Reference | Chuppava_2018_VeteMicr (10269)

A total of 480 female one-day-old turkeys (BUT-Big6), were investigated in two experiments, 240 animals in each. Turkeys originated from two different hatcheries, as due to an outbreak of avian influenza in Germany the hatchery was closed, from which the animals for the first trial came. Before the experiment, the birds were housed in four floor pens covered with wood shavings, which were kept dry and clean. All turkeys were fed ad libitum with a commercial pelleted starter diet. After a one-week adaptation period, each experiment was started. The birds were divided into four groups, each having three identical subgroups (n = 20 birds), until the end of the rearing period at day 36. Twelve experimental pens (1.20 m × 0.80 m) were placed in randomised sequence and divided into 4 subgroups (G1–G4) in the same stable, six each on the right and on the left-hand side of the central corridor (∼1.70 m width). Direct contact of birds from each sub-group with those from other sub-groups was not possible. Stocking densities reached about 25 kg/m2 at the end of the trial. The slatted floor pen consisted of holes (15 × 10 mm) and bridges (plastic covered steel; width 3.5 mm). The excreta were stored during the entire fattening period under the slatted floor at a depth of approximately 30 cm. Before beginning with the trials, stables and all materials had been disinfected and tests had been carried out to confirm that they were free of Enterobacteriaceae contamination. In the groups, different flooring designs were used to establish different degrees of contact intensity of the animals to the manure. The first group was kept on dry wood shavings (G1 – entire floor pen covered with litter); the second group was kept on dry wood shavings but also with floor heating (G2 – floor pen with litter with floor heating). Animals in G1 and G2 had full contact with manure over the whole study period. An electrical floor heating system supplied with an adjuster to control the temperature was used only in G2. The third group (G3) was housed in a floor pen that was divided into two equal parts consisting of 50% wood shavings on the right-hand side and 50% plastic slatted flooring on the left-hand side. The fourth group (G4) was housed completely on plastic slatted flooring with a sand bath (900 cm2), the bath being disinfected and the sand replaced on a daily basis. Animals in G4 had no contact with litter except possibly with the sand bath. In both trials, the animals were treated with Baytril® 10% (10 mg enrofloxacin/kg body weight per day, in accordance with the recommended dosage) administered in the drinking water. This treatment was started when the birds were ten days of age and was continued for five consecutive days. In trial 1 (T1), birds remained in the same stable until the end of the trial, whereas in trial 2 (T2) after enrofloxacin treatment (at day 15), all turkeys were moved to the other pens all newly equipped with four identical flooring designs and housed in the same room. At day 22 in each subgroup of 20 animals eight birds were dissected because stocking density had to be comparable to ten other similar trials. Concerning several objectives and parameters such weekly scoring of footpad dermatitis, which were simultaneously tested in this experiment, dissection of part of the group is mandatory. At day 36, all remaining turkeys (n = 12/box) were dissected.

Two kinds of samples were collected. Cloacal swabs were collected from two-day-old chicks, at day 21 and at the end of day 35. As well, poultry manure samples were also taken at day 9, day 15 and day 35. All samples were allocated to the three stages of sampling: (i) Before treatment stage (BT): Cloacal swabs were collected at day 2 and manure samples at day 9. (ii) After treatment stage (AT): Manure samples were collected at day 15 and cloacal swabs at day 21. (iii) End of trial stage (ET): Manure samples and cloacal swabs were collected at day 35. The cloacal swabs were taken from 24 animals per group or rather, in total 96 randomly selected animals. In total 24 samples of manure or six samples from each type of flooring design were taken from two defined locations in every pen at all trial stages. Manure samples were taken with a plastic cup (diameter: 6 cm) from the bottom of the pen. All collected samples were immediately transferred to the laboratory. For bacteriological analyses, manure samples of 25 g each were put into a sterile Whirl-Pak® Bag (Nasco, USA), and 50 mL of peptone water (Oxoid, Germany) was added. These were mixed for three minutes with a Bag Mixer® 400 VW (Interscience, France). A sterile loop (10 μL) was put into the mixed-sample, streaked on Gassner agar (Oxoid, Germany) and incubated at 37 °C for 18–24 h. Similarly, each cloacal swab was spread onto Gassner agar plates and incubated overnight at 37 °C

AST Method: Broth Microdilution

Reference explicitly reports AST breakpoints: False

Reference reports using a MIC table: Uncertain