Lines Of Quails Research Articles

EFFICIENCY OF DIFFERENT LEVELS OF L-CARNITINE SUPPLEMENTATION ON GROWTH PERFORMANCE AND BLOOD PARAMETERS IN THREE LINES OF KURDISH QUAILS (COTURNIX COTURNIX)

This study was aimed to assess the impact of genetic groups (comprising three distinct lines of Kurdish quails, which are desert, brown, and white), graded levels of L-carnitine and their interaction on the performance of growth traits and blood parameters. For this purpose, the same basic diet was given to 480 Kurdish quail chicks one day old, which was then supplemented for two to seven weeks of age with 0 (control), 150, 350, or 550 mg of L-carnitine per kg of diet. The statistical analysis showed that the lines, L-carnitine supplementation, and their interaction had a significant (p≤0.01) impact on the Kurdish quail's blood parameters, feed intake, feed conversion ratio, body weight, and body weight gain. The desert lines exhibited significantly higher growth performance values in all weeks. Furthermore, supplementation with 350 and 550 mg/kg L-carnitine throughout the experimental period significantly improved these characteristics compared to the control group, with the other experimental treatment (150 mg L-carnitine/kg diet) having the highest values. As well as for the interacted groups, the desert lines with diet of 350 mg/kg L-carnitine had significant influence on body weight, and weight gain. On the other hand, the white lines with a diet of 350 mg/kg L-carnitine showed significantly (P≤0.01) better feed intake and better feed conversion ratio than all other treatments in the same period. It was concluded that L-carnitine supplementation at 350 and 550 mg/kg was sufficient to improve growth characteristics and blood parameters in Kurdish quail lines.

Laying performance, genetic parameters, and the expression of FSHβ, LHβ, FSHR, and LHR genes in Japanese quails selected for early egg production

Investigating the impact of early egg production selection (the first 90 d of laying) on egg production features, cumulative selection response (CSR), and the mRNA expression of gonadotropins (FSHβ and LHβ), and their receptors (FSHR and LHR), in Japanese quails was the goal. The selection experiment involved 1293 females in all, 257 from the base group and 1036 from the 4 selected generations. Age and body weight at sexual maturity (ASM, BWSM), weight of the first egg (WFE), days to the first 10 eggs (DF10E), egg mass for the first 10 eggs (EMF10E), egg weight (EW), egg number at the first 90 d of laying (EN90D), and egg mass at the first 90 d of laying (EM90D) were all recorded. Most egg production traits had heritability estimates that were low to moderate and ranged from 0.17 to 0.33., where the highest estimates were reported for EN90D (0.33) and BWSM (0.32). With the exception of EN90D, low to moderate positive genetic correlations were observed between ASM and other egg production traits (0.17-0.44). The fourth generation showed significantly (P < 0.05) lower ASM and DF10E but higher BWSM, WFE, EN90D, EM10E, and EM90D when compared with the base generation. CSR were significant (P < 0.05) for ASM (-6.67 d), BWSM (27.13 g), WFE (0.93 g), DF10E (-1.25 d), EN90D (7.24 egg), EM10E (10.57 g), and EM90D (140.0 g). FSHβ, LHβ, FSHR, and LHR gene mRNA expression was considerably (P < 0.05) greater in the fourth generation compared to the base generation. In conclusion, selection programs depending on the efficiency of egg production (EN90D) could improve the genetic gain of egg production traits and upregulate the mRNA expression of FSHβ, LHβ, FSHR, and LHR genes in selected quails (fourth generation). These findings might help to enhance breeding plans and create commercial lines of high egg production Japanese quails.

Influence of Supplementation of Dietary with Varying Levels of L-carnitine on Laying Performance And Egg Quality Parameters in Different Lines of Kurdish Quails

Influence of Supplementation of Dietary with Varying Levels of L-carnitine on Laying Performance And Egg Quality Parameters in Different Lines of Kurdish Quails

Influence of Supplementation of Dietary with Varying Levels of L-carnitine on Laying Performance And Egg Quality Parameters in Different Lines of Kurdish Quails

Influence of Supplementation of Dietary with Varying Levels of L-carnitine on Laying Performance And Egg Quality Parameters in Different Lines of Kurdish Quails

Effect of Adding Grinded Flax Seed to The Diet on Productive Performance and Some Hematological Traits in Different Lines of Local Quails

This study was conducted to investigate the effect of a dietary supplementation with two levels of powdered flax seed and the impact of different quails' lines and the influence of diet × line on the productive performance, and some hematological traits. A total of 162 laying quail in three lines of color as white (W); black (B); and yellowish brown (Y) were randomly distributed into three treatment groups with three replicates/treatment/line T0: control (standard diet); T1 and T2 were standard diet supplemented with 3% and 6% flax seed powder (FSP), respectively. The results upon the overall period of rearing showed that: both FI (g/bird/d) and FCR (g feed: g egg) were the lowest in T1 group than both T2 and T0 groups. HDEP (%) and egg mass (g/ hen/d) of T1 group were significantly higher than other groups. Hematological results explain that T1 group owned significantly higher RBC and HCT (%) than both control and T2 groups. Genetic distance results showed that genetic similarity values range between 0.795 to 0.800. According to the UPGMA dendogram test the white line was the most distant than other two lines genetically. Genetic variation refers to the good genetic resources in the local quail. This study is one of the few studies on determining the effect of interaction between diet and line in the local quail in Kurdistan Region of Iraq, also it represents the first study in Erbil province that depending on the use of RAPD - PCR as a tool to genetic diversity for local quail. Generally, can be concluded and recommended that using 3% flaxseed powder has satisfactorily impacts on performance and health in different local quails' lines.&#x0D;

Impact of family-based selection on growth performance and immune response of Japanese quail.

The present study was aimed to evaluate the growth performance and immune response of three genetic lines of Japanese quails. These lines i.e., selected for 4-week body-weight group (WBS), selected for egg number (EBS), and random-bred control (RBC), were selected for three consecutive generations from a base population of 1125 quails. In total, 2700 four-week-old quails from three selected groups were slaughtered in total of four generations (G0 to G3). Effects of selection and generations as well as their interactions were assessed for growth performance and immune response by applying a two-way analysis of variance. Significant means were compared with Duncan's Multiple Range Test. The statistical analysis showed a significant effect of selection and generations on most of the growth and immune response parameters. WBS in G3 presented significantly higher values of body weight, weight gain, and FCR than RBC and EBS. FCR was better in WBS during G3 than those of EBS and RBC. However, Livability% was highest in RBC while the lowest was noted in G3 of WBS line. Thymus% and spleen% were higher in EBS as compared to RBC and WBS. RBC presented a better B/S ratio and ND titer than those of EBS and WBS. The decreasing trend of ND titer in both lines of WBS and EBS as compared to RBC suggested a decrease in New Castle disease resistance in progressive generations of selection. It was concluded that selection for body weight and egg number has a positive impact on respective traits but negatively affects the immunity in later generations.

Quail growth curve model identity

In this study, we sought to apply the model identity technique to compare the influence of eight treatments on growth parameters for three broiler quail lines, estimated using a logistic nonlinear regression model. For the analysis, we used the weight and age data obtained for three lines of European broiler quails (Coturnix coturnix coturnix) in a completely randomized 2×4 factorial scheme, with two levels of metabolizable energy (2900 and 3100 kcal of ME kg-1 of diet), four levels of raw protein (22%, 24%, 26% and 28% crude protein), and six repetitions. Results obtained for model identity tests indicated that although there were no significant differences among the parameters of the model between the treatments evaluated in each strain, there were, with the exception of Treatment 5 (3100 kcal of ME kg-1 and 22% crude protein), significant differences with respect to the adult weight parameter between lines within each treatment.

COMPARATIVE STUDY OF HATCHABILITY AND FERTILITY RATE AMONG LOCAL QUAILS

An experiment was conducted to evaluate fertility, hatchability, egg weight and egg production traits from three different lines of local quails. A total number of 945 eggs (334, 321 and 290 for desert, brown and white, respectively), from 20 weeks of age were used in the study. White quail significantly (P≤0.05) produce higher egg weight (12.79 ± 0.08 g), chicks' weight (8.89± 0.02 g), percentage of mortality (2.34 ± 0.70 %) and Hen-day egg production (79.33 ± 0.98 %) comparing with other local quails. While local brown quail have significantly (P≤0.05) higher percentages of fertility and hatchability which averaged 79.11 and 86.80%, respectively. The higher total number of egg and low mortality percentage (0.93 ± 0.40 %) were recorded for desert local quail. The significant positive correlation (P≤0.001) were observed between the eggs weight and chick weight, fertility and hatchability, eggs weight and hatchability were arrived 0.276, 0.180 and 0.872, respectively. But non significant negative correlation recorded between chick weight with both of fertility and hatchability. These results show that there are good among of variance in performance production among different local quails, its means the selection process among these types of bird can play major role to speed up and increasing the economical traits of local quail in Iraqi Kurdistan region.

Potential mitochondrial diversity role in the productivity of three lines of Japanese quails

Abstract. Hussein TH, Al-Shuhaib MBS, Al-Thuwaini TM. 2020. Potential mitochondrial diversity role in the productivity of three lines of Japanese quails. Biodiversitas 21: 2258-2265. This study was conducted to identify the mitochondrial D-loop genetic diversity in three lines of Japanese quails that differ in productive performance. A total of 223 quails consisting of 54, 84, and 85 of black (control line), white (egg-producing line), and brown (meat-producing line) quails respectively were genotyped by PCR-single strand conformation polymorphism (SSCP). The genetic and phylogenetic differences within and among quails’ populations were analyzed. Three different SSCP banding patterns were observed in black and brown quails, while white quails exhibited six different SSCP-banding patterns. Sequencing reactions confirmed the presence of 12 haplotypes with 48 variations distributed among the studied birds. The white line exhibited the most diverse nucleotide variability, followed by the brown, and black lines respectively. The mean diversity for all populations was mainly due to within-population variation (71.6%), while among-population variation accounted for much less value (28.4%). Tajima’s D test showed significant values for both productive white (2.45680) and brown (3.07723) lines. In conclusion, this study suggested a wide nucleic acid variation in the investigated egg productive line than the meat productive line respectively compared with the black line control, implying a positive correlation between mitochondrial variability and productive performance.

Comparison of Some Biomechanical Properties of Tibiotarsus in Four Different Feather Color Lines of 60-Day Old Female Quails

ABSTRACT This study aimed to compare some morphological and mechanical measurements of four different color female quails to contribute to the formation of the morphological database. Quails are the smallest farmed avian species which are becoming more important for the poultry industry. They are also used as experimental animals and are valuable birds for researches. Genetic factors are important determinants of bone strength. Thus, skeletal disorders may be reduced by breeding selection in quails. Forty female quails with four different feather colors, including wild, white, yellow, and black, were compared at 60 days of age. Each quail group contained ten individuals. A three-point bending test was performed with a custom-made testing machine designed for low strength materials. No significant difference was found between the groups in terms of body weight. The tibiotarsus weight in wild and black (0,665±0,055g and 0,687±0,025g, respectively) was significantly lower than in the others but, the significant highest value was in white quails (0,758±0,063g) (p=0.001). Significantly shorter tibiotarsus was observed in the black quails (51,286±1,374mm), while the tibiotarsi of the white and yellow quails were the tallest (53,216±1,796mm and 53,083±1,092mm, respectively) (p=0.005). There were no significant differences among the groups in the biomechanical properties of tibiotarsus, except stiffness. Stiffness was the highest in the white quails (109,500±3,807 N/mm) and the lowest in the black quails (99,000±9,498 N/mm) (p=0.042). In conclusion, white quails have been observed to have relatively better bone biomechanical properties compared to the other color groups at 60 days of age.

Estimação de valores genéticos para codornas europeias em função dos níveis da relação treonina: lisina da dieta: do nascimento aos 21 dias de idade

RESUMO O presente trabalho foi realizado com o objetivo de avaliar a sensibilidade dos valores genéticos dos pesos corporais e as características de carcaças de codornas europeias às mudanças do gradiente ambiental (níveis da relação treonina com a lisina das dietas), do nascimento aos 21 dias de idade, por meio de modelos de regressão aleatória com diferentes classes de variância residual. Os dados utilizados neste estudo são provenientes de 915 codornas de corte da linhagem LF1 e 839 da linhagem LF2, pertencentes ao Programa de Melhoramento Genético da Universidade Federal dos Vales do Jequitinhonha e Mucuri. Foram avaliados os pesos corporais e os rendimentos da carcaça das aves. As sensibilidades dos valores genéticos às mudanças nos níveis da relação treonina:lisina (interação genótipo x ambiente) foram obtidas por modelos de regressão aleatória (utilizando normas de reação) por meio do programa Wombat, que utiliza o princípio da máxima verossimilhança restrita (REML). O modelo de regressão aleatória que considerou duas classes de variância residual foi o mais indicado para a maioria das análises realizadas. Verificaram-se alterações na classificação dos valores genéticos para as duas linhagens de codornas de corte estudadas. Esse comportamento indica sensibilidade de valores genéticos aditivos às mudanças nutricionais, o que caracteriza a existência de interação genótipo x ambiente. A predição dos valores genéticos deve ser feita com o mesmo nível da relação treonina:lisina da dieta com a qual as codornas serão alimentadas no sistema de produção.

Genetic appraisal of four Japanese quail lines using microsatellites

Genetic appraisal of four specialized lines of quails developed at CARI Izatnagar: CARI UTTAM (CU), CARI UJJWAL (CJ), CARI SWETA (CS) and CARI PEARL (CP) were carried using quail-specific microsatellites to elucidate the present genetic constitution and diversity in light of breeding history. The microsatellite genotyping data generated from 44 polymorphic loci was analysed to arrive at various population parameters like allele distribution, polymorphic information content (PIC), heterozygosity, F-statistics, genetic distance, genetic identity and phylogenetic distribution of the four lines. Population parameters derived from microsatellite analyses were indicative of ample genetic diversity existent within and between four lines and some of the diversity indices corroborated well with the breeding history of four lines. Phylogenetic study revealed faithful clustering of individuals within a population together with no outliers however, overall relationship between the four lines thatindicated that CS and CP lines were phylogenetically closer to each other and CU stood distinctly apart, did not corroborate well with the breeding and selection history but, went down well with pair wise measures of diversity such as Nei's genetic distance and Nei's genetic identity.

Divergência genética entre codornas de corte para características de produção

Objetivou-se verificar a divergência genética entre linhagens de codornas de corte e seus cruzamentos para as características de desempenho através da análise multivariada. Foram utilizadas quatro linhagens de codornas de corte em um sistema de cruzamentos dialélicos completos, proporcionando a formação de 16 grupos de progênies, sendo quatro parentais puros: L1, L2, L3 e L4; seis grupos genéticos mestiços F1: G12, G13, G14, G23, G24 e G34; e seis grupos genéticos mestiços F1 recíprocos. Foram avaliadas as seguintes variáveis: peso corporal médio ao nascimento, aos 28, aos 35 e aos 42 dias de idade; o consumo médio de dieta do nascimento aos 35 e aos 42 dias de idade; a conversão alimentar do nascimento aos 35 e aos 42 dias de idade; e o ganho em peso do nascimento aos 35 e aos 42 dias de idade. O desempenho dos grupos genéticos foi avaliado por meio da análise de variância multivariada e a primeira variável canônica, usando os testes do maior autovalor de Roy e da união-interseção de Roy para as comparações múltiplas. O estudo da divergência genética foi feito por meio da análise por variáveis canônicas e pelo método de otimização de Tocher. As três primeiras variáveis canônicas explicaram 88,82% da variação entre os grupos genéticos. A divergência genética entre os grupos genéticos avaliados permitiu a formação de quatro grupos: 1 - L1, G12, G23, G21 e G41; 2 - G13 e G31; 3 - L4 e G43; 4 - G32; 5 - G14 e G24; 6 - G42 e 7 - L2, L3 e G34, identificando a L4 como a linhagem que mais influiu na formação de novo grupos.

Canonical-correlation analysis applied to selection-index methodology in quails

Genetic evaluations in dual-purpose quails (Coturnix coturnix) have demonstrated that overall genetic gains in a breeding program are achieved not only based on a specific trait, but on several. The most common technique to use all this information is the selection index. Another alternative may be the canonical-correlation analysis applied to selection index. There is, however, a lack of studies using canonical correlation in quails. Hence, the objectives of this study were to apply canonical-correlation analysis to estimate the relationship of nine traits and to compare genetic gains obtained by this methodology to desired-gain selection index in three lines of quails. Data for three lines of layer quails consisted of body weight at 28 days (W28), egg weight (EW), age at first egg (AFE) and egg production at 30, 60, 90, 120, 150 and 180 days after onset of lay. Two sets of traits were established: the first one contained predictor variables (W28, EW and AFE) and the second one contained variables related to egg production. A selection index was constructed using the standardized coefficients of canonical covariates as weighting factors when a given canonical correlation was significant. We constructed two desired-gain selection indices: DG-SI1 and DG-SI2. The difference between them is that DG-SI2 had a desired gain for body weight set to 0. The estimated canonical correlations were as follows: 0.811, 0.058 and 0.003 for the yellow, 0.821, 0.181 and 0.076 for the red, and 0.825, 0.117 and 0.038 for the blue line. Only the first pair of canonical variates was significant (P<0.05). AFE and early stages of egg production were very influent and showed great importance in defining the canonical variates and, consequently, the estimated canonical correlations. All lines had, in general, similar results for the canonical analysis indicating that traits that drive management decisions in these lines would be the same. The indices under study showed differences in response to selection; however, they generally resulted in consistent favorable genetic gains. For all lines, the canonical selection index resulted in the lowest AFE and highest egg production at 30 days. The DG-SI1 showed the highest genetic gains for W28 in all lines. There was a general lower genetic gain of other traits for DG-SI1 at the expense of the desired genetic gain for W28. Selection for AFE, according to the canonical-correlation analysis, would have a great impact on the number of eggs produced. Canonical selection index is a good alternative for a desired-gain selection index.

A higher inherent trait for fearfulness is associated with increased anxiety-like behaviours and diazepam sensitivity in Japanese quail

This study tested whether lines of Japanese quails divergently selected for a fear response, the tonic immobility, might constitute a reliable bird model for studying anxiety. Previous studies demonstrated that the selection modifies the general underlying emotionality of the birds rather than exerting its effect only on tonic immobility. The behavioural effects of intraperitoneal injections of diazepam, an anxiolytic drug, were assessed in two lines of quail selected either for their short (STI) or long (LTI) duration of tonic immobility. Effects of diazepam were examined in two tests used for measuring emotionality in birds, the open field and the tonic immobility tests. After being placed in the centre of the open field, birds with a high emotionality (LTI quails) stayed longer in the centre of the apparatus than STI quail. Diazepam had anxiolytic effect in LTI birds as it increased the time spent in the outer area. This effect of diazepam appears to be selective because the drug has no effect on other behaviours such as distress calls or escape attempts. The drug has also no effect on the tonic immobility response in any of the two lines. These findings reveal an “anxiogenic” trait of LTI birds in the open field test that can be modulated by the administration of an anxiolytic drug. Therefore quails selected for LTI and STI represent a valuable model to study the mechanisms underlying anxiety in birds.

Estimation of Additive and Non-Additive Genetic Variances of Body Weight, Egg Weight and Egg Production for Quails (Coturnix coturnix japonica) with an Animal Model Analysis

Abstract. This study estimates the additive and non-additive variances for egg production and body weight traits of two lines of quails from a long-term selection with the help of the REML method. For the body weight of 42-day-old females (BW42f) and males (BW42m), a total of 7,934 records for line 1 and 7,214 records for line 2 from 21 generations were used in our analyses. Additionally, 1,717 records of females from line 1 and 1,671 records of females from line 2 contained information on their egg production at an age of 42 to 200 days (EN200), on the average egg weight for the first 11 weeks of their laying season (EW1), on the average egg weight from weeks 12 to 23 (EW2), and on their body weight at an age of 200 days (BW200f). A multivariate additive animal model and one-trait dominance models, which include the inbreeding coefficients as covariates, were fitted to the data. The estimates of the heritability gained from our dominance models were smaller than those from the additive model. For line 1, the heritability values decreased for EN200 from 0.35 to 0.32, for EW1 from 0.66 to 0.56, for BW200f from 0.42 to 0.38, and for BW200m from 0.51 to 0.49, respectively. For the first line, the respective ratio (d2) of the dominance variance to the phenotypic variance for EN200, EW1, BW200f and BW200m was 0.08, 0.22, 0.09 and 0.21, and the values for the second line were 0.12, 0.06, 0.001 and 0.23.

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.

Behavioural evidence of hybridization (Japanese × European) in domestic quail released as game birds

The European quail is a partial migrant bird considered ‘vulnerable’ by the European community. The decline of this subspecies has spurred an annual release of large numbers of domestic Japanese quail. Prezygotic and postzygotic isolating mechanisms have not been established between these two subspecies, enhancing the risk of hybridization. In addition, anecdotal reports suggest that hybridization is commonly practiced in game farms of domestic quails. In this article, we present the results of behavioural characterization of the quails produced by two European game farms: one French and one Italian. First, we looked for evidences of hybridization in both game farms. Using actographic methods, we measured migratory tendency. Birds, hatched in summer, were submitted in autumn to an artificial increase of daylength (LD 14:10) for 60 days. In quails, the length of the cloacal vent which is a good indicator of sexual development, was monitored every 10 days. We noted the appearance of cloacal foam in males and egg-laying activity in females. In addition, mating calls produced by the males when sexually mature were recorded and analyzed using spectrographic methods. Seventeen males of 27 from the French game farm exhibited nocturnal restlessness. Most of the birds of the Italian game farm (40/44) developed sexually without showing any migratory activity. Since Japanese quail has lost its migratory impulse during the domestication process, the presence of migratory activity in quails of both game farms clearly demonstrated the introduction of wild European quail. Spectrographic analysis of male mating calls confirmed this assumption: some males in both game farms (21/27 in the French game farm, 5/22 in the Italian game farm) produced calls similar to those produced by control lines of hybrid quails (Japanese × European). In an additional experiment, we report the results of encounters between males of the French game farm and males of European quail. One bird of each strain were put together on day 1 and on day 3, we introduced in the pen a female European quail. In 11 cases out of 11, the male of the French game farm dominated the male European quail and monopolized the female. These results imply that releasing hybrid and Japanese quails in the wild could rapidly lead to widespread genetic pollution of the western Palaearctic populations of the European quail.

A comparative study of growth, skeletal development and eggshell composition in some species of birds

AbstractSome studies of birds suggest that the development of the skeleton may invoke a constraint on the rate of postnatal growth. Other studies have shown that the eggshell is the major source of calcium for skeletal development of the embryo. To test whether avian growth rate is indeed associated with different patterns of skeletal development, we compared the degree of skeletal ossification of the long bones of the wing and the leg of one slowly growing precocial species (quail Coturnix japonica) with that of two rapidly growing altricial species (starling Sturnus vulgaris and fieldfare Turdus pilaris). The degree of skeletal ossification of the long bones of the wings and legs of lines of quails that had undergone long‐term selection for high‐ and low‐growth rate, respectively, also was compared with a non‐selected control line. Next, the fine structure of the inner eggshell surface (mammillary layer) of both pre‐ and post‐incubated eggs, i.e. before and after embryonic development/calcium removal was compared. The data show that the skeleton of the more rapidly growing species and lines was less ossified than that of the more slowly growing ones. This difference appeared to be associated with different rates of calcium removal from the eggshell. Removal was more extensive in eggs of quail than in eggs of starling and fieldfare, i.e. more extensive in shells with a high number of mammillary tips per unit of surface area than in shells with a lower number. It is therefore concluded that growth rate is of fundamental importance for the pattern of skeletal development. Moreover, the mammillary density varies between different bird species, it is suggested, in order to support the different rates of calcium removal by developing embryos.

Direct and correlated responses to selection for 4-week body weight in two lines of Japanese quails

Abstract. Data on 29,411 quails of two selected lines along with a control line were examined over nine generations. Significant genetic gains/generation for 4-week body weight were realized in the two strains (3.70 and 3.10 g). Significant correlated genetic changes were also observed in early body weights (day-old to 3-weeks) as well as in 16-week body weight. Egg number and sexual maturity did not show any significant response while egg weight and egg mass showed desirable genetic gains. Natural selection did not seem to exert any effect. Inbreeding levels of 0.32 to 0.43 % per generation did not appear to be of any significance in affecting the response. Realized heritabilities (0.21–0.24) were reasonably consistent between sexes and matched fairly well with the nine-generation pooled sire-component heritabilities of 0.20 ± 0.04 and 0.25 ± 0.04 in the two lines. There was evidence of maternal effects as indicated by excess of dam- over the sire-component heritability. Time-trend in heritabilities was non-significant. There was good agreement between the predicted and realized genetic gains.