Lines Of Japanese Quail Research Articles

Genetic Parameters Estimated for Sexual Maturity and Weekly Live Weights of Japanese Quail (Coturnix coturnix japonica)

Covariance components and genetic parameters of weekly live body weight from hatching to six weeks of age and age of sexual maturation were estimated in a laying type Japanese quail line. The univariate and bivariate animal model analysis included hatching group and sex as fixed effects. Each trait was analysed with animal as random effect to fit the additive direct effect. Additional random effects incorporated in the models were changed according to the trait examined. The best model for a trait was chosen based on a likelihood ratio test, comparing the models with and without maternal additive genetic and maternal permanent environmental effects. Heritability estimates of live-weight at hatch and one to six weeks of age with their standard errors were 0.22±0.088, 0.39±0.099, 0.31±0.086, 0.38±0.056, 0.46±0.055, 0.50±0.059, and 0.56±0.062, respectively. Direct heritability value of age of sexual maturation was moderate (0.24±0.055). The variances due to permanent environmental effect of dam after one week of age and maternal genetic effect after two weeks of age were not important sources of variation. The correlations between direct and maternal genetic effects were negative and ranged from high to moderate values (-0.21 to -0.83). Among the weekly live weights, genetic correlations were generally high between not only successive but also early and late weightings. It suggests that selection for final weight may be based on early weight records. Genetic correlations between age of sexual maturation and live weights were low, favourable but had high standard errors. These results indicate that selection for high weight will potentially result in lower age of sexual maturation only with accurate determination of breeding values.

USING STEPWISE REGRESSION ANALYSIS TO PARTITION THE VARIABILITY IN GROWTH AND SOME CARCASS TRAITS IN THREE LINES OF JAPANESE QUAIL DIFFERING IN GENETIC BACKGROUND.

Data of blood and/or plasma constituents of three weeks old Japanesequail were used to predict the growth and some carcass traits of 6 weeks oldquail. Stepwise regression analysis was performed to partition the variability ingrowth and carcass traits of three lines of Japanese quail differing in geneticbackground. The first and second lines were selected over three generations forhigh six week-body weight (HBW6) and high 0-6 week growth rate (HGR0-6)respectively, whereas the third randombred control line (RC) was kept in orderto facilitate comparison among lines. The results cleared that the mostimportant predictor for live body weight at six weeks of age (LBW6) in bothmales of RC and males of HGR was thyroxine (T4). Both plasma total lipidsand total proteins (TL and TP) were the best predictors for LBW6 for femalesof RC line. Model 2 which used hemoglobin (Hb) and T4 was the best modelfor predicting LBW6 for males of HBW6. Whereas, TL was the most importantpredictor for LBW6 for females of HBW6 line. The most important predictorsfor feed conversion (FC) were TL and T4 for males of RC line, white and redblood cells (WBC and RBC) for females of RC, T4 and packed cell volume(PCV) for males of HGR0-6, triglycerides (TG) and TL for females of HGR0-6,TL and WBC for males of HBW6 and growth hormone (GH) and PCV forfemales of HBW6 line. Performance index (PI) was predicted through TL andalbumin (Alb) for males of RC, TP and GH for females of RC, T4 and PCV formales of HGR, TG and TP for females of HGR, TL and ratio oftriiodothyronine to thyroxine (T3/T4) for males of HBW6 and TG and T3/T4 forfemales of HBW6. For predicting dressing% in all studied groups, the mostimportant predictors were T3/T4 and TP for males of RC, TP and GH forfemales of RC, ratio of T3/T4 and T3 for males of HGR0-6, Alb and TP forfemales of HGR0-6, PCV and RBC for males of HBW6, Alb and T3/T4 forfemales of HBW6, respectively. Carcass% for all studied groups could bepredicted using these predictors: PCV and GH for males of RC, GH and TG forfemales of RC, GH and RBC for males of HGR0-6, WBC and T3 for females ofHGR0-6, T3/T4 and Hb for females of HBW6, respectively. The most importantpredictors for boneless meat% (BLM) were RBC and TP for males of RC, Hband Alb for females of RC, TG and T4 for males of HGR0-6, TP and T4 forfemales of HGR0-6, T3/T4 and Alb for males of HBW6 and TL and Hb forfemales of HBW6, respectively. The major predictor in determining protein%for both males and females of the HBW6 line was T3. The most importantpredictors for fat% were T3/T4, TL and TP in a descending order for males andfemales of the RC line and males of HBW6, respectively. The predicted traitswere insignificantly differed than the actual values or percentages(P>0.05). Therefore, results of the stepwise regression analyses revealed thateither certain studied hematological values or plasma constituents at threeweeks of age in studied lines of both sexes could be used to predict carcass andgrowth productive traits in Japanese quail with high precision and low error.

USING PATH ANALYSIS TO PARTITION THE VARIABILITY IN GROWTH AND CARCASS TRAITS IN THREE LINES OF JAPANESE QUAIL.

Chicks of two selected lines of Japanese quail for high six weekbody weight and high 1-6 week growth rate (HBW6 and HGR0-6) overthree generations were used to partition the variability of growth andcarcass traits. A randombred control line (RC) was kept in order tofacilitate comparison between lines. The RC had the lowest bonelessmeat% (BLM), fat% and live body weight at slaughter (LBW6) being48.13%, 16.09% and 184.65g, respectively. Although HGR had thehighest BLM% and dressing%, birds of this line had significantlypoorer feed conversion (FC) and performance index (PI) than otherlines. On the other hand, birds of the HBW line had the highest LBW6and PI but had higher carcass' fat% (200.25g, 3.55 and 20.51%,respectively). Sex significantly affected BLM%, carcass %, dressing%,LBW6, FC and PI. Although males had significantly higher carcass%,their PI were poorer than females, this may be due to the superiority offemales growth than males at different ages of growth and thisdifference may be attributed primarily to the relatively large ovaries,liver and intestines of the females. When these parts were excluded,lower carcass% for female was obtained. Except triglycerides (TG),line significantly affected all plasma constituents. The RC line had thehighest growth hormone (GH) and the lowest albumin (Alb), totallipids (TL), total protein (TP), triiodothyronine (T3) and ratio of T3 tothyroxine (T3/T4). Whereas, HGR had the lowest GH and the highestAlb, TP, T3 and T4. Females had significantly higher Alb, TP and T3/T4than males, however, males had higher T3 than females. The results ofpath analyses revealed that the studied plasma constituents measured atthree weeks of age in both sexes could be used to predict carcass traitsand growth productive performance in Japanese quail. Each of GH,TG, TL, Alb, TP and T3/T4 was the first contributors of studiedproductive traits in line by sex groups indicating direct effects whichranged from 0.530 to 0.763, 0.504 to 0.945, 0.887 to 0.906, 0.513 to0.990 and 0.609 to 0.892, respectively. Plasma constituents showedhigher indirect coefficients of determination for their effects on allstudied productive traits than their direct effects. This suggests that apart of the variations in these traits could be attributed to a trait ormore, not handled in this study and may diminish the random errorvariation when considered.

Stressor-induced changes in open-field behavior of Japanese quail selected for contrasting adrenocortical responsiveness to immobilization

The effect of no treatment (undisturbed controls; CON) or 5 min exposure to immobilization stress (STR) before assessment of open-field behavior in Japanese quail lines selected for high (high stress; HS) or low (low stress; LS) plasma corticosterone (B) response to a similar immobilization stress was examined. During a 5-min test period in an open field, the following behavioral measurements were made: the latency to ambulate (LAMB), the number of open-field floor sectors entered (SECTORS), and freezing behavior (total time spent in complete silence and inactivity, apart from slight movements associated with respiration; FREEZE). A further measure of ambulation across time (ambulation rate; ARATE) was calculated using the formula: ARATE = (SECTORS/[(300 s test ceiling)–LAMB)]. The LS-quail showed higher (P < 0.04) ARATE and lower (P < 0.05) FREEZE behavior than did their HS counterparts. When compared with the CON, quail exposed to STR showed decreased ARATE (P < 0.02) and numbers of open-field SECTORS entered (P < 0.04). More importantly, the LS-CON exhibited a higher (P < 0.05) mean ARATE, less FREEZE behavior, and increased numbers of SECTORS entered than did the other 3 treatment groups (LS-STR, HS-CON, and HS-STR), all of which showed similar responses for these variables. The LS-CON vs. HS-CON findings support our contention that selection for reduced adrenocortical responsiveness has been accompanied by a concomitant decrease in underlying fearfulness (exemplified herein by heightened activity in the open field in LS-CON). We further show here that this relationship was eliminated by application of an acute stressor before open-field testing of LS quail, wherein a reduction in activity similar to that found in both HS quail treatment groups was evident in comparison to the LS-CON.

Relationship of cloacal gland with testes, testosterone and fertility in different lines of male Japanese quail

An attempt has been made to investigate the relationship of cloacal gland with testes, testosterone and fertility in different lines of Japanese quail ( Coturnix coturnix japonica). For this study, three lines of healthy adult male Japanese quails (<12 weeks) viz., heavy body weight (HB), white breasted (WB), and white egg shell (WES) were taken. They were housed in individual cages under uniform husbandry conditions and were provided with normal quail breeder ration and water ad libitum, with 14 h light/day. The experimental birds were selected from each of these three lines and categorized into different groups (15 birds/group) based on the increasing order of the area of cloacal gland. At the end of this experiment (24 weeks) the data indicated that size of the cloacal gland was directly proportional to foam discharge, foam weight, testicular weight, fertility and testosterone concentration in plasma. From this study it may be concluded that area of cloacal gland in Japanese quail is positively correlated with testicular weight, level of testosterone in plasma and fertility. Visual examination of cloacal gland and cloacal foam may provide a valuable non-invasive tool for predicting the fertilizing ability of individual male bird.

Enzyme Polymorphism in Two Japanese Quail (Coturnix Coturnix Japonica) Lines with Different Concentrations of Plasma Lactate

Japanese Quail (Coturnix coturnix japonica) lines selected for different physiological traits such as metabolic rate are expected to be more suitable for experiments than random populations. The general level of lactate in a randomly bred Japanese Quail population varies within the limits 3.6 mM•L-1. Breeding experiments were performed in order to reduce the variation of plasma lactate. The two quail lines, exhibiting low (L line with 5.281–5.840 mM•L-1) and high (H line with 3.157–4.529 mM•L-1) plasma lactate concentration were divergently selected. During the selection process, genetic variation in loci for liver and heart tissue malate dehydrogenase (Mdh), malic enzyme (Me), esterase (Es) as well as for plasma glucose-6-phosphate dehydrogenase (G-6-Pdh) and common serum proteins was investigated in individual animals. A phenotypic difference in the spectrum of MDH isozymes was detected between the two quail lines L and H. Our data suggest that the genetic constitution of quail lines and the control pop...

Daily and photoperiod variations of hypothalamic-pituitary-adrenal axis responsiveness in Japanese quail selected for short or long tonic immobility

The aims of this study were to investigate the existence of a circadian rhythm of basal corticosterone (B) plasma concentrations in male and female Japanese quail lines divergently selected for long (LTI) or short (STI) duration of tonic immobility (TI) and the possible effects of photoperiod length on corticotropic axis reactivity. Significant peaks in B levels were observed throughout the day in 3 out of the 4 groups used in our experiments. However, B levels remained very low for all groups (< 5.0 ng/mL) and there was no consensus between groups. We therefore have no evidence from our results that basal B levels follow a circadian rhythm in adult STI and LTI quail held under a long photoperiod (16L:8D). We also showed that rearing under a long photoperiod (16L:8D) was associated with higher basal B levels and higher B adrenal response capacity to 1-24 adrenocorticotropic hormone (ACTH) injection in the STI and LTI lines compared with a shorter period (8L:16D). Higher hypothalamic-pituitary-adrenal (HPA) axis responsiveness to restraint in a crush cage was also measured in female quail reared under the long photoperiod, and similar responses were measured under both photoperiods in males. This result suggests that the effects of photoperiod length involve both local and more central mechanisms in the control of HPA axis responsiveness according to sex. On the other hand, we showed that the genetic selection program for TI responses induced greater increases in the B level following restraint in STI quail than in LTI quail of both sexes under both photoperiods, but the B adrenal response capacity was similar for both lines and sexes. Although further investigations on both lines regarding adrenal sensitivity are necessary before being able to conclude definitively, our findings strongly suggest that the differences observed in HPA axis responsiveness to restraint between lines are probably not due to differences in adrenal function itself but may involve upstream structures of the HPA axis.

Incorporation of Competitive Effects in Forest Tree or Animal Breeding Programs

Competition among domesticated plants or animals can have a dramatic negative impact on yield of a stand or farm. The usual quantitative genetic model ignores these competitive interactions and could result in seriously incorrect breeding decisions and acerbate animal well-being. A general solution to this problem is given, for either forest tree breeding or penned animals, with mixed-model methodology (BLUP) utilized to separate effects on the phenotype due to the individuals' own genes (direct effects) and those from competing individuals (associative effects) and thereby to allow an optimum index selection on those effects. Biological verification was based on two lines of Japanese quail selected for 6-week weight; one line was selected only for direct effects (D-BLUP) while the other was selected on an optimal index for both direct and associative effects (C-BLUP). Results over 23 cycles of selection showed that C-BLUP produced a significant positive response to selection (b=0.52+/-0.25 g/hatch) whereas D-BLUP resulted in a nonsignificant negative response (b=-0.10+/-0.25 g/hatch). The regression of percentage of mortality on hatch number was significantly different between methods, decreasing with C-BLUP (b=-0.06+/-0.15 deaths/hatch) and increasing with D-BLUP (b=0.32+/-0.15 deaths/hatch). These results demonstrate that the traditional D-BLUP approach without associative effects not only is detrimental to response to selection but also compromises the well-being of animals. The differences in response show that competitive effects can be included in breeding programs, without measuring new traits, so that costs of the breeding program need not increase.

Model parameters of growth curves of three meat-type lines of Japanese quail

This study was focused on a comparison of the growth characteristics and parameters of three meat-type lines of Japanese quail. The body weight data of wild-type, dotted-white and extended-brown quail lines over time were collected and fitted to Richards equation. The relevant parameters were compared based on the Confidence Interval Test. Confidence Interval Test calculates the percentages of model predictions staying in the confidence intervals of the corresponding experimental data. Both sexes of brown quails showed lower weight gains than the other two lines. Behind the inflection point a decline in the absolute growth rate was slowest for brown females. In general, Richards model parameter values showed deviations of one line from the other lines to a varying extent. Shape parameter for males (0.335&amp;ndash;0.618) and maturation index for females (0.067&amp;ndash;0.077) tend to be the most critical parameters. When the overall models were used to predict the weight of other lines, the models of white and wild males showed great similarity. Overall model predictions for male brown and white quails, for female brown and wild-type quails showed the largest differences. Like in males, white and wild females were the closest lines but the likeliness percentage was lower than that for males. The proposed method of parameter comparison can be a useful tool for researchers working on biological modelling. &amp;nbsp;

Two Japanese Quail Lines Selected for High and Low Antibody Response were Homozygous at Major Histocompatibility Complex

In the present study, Southern hybridization analysis was used to investigate whether segregated major histocompatibility complex (MHC) genes were selected in two partly inbred Japanese quail (Coturnix japonica) lines, the H and L lines, which were selected for high (H) and low (L) antibody response against inactivated Newcastle disease virus (NDV) vaccine as a result of breeding over 45 generations by reciprocal mating. The results showed that the each restriction fragments length polymorphisms (PFLP) pattern of MHC class I, II and IV of all the individuals within the H and L lines were identical. The RFLP patterns of MHC class II in F1 offspring resulting from the H and L lines were inherited equally. This suggested that divergent selection for antibody response to inactivated NDV in Japanese quails might have induced two different MHC-homozygous lines.

Analysis of growth characteristics in short-term divergently selected Japanese quail

This study was carried out to examine the effect of short-term selection for 5-weeks of age body weight in divergent lines of Japanese quail. Growth curves for both sexes within each selection group resembled the general sigmoid shape of a typical growth curve. Gompertz model curves and the observed growth curves were very similar. In both males and females the parameter estimates of the Gompertz growth curve were obtained with a high determination coefficient (0.9898 ≥ R2 ≥ 0.9840). Sex differences in asymptotic weight were found to be significant across lines. Similarly, in both sexes a significant divergent selection effect was determined for parameter A. The growth rate in all the Japanese quail lines was significantly higher in males than in females. There was also a significant increase in growth rate of the females selected for increased 5-week body weight over the control females, as well as a significant decline in growth rate of males selected for decreased 5-week body weight compared to the unselected control group. Keywords : Gompertz model; growth curve; asymmetric response;growth rate South African Journal of Animal Sciences Vol. 35 (2) 2005: pp.83-89

Effects of Dietary Protein Levels on Production and Characteristics of Japanese Quail Eggs

Three different lines (normal, brown and crossbred) of Japanese quail were used in this study to examine the effects of dietary protein level on the production and quality of eggs. In all lines, poor egg production was evident throughout the experiment on a diet with 16% crude protein (CP). Egg production increased as the CP levels of diets increased. Until 32 weeks, normal (N) and brown (B) lines showed higher egg production at 24% CP, while the crossbred (BN) line showed higher egg production at 22% CP. The cumulative egg production at 24% CP was higher than or similar to that at 26% CP. A comparison of egg production among different lines showed that BN produced significantly (P<0.05) more eggs than N at the lower protein levels of 20% and 22% CP. Weight of eggs was lowest in all lines at 16% CP, and tended to increase with increasing protein level. No difference in egg weight was observed among lines. Egg weight and yolk color were significantly (P<0.05) affected by different levels of protein. It appears that 24% CP was optimal for higher egg production and egg weight for N and B lines and 22% CP for BN lines. Furthermore, our data indicate that heterosis was obtained in BN for egg production at the lower protein levels.

CDNA array analysis of Japanese quail lines divergently selected for four-week body weight

Decades of divergent selection for 4-wk BW has produced 3 lines of growth-selected Japanese quail. P line quail have been selected for >110 generations for 4-wk posthatch BW and are nearly 3-fold larger than the randomly bred control C line. The H line has been selected for high 4-wk BW for 52 generations and the L line has been selected for low 4-wk BW for 54 generations. To identify differentially expressed genes that may play a role in defining the differences in these lines, a DNA array containing 4,704 random anonymous cDNA clones from 8-d C line embryos was screened using isotopically-labeled cDNA from the different quail lines. Array analysis yielded 3 differentially expressed cDNA clones that were confirmed by Northern blot analysis. The 35-kD quail EB1 protein, previously unidentified, was shown to have elevated transcripts in the L line and decreased transcripts in the H and P lines, compared with the C line. It was also widely expressed in embryonic and adult tissues by BLASTN analysis of chicken expressed sequence tag (EST) libraries. Two other cDNA clones are novel sequences expressed at higher levels in the L line and at lower levels in the H and P lines, one of which was more selectively expressed in embryos and adult tissues by BLASTN analysis. These limited findings suggest that anonymous cDNA array analysis is a productive means to identify differentially expressed genes in growth-selected poultry.

Divergent selection for shape of growth curve in Japanese quail. 2. Embryonic development and growth

1. Embryonic growth and development were analysed using meat type lines of Japanese quail, HG and LG, divergently selected for shape of the growth curve. A total of 1020 embryos of generations 9, 10 or 13 were used for analysis. 2. Considerable inter-line differences were observed in the rate of embryonic development. When compared to HG, LG embryos appeared to be developmentally accelerated during the first 42 h of incubation (larger blastoderm diameter, more somites and higher frequency of more advanced Hamburger–Hamilton stages) as well as at the end of the prenatal period (more embryos with the yolk sac inside the body cavity, shorter incubation period). This corresponded with the trend in postnatal development. 3. Embryonic growth of both lines exhibited an exponential trend. However, considerable inter-line differences were noted in the rate of embryonic growth. Initial growth retardation compensated subsequently by a higher growth rate of HG vs LG quail, characterised the lines after hatching. The same growth pattern repeated three times during the prenatal period (between d 0 and 3, 3 and 8, and 8 and 16). 4. The repeated occurrence of transient decreases in growth rate of the developmentally delayed HG line could be associated with a delayed onset of genetically determined physiological functions mediating utilisation of nutrient supply. 5. Hence, different shapes of growth curves in two genotypes with similar growth potential reveal inter-line differences in physiological age persisting during the whole ontogenesis.

Purebred and crossbred performances from a Japanese quail line with very small body size

In this study on Japanese quail, heterosis for weight, growth rate, and fitness traits were estimated and growth curves were fitted to traits and were compared. Crossing (SR) was performed between females of a very small line (SS) which was selected for low body weight at the age of six weeks and males of a randombred population (RR) from the same origin. Heterosis for female body weight was observed at 4 and 6 weeks of age, but it was not significant for adult size in males and females. The four growth curve models of Brody, Logistic, Gompertz and Bertalanffy were compared and the Gompertz model was the most suitable. Heterosis by the Gompertz model was negative for the age at the point of inflexion and the age at the 90% body weight of the asymptote in both sexes, but it was larger for the second trait. There was no heterosis for fertility and viability from 6 weeks up to 100 days of age in the female, but it was significant for hatchability and survival rate up to 6 weeks of age. Large heterosis was found for the age at first egg, the number of eggs and the total egg weight up to 100 days of age. However, the average egg weight of SR was lighter than that of RR, showing no heterosis.

Diphasic Analysis of Growth in Japanese Quail

A line of Japanese quail selected for increased body weight for 15 generations (C) and an unselected control line (K) were used to examine the impact of selection for body weight on the growth curve of Japanese quail. In addition, the effect of sex on the growth curve in each line was also studied, namely females of C (CF), males of C (CM), females of K (KF) and males of K (KM). The monophasic and diphasic growth models were studied for adequacy in describing growth curves of quail in both sexes of the C and K lines. The monophasic function provided almost the same growth rate for both sexes in both lines. However, the growth rates calculated by means of the diphasic function differed between sexes for both lines, except for those calculated for C during the second growth phase. While there were 2-3 days difference between sexes in age at maximum gain in both lines with a monophasic model, the difference between sexes in the age at maximum gain in both lines became greater according to the diphasic model. There were 5 and 7 days difference between sexes in the age at maximum gain in line C for the first and second growth phases, respectively. A difference between sexes of 18 and 11 days in the age at maximum gain for the first and second phases, respectively, was estimated for line K when the diphasic function was fitted. The use of diphasic functions provides more detailed information on growth patterns. The results showed that the use of the diphasic function was better because it provided greater insights into understanding the biology of growth.

Effect of long-term divergent selection on growth characteristics in Japanese quail

The current study was undertaken to examine the effect of long-term selection for 4-wk BW on growth characteristics in divergent lines of Japanese quail and their control. Growth rate was significantly higher in males than females in all the lines. There was a significant increase in growth rate of the females selected for increased 4-wk BW over the control females, as well as a significant decline in growth rate of males selected for decreased 4-wk BW compared to their control counterparts. It appeared that selection for increased 4-wk BW did not alter the rate of growth in the males compared to the control males; however, in the females, selection for increased 4-wk BW resulted in an increase in growth rate. On the other hand, selection for decreased 4-wk BW resulted in a decline in growth rate in males but not in the females. The dynamics of the growth curve parameters indicate that selection for decreased 4-wk BW shifted the growth curve for females as well as altering the trajectories of growth in both sexes. However, selection for increased 4-wk BW only resulted in altering the trajectory of growth in the males. Long-term selection resulted in asymmetry of response in the low and high lines. In addition, different genes may respond differently to the same selection pressure in opposite directions. The use of the 4-parameter Richards model to analyze growth data from such an experiment provided a better understanding of how selection can alter the rate and trajectory of growth to affect the genetically determined growth potential of quail. Consequently selection for increased or decreased 4-wk BW affected the sexes differently.

Effect of selection for growth on onset of sexual maturity in randombred and growth-selected lines of Japanese quail

An experiment was conducted to determine the effect of selection for growth (BW) on the onset of reproduction (first egg) in Japanese quail hens from growth-selected (HW) and randombred (R1) lines. The HW line had undergone over 40 generations of selection for increased 4-wk BW and was originally developed from the R1 line. Data were collected over two consecutive hatches and summarized by hatch and within lines. Body weight at 35 d of age was positively correlated with BW at sexual maturity (first egg) in both the R1 and HW lines, but these correlations were not significant in both hatches for either line (Hatch 1-R1; Hatch 2-HW; P < or = 0.05). There was a negative correlation between age at sexual maturity (days to first egg) and 35 d BW in both lines with the exception of the HW hens in Hatch 2. Age at sexual maturity and BW at sexual maturity was positively correlated (P < or = 0.001) in the R1 line but did not show the same relationship in the HW line. Age at sexual maturity and weight of the abdominal fat pad were positively correlated in the R1 line (Hatch 1, P < or = 0.01; Hatch 2, P < or = 0.001), but this relationship was not significant in the HW line. Age at sexual maturity and follicle number was negatively correlated in both lines but was not significant in Hatch 2 of the HW line. Follicle size, however, was positively correlated with days to first egg in only Hatch 2 (P < or = 0.001) of the HW line. The data suggest that the relationships between the onset of sexual maturity and both reproductive parameters and carcass traits in hens from consecutive hatches of HW quail are less clear than in the R1 line.

Reproductive phenotype of two lines of Japanese quail (Coturnix coturnix japonica) under two different room temperatures

Line as well as ambient temperature, substantially affected the reproductive performance of birds, hence in this study lines C (control) and P (meat type) were assigned into two room temperatures i.e. 18 and 35°C, represented higher and lower land areas of Indonesian archipelago. This study was conducted to find out the effect of line, ambient temperature and it’s interaction on the reproductive phenotype of Japanese quail. A Completely Randomed Design with 23 factorial arrangement was applied using 8 males and 24 females of each room temperature, every bird was kept in individual cage. Each male was mated to one female for 5 minutes per day for 3 consecutive days, 15 days later the same male was mated to the second female using the same manner. The third female was mated to this male using the same previous way. Parameters measured were copulation number, egg mass, testes weight, fertility and duration of fertility. Results showed that copulation number of line P (1.10 ± 0.29) were lower than (P<0.05) that of line C (1,84 ± 0,33). Within 14 day period line P produced higher egg mass compared with line C (66.91 g vs 55.88 g). Line P testis weight (6.82 ± 0.36 g) were significantly (P<0.01) higher than that of line C (3.18 ± 0.34 g), while room temperature slightly affected the testis weight. Fertility rate of line P (29.07 ± 14.12%) was much lower (P<0.01) than that of line C (46.90 ± 15.44 %). Duration of fertility of line P (1.10 ± 0.35 days) was also lower (P<0.01) than that of line C (3.48 ± 1.28 days). Copulation number and egg mass were not influenced by high room temperature while rate and duration of fertility were substansially affected. It was concluded that some reproductive parameters of male and female of Japanese quail were affected by body weight and room temperature in different way. Key words: Line, quail, room temperature, reproductive

Analysis of censored survival data in Japanese quail divergently selected for growth and their control

The aim of the current study was to characterize and quantify risk factors involved in juvenile mortality in divergently selected and control lines of Japanese quail. Survival analysis and Cox proportional hazards regression were used to describe mortality in the three experimental lines with hatch weight and posthatch BW evaluated as risk factors. Survival function distribution indicated that the proportional mortality was highest in the line selected for high 4-wk BW compared to the low and control lines. In all the experimental lines mortality declined when posthatch BW increased; however, the magnitude of reduction was highest in the control line compared to the divergently selected lines (57 vs. 22%). Any factor that influences growth after hatching may likely have a direct impact on mortality. Lack of accessibility to water, feed, warmth, and potential negative social interaction are factors that could affect mortality immediately after hatch. The posthatch BW at time of mortality used as a risk factor indicated that the divergently selected lines have about the same risk and are less sensitive to reduced BW compared to the control population. Through survival analysis, the present study has demonstrated that factors causing reduction in posthatch BW are likely risk factors for mortality in growing birds.