Tetracyclines continue to be important antimicrobials in veterinary medicine. However, the pharmacokinetics ( PK ) of tigecycline ( TIG ) and minocycline ( MIN ) in broiler chickens has not been investigated to date, and the PK of chlortetracycline ( CTC ) and tetracycline ( TET ) remains insufficiently researched, especially in terms of absorption. These antimicrobials have never been compared in a single setting in a single species; therefore, the aim of the present study was to compare the PK of TIG, MIN, CTC, and TET in broiler chickens. Each drug (10 mg/kg) was administered intravenously ( IV ) and orally ( PO ). The plasma concentrations of each drug were determined by liquid chromatography-tandem mass spectrometry, and the results were analyzed using compartmental and non-compartmental PK models. Despite the fact that all of the studied antimicrobials were administered at an identical IV dose, the area under the concentration–time curve between zero and the last sampling point (AUC 0→t ) for MIN (35,014 ± 3,274 μg × hour/mL) and CTC (41,851 ± 10,965 μg × hour/mL) differed significantly from that determined for TIG (18,866 ± 4,326 μg × hour/mL) and TET (17,817 ± 4,469 μg × hour/mL). After IV administration, the values of AUC 0→t were also directly related to total body clearance values which were significantly higher for TIG (0.56 ± 0.14 L/hour × kg) and TET (0.60 ± 0.14 L/hour × kg) than for CTC (0.25 ± 0.05 L/hour × kg) and MIN (0.29 ± 0.03 L/hour × kg). In turn, after PO administration, TIG was absorbed in only 1.55% ± 0.82, and CTC in 30.54% ± 6.99, whereas the bioavailability of MIN and TET was relatively high at 52.33% ± 3.92 and 56.45% ± 9.71, respectively. The differences in PK parameters between these drugs, despite their structural similarities, suggest that active transport mechanisms may play a role in their absorption and distribution.

Definitions of biological medicinal products (BMPs) vary depending on the source. BMPs are manufactured using complex biological/biotechnological processes involving living cell lines, tissues and organisms such as microorganisms, plants, humans and even animals. Advances in modern biotechnological methods and genetic engineering have made it possible to search for new drugs with a targeted effect and simultaneous reduction of adverse effects, which has resulted in BMPs dynamically increasing their share in the pharmaceutical market. Currently, these drugs are widely used in the treatment of many human diseases, but an increasing number of drugs of this group are also being used in the treatment of animals, mainly in dermatology, rheumatology and oncology. This article presents the current state of knowledge in the field of biological medicinal products used in animal therapy.

Quercetin is a polyphenolic flavonoid occurring in leaves, stems, flowers and fruits of many plants. In traditional Chinese medicine, it is used as a natural therapeutic agent with a broad spectrum of activities (antioxidant, neuroprotective, anti-inflammatory, anticancer, antibacterial and antiviral). Moreover, quercetin affects function of the reproductive tract, however the knowledge of this activity is still fragmentary. Therefore, this study aimed to determine the influence of quercetin on the contractile activity of the porcine myometrium collected from immature (n = 6), cyclic (n = 6) and early pregnant (n = 6) gilts. Strips of the myometrium (comprising longitudinal and circular layer) were resected from the middle part of the uterine horns and the isometric contractions were recorded. After 60–90 min of preincubation, the strips were stimulated with quercetin in increasing (10−13–10−1 M) concentrations and the changes in the tension amplitude and frequency of contractions were measured. Quercetin decreased (P<0.01–0.001) the amplitude of contractions at concentrations 10−11–10−1 M and 10−10–10−1 M in cyclic and early pregnant groups, respectively. The frequency of contractions decreased in all groups but was the highest (at concentrations 10−11–10−1 M; P<0.05–0.001) in the cyclic group and the lowest (at concentrations 10−5–10−1 M; P<0.01) in the immature group. The tension decreased only in the cyclic group after quercetin administration in high concentrations (10−6–10−1 M; P<0.05–0.01). The results indicate that quercetin causes relaxation of the porcine uterine smooth muscle but this activity is strongly related to the physiological status of the gilts.

Introduction Bisphenols, as endocrine disruptors, may cause a wide range of health problems in humans, but so far, not all of them have been confirmed in animals, including pigs. Since animals are also exposed to bisphenols, we hypothesised that these substances may have an effect on uterine contractility in pigs. Therefore, the aim of the study was to investigate the effect of the most-used bisphenol, bisphenol A (BPA), and a selected analogue, bisphenol F (BPF), on the contractile activity of the pig uterus. Material and Methods The investigation utilised smooth muscles from immature pigs (n = 6), cyclic pigs on days 12–14 of the oestrous cycle (n = 6) or early pregnant pigs on days 12–16 of pregnancy (n = 6). Strips of the myometrium were exposed to BPA and BPF at concentrations of 10−13–10−1 M. Smooth muscle contractility was determined with equipment for measuring isometric contractions. Results BPA caused a significant decrease in contraction amplitude, and frequency and in myometrial tension in all groups examined. BPF caused a decrease in the amplitude and frequency of contractions in all groups and in myometrial tension in the early pregnant group. Conclusion The obtained results indicate that both BPA and BPF relaxed the porcine myometrium, but these changes, especially in the amplitude and frequency of contractions, were more evident after BPF treatment. The extent of relaxation is dependent on the physiological status of the animals.

Abstract. The aim of the current study is to evaluate Virginia fanpetals silage based on an apparent digestibility and palatability test performed on six adult rams. Alfalfa silage was used as standard forage for comparison. Virginia fanpetals samples were harvested in the bud-formation stage and alfalfa samples were harvested in the late bud stage. Virginia fanpetals silage had a crude protein (CP) content of 176 g kg−1 dry matter (DM), a neutral detergent fiber (NDF) content of 378 g kg−1 DM, and a lignin content of 42.8 g kg−1 DM. Virginia fanpetals silage had higher acidity (pH of 4.30) and was characterized by intense lactic acid fermentation compared with alfalfa silage (80 % vs. 51 % of the total acids). The digestibility coefficient of Virginia fanpetals silage was as follows: for DM it was 0.707, for organic matter (OM) it was 0.724, for CP it was 0.861, and for NDF it was 0.609. In comparison with alfalfa silage, Virginia fanpetals silage was characterized by higher apparent digestibility of nutrients, but a significant difference was noted only for CP. The voluntary intake of Virginia fanpetals silage was significantly higher than that of alfalfa silage (1427.4 vs. 954 g DM). The greatest differences in voluntary intake were observed 0–2 and 8–12 h after feeding. Virginia fanpetals silage had a chemical composition similar to that of alfalfa, but it was characterized by a more desirable fermentation pattern and higher digestibility, and it was more willingly consumed by rams. The present findings indicate that Virginia fanpetals silage can be fed to sheep.