Comparison of productive traits and egg quality characteristics of two Italian chicken breed and their crossbreeds reared in enriched-cage and free-range systems.

Egg production is essentially based on the use of highly selected commercial hybrids, which show greater laying performance and feed efficiency than local breeds (LB). However, the reduced diffusion and interest in LB has led to a progressive decrease in poultry biodiversity besides increasing the risk of their extinction. Crossbreeding with more productive genotypes could be considered as a potential strategy to improve the LB utilization allow the preservation of genetic variability while achieving acceptable levels of efficiency. This study aimed to evaluate the productivity and egg quality traits of two Italian LB (Bionda Piemontese and Robusta Maculata) and their respective crossbreeds (CB) with a hybrid strain (Sassò) compared to Lohmann brown as well as the effect of the housing system (enriched-cage vs. free-range). A total of 300 laying hens (18 wks of age) were raised in enriched cages (EC) and free-range (FR) pens (3 replicates of 10 birds/genotype/housing system) and fed the same commercial feed. Individual body weight (BW) was recorded at 25, 34, 50 and 66 wks of age, while egg deposition, egg mass, feed intake and feed conversion ratio (FCR) were evaluated every fourteen days from 25 to 66 wks of age. Also, 100 eggs/genotype/ housing system were collected at 32, 47 and 66 wks of age and used for assessing Haugh index (HI), eggshell breaking strength (EBS) and eggshell-yolk-albumen/egg proportions. Lohmann brown showed higher egg deposition, egg mass and better FCR than other genotypes (p < 0.01). CB increased BW compared to LB (p < 0.01), improving parameters related to productivity (egg deposition, egg weight, egg mass) and FCR (p < 0.01). Considering the housing system, hens kept in EC showed better performance than those raised in FR. At 66 wks, hens in EC had greater BW than those in FR (2649 vs. 2517 g, respectively; p < 0.01). Eggs from LB had a lower weight and albumen proportion compared to others, whereas CB showed a lower eggshell to egg ratio (p < 0.01). LB and CB laid eggs with a higher yolk to egg ratio and a lower EBS than the commercial hybrid (p < 0.01). In addition, Lohmann brown’s eggs showed the highest HI (p < 0.01). Surprisingly, EBS was higher in eggs obtained in FR (4.17 vs. 3.93 kg, respectively; p < 0.01). Further investigations are ongoing to detect the content of vitamin D and related metabolites in plasma and yolk to establish if sunlight exposure in FR boosted vitamin D synthesis, thereby positively affecting calcium metabolism.