Enrofloxacin is a concentration‐dependent antimicrobial used in bacterial infections in poultry. During a few months of a turkey's life, pharmacokinetics of drugs undergoes substantial changes which may compromise their efficacy due to variability in internal exposure (measured by area under the concentration–time curve, AUC). The aim of this study was to describe the effects of age on the pharmacokinetics of a single intravenous (i.v.) and oral administration of enrofloxacin at a dose of 10 mg/kg to turkeys. It was found that during a 2.5‐month‐long period of growth from 1.4 to 14.6 kg, the AUC after i.v. administration increased almost threefold due to a significant decrease in the body clearance (from a mean of 0.76–0.28 L hr−1 kg−1). Over the same period, the mean elimination half‐life was prolonged from 2.65 to 7.03 hr. Oral administration resulted in a similar trend in pharmacokinetic parameters. For both routes, formation of the major metabolite, ciprofloxacin, was marginal. Protein binding was not age‐dependent and never exceeded 50%. Body clearance, volume of distribution and elimination half‐life were subjected to an allometric analysis and a novel, nonlinear dosage protocol has been proposed to improve the internal exposure to the drug in different age groups of turkeys.

The pharmacokinetics of florfenicol (FF) and thiamphenicol (TP) after single intravenous (IV) and oral (PO) administration was investigated in Mulard ducks. Both antibiotics were administered at a dose of 30 mg/kg body weight, and their concentrations in plasma samples were assayed using high‐performance liquid chromatography with ultraviolet detection. Pharmacokinetic parameters were calculated using a noncompartmental method. After IV administration, significant differences were found for the mean residence time (2.25 ± 0.21 hr vs. 2.83 ± 0.50 hr for FF and TP, respectively) and the general half‐life (1.56 ± 0.15 hr vs. 1.96 ± 0.35 hr for FF and TP, respectively) indicating slightly slower elimination of TP as compared to FF. The clearance, however, was comparable (0.30 ± 0.07 L/hr/kg for FF and 0.26 ± 0.04 L/hr/kg for TP). The mean volume of distribution was below 0.7 L/kg for both drugs. Pharmacokinetics after PO administration was very similar for FF and TP suggesting minor clinical importance of the differences found in the IV study. Both antimicrobials showed rapid absorption and bioavailability of more than 70% indicating that PO route should be an efficient method of FF and TP administration to ducks under field conditions.

New types of contactless luminescence nanothermometers, namely, LiAl5O8:Fe3+ and LiAl5O8:Fe3+, Nd3+ are presented for the first time, revealing the potential for applications in biological systems. The temperature-sensing capability of the nanocrystals was analyzed in wide range of temperature (−150 to 300 °C). The emission intensity of the Fe3+ ions is affected by the change in temperature, which induces quenching of the 4T1 (4G) → 6A1 (6S) Fe3+ transition situated in the 1st biological window. The highest relative sensitivity in the temperature range (0 to 50 °C) was found to be 0.82% °C (at 26 °C) for LiAl5O8: 0.05% Fe3+ nanoparticles that are characterized by long luminescent lifetime of 5.64 ms. In the range of low and high temperatures the Smax was calculated for LiAl5O8:0.5% Fe3+ to be 0.92% °C at −100 °C and for LiAl5O8:0.01% Fe3+ to be 0.79% °C at 150 °C. The cytotoxicity assessment carried out on the LiAl5O8:Fe3+ nanocrystals, demonstrated that they are biocompatible and may be utilized for in vivo temperature sensing. The ratiometric luminescent nanothermometer, LiAl5O8:Fe3+, Nd3+, which was used as a reference, possesses an Smax = 0.56%/°C at −80 °C, upon separate excitation of Fe3+ and Nd3+ ions using 266 nm and 808 nm light, respectively.

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