Effect of Genotype and Husbandry System on Blood Parameters, Oxidative and Native Immune Status: Welfare and Implications on Performance of Organic Laying Hens

The aim of the present work was to compare the effect of organic production vs standard cage system on welfare and performance of a pure breed (Ancona) vs a commercial strain (Brown Hy-Line) of laying hens through a multifunctional approach (behaviour, tonic immobility, feathers score, antioxidant status of the body, blood parameters, innate immunity and mortality). The trial was carried out in farm of the Dpt. of Applied Biology (University of Perugia), where 17-weeks-old females of Ancona breed (n=200) and Brown Hy-Line (n=200) were divided in 2 homogenous groups of 100 birds each and assigned to cage or organic rearing systems. The genotype of the hens affected in a degree which depends on rearing system almost all the variables. The feeding and resting activities were higher in caged whereas moving activities were higher in organic hens and especially in Ancona birds. Social relationships showed genotype and rearing system effects being higher in Brown Hy-Line hens particularly when reared in cage. The TI duration was affected by genotype and rearing system being the immobility time longer in Brown Hy-Line. The plumage condition showed a great rearing system effect and genotype effects was observed only between organic groups where Ancona hens showed the better feathers condition. Regarding native immune status serum bactericidal activity showed the highest values in organic hens and mainly in Ancona ones. On the contrary, lysozyme showed greater value in caged hens. The haptoglobin value was lower in organic Ancona group, the same hens showed about 30% greater reactive oxygen substances, but accompanied by highest the antioxidant power. Organic rearing system, mainly in the Ancona hens, induced the highest red blood cells, haemoglobin and hematocrite values. Lymphocytes were higher in Organic birds thus reducing the H/L ratio in Organic hens. As expected, organic birds showed the worst feed efficiency and percentage of deposition, but the lowest mortality rate. In conclusion, on the basis of all these information together with the low mortality rate, Ancona hens showed the better welfare status, mainly when they were organically reared.