform began at 3 and 7 d posthatch in RBC and HW quail lines, respectively. In the RBC quail line, adult MyHC isoform, as a marker for muscle maturation, was expressed at 28 d posthatch with sustained expression through 75 d posthatch, whereas this protein was detected only at 75 d posthatch in the HW quail line. Moreover, Pax7 expression continued from embryonic ages to 14 d posthatch in the HW quail line and to 7 d posthatch in the RBC quail line. These expression patterns of MyHC isoforms and Pax7 in the HW quail line were accompanied by delayed muscle maturation and prolonged growth compared with the RBC quail line. Temporal expressions of the primary MRF showed that higher expression levels of MyoD and Myf-5 were observed at 9 and 11 d embryo in the HW quail line compared with the RBC quail line (P < 0.05). The HW quail line exhibited approximately 2 times greater average levels of myogenin expression from 7 to 75 d posthatch (P < 0.05) than the RBC quail line. Prolonged upregulation of these primary and secondary MRF during muscle development is associated with delayed maturation and continued muscle growth, which consequently would permit muscle hypertrophic potentials in the HW quail line compared with the RBC quail line.

Divergent selection for muscle color in broilers

One consumer-related physiological abnormality that is a recent concern for the poultry industry is atypical meat quality. Currently in the processing plant, meat is characterized on appearance such as tears, bruises, discoloration, or missing parts. Unfortunately, this method ignores physical properties such as palatability, texture, tenderness, taste, color, pH, and water-holding capacity (WHC). The growing demand for a convenient, economical, and palatable product has shifted the market toward value-added poultry products. The effect of a meat's physical properties on its marketability and versatility has become apparent to processors attempting to utilize poor quality meat. After 8 generations of divergent selection for muscle color or lightness (L*) in broilers, muscle quality parameters were investigated. The 2 broiler lines divergently selected for high (HMC) and low (LMC) muscle color along with their randombred control line (RBC) were included in the study. Heritability estimates for L* were 0.47 ± 0.05 and 0.51 ± 0.05 in the HMC and LMC lines, respectively. For generation 8, the mean L* for the HMC, RBC, and LMC lines were 53.91, 49.70, and 46.86, respectively. Selection for increased L* was found to result in increased breast fillet yellowness (b*), whereas selection for decreased L* resulted in an increase in breast fillet redness (a*). Selection for increased L* has resulted in increased rate of pH decline over time, whereas selection for decreased L* has resulted in a decreased rate of pH decline. The HMC line exhibited a higher percentage fillet drip loss than both the LMC and RBC lines, which did not differ from each other. Overall selection for L* was effective in modifying breast muscle color as well as correlated responses associated with atypical poultry meat such as drip loss and postmortem muscle pH. These selected lines can serve as resource populations for the study of PSE and DFD-like meat in poultry and demonstrate that L* selection could be applied to primary breeding programs as a way to improve or manage muscle quality in pedigree elite lines.

Skeletal muscle characterization of Japanese quail line selectively bred for lower body weight as an avian model of delayed muscle growth with hypoplasia.

This study was designed to extensively characterize the skeletal muscle development in the low weight (LW) quail selected from random bred control (RBC) Japanese quail in order to provide a new avian model of impaired and delayed growth in physically normal animals. The LW line had smaller embryo and body weights than the RBC line in all age groups (P<0.05). During 3 to 42 d post-hatch, the LW line exhibited approximately 60% smaller weight of pectoralis major muscle (PM), mainly resulting from lower fiber numbers compared to the RBC line (P<0.05). During early post-hatch period when myotubes are still actively forming, the LW line showed impaired PM growth with prolonged expression of Pax7 and lower expression levels of MyoD, Myf-5, and myogenin (P<0.05), likely leading to impairment of myogenic differentiation and consequently, reduced muscle fiber formation. Additionally, the LW line had delayed transition of neonatal to adult myosin heavy chain isoform, suggesting delayed muscle maturation. This is further supported by the finding that the LW line continued to grow unlike the RBC line; difference in the percentages of PMW to body weights between both quail lines diminished with increasing age from 42 to 75 d post-hatch. This delayed muscle growth in the LW line is accompanied by higher levels of myogenin expression at 42 d (P<0.05), higher percentage of centered nuclei at 42 d (P<0.01), and greater rate of increase in fiber size between 42 and 75 d post-hatch (P<0.001) compared to the RBC line. Analysis of physiological, morphological, and developmental parameters during muscle development of the LW quail line provided a well-characterized avian model for future identification of the responsible genes and for studying mechanisms of hypoplasia and delayed muscle growth.

Comparative growth performance in different Japanese quail lines: The effect of muscle DNA content and fiber morphology

The aim of this study was to investigate the DNA content and morphological characteristics of muscle fibers, and their relation to the growth performance in random bred control (RBC) and heavy weight (HW) Japanese quail lines. The 2 lines were of similar embryo size at 6 and 8 d of incubation; however, HW quail were significantly larger than their counterparts after 10 d of incubation (P < 0.05). The hatch weight of the HW quail line was approximately 1.3-fold higher than the RBC quail line (P < 0.001). After 15 d posthatch, the BW and pectoralis major muscle weight (PMW) exhibited remarkable differences between the 2 quail lines. The RBC line showed a faster rate of increase in PMW (2.7- vs. 2.1-fold) and total DNA mass (2.2- vs. 1.6-fold) between 0 and 4 d posthatch. The HW line exhibited a greater rate of the PMW (33.0- vs. 12.9-fold) and total DNA mass (10.3- vs. 4.0-fold) between 4 and 15 d posthatch than the RBC line. Moreover, the greatest increase in total DNA mass occurred between 0 and 8 d posthatch for the RBC line and 4 to 15 d posthatch for the HW line. These differences in the DNA content indicate a difference in the hypertrophic potential of muscle fibers between the 2 quail lines. The cross-sectional area of muscle fibers was 1.3-fold greater in the HW line compared with the RBC line at 8 d posthatch (158.5 vs. 97.11 μm(2), P < 0.001), and this difference increased with age (over 2.1-fold greater in the HW line). Thus, the most important time windows affecting ultimate body and muscle weights in the RBC and HW quail lines are between 0 to 8 d and 4 to 15 d posthatch, respectively. Rapid muscle growth rate and a greater muscle mass in the HW quail line may be partially due to the hypertrophic potential of muscle fibers, which is characterized by larger fiber size.

Differential gene expression between normal and pale, soft, and exudative turkey meat

In response to high consumer demand, turkeys have been intensively selected for rapid growth rate and breast muscle mass and conformation. The success in breeding selection has coincided with an increasing incidence of pale, soft, and exudative (PSE) meat defect, especially in response to heat stress. We hypothesized that the underlying mechanism responsible for the development of PSE meat arises from differences in expression of several critical genes. The objective of this study was to determine differential gene expression between normal and PSE turkey meat using a 6K turkey skeletal muscle long oligonucleotide microarray. Breast meat samples were collected from Randombred Control Line 2 turkeys at 22 wk of age, and classified as normal or PSE primarily based on marinade uptake (high = normal, low = PSE). Total RNA was isolated from meat samples with the highest (normal, n = 6) and the lowest (PSE, n = 6) marinade uptake. Microarray data confirmation was conducted using quantitative real-time PCR. Selection of differentially expressed genes for pathway analysis was performed using a combination of fold change (FC) ranking (FC < -1.66, FC >1.66) and false discovery rate (<0.35) as criteria. The calcium signaling pathway was highlighted as the top canonical pathway associated with differential gene expression between normal and PSE turkey. Dramatic downregulation of fast-twitch myosin heavy chain coupled with upregulation of slow-twitch myosin and troponin C suggested a switch of skeletal muscle isoforms, which may alter muscle fiber arrangement and formation of actin-myosin complexes. Changes in expression of genes in the actin cytoskeleton signaling pathway also suggest altered structures of actin filaments that may affect cell motility as well as strength and flexibility of muscle cells. Substantial downregulation of pyruvate dehydrogenase kinase, isozyme 4 was observed in PSE samples, suggesting altered regulation of the aerobic metabolic pathway in the birds that developed PSE meat defect.

Growth and sex effects on the expression of syndecan-4 and glypican-1 in turkey myogenic satellite cell populations

The adult skeletal muscle stem cells, satellite cells, are responsible for skeletal muscle growth and regeneration. Satellite cells represent a heterogeneous cell population that differentially express cell surface markers. The membrane-associated heparan sulfate proteoglycans, syndecan-4, and glypican-1, are differentially expressed by satellite cells during the proliferation and differentiation stages of satellite cells. However, how the population of syndecan-4- or glypican-1-positive satellite cells changes during proliferation and differentiation, and how sex and muscle growth potential affect the expression of these genes is unknown. Differences in the amount of satellite cells positive for syndecan-4 or glypican-1 would affect the process of proliferation and differentiation which would impact both muscle mass accretion and the regeneration of muscle. In the current study, the percentage of satellite cells positive for syndecan-4 or glypican-1 from male and female turkeys from a Randombred Control Line 2 and a line (F) selected for increased 16-week body weight were measured during proliferation and differentiation. Growth selection altered the population of syndecan-4- and glypican-1-positive satellite cells and there were sex differences in the percentage of syndecan-4- and glypican-1-positive satellite cells. This study provides new information on dynamic changes in syndecan-4- and glypican-1-positive satellite cells showing that they are differentially expressed during myogenesis and growth selection and sex affects their expression.

Response of restraint stress-selected lines of Japanese quail to heat stress and Escherichia coli challenge

Japanese quail selected for divergent corticosterone response to restraint stress were evaluated for their susceptibility to heat stress and challenge with Escherichia coli. These quail lines are designated as high stress (HS), low stress (LS), and the random-bred control (CS) lines. Heat stress (35°C, 8 h/d) began at 24 d until the end of the study at 39 d. Birds were challenged with an aerosol spray containing 2 × 10(9) cfu of E. coli at 25 and 32 d. At 38 d, the surviving birds were necropsied and the intestinal tract was screened for both Salmonella and Campylobacter. Body weights of the CS birds were higher than both HS and LS at 17, 25, and 32 d. At 32 d, there was no difference in mortality between males and females and the CS line had higher mortality compared with the LS line with the HS line being intermediate. At 38 d, females of the CS line that were both heat stressed and challenged had a mortality incidence of 25%, which was significantly higher than male birds of the same line and treatment (5.3%). There was an increased incidence in Salmonella enterica serotype Agona isolation after heat stress, with the LS birds having less isolation than the HS birds. Mean corticosterone levels of male birds were not significantly affected by line, heat stress, or E. coli challenge; however, the LS line subjected to heat stress had one-third the level of the HS line, a difference identical to that seen in the original selection for response to restraint stress.

Muscle fiber characteristics of pectoralis major muscle as related to muscle mass in different Japanese quail lines

The objectives of this study were to investigate the muscle fiber characteristics of the pectoralis major muscle, and its relation to growth performance in the random bred control (RBC) and heavy weight (HW) Japanese quail lines at 42 days of age. The HW line had greater body (232.0 v. 100.2 g, P < 0.001) and pectoralis major muscle (19.0 v. 6.2 g, P < 0.001) weights than the RBC line. Color differences were observed between the superficial and deep regions of the pectoralis major muscle, with the superficial region showing a higher value of lightness than the deep region of the RBC or HW lines (P < 0.001). The percentage of the superficial region in the pectoralis major muscle was higher in the HW line compared with the RBC line (46.2% v. 38.0%, P = 0.017). There were no significant differences in the total fiber number in the superficial and deep regions between the two quail lines (P = 0.718). The HW quail line showed a larger mean fiber cross-sectional area (CSA; 375.5 v. 176.6 μm2, P < 0.001) and type IIA fiber CSA (243.7 v. 131.9 μm2, P < 0.001) than the RBC quail line. The HW line also had greater CSA percentage (60.2% v. 34.2%, P < 0.001) and number percentage (41.6% v. 14.2%, P < 0.001) of type IIB fibers, although there were no significant differences in type IIB fiber CSA between the RBC and HW lines (P = 0.219). Therefore, greater body and muscle weights of the HW line are caused by differences in muscle fiber characteristics, especially the proportion of type IIB fiber and the CSA of type IIA fiber, compared with the RBC line. The results of this study suggest that muscle fiber hypertrophy has more impact on body and muscle weights of the different quail lines than muscle fiber hyperplasia.

Differential expression of calcium-regulating genes in heat-stressed turkey breast muscle is associated with meat quality

Aberrant postmortem Ca(2+)-regulation in the early postmortem period is associated with the occurrence of inferior meat quality in turkeys, described as pale, soft, and exudative (PSE). The objective of the current study was to quantify expression of 4 candidate genes responsible for maintaining Ca(2+) homeostasis in turkey skeletal muscle as a function of heat stress: α and β ryanodine receptors (RYR; Ca(2+)-release channels), the sarco/endoplasmic reticulum Ca(2+)-ATPase 1 (SERCA1), and the sarcoplasmic reticulum, Ca(2+)-storage protein calsequestrin (CASQ1). Two genetic lines of turkeys were used: a growth-selected commercial line and a randombred control line. Market-age birds were subjected to one of 5 heat stress treatments: no heat, 1 d, 3 d, 5 d, or 7 d of heat followed by 7 d of ambient temperature. Breast muscle samples were harvested and classified as normal or PSE using the meat quality parameters percentage of marinade uptake and percentage of cook loss. These parameters differed significantly by line, heat stress treatment, and meat quality status. Expression of candidate genes was measured using TaqMan quantitative PCR. Heat treatment was associated with significantly enhanced expression of αRYR, βRYR, and CASQ1 in normal muscle from both lines. Conversely, mRNA abundance of these genes was reduced in PSE muscle from both lines and recovered or increased by 7 d + 7 d of rest. Genetic line differences were observed at several time points. Expression of SERCA1 in both normal and PSE samples from both lines was unchanged or trended downward with heat stress. Taken together, genetic line and heat-stress treatment affected the expression of important Ca(2+)-regulating genes in association with meat quality status. The data suggest that birds whose meat leads to PSE may fail to respond to heat stress appropriately due to a delay in the upregulation of the important calcium-regulating genes: αRYR, βRYR, and CASQ1.

The effects of genotype on embryonic development in eggs from divergent turkey genotypes

Unique turkey genotypes and reciprocal crosses of these lines were used to study the relationship between egg size, posthatch growth potential, and selected aspects of embryonic development. A line of turkeys selected for increased egg production (E), its randombred control line (RBC1), a line selected for increased 16-wk BW (F line), and its randombred control line (RBC2) were the pure lines used in each of 2 experiments. In experiment 1, a sample of E-line hens were mated to either E line (E/E) or RBC1 toms (RBC1/E), and RBC1 hens were mated to RBC1 toms (RBC1/RBC1). Egg weight at set and at 25 d of incubation was significantly lower in the E/E and RBC1/E crosses compared with that of the RBC1/RBC1 eggs. On d 21 and 25 of incubation and at hatch, the yolk-free wet embryo weights of E/E and RBC1/E embryos were similar, and both weighed significantly less than the RBC1/RBC1 embryos (P ≤ 0.001). Similar observations were observed for the residual yolk sac weight at each of those developmental ages. In experiment 2, embryos from the F line, RBC2, RBC1, E, and 2 reciprocal crosses (RBC1/E, E/RBC1) were compared at various time points during the course of incubation. Egg weight was consistently highest in the F line and lowest in the E line and intermediate in the RBC1 and RBC2 lines. Egg weight followed the maternal genotype in the E/RBC1 and RBC1/E reciprocal crosses. On embryonic d 19, 23, and 26, the order of yolk-free weight embryo weights followed closely the pattern observed for egg weight. In summary, egg weight and embryonic development is largely controlled by the maternal genotype. This should be considered when making inference to posthatch selection effects on embryonic development.

Transcriptional profiling identifies differentially expressed genes in developing turkey skeletal muscle

BackgroundSkeletal muscle growth and development from embryo to adult consists of a series of carefully regulated changes in gene expression. Understanding these developmental changes in agriculturally important species is essential to the production of high quality meat products. For example, consumer demand for lean, inexpensive meat products has driven the turkey industry to unprecedented production through intensive genetic selection. However, achievements of increased body weight and muscle mass have been countered by an increased incidence of myopathies and meat quality defects. In a previous study, we developed and validated a turkey skeletal muscle-specific microarray as a tool for functional genomics studies. The goals of the current study were to utilize this microarray to elucidate functional pathways of genes responsible for key events in turkey skeletal muscle development and to compare differences in gene expression between two genetic lines of turkeys. To achieve these goals, skeletal muscle samples were collected at three critical stages in muscle development: 18d embryo (hyperplasia), 1d post-hatch (shift from myoblast-mediated growth to satellite cell-modulated growth by hypertrophy), and 16wk (market age) from two genetic lines: a randombred control line (RBC2) maintained without selection pressure, and a line (F) selected from the RBC2 line for increased 16wk body weight. Array hybridizations were performed in two experiments: Experiment 1 directly compared the developmental stages within genetic line, while Experiment 2 directly compared the two lines within each developmental stage.ResultsA total of 3474 genes were differentially expressed (false discovery rate; FDR < 0.001) by overall effect of development, while 16 genes were differentially expressed (FDR < 0.10) by overall effect of genetic line. Ingenuity Pathways Analysis was used to group annotated genes into networks, functions, and canonical pathways. The expression of 28 genes involved in extracellular matrix regulation, cell death/apoptosis, and calcium signaling/muscle function, as well as genes with miscellaneous function was confirmed by qPCR.ConclusionsThe current study identified gene pathways and uncovered novel genes important in turkey muscle growth and development. Future experiments will focus further on several of these candidate genes and the expression and mechanism of action of their protein products.

Genetic parameters for levels of natural antibodies in chicken lines divergently selected for specific antibody response

The present study estimated the heritability of natural antibody (NAb) levels binding rabbit red blood cells at the day of immunization with SRBC (NAb0) and 5 d postimmunization (NAb5) in 2 chicken lines divergently selected for specific antibody levels (SpAb) against SRBC and a randombred control line. In addition, genetic correlations between the levels of NAb binding rabbit red blood cells and levels of SpAb binding SRBC were estimated. The heritability of the SpAb level against SRBC was estimated based on data from 23 generations of selection and in total 21,842 chickens. The heritability of NAb levels against rabbit red blood cells was estimated on 1,764 chickens in generations 22 and 23 using a bivariate analysis including the trait under selection (i.e., SpAb responses to SRBC). Maternal environmental effects were accounted for in the analyses. The heritability for SpAb was 0.17, the heritability for NAb0 levels was 0.23, and the heritability for NAb5 was 0.09. The genetic correlation between SpAb and NAb0 was 0.15 and the genetic correlation between SpAb and NAb5 was 0.50. The weak, though positive, genetic correlation between SpAb responses and the NAb0 levels in nonimmunized chickens, as well as the moderate genetic correlation between SpAb responses and the NAb levels 5 d postimmunization with SRBC, suggest that selection for enhanced adaptive immune system results in a positive correlated response of the innate immunity of chickens.

Effects of Season and Line on Sexual Maturity and Some Egg Yield Traits in Selected Japanese Quails (Coturnix Coturnix japonica)

Alkan, S., Karabag, K., Galic, A. and Balcioglu, M.S. 2009. Effects of season and line on egg yield traits in Japanese quails. J. Appl. Anim. Res., 35: 105–108. This study was conducted to determine the effects of season and lines on age at sexual maturity, body weight at sexual maturity and some egg yield traits in 11 generations of selected Japanese quail. The material used in this research was selected from high (HL) or low (LL) body weight Japanese quail lines according to 5-week body weights and their random bred control line and layer line (L) for 120 d egg production. Average egg weight was the lowest in summer and in LL line, which also had lowest total egg number, total egg weight and hen day egg production. Maximum eggs were produced by L line, while heaviest eggs were produced by HL line. The highest and lowest ages at sexual maturity were determined in winter and summer seasons, respectively. Also, the heaviest first egg weight was found in winter season. It is concluded that lines and seasons generally affected quail egg production.

Determination of Body Weight and Some Carcass Traits in Japanese Quails (Coturnix coturnix japonica) of Different Lines

Summary The purpose of this study was to determination of body weight and some carcass traits in Japanese quails (Coturnix coturnix japonica) of different lines. The material used in this experiment was selected from three lines: high body weight line (HL), low body weight line (LL) of 5-week body weight and a random bred control line (C). There were significant differences among the lines in respect to body weight and carcass weight. Highest and lowest body weight and carcass weight were measured in HL and LL lines, respectively. While there were no significant differences among the lines in terms of relative proportion of breast, the sex affected significantly (P<0.01). No significant differences were found in terms of left wing, right wing, neck and back percent of body weight for lines and sexes. Also, there were found significant correlations among the carcass traits..

Effects of Selection for Body Weight and Egg Production on Egg Quality Traits in Japanese Quails (Coturnix coturnix japonica) of Different Lines and Relationships between These Traits

Summary This research was conducted to investigate the effects of selection on egg weight, shell thickness, shell weight, shape index, albumen index, yolk index and Haugh Unit in 11 generations selected Japanese quails (Coturnix coturnix japonica). The material used in this research was selected for 11 generations from high (HL) or low (LL) body weight Japanese quail lines according to 5-week body weights and their random bred control line (C) and layer line (L) for 120 d egg production. There were found significant differences among the lines in terms of all egg traits (P<0.01). The egg weights were determined in HL, LL, L and C lines as 14.14±0.17 g, 9.23±0.07, 10.49±0.10 and 11.43±0.13 g respectively. Besides there were significant (P<0.01) differences among the lines for the shell weight, and highest and lowest values were determined as 1.15±0.02 g and 0.84±0.02 g in HL and LL lines. Once again, there were found significant (P<0.05) differences among the lines in point of Haugh Unit. The highest positive correlation (P<0.01) was found between egg weight and egg width (0.938), and the highest negative correlation (P<0.01) was found between shape index and egg length (-0.531). Almost all of the internal quality traits of the egg changes depending on external quality traits of the egg.

Circulating Corticosterone Reaction to Restraint and Adrenocorticotropin Hormone Administration in White Leghorns Selected for Immune Response Traits

Corticosterone plasma concentration was measured in a random-bred control line and in 3 White Leghorn chicken lines previously selected over 9 generations for 3 different in vivo immune responses: high antibody response to Newcastle disease virus vaccine 3 wk after vaccination (ND3), high cell-mediated immune response (response to phytohemagglutinin, PHA), and high phagocytic activity measured as carbon clearance (CC). The objective of the study was to estimate if selection on immune response had an effect on the response to stress assessed by measures of corticosterone concentration before and after physical stress or adrenocorticotropin hormone injection and if the effect was dependent on the immune response trait that had been selected for, by joint analyses of immune responses and concentrations. The mean values of plasma corticosterone measures did not differ between lines, indicating that selection for different high immune responses had little effect on response to stress. Within line, however, significant negative correlations (−0.46 ≤ r ≤ −0.39) were found between cell-mediated immunity and corticosterone plasma concentrations in 3 of the 4 lines. Moreover, in the line selected for high antibody titers (ND3-L), corticosterone levels were positively correlated to ND3 (r = 0.41 and 0.47) and negatively correlated to CC (r = −0.48).