Pharmacokinetic study of meropenem in healthy beagle dogs receiving intermittent hemodialysis

Meropenem, a second carbapenem antimicrobial agent with a broad spectrum of activity, is used to treat sepsis and resistant‐bacterial infections in veterinary medicine. The objective of this study was to identify the pharmacokinetics of meropenem in dogs receiving intermittent hemodialysis (IHD) and to determine the proper dosing in renal failure patients receiving IHD. Five healthy beagle dogs were given a single i.v. dose of 24 mg/kg of meropenem and received IHD. The blood flow rate, dialysate flow, and ultrafiltration rate were maintained at 40 mL/min, 300 mL/min, and 40 mL/h, respectively. Blood samples were collected for 24 h from the jugular vein and from the extracorporeal arterial and venous line. Urine samples and dialysate were also collected. The concentrations of meropenem were assayed using HPLC/MS/MS determination. The peak plasma concentration was 116 ± 37 μg/mL at 15 min. The systemic clearance was 347 ± 117 mL/h/kg, and the steady‐state volume of distribution was 223 ± 67 mL/kg. Dialysis clearance was 71.1 ± 34.3 mL/h/kg, and the extraction ratio by hemodialysis was 0.455 ± 0.150. The half‐life (T_1/2) in dogs with IHD decreased compared with those without IHD, and the reduction in T_1/2 was greater in renal failure patients than in normal patients. Sixty‐nine percent and 21% of the administered drug were recovered by urine and dialysate in the unchanged form, respectively. In conclusion, additional dosing of 24 mg/kg of meropenem after dialysis could be necessary according to the residual renal function of the patient based on the simulated data.     

Pharmacokinetics of single‐dose oral ponazuril in weanling goats

Ponazuril (toltrazuril sulfone) is a triazine antiprotozoal agent that targets apicomplexan organisms. Ponazuril may have clinical application in the treatment of clinical coccidiosis due to Eimeria species in goats, along with other protozoal infections. To evaluate the absorption, distribution and elimination characteristics of ponazuril in goats, a sensitive, validated high‐pressure liquid chromatography and mass spectroscopy method for ponazuril in caprine plasma was developed. After a single oral dose of ponazuril at 10 mg/kg, plasma samples from seven weanling goats were collected and assayed. Plasma concentrations of ponazuril in the goats peaked at 36 ± 13 h post drug administration at a concentration of 9 ± 2 μg/mL. Concentrations declined to an average of 4.2 ± 0.8 μg/mL after 168 h with an average elimination half‐life of 129 ± 72 h post drug administration. This study shows that ponazuril is relatively well absorbed after a single oral dose in goats. Efficacy trials are underway to determine clinical efficacy of ponazuril in the treatment of clinical coccidiosis in goats at 10 mg/kg dosage.     

Comparative plasma and milk dispositions,faecal excretion and efficacy of per os ivermectin and pour‐on eprinomectin in horses

The horse milk gains increasing interest as a food product for sensitive consumers, such as children with food allergies or elderly people. We investigated the plasma and milk disposition, faecal excretion and efficacy of per os ivermectin (IVM) and pour‐on eprinomectin (EPM) in horses. Ten mares were divided into two groups. The equine paste formulation of IVM and bovine pour‐on formulation of EPM were administered orally and topically at dosage of 0.2 and 0.5 mg/kg bodyweight. Blood, milk and faecal samples were analysed using high‐performance liquid chromatography. The plasma concentration and persistence of IVM were significantly greater and longer compared with those of EPM. Surprisingly, EPM displayed a much higher disposition rate into milk (AUC_milk/plasma: 0.48) than IVM (AUC_milk/plasma: 0.19). IVM exhibited significantly higher faecal excretion (AUC_faeces: 7148.54 ng·d/g) but shorter faecal persistence (MRT_faeces: 1.17 days) compared with EPM (AUC_faeces: 42.43 ng·d/g and MRT_faeces: 3.29 days). Faecal strongyle egg counts (EPG) were performed before and at weekly intervals after treatment. IVM reduced the EPG by 96–100% for up to 8 weeks, whereas the reduction in the EPM group varied from 78 to 99%. In conclusion, due to the relatively low excretion in milk, EPM and IVM may be used safely in lactating mares if their milk is used for human consumption. Nevertheless, much lower plasma and faecal availabilities of EPM could result in subtherapeutic concentrations, which may increase the risk of drug resistance in nematodes after pour‐on EPM administration compared with per os IVM.     

Early and 24 h post-mortem changes in breast muscle quality traits of two turkey genotypes and their reciprocal crosses raised under semi-confined conditions

1. An experiment was conducted to determine the effect of reciprocal crossing of turkeys on early and 24 h post-mortem changes in quality traits of their breast muscles.

2. The turkeys of slow-growing (SG) and fast-growing (FG) lines as well as SF (SG × FG) and FS crosses (FG × SG) were reared with access to free range.

3. After slaughter turkey breast muscles were examined in the following terms: 5 min, 45 min, 2 h and 24 h post-mortem, for: temperature, pH, glycogen content (G), lactate content (L) and electrical conductivity (EC). Quality attributes of the breast meat were evaluated based on chemical composition, water holding capacity (WHC), cooking loss (%), shear force (N) and colour (L*, a*, b*).

4. Despite differences in the rate of post-mortem changes, the genotype of turkeys had no significant effect upon many quality traits assessed 24 h post-mortem. Meat of lighter birds (SG and SF) was characterised by a lower fat content but a similar protein content compared to meat of FS and FG turkeys. In addition, meat of males from these groups was darker. Meat from the breast muscles of heavier birds (FS and FG) was harder.

5. Significant negative maternal effects were determined for temperature of meat of both male and female turkeys, for pH₂ and EC₂₄ of males as well as for L₂, L₂₄ and cooking loss of female meat. Positive heterosis was confirmed only for pH₂ of female meat and for G₂ of male meat.

6. In summary, the direction of fast- and slow-growing turkey crossing may affect the quality of their meat. However, meat of both types of hybrids reared under semi-confined conditions (with the possibility of using free range) was characterised by appropriate quality parameters.

     

Effect of supplementing broiler chicken diets with green tea extract on the growth performance,lipid profile,antioxidant status and immune response

1. A trial was conducted to explore the effect of feeding graded concentrations of green tea extract (GTE; 125, 250, 500, 1000 and 2000 mg/kg) on the growth performance, serum lipid profile, liver glutathione-reduced, thigh muscle malondialdehyde and humoral immune response against Newcastle disease virus vaccines of broiler chickens from hatching to 42 d of age. The results of broilers fed on GTE were contrasted to those fed on butylated hydroxytoluene (BHT; 125 mg/kg) or unsupplemented controls.

2. The obtained results revealed no significant difference among treatments in the measured growth performance parameters (body weight, average daily gain, average daily feed intake and feed conversion ratio), per cent liveability and serum lipid profile (total lipid, total cholesterol, high-density, low-density and very low-density lipoprotein cholesterols).

3. Dietary intake of GTE resulted in a significant increase in the liver glutathione-reduced level compared to the control. The glutathione-reduced level of broilers fed on the BHT diet was not significantly different from that of broilers fed on GTE or control diets. Feeding GTE or BHT resulted in a significant decrease in the malondialdehyde level of meat tissue.

4. The specific antibody titre against Newcastle disease virus vaccines was significantly increased at 28 and 35 d of age in broilers fed on diets supplemented with GTE but not with BHT.

5. In conclusion, GTE was found to possess antioxidant and immunostimulant characteristics for broilers when supplemented to their diets, and its optimum inclusion level ranged from 125 to 500 mg/kg.

     

Anti-predator behaviour of adult red-legged partridge (Alectoris rufa) tutors improves the defensive responses of farm-reared broods

1. The aim of this work was to improve natural anti-predator behaviour of farm-reared gamebirds.

2. We evaluated the anti-predator behaviour of reared red-legged partridge Alectoris rufa chicks kept in brooder houses in large groups (>350 chicks), trained and not trained by parent red-legged partridges acting as experienced tutors.

3. The experiment consisted of two conditioned tests (a raptor model and a human) and two control tests, which were conducted during three consecutive phases of life (1–4, 15–17 and 30–32 d after hatching). The motor anti-predator behaviour, its duration, the intensity of response in chicks and alarm calls elicited by adults were recorded.

4. Tutors elicited aerial alarm calls (76% of tests) and showed prolonged crouching (59% of tests) in response to the raptor model whereas uttering the ground alarm call (73% of tests) and showing vigilance behaviour (78% of tests) was the main pattern during the human test.

5. Trained and not trained chicks showed similar motor behaviour in response to the raptor model (crouching) and the human test (escaping), but frequency of strong responses (all chicks responding) from chicks trained with tutors was double that of chicks trained without them, and chicks trained with tutors showed a higher frequency of long responses (41–60 s).

6. This study indicates that anti-predator training programmes before release may improve behaviour of farm-reared partridges which may confer benefits to survival of birds.

     

Influence of thermal stimulation during the late phase of incubation on hatching results and post-hatch broiler performance under commercial conditions

1. Two experiments, which differed in breeder age, strain and season, were conducted to study the influence of low-intensity, short-duration thermal stimuli during the late phase of incubation on hatchability and performance. The first experiment conducted in April–June used eggs from Cobb × Ross broiler breeders at 35–41 weeks of age and the second experiment performed in February–April used eggs from Hubbard × Cobb broiler breeders at 49–53 weeks of age.

2. Eggs in the test group had the same physical environment as eggs in the control group except that incubation temperature was increased by 1?C for 2 h/d above the control group from 18 to 20 d of incubation (DI).

3. The results demonstrated that thermal stimulation of 1?C for 2 h/d above control incubation temperature during 18–21DI did not have any adverse effects on hatch and post-hatch performance of broilers.

4. In both experiments, treatment did not significantly alter the secondary sex ratio in hatched chickens, but hatch residue showed that the proportion of unhatched male embryos was significantly lower in the test groups than in the control groups.

5. In the first experiment, thermal stimulation improved feed conversion by 1.82% compared with the control.