Slaughtering yields and some meat physical and sensorial parameters of laying hens reared under organic system production were studied. The hens belonged to both Italian dual-purpose breeds [Ermellinata di Rovigo (ER; brown eggshell) and Robusta Maculata (RM; brown eggshell)] as well as hybrid genotypes [Hy Line White 36 (white eggshell) and Hy Line Brown (brown eggshell)]. The birds were reared under organic farming system production from 24 to 44 wk of age, when they were slaughtered. They were reared throughout summer and autumn, and the temperature ranged from about 28 to 3 degrees C. Local breeds presented higher (P < 0.01) live BW and dressing percentage compared with hybrids. The RM and ER carcasses had (P < 0.01) the highest breast and leg (thigh and drumstick) percentage, respectively. The muscle-bone ratio of the Hy Line White 36 drumstick was lower (P < 0.05) than the RM ratio, whereas the other groups were intermediate. The ER breast presented the highest (P < 0.01) lightness value and the lowest (P < 0.01) final pH value compared with the other 3 groups. The breast meat significantly differed according to genotype for almost all the studied sensorial parameters (adhesivity, fibrousness, chewiness, solubility, juiciness, tenderness, shear resistance), with the exception of aroma and odor intensity. In the thigh, genotype significantly affected aroma, adhesivity, fibrousness, solubility, tenderness, and shear resistance.

Hens of 2 hybrid lines (Hy Line Brown -HLB, Hy Line White -HLW) and 2 local breeds (Robusta maculata -RM and Ermellinata of Rovigo -ER) were reared following the organic production procedure and their egg yield and quality were studied at two different ages (30 and 42 weeks). The experimental period was between 26 and 42 weeks of age, starting in summer and lasting until autumn. Age significantly (P<0.01) affected the hen-day egg production and the daily egg mass of the HLB (84 vs. 94% and 44.5 vs. 59.4 g), of the HLW (81 vs. 89% and 42.4 vs. 54.7 g) and of the RM hens (27 vs. 63% and 12.9 vs. 36.7 g), which was the least precocious. Age did not affect the daily egg production of the ER hens (which was maintained around 58%), although it was observed a slight (P<0.05) increase of the daily egg mass (28.6 vs. 32.1 g). Age increased (P<0.01) the egg weight, yolk colour, yolk percentage and yolk:albumen ratio and decreased the albumen percentage in all groups.

A trial was done to study the chemical composition of meat and egg yolk of laying hens belonging to different genotypes reared using an organic production system. Two commercial hybrid hens (Hy-Line Brown and Hy-Line White 36) and 2 Italian dual-purpose breed hens (Ermellinata di Rovigo and Robusta Maculata) were reared from 25 to 44 wk of age. During the experimental period (July to December), the environmental temperature decreased from about 25 to 13 degrees C and the RH increased from 62 to 73%. The photoperiod was 16L:8D. Meat and egg yolks of 44-wk-old hens were analyzed. The Italian breeds showed higher meat production and lower egg production when compared with the hybrids. Genotype affected protein, lipid, and ash content of breast and thigh meat. Hy-Line White and Ermellinata di Rovigo showed the lowest (P<0.01) breast lipid and Hy-Line White had the lowest (P<0.01) thigh lipid. Hy-Line White showed higher (P<0.05) breast and thigh cholesterol. Genotype affected egg yolk cholesterol, which was higher (P<0.01) in Italian breeds than in hybrids. The fatty acid profiles of meat and yolk were significantly affected by genotype. The hybrid and Robusta Maculata meat and egg fatty acid composition may be considered to be more favorable to human health. The results indicate that the ability of laying hens to incorporate fatty acids is genetically dependent and a possible interaction between strain and environmental conditions may exist for the absorption and utilization of dietary components.

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In this trial male and female chickens belonging to a dual-purpose Italian breed, Ermellinata di Rovigo (ER), were reared under a free-range production system (June-October) from 47 days of life until slaughter age, at 138 (I age) and 168 (II age) days of age. At both ages, the final body weight, the dressing-out percentage and the ready-tocook carcass weight were higher (P<0.01) in males. At II age the female carcass showed higher (P<0.01) proportion of breast and lower (P<0.01) proportion of leg. At both ages, the redness index (a*) of breast and thigh were lower (P<0.01) in females, whereas the yellowness index (b*) showed the opposite trend; the females showed higher lipids in breast meat (P<0.05), thigh meat (P<0.01) and skin (P<0.01). The breast tenderness did not change. The results indicate that the ER birds have a different live body weight, slaughter performance and meat quality according to sex, both at I and II age. At 168 days, under the studied environmental conditions, the chickens were in prepubertal period and the sex affected the dressing-out percentage, meat colour and skin lipids in particular