Influence of laying hen-systems and ecologic variables on mites of medical and veterinary importance

Abstract

The search for improvements in the poultry production chain and for increased egg productivity have grown significantly. However, intensive production with or by using of confinement systems negatively affect the welfare of animals and is favoring the appearance of harmful ectoparasites in production. Due to differences in the existing management systems, (e.g. Californian and cage-free systems) and given the importance of the poultry industry in the international market, the aim of the present study was: (1) to compare mite community between SIG (Intensive system – cage: Californian) and SIF (Intensive system – free: cage free); (2) egg-laying systems to analyze how the abundances of the ectoparasites Dermanyssus gallinae, Megninia ginlgymura, and Ornithonyssus sylviarum are affected by these egg-laying models; (3) to evaluate the association between the functional diversity found in traps, organic matter, and feathers in both systems; and finally, (4) to analyze how abiotic factors (e.g. humidity, temperature at sampling) affect mite community composition inside each model. A total of 860,571 mites were sampled, belonging to 59 taxa from six functional groups. Mite composition in the SIF system was different from the SIG system, while their variations in dispersion homogeneity were quite similar to each other. Although taxonomic composition is different between them, they are quite similar when clustered according to functional diversity. The variables 'humidity' and 'temperature' were not determining factors for the appearance of species. The species that most contributed for distinguishing the models were: M. ginlgymura, Dermatophagoides farinae, D. gallinae, Tyrophagus putrescentiae, O. sylviarum, Blattisocius keegani, Glycyphagus sp., Acotyledon sp., and Cheyletus malaccensis, respectively. Dermanyssus gallinae was strongly associated with the Californian model. Two taxa were highly correlated with cloaca, neck, dorsum, and inner wings; variations in relative air humidity also affected M. ginlgymura and O. sylviarum populations. Organic matter had a high abundance of predatory mites with potential for controlling mites of sanitary importance in the poultry chain.