-The effect of caponisation on fat composition by parts (wing, breast, thigh, and drumstick) and tissues (skin, subcutaneous adipose tissue, intermuscular adipose tissue and muscle) was examined in the present study and fatty acid profiles of abdominal fat and edible meat by parts and tissue components were determined. The sample was made up of twenty-eight castrated and twenty male Penedesenca Negra chicks reared under free-range conditions and slaughtered at 28 wk of age; the birds were castrated at four or eight weeks. Caponisation significantly increased (P < 0.01) the chemical fat content in all parts (16.31% to 37.98% in breast; 21.98% to 34.13% in wing; 21.09% to 49.57% in thigh; 14.33% to 24.82% in drumstick) and led to minor modifications in fat characteristics, particularly in the thigh and the drumstick, where the unsaturated vs. saturated fatty acid ratio increased from 1.31 to 1.76 ( P < 0.01) and from 1.48 to 2.07 (P < 0.01), respectively. Delaying the age of castration from 4 to 8 weeks increased this ratio by 0.35 in the edible meat. Even though the profile of the abdominal fat is less saturated in capons, all changes occurring on fat quality after caponisation indicate that increased fatness after castration does not imply worse fat nutritional properties. chicken / capon / edible meat / fatty acids Résumé -Comparaison de la composition lipidique de la viande, des tissus adipeux et des muscles de coqs et de chapons. Les effets de la castration sur la composition de la graisse de différents morceaux (ailes, filets, cuisses, pilons) et de tissus (peau, graisse sous cutanée, tissus adipeux intermusculaires et muscles) ont été mesurés dans la présente étude. Les profils en acides gras (AG) de la graisse abdominale et des morceaux ont été déterminés. Les prélèvements ont été faits sur 28 chapons et 20 coqs Penedesenca Noirs élevés en plein air et sacrifiés à l'âge de 28 semaines, le chaponnage étant réalisé à l'âge de 4 ou de 8 semaines. Le chaponnage fait augmenter significativement (P < 0,01) la concentration en graisse de tous les morceaux (de 16,31 à 37,98 % dans les filets ; de 21,98 à 34,13 % dans les ailes ; de 21,09 à 49,57 % dans les cuisses et de 14,33 à 24,82 % dans les pilons, en moyenne) et induit quelques modifications mineures des caractéristiques des graisses, particulièrement dans les cuisses et les pilons. Le chaponnage fait augmenter le rapport AG insaturés/AG saturés de 1,31 à 1,76 (P < 0,01) et de 1,48 à 2,07 (P < 0,01) dans les cuisses et les pilons, respectivement. En retardant l'âge de la castration de 4 à 8 semaines, ce rapport augmente de 0,35 en moyenne dans la viande consommée. Bien que le profil en AG de la graisse abdominale soit moins saturé chez les chapons, l'ensemble des changements se produisant sur la qualité des graisses après chaponnage suggère que l'engraissement supérieur des chapons n'implique pas une réduction de la qualité nutritionnelle des graisses. poulet / chapon / viande / acides gras

Heritabilities for egg number, egg weight, and eggshell color (percentage light absorbance) at 39 wk of age, and the genetic correlations between them were estimated by restricted maximum likelihood in three Catalan poultry breeds: Penedesenca Negra (PN), Prat Lleonada (PL), and Empordanesa Roja (ER). Additive genetic differences between these breeds were also estimated. Data were from the IRTA Poultry Genetic Conservation Program and consisted of records from 1,309 PN, 1,466 PL, and 1,440 ER hens, which were obtained from 80 contemporary batches per breed hatched between 1987 and 1992. Estimates of heritability for egg number, egg weight, and eggshell color were, 0.20, 0.59, and 0.49 for PN, 0.31, 0.48, and 0.53 for PL; and 0.33, 0.50, and 0.27 for ER. Estimated genetic correlations between egg number and egg weight, egg number and shell color, and egg weight and shell color were, for PN, -0.22, -0.03, and 0.00; for PL, -0.21, -0.06, and 0.09; and -0.19, -0.29, and 0.30 for ER. Heritability for eggshell color and genetic correlation between eggshell color and other traits showed a different genetic pattern in ER breed. Significant additive genetic differences (P < 0.05) were found between ER and PN base populations for egg number (3.89), egg weight (0.91), and eggshell color (-3.50); and between ER and PL for egg number (6.69) and eggshell color (35.39). The PN and PL breeds differed significantly (P < 0.05) for eggshell color (38.22), which was darker in PN. These results could be taken as the expected genetic differences for these breeds.

We examined the relationship between embryo development and egg hardness in two ground nesting bird species, the red-legged partridge (Alectoris rufa; n = 165 eggs) and the quail (Coturnix japonica; n = 148 eggs). For both species, we observed a strong effect of developmental stage on egg hardness. Eggs near hatching were significantly weaker than unincubated eggs (partridge: 18 and 23 N, respectively, and the quail 7 and 10 N, respectively). We additionally explored the effect of incubation on egg hardness in a control sample of non-fertilised quail eggs (i.e., without embryo development). The control eggs maintained in the incubator for the full incubation time (17 days) were significantly harder (7-9 N) than eggs containing fully developed chicks (5-7 N). Thus, the incubation conditions of high temperature and humidity alone seem not to have a significant effect on egg hardness, and support the important effect of calcium uptake.

The current study proposes a method for the morphological characterization of chicken. It involves the measurement of 25 variables, 12 from head measures and the other 13 from rest of the body. This method was used to compare two Catalonian autochthonous chicken breeds: partridge Penedesenca and blond Empordanesa with measurements of 30 hens each. Measurements were taken by two operators, each measured 15 hens per breed. Hens were 30 weeks old, and were bred under the same conditions. As a whole the results showed us that both breeds are very similar morphologically. Nevertheless, nine variables were different between the two breeds and six were different between the two operators, most of them were head measurements. So it is suggested that the measurements on head must be accurate. Only four variables, beak length and width, comb width and ear lobes length, showed interaction among the factors that do not allow us to address the differences between the breeds. The comparison results between Empordanesa and Penedesenca showed that Empordanesa had higher values in wattle length, wattle width and ear lobes width than Penedesenca. Regarding the corporal measures, Empordanesa had higher values of the folding wing and tarsus diameter than Penedesenca although Penedesenca had larger values in keel of sternum length and breast angle than Empordanesa. Empordanesa was a little heavier than Penedesenca.Penedesenca. Respecto a las medidas corporales, la Empordanesa obtuvo una mayor longitud del ala plegada y del diámetro del tarso aunque la raza Penedesenca obtuvo una mayor longitud de la quilla y del ángulo de pechuga. La Empordanesa resultó algo más pesada que la Penedesenca.

We compared membrane thickness of fully developed eggs with those of non-developed eggs in different endangered falcon taxa. To our knowledge, membrane thickness variation during development has never been examined before in falcons or any other wild bird. Yet, the egg membrane constitutes an important protective barrier for the developing embryo. Because eggshell thinning is a general process that occurs during bird development, caused by calcium uptake by the embryo, eggs are expected to be less protected and vulnerable to breakage near the end of development. Thus, egg membranes could play an important protective role in the later stages of development by getting relatively thicker. We used linear mixed models to explore the variation in membrane thickness (n = 378 eggs) in relation to developmental stage, taxon, female age, mass and identity (73 females), egg-laying sequence (105 clutches) and the study zone. Our results are consistent with the prediction that egg membranes are thicker in fully developed eggs than in non-developed eggs, suggesting that the increase in membrane thickness during development may compensate for eggshell thinning. In addition, our data shown that thicker membranes are associated with larger, heavier and relatively wider eggs, as well as with eggs that had thinner eggshells. Egg-laying sequence, female age and the study zone did not explain the observed variation of membrane thickness in the falcon taxa studied. As we provide quantitative data on membrane thickness variation during development in falcons not subjected to contamination or food limitation (i.e. bred under captive conditions), our data may be used as a reference for studies on eggs from natural populations. Considering the large variation in membrane thickness and the multiple factors affecting on it and its importance in the protection of the embryo, we encourage other researchers to include measurements on membranes in studies exploring eggshell thickness variation.