Evaluation of Thuringiensin as a Feed-Through Treatment for the Control of the House Fly, 1985

Forty White Leghorn hens were caged individually in a 7.3 × 7.3 m shelter at the University Poultry Research Farm. The shelter contained 2 banks of single deck, double row cages (46 × 46 × 30 cm) separated by a 2.3-m aisle with 20 cages/bank. Five treatments: 0.0, 5.0, 10.0, 15.0 ppm (AI) Thuringiensin or Larvadex (0.3% premix at 1.5 ppm as a standard) were randomly assigned to each hen (8 hens/treatment). The study was initiated 10 Aug and the hens were given treated feed ad libitum for 52 days. An untreated feed ration for all hens was resumed 1 Oct for 22 days posttreatment. Manure samples from each hen were collected every other day during treatment and posttreatment periods, pooled by treatment and frozen for at least 24 h to kill any resident house fly larvae and macrochelid mites. Pretreatment means were based on samples taken 12, 10, and 1 day prior to initiation of the feeding trial. Ten g of manure was placed in 29.6-ml clear plastic portion cups, with 3 cups/treatment. Ten newly emerged house fly larvae were added to each cup and held at room temp for adult emergence. Feed consumption, weight gain and egg production were recorded for 3.5, 8, and 33 wk, respectively, prior to the initiation of the feeding trial, during treatment and at least 22 days posttreatment.