Population Pharmacokinetics and Absolute Oral Bioavailability of Lasalocid after Single Intravenous and Intracrop Administration in Laying Hens.

Lasalocid sodium is a polyether carboxylic ionophore agent authorized by the EU for use as a coccidiostat in broilers, turkeys, and pullets up to 16 weeks of age, except for laying hens. However, laying hens are the most common nontarget species exposed to lasalocid sodium, mainly due to cross-contamination from feed mills. This exposure may result in potential drug residue deposition in eggs, which could potentially expose consumers to the drug. The breeds commonly used for commercial egg production in Poland are Isa Brown and Green-legged Partridge hens, which have been found to significantly differ in egg-laying performance. This variability may also affect the pharmacokinetics of lasalocid. Data on lasalocid plasma pharmacokinetics in laying hens are lacking. In this study, we aimed to determine typical population pharmacokinetic parameters, absolute oral bioavailability, and how breed may influence the pharmacokinetics of lasalocid. Twenty-layer hens of the two breeds were used in this study. Lasalocid was administered orally at a single dose of either 1 mg or 5 mg/kg body weight or intravenously at a dose of 1 mg/kg body weight, in a crossover design with a three-week washout period between study periods. Blood samples were collected for 72 h, and lasalocid concentrations were measured using high-performance liquid chromatography with fluorescence detection. A population pharmacokinetic analysis was conducted using nonlinear mixed effects modeling. Standard numerical and graphical criteria were used to select the best model, and a stepwise covariate modeling approach was used to determine any influencing factors. The best model was a three-compartment mammillary model with first-order absorption, transit compartments, and linear elimination. The estimated absolute oral bioavailability was low (36%). It was found that breed significantly influenced not only absorption but also the elimination of lasalocid. This study revealed that lasalocid absorption and elimination varied between the two breeds. This variability in pharmacokinetics may result in breed-related differences in drug residue accumulation in eggs, and ultimately, the risk associated with consumer exposure to drug residues may also vary.

Investigation of the correlation between virulence factors and genotypic profiles of Candida albicans isolated from turkeys.

Candida albicans exists as an element of the normal flora in the skin, mucosa, and gastrointestinal tract, which is the principal reservoir for this organism. When the delicate balance in the host-yeast relationship is tipped in favour of the microorganism by antimicrobial treatment, illness, or other debilities of the host, fungi may overgrow and cause disease, such as candidiasis. The aim of this study was to analyse three virulence factors, haemolysin, proteinase, and phospholipase, with the genotypic profiles of C. albicans isolated from turkeys and to investigate if any correlation between these features exists. The genotypic profiles were generated using the polymerase chain reaction (PCR) with the RDS6 primer, and the enzymatic activity was evaluated in culture. Among the C. albicans isolates, four genotypic profiles using random amplified polymorphic DNA (RAPD) and three enzymatic profiles were defined. Genotypic profile A was characterised by seven bands, genotypic profile B was characterised by nine bands, genotypic profile C was characterised by nine bands, and genotypic profile D was characterised by four bands. Enzymatic profile I demonstrated no haemolysin or proteinase activity, but phospholipase activity was present; enzymatic profile II displayed no proteinase activity, but haemolysin and phospholipase activity were produced; and enzymatic profile III revealed all three types of enzymatic activity. The genotypic profiles were strictly correlated with the enzymatic profiles among the C. albicans isolates from poultry.

Molecular analysis of Trichomonas gallinae in racing pigeons from Upper Silesia, Poland.

The aim of the study was the molecular analysis of ITS1/5.8S rRNA/ITS2 region of Trichomonas gallinae isolates from racing pigeon lofts in Upper Silesia, Poland. The analysed region is very useful for the taxonomy of the Trichomonadidae family and indicates the possible existence of different genotypes or species within the T. gallinae. A comparison of the complete ITS1-5.8S-ITS2 region of obtained sequences revealed two different sequences. Twenty-three of the isolates (62%) showed the first sequence (KU954106) while fourteen isolates (38%) showed the second sequence type (KU954107), which were homologous with sequences from Genbank. The phylogenetic analysis showed that the two T. gallinae genotypes which occurred in the pigeons from Upper Silesia are widespread among European countries.

Metronidazole pharmacokinetics during rapid growth in turkeys - relation to changes in haemodynamics and drug metabolism.

Whereas interspecies variation in pharmacokinetics is a commonly investigated issue, variations in drug kinetics within a species are less documented. The aim of the study was to assess the influence of age-related changes in haemodynamics on the pharmacokinetics of metronidazole (MTZ) and its hydroxy metabolite (MTZ-OH) in turkeys. MTZ was administered intravenously and orally at a dose of 25 mg/kg. Plasma drug and metabolite concentrations were assessed by high-performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. Haemodynamic parameters (heart rate, stroke volume, cardiac output) were assessed by echocardiography and extraction ratio for MTZ was calculated based on total body clearance (ClB ). Between the 5th and 15th week of age, ClB of MTZ decreased from 3.6 to 1.2 mL/min/kg causing a twofold increase in the mean residence time (MRT) and elimination half-life (T1/2el ). The MTZ-OH production decreased threefold and its MRT and T1/2el increased. Although heart rate significantly decreased with age, cardiac output increased. Extraction ratio was low in all age groups. It is concluded that significant age-dependent decrease in ClB of MTZ in turkeys resulted from decreased perfusion of the clearing organs and their reduced metabolic capacity. This phenomenon is probably species specific and may apply to other therapeutic agents.

Prevalence of inclusion body hepatitis (IBH) in Poland from 2010-2014.

This study investigated the prevalence of inclusion body hepatitis (IBH) infections during the past five years (2010-2014) in broiler chicken flocks in Poland. The diagnosis of IBH was based on anatomopathological investigations and histopathological analyzes. IBH was the most prevalent disease in broiler flocks in Poland (10.4%) during this time period, and occurred as a primary infection. The fewest cases of IBH occurred in the summer, suggesting that the temperature may have been a possible stressor that increased susceptibility to IBH. However, over the last 5 years the occurrence of clinical IBH cases in Poland has systematically decreased.

Adverse effects associated with high-dose acetylsalicylic acid and sodium salicylate treatment in broilers.

1. Acetylsalicylic acid (ASA) and sodium salicylate (SS) are considered safe for poultry and often used in avian medicine. However, information on tolerance and specific side effects of these drugs in birds is lacking. 2. The aim of this study was to determine the effects of 14 d administration of high doses (200 or 400 mg/kg) of either ASA or SS on body weight gain, blood biochemistry, white and red blood cell counts and pathology in broilers. In addition, minimal plasma salicylate concentrations were determined on the 1st, 5th, 10th and 14th d of treatment. 3. The results showed that the dose of 400 mg/kg of either ASA or SS decreased weight gain and induced gizzard ulceration. Kidney to body weight ratio was increased in a dose-dependent manner, but serum concentrations of creatinine and uric acid were not affected. A time-dependent decrease in the minimal plasma salicylate concentration was evident.