Influence of laying hen systems on the mite fauna (Acari) community of commercial poultry farms in southern Brazil.

Intensive production of confined laying hens affects their welfare and increases the risk of epidemics. Ectoparasites as hematophagous and feather mites cause low productivity and decreased egg quality. This study aimed to determine the diversity of mites captured with traps in different commercial systems of laying hens (Gallus gallus L.) (Phasianidae) in Taquari Valley, Rio Grande do Sul, Brazil. Samplings were conducted from August 2013 to August 2014, totaling 21 sampling events in three different commercial laying hen systems: automatic production systems (A(1), (2), (3)), semiautomatic systems (S(1), (2)), and free-range system (FR). A total of 9981 mites belonging to 21 families, 31 genera, and 35 species were found. Acaridae, Caligonellidae, and Cheyletidae showed the highest richness with four species each. Megninia ginglymura (Mégnin, 1877) (Analgidae) was the most abundant ectoparasite species with 1328 specimens and was present in all commercial laying hen systems. No hematophagous mites were found. Cheyletus malaccensis(Cheyletidae) (3503), Typhlodromus transvaalensis (Phytoseiidae) (304), and Blattisocius keegani (Blattisocidae) (181) were the predators present in all systems. The similarity with control system (S(1)--without pesticide) was low (36.5 %) when compared to all other commercial laying hen systems, and it had the highest richness. In FR, low populations of mites and highest diversity were observed. The commercial laying hen system and the management influence the mite fauna in poultry farms.