Active-controlled commercial field evaluation of an independently developed fluralaner oral solution for poultry red mite control in laying hens.

Poultry red mite (Dermanyssus gallinae, PRM) remains an important ectoparasite in commercial laying-hen production, and drinking-water administration of systemic acaricides provides a practical option for whole-flock control. This study compared the field efficacy and laying performance of an independently developed 10 mg/mL fluralaner oral solution with Exzolt 10 mg/mL Solution and assessed target-animal safety and bioequivalence. A double-blind, active-controlled trial was conducted at a naturally infested commercial layer farm with a 5-row × 5-tier cage system. The products were randomly assigned to 2 independent drinking-water systems with farm-installed proportional dosing devices, with 2,400 hens monitored per area. Fluralaner was administered at 0.5 mg/kg on d 0 and d 7. Mite-trap counts, infestation severity, adverse events, and laying rate were monitored. Mean mite reduction exceeded 98% by d 1 and 99% by d 3, reached 100% by d 14, and remained above 99% through d 90. Infestation scores declined from 2.70 ± 0.67 and 2.80 ± 0.42 before treatment to 0.10 ± 0.32 and 0.20 ± 0.42 by d 7 in the test and reference areas, respectively, and were 0 from d 14 onward. Exploratory between-area comparisons detected no significant differences in mite reduction or infestation scores. Laying rate remained stable, and no treatment-related adverse events were observed. In the target-animal safety study, 80 hens received untreated water or the test product at 1 ×, 3 ×, and 5 × the recommended dose, with no consistent dose-related adverse effects identified in clinical, hematological, biochemical, pathological, production, or egg-quality outcomes. In the bioequivalence study, 66 hens received a single 0.5 mg/kg oral dose of either product. The 90% confidence intervals for the geometric mean ratios of C