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Fearfulness and economic traits were studied in three lines of Japanese quail. Two of the lines were of the same genetic origin and were subjected to divergent selection for the duration of tonic immobility (TI), a measure of fearfulness. Birds were selected for long (LTI) or short (STI) duration of TI. The third line (DD) was of a different genetic origin and had been selected for early egg production. Fear, growth, residual feed intake, and measures of egg composition and production varied among lines. The distribution of TI in Line DD was closer to that from Line STI. Residual feed intake and shell content were lowest in the DD line. The DD birds laid more broken eggs than quail of the other lines. The STI line birds had higher BW and laid more, but smaller, eggs than LTI line birds. Eggs laid by LTI line birds had higher albumen content, but lower percentage shell, than those laid by STI line birds. When all traits were considered together, there was an overall tendency for STI line birds to out perform LTI birds with DD line birds showing intermediate performance. This finding supports the notion that there is a relationship between fearfulness and productivity. However, the skewed distribution of TI precluded estimation of correlation with production traits in the LTI and STI lines. No significant relationships among fear and production-related traits were found in the DD line, which contradicts the notion that fearfulness and production are related.

1. Four Japanese quail lines were developed using 13 generations of reciprocal recurrent (lines AA and BB) or within-line selection (lines DD and EE) for high egg number until 98 d of age. In these lines and their reciprocal crosses, egg production, egg weight and mortality were monitored for up to 21 months to evaluate the impact of selection method and line origin on long-term production and heterosis. 2. Both hen-housed total egg number (EN) and hen-day egg laying rate (ELR) were consistently lower in recurrent lines than in lines under within-line selection: after 13 months of test, the difference was -47.1 eggs for EN and -20% for ELR%, whereas mortality was similar at around 20%. 3. Line EE was the best pure line for early egg production (55.2 eggs at 98 d of age) and also gave eggs which were consistently about 2 g larger than those from line DD but it had the highest overall mortality (78.5%) of all lines. On average, line DD laid 399 eggs (EN) over the whole experiment, 84 more than Line EE. 4. Crossbreds from the 2 types of pure lines and line DD had similar patterns and rates of egg production during the whole experiment, as indicated by the similarity of the curves adjusted for those lines by using the monomolecular model for EN and the modified compartmental model for ELR. 5. However, heterosis was higher from recurrent selection lines and it increased more with time than did heterosis from within-line selection lines.

Introduction In much animal production, commercial animals are crossbreds from closed lines or breeds under long-term directional selection. Therefore it is desirable to be able to predict heterosis gains over the generations as it is done for genetic progress under within-line selection. However, heterosis is the phenotypic expression of a complex phenomenon which may involve several types of genetic effects like dominance and epistasis. In animal breeding, basic quantitative genetics theory indicates that heterosis should be proportional to (squared) differences in gene frequency between populations (e.g. F alconer and M acK ay 1996), and it has been found approximately correct, so it is commonly used for planning crosses. Under that type of heterosis, however, selection towards the same objective in two populations should bring gene frequencies closer, and therefore it should eventually decrease heterosis. On the other hand, reciprocal recurrent selection designed to increase genetic distance between lines should eventually achieve maximum heterosis (O llivier 1982). Some experiments reviewed by brun (1982) have already compared genetic progress under within-line and reciprocal recurrent selection, but they did not focus on comparing the trend of heterosis with generations between the two selection methods. Also, heterosis was monitored periodically in some selection experiments on poultry, and results were reviewed by F airfull (1990). They were somewhat contradictory, but they generally failed to relate genetic progress to loss of heterosis under within-line selection. Moreover, in commercial production, as purebreds and crossbreds are not contemporaries and are generally maintained under very different management systems, estimations of heterosis and of the evolution of crossbred advantage over the generations may be difficult to obtain. Using the Japanese quail as an experimental animal, the present work was initiated specifically to follow the changes in heterosis brought about by selection for a single heterotic trait, early egg production (M invielleet al. 1995). For that purpose, two selection methods expected to have opposite effects on heterosis, directional within-line (or individual) selection and reciprocal recurrent selection, were applied for 13 generations in four quail lines started from two different origins, and trends of heterosis in the selected character and in weight and egg traits were evaluated.

An exponential curve, W = P - Q exp (-Rt) was fitted to egg weights (W) of individual hens from 8 genetic groups tested for egg production from 18-51 weeks of age (t). The groups were constituted of the combination of genotype at the sex-linked dwarfism locus (normal or dwarf) and line (White Leghorn, Brown Egg and both reciprocal crosses). The least-squares mean of the residual standard deviation about the curve was between 1.27 and 1.74 g in the 8 groups and estimated values of the initial P-Q and mature egg P weights were between 26.9 and 33.9 g and 56.9 and 65.8 g, respectively. Effects of genotype and line as well as heterosis were estimated for both egg weights and for rate of growth relative to the remaining expected growth (R). R was smaller for dwarf hens which thus reached mature egg weight later than normal females. Significant heterosis was found for both egg weights of dwarf hens (12.6 and 9.5%) and for the initial egg weight of normal ones (12.8%). Negative heterosis for R obtained for dwarf hens (-17.4%) corresponded to a flatter egg weight curve of these crossbreds., On a ajusté individuellement une courbe de la forme W = P - Q exp (-Rt) au poids de l’oeuf (W) mesuré entre 18 et 51 sem d’âge (t) chez des poules de 8 groupes génétiques définis par la combinaison du génotype au locus de nanisme lié au sexe (normal ou nain) et de la lignée (souche Leghorn blanche, souche à oeuf brun et leurs croisements réciproques). L’écart type résiduel après ajustement de la courbe exponentielle aux valeurs de poids, évalué pour chaque groupe par la méthode des moindres carrés, a pris des valeurs comprises entre 1,27 et 1,74 g. De la même manière, les estimations des poids du premier oeuf (P - Q) étaient situées entre 26,9 et 33,9 g, et celles de l’oeuf à maturité entre 56,9 et 65,8 g d’autre part. On a évalué les effets du génotype et de la lignée et l’hétérosis pour les poids de l’oeuf et l’accroissement de poids journalier relativement au poids restant à gagner (R). La valeur de R était inférieure pour les poules naines qui par conséquent ont atteint leur poids d’oeuf à maturité plus tard que les femelles normales. Un hétérosis significatif a été obtenu pour les 2 poids d’oeuf chez les poules naines (12,6 et 9,5%) et pour le poids du premier oeuf chez les femelles normales (12,8%). L’hétérosis négatif trouvé pour R chez les poules naines (-17,4%) correspond au fait que la courbe du poids de l’ceuf étaient plus aplatie chez les croisés de ce génotype.

The effect of a dietary triiodothyronine (T3) supplement, of either 0.1 or 0.5 microgram/g of feed, was studied on the thyrotropin-releasing hormone (TRH)-induced growth hormone (GH) secretion in sex-linked dwarf (dw) or normal (Dw) chicks of both sexes. In normal chicks, 0.1 microgram/g T3 decreased plasma GH levels before TRH as well as the GH increase after TRH, and 0.5 microgram/g T3 totally suppressed any response to TRH, either at 4 or at 7 weeks of age. Dwarf chicks were more sensitive to TRH than normals when receiving either 0 or 0.1 microgram/g T3; 0.5 microgram/g T3 abolished the difference between genotypes at 4 weeks of age but not so clearly at 7 weeks of age, where dwarf females showed a slight but still significant GH increase after TRH. Interactions between genotype, TRH injection, and T3 treatments were often significant at 4 weeks of age and even more at 7 weeks of age. Dwarf chicks receiving 0.1 microgram/g T3, expected to have normal plasma T3 levels, showed a higher GH response after TRH. This suggests that other hormones may be involved in the regulation of this response, particularly IGF-I, which is known to remain at a low level in T3-treated dwarf chicks.

Background By comparing the quail genome with that of chicken, chromosome rearrangements that have occurred in these two galliform species over 35 million years of evolution can be detected. From a more practical point of view, the definition of conserved syntenies helps to predict the position of genes in quail, based on information taken from the chicken sequence, thus enhancing the utility of this species in biological studies through a better knowledge of its genome structure. A microsatellite and an Amplified Fragment Length Polymorphism (AFLP) genetic map were previously published for quail, as well as comparative cytogenetic data with chicken for macrochromosomes. Quail genomics will benefit from the extension and the integration of these maps. Results The integrated linkage map presented here is based on segregation analysis of both anonymous markers and functional gene loci in 1,050 quail from three independent F2 populations. Ninety-two loci are resolved into 14 autosomal linkage groups and a Z chromosome-specific linkage group, aligned with the quail AFLP map. The size of linkage groups ranges from 7.8 cM to 274.8 cM. The total map distance covers 904.3 cM with an average spacing of 9.7 cM between loci. The coverage is not complete, as macrochromosome CJA08, the gonosome CJAW and 23 microchromosomes have no marker assigned yet. Significant sequence identities of quail markers with chicken enabled the alignment of the quail linkage groups on the chicken genome sequence assembly. This, together with interspecific Fluorescence In Situ Hybridization (FISH), revealed very high similarities in marker order between the two species for the eight macrochromosomes and the 14 microchromosomes studied. Conclusion Integrating the two microsatellite and the AFLP quail genetic maps greatly enhances the quality of the resulting information and will thus facilitate the identification of Quantitative Trait Loci (QTL). The alignment with the chicken chromosomes confirms the high conservation of gene order that was expected between the two species for macrochromosomes. By extending the comparative study to the microchromosomes, we suggest that a wealth of information can be mined in chicken, to be used for genome analyses in quail.

Background Egg production is of critical importance in birds not only for their reproduction but also for human consumption as the egg is a highly nutritive and balanced food. Consequently, laying in poultry has been improved through selection to increase the total number of eggs laid per hen. This number is the cumulative result of the oviposition, a cyclic and repeated process which leads to a pattern over time (the egg laying curve) which can be modelled and described individually. Unlike the total egg number which compounds all variations, the shape of the curve gives information on the different phases of egg laying, and its genetic analysis using molecular markers might contribute to understand better the underlying mechanisms. The purpose of this study was to perform the first QTL search for traits involved in shaping the egg laying curve, in an F2 experiment with 359 female Japanese quail. Results Eight QTL were found on five autosomes, and six of them could be directly associated with egg production traits, although none was significant at the genome-wide level. One of them (on CJA13) had an effect on the first part of the laying curve, before the production peak. Another one (on CJA06) was related to the central part of the curve when laying is maintained at a high level, and the four others (on CJA05, CJA10 and CJA14) acted on the last part of the curve where persistency is determinant. The QTL for the central part of the curve was mapped at the same position on CJA06 than a genome-wide significant QTL for total egg number detected previously in the same F2. Conclusion Despite its limited scope (number of microsatellites, size of the phenotypic data set), this work has shown that it was possible to use the individual egg laying data collected daily to find new QTL which affect the shape of the egg laying curve. Beyond the present results, this new approach could also be applied to longitudinal traits in other species, like growth and lactation in ruminants, for which good marker coverage of the genome and theoretical models with a biological significance are available.

Background The Japanese quail (Coturnix japonica) is both an animal model in biology and a commercial bird for egg and meat production. Modern research developments with this bird, however, have been slowed down by the limited information that is available on the genetics of the Japanese quail. Recently, quail genetic maps with microsatellites and AFLP have been produced which open the way to comparative works with the chicken (Gallus gallus), and to QTL detection for a variety of traits. The purpose of this work was to detect for the first time QTL for commercial traits and for more basic characters in an F2 experiment with 434 female quail, and to compare the nature and the position of the detected QTL with those from the first chicken genome scans carried out during the last few years. Results Genome-wide significant or suggestive QTL were found for clutch length, body weight and feed intake on CJA01, age at first egg and egg number on CJA06, and eggshell weight and residual feed intake on CJA20, with possible pleiotropy for the QTL affecting body weight and feed intake, and egg number and age at first egg. A suggestive QTL was found for tonic immobility on CJA01, and chromosome-wide significant QTL for body temperature were detected on CJA01 and CJA03. Other chromosome-wide significant QTL were found on CJA02, CJA05, CJA09 and CJA14. Parent-of-origin effects were found for QTL for body weight and feed intake on CJA01. Conclusion Despite its limited length, the first quail microsatellite map was useful to detect new QTL for rarely reported traits, like residual feed intake, and to help establish some correspondence between the QTL for feed intake, body weight and tonic immobility detected in the present work and those reported on GGA01 in the chicken. Further comparative work is now possible in order to better estimate and understand the genetic similarities and differences of these two Phasianidae species.

Summary A linkage map of the Japanese quail (Coturnix japonica) genome was constructed based uponsegregation analysis of 72 microsatellite loci in 433 F 2 progeny of 10 half-sib familiesobtained from a cross between two quail lines of different genetic origins. One line wasselected for long duration of tonic immobility, a behavioural trait related to fearfulness,while the other was selected based on early egg production. Fifty-eight of the markers wereresolved into 12 autosomal linkage groups and a Z chromosome-specific linkage group,while the remaining 14 markers were unlinked. The linkage groups range from 8 cM (twomarkers) to 206 cM (16 markers) and cover a total map distance of 576 cM with anaverage spacing of 10 cM between loci. Through comparative mapping with chicken (Gallusgallus) using orthologous markers, we were able to assign linkage groups CJA01, CJA02,CJA05, CJA06, CJA14 and CJA27 to chromosomes. This map, which is the first in quailbased solely on microsatellites, is a major step towards the development of a qualitymolecular genetic map for this valuable species. It will provide an important framework forfurther genetic mapping and the identification of quantitative trait loci controlling eggproduction and fear-related behavioural traits in quail.Keywords chromosomes, genetic map, Japanese quail, linkage groups, microsatellite

International audience; The interactions between the effects of three plumage color mutations taken two-by-two (sex-linked recessive roux, autosomal recessive lavender, and autosomal dominant beige) were studied in Japanese quail by producing a total of 121 F1 and 1118 F2 quail from the three pure stocks. Three new plumage colors were obtained in F2 quail: roux-diluted beige, cream, and lavender-diluted beige. Two of them, roux-diluted beige (from the roux and beige mutations) and cream (from the roux and lavender mutations) corresponded to double homozygotes or hemizygous birds, and could therefore be used to tag a quail line. On the other hand, an F3 from F2 birds with lavender-diluted beige plumage was necessary to show that quail with this plumage color were homozygous for the lavender mutation, but were either homozygous or heterozygous for the beige gene. In all three F2s, observed segregation of plumage colors fit simple two-locus Mendelian inheritance.

Coccidiosis causes dramatic economic losses in the poultry industry. Next to the extensive use of anticoccidial drugs, improving genetic resistance of birds to this parasitic disease represents an attractive alternative. An experiment was run in order to identify lines of chickens resistant and susceptible to coccidiosis as a tool to search for genetic markers of resistance. Five outbred lines were used: two Egyptian lines (Mandarah and Fayoumi), a Rhode Island Red line, and two White Leghorn lines (WLB21 and WLDW). The WLDW line segregated for three MHC haplotypes, B15, B19, and B21, and for the sex-linked dwarf gene, DW. Chicks were challenged at 4 wk of age with a high dose of Eimeria tenella (150,000 oocysts) and slaughtered 8 d postinoculation. Innate resistance was assessed individually by measures of lesion score, mortality, and body weight gain at slaughter, and plasma coloration 4 d postinoculation. Large differences in resistance to E. tenella were observed between lines. The Fayoumi line appeared clearly as the most resistant line, showing no mortality, less severe lesions than other lines, and a 30% reduction of growth as compared to control birds. The WLDW line was the most susceptible, with 27% mortality and a 85% reduction in growth. No major effect of MHC or dwarfism on resistance to E. tenella was found.

This study used a sex-linked dwarf mutant (SLD) chicken to evaluate growth-promoting and metabolic effects of recombinant human insulin-like growth factor-I (rhIGF-I) treatment. The SLD chicken is characterized by a 30% reduction in body weight and by high plasma GH levels, low plasma IGF-I and triiodothyronine (T3) levels and very low GH binding on liver membranes, suggesting reduced functional GH receptors compared with normal chickens. The effects of a continuous s.c. infusion by osmotic mini-pump of 0·1 mg rhIGF-I/kg per day from 4 to 8 weeks of age on body weight, bone growth and body composition were investigated in female SLD and normal chicks. In addition, half of the birds received a dietary supplement of T3 (0·1 parts per million). Plasma levels of IGF-I, GH, T3, thyroxine and insulin were followed during the treatment. In normal chicks, rhIGF-I infusion had no effect on growth and little effect on plasma hormone levels except for a decrease in plasma insulin. In dwarf chicks, rhIGF-I infusion slightly increased body weight but had no effect on longitudinal bone growth. In addition, plasma GH levels were decreased and T3 levels remained lower than in normal chicks. Normal and dwarf chicks showed a decrease in abdominal fat after both IGF-I administration and T3 supplementation, the treatments having additive effects in dwarf chicks only. The combined rhIGF-I and T3 treatment restored a quasi-normal hormonal pattern in dwarf chicks, except for insulin which remained lower than in normal chicks. These results suggest that IGF-I in the chicken has no direct endocrine effect on statural growth. Journal of Endocrinology (1992) 133, 101–110

International audience; DNA fingerprints of Japanese quail male and female pure line breeders were obtained with probes 33.6, 33.15, and R18.1 and they yielded a total of 59 scoreable bands. Bandsharing ($0 < {\rm BS} < 1$) was calculated within and between six quail lines of two origins, and under reciprocal recurrent (AA and BB), within-line (DD and EE) or no (PP and FF) selection. Twenty one pair types were compared. BS was 0.30 higher within line than between lines. BS with the control line was smaller for reciprocal recurrent selection lines than for lines under individual selection. Bandsharing between the two reciprocal recurrent selection lines was 0.19 lower than between lines under individual selection. These results indicate that the two selection methods had different effects on the genetic constitution of the lines, in agreement with previous observations made from the analysis of biochemical polymorphisms with the same set of birds. Egg production and weight traits of pure and crossbred progeny from fingerprinted quail were obtained and compared, and a linear relationship with the measure of bandsharing was estimated. No significant regression coefficient of performance on BS was found over all progeny genetic types. Heterosis from individual matings could also be estimated under the two selection methods since the same birds were parents of both pure and crossbred performance-tested quail. The association of heterosis with the difference between BS of parents of the purebreds and BS of parents of their half-sib crossbreds was favourable and significant for early production traits in lines DD and EE, but no relationship was found in lines AA and BB. These results indicate that the high level of heterosis obtained through reciprocal recurrent selection, and the heterosis observed under within-line selection may have, partly at least, a different genetic determinism. Therefore, the relationship of heterosis with BS may also depend on the past history of selection in the lines.; Ressemblance des empreintes génétiques et liaisons avec les performances et l'hétérosis chez des cailles japonaises de deux origines et sous sélection directe ou réciproque récurrente pour la ponte précoce. Les sondes 33.6, 33.15 et R18.1 ont été utilisées pour obtenir les empreintes génétiques à partir de l'ADN de cailles japonaises reproductrices mâles et femelles de six lignées en sélection récurrente réciproque (AA et BB), en sélection individuelle (DD et EE) ou maintenues sans sélection (PP et FF), et provenant de deux origines. Les 21 types de paires possibles ont été comparés à l'aide du coefficient de partage de bande BS ($0 < {\rm BS} < 1$). BS était plus élevé de 0,30 intra-lignée qu'inter-lignée. La ressemblance génétique avec la lignée contrôle non sélectionnée, mesurée par BS, était moindre pour les lignées AA et BB que pour DD et EE. De plus, BS entre les deux lignées sous sélection réciproque récurrente était inférieur de 0,19 à la valeur obtenue entre celles sous sélection individuelle. Ces résultats indiquent que les deux méthodes de sélection ont bien eu chacune un effet différent sur la constitution génétique des lignées. Ils confirment ainsi des observations antérieures issues de l'analyse des polymorphismes biochimiques du même échantillon d'animaux. La descendance femelle pure et croisée des cailles aux empreintes génétiques connues a été mise en épreuve de ponte de façon à étudier la relation linéaire entre les performances de chaque caille et le BS de ses parents mais aucun lien significatif n'a été mis en évidence. L'hétérosis des croisements individuels a pu être estimé car les mêmes parents ont eu une descendance pure et croisée. L'association de l'hétérosis avec la différence de BS entre les paires de cailles parentes de la descendance pure et celles parentes de la descendance de leurs demi-sœurs croisées était significative et favorable pour les caractères mesurés en début d'épreuve de ponte chez les lignées DD et EE, mais aucune relation n'a été trouvée chez les lignées AA et BB. Ces résultats indiquent que le fort hétérosis obtenu par la sélection réciproque récurrente et l'hétérosis observé dans les lignées sous sélection individuelle pourraient avoir, au moins en partie, un déterminisme génétique différent. Plus généralement, il semble que la relation de l'hétérosis avec BS puisse dépendre aussi de la sélection pratiquée dans les lignées.

International audience

Nous avons recherché les effets directs ou maternels sur diverses performances associés à un gène autosomal récessif (we), responsable de l’absence de pigmentation des coquilles d’oeufs chez la caille japonaise. A partir d’animaux des deux sexes de même origine, respectivement de génotype hétérozygote We+ we et homozygote récessif wewe, les croisements réciproques ♂ we we x ♀ We+ we et ♂ We+ we X ♀ we we ont été réalisés deux années consécutives. Ces croisements donnaient tous deux des filles We+ we pondant des oeufs à coquille pigmentée et des filles wewe pondant des oeufs à coquille blanche, permettant de comparer l’effet du génotype des filles sur leur propre performance ainsi que l’effet du type de croisement à génotype égal pour les filles. Concernant les effets directs, le génotype « coquille blanche » comparé au type sauvage à coquille colorée s’accompagne d’une réduction de l’ordre de 10% de l’épaisseur totale des coquilles (membrane et cuticule comprises) et de leur poids, d’une augmentation de la proportion d’oeufs cassés ou sans coquille, d’une perte d’eau proportionnellement plus élevée des oeufs non fécondés incubés (une année sur deux), d’une oviposition moins tardive dans la journée, suggérant une réduction de la durée de formation de l’oeuf. Enfin le poids corporel des femelles à coquille blanche est légèrement inférieur à celui des femelles « sauvages ». En relation avec le type de croisement, quel que soit le génotype des filles, on observe que le génotype «coquille blanche» we we chez la mère s’accompagne d’une survie embryonnaire et juvénile inférieure et d’un retard modéré de la croissance pondérale des descendants, mais par contre d’une meilleure ponte des filles. Il est suggéré que tout ou partie des effets associés à l’absence de pigment des coquilles peut être de nature pléiotropique par modification de l’épaisseur, de la solidité et de la perméabilité des coquilles à la vapeur d’eau et à la pénétration d’agents pathogènes; des expériences ultérieures seraient nécessaires à cet égard., We looked for direct or maternal effects on various performances associated with the autosomal recessive gene (we), responsible for the lack of eggshell pigmentation in the Japanese quail. From male and female birds of the same origin, of the heterozygous (We+we) and recessive (wewe) genotype respectively, the reciprocal crosses ♂ we we x ♀ We+ we and ♂ We+we x ♀ wewe were obtained for two consecutive years. Both crosses gave We+we (colored eggshell) and wewe (white eggshell) daughters, allowing comparison of the effect of the genotype of female progeny on their own performance together with the effect of the type of crossing irrespective of the progeny genotype.Concerning the direct effects, the "white shell" genotype as compared to the wild type with colored shells is associated with a reduction of the order 10% of total eggshell thickness (including the shell membrane and cuticle) and weight, an increase in the proportion of cracked eggs and eggs without shell, a proportionally higher water loss of incubated unfertilized eggs (one year out of 2), an earlier average oviposition time in the day, suggesting a reduced duration of egg formation. In addition, the body weight of females with white eggshells is slightly inferior to that of wild type females. In relation with the type of crossing, independent of the progeny genotype, it is observed that. the "white eggshell" (wewe) genotype of the dam is associated with an inferior embryonic and early postembryonic survival and a moderately delayed growth of the progeny, but with a higher egg production of the daughters. It is suggested that part or all of the effects accompanying the absence of eggshell pigmentation may be pleiotropic through modification of eggshell thickness, strength and permeability to water vapor and to the penetration of some pathogens; further experiments are, however, required.