Pharmacokinetics of tapentadol in laying hens and its residues in eggs after multiple oral dose administration

Effects of Selenium Conjugated to Insect Protein on Pharmacokinetics of Florfenicol and Enrofloxacin in Laying Hens

In the context of increasing awareness on the dietary supplementation of organic selenium in commercial poultry production and ensuring safe egg production, the present study investigated the effects of selenium on the pharmacokinetics of the therapeutic use of florfenicol and enrofloxacin from perspectives of laying performance, selenium deposition in eggs, and drug residue in plasma, organs, and eggs. A 2 × 3 factorial arrangement with two kinds of drugs (florfenicol vs. enrofloxacin, 200 mg/kg) and three levels of dietary organic selenium SCIP (selenium conjugated to insect protein) (0, 2, and 5 mg/kg) was designed together with a blank control group. Healthy Hy-Line Brown laying hens (n = 252, 40-week-old and 90.0 ± 1.7% of egg production rate) were randomly allocated into one of seven treatments with six replicates and six hens per replicate. The experiment lasted for 42 days and consisted of three periods (adjusted stage, depositional stage, and eliminating stage) of 14 days each. These stages entail feeding of the laying hens with basal diets, addition of drugs and selenium synchronously into the diets, drug withdrawal from diet, and supply of selenium uninterruptedly in the diet. Egg production and feed intake were recorded on daily and weekly bases, respectively. The selenium content in egg yolk, egg white, and whole eggs and the drug residues in eggs, plasma, liver, kidney, and breast muscle were determined on days 2, 3, 5, 6, 7, 9, 11, and 14 of the depositional and eliminating stages. There was no significant difference (p > 0.05) in egg production among the dietary treatments, but feed intake decreased significantly (p < 0.05) in the drug treatment group compared to other groups. Dietary organic selenium decreased the residue of drugs in tissues and eggs, while the metabolism and deposition of selenium in laying hens were suppressed due to drug effects. The results of the present study are of significance to enrich the knowledge of the pharmacokinetics of florfenicol and enrofloxacin in laying hens and ensure the quality of poultry products.

Pilot Study of a Single Dose of Orally Administered Tapentadol Suspension in Hispaniolan Amazon Parrots (Amazona ventralis)

Tapentadol is an analgesic agent that acts as both a µ-opioid receptor agonist and a norepinephrine reuptake inhibitor. It is a common therapeutic agent in human medicine for management of acute and chronic pain, and it is currently being investigated for use in veterinary medicine. Tapentadol was evaluated in Hispaniolan Amazon parrots (Amazona ventralis) because there is only 1 other oral opioid-like analgesic agent, tramadol, which has been evaluated in an avian species. The effectiveness of tramadol after administration to a patient involves a complex physiologic metabolism and has been found to have variable pharmacokinetics between species. Because of the lack of active metabolites from tapentadol, less interspecific variation was expected. Seven Hispaniolan Amazon parrots were used to evaluate the pharmacokinetics of tapentadol after a single 30 mg/kg PO administration of a compounded 5 mg/mL tapentadol suspension. Blood samples were collected before (time 0) and 0.25, 0.5, 0.75, 1, 1.5, 3, and 6 hours after administration, following a balanced, incomplete-block design. Plasma tapentadol concentrations were measured by high-pressure liquid chromatography with mass spectrometry. Results revealed detectable plasma concentrations in only 2 of 7 birds (29%), and the bird with the highest plasma levels had a peak concentration (C_max) of 143 ng/mL and a half-life (T _1/2) of 24.8 minutes. The variable plasma concentrations and short half-life of this drug in Hispaniolan Amazon parrots suggests that this drug would be of limited clinical use in this species; however, it is possible that this drug will be more bioavailable in other avian species.