Effects of melatonin on morphology and development of primordial follicles during in vitro culture of bovine ovarian tissue

This study aims to investigate the effect of melatonin on activation, growth and morphology of bovine primordial follicles, as well as on stromal cells density in ovarian tissues after in vitro culture. Ovarian fragments were cultured in α‐MEM⁺ alone or supplemented with melatonin (250, 500, 1,000 or 2,000 pM) for a period of six days. Non‐cultured and cultured tissues were processed for histological analysis; according to developmental stages, follicles were classified as primordial or growing follicles. These follicles were further classified as morphologically normal or degenerated. Ovarian stromal cell density was also evaluated. The percentages of primordial and developing follicles, as well as those classified of normal follicles, were compared by Fisher's exact test, and the differences were considered significant when p < .05. The results showed that the presence of 1,000 and 2,000 pM melatonin in culture medium promoted a reduction in the percentage of primordial follicles and an increase in the percentage of development follicles, when compared to follicles cultured in control medium. On the other hand, the presence of 250 or 500 pM melatonin did not show a significant effect on the percentage of primordial and developing follicles. Besides that, the presence of 500, 1,000 and 2,000 pM melatonin maintained the percentage of normal follicles similar to those seen uncultured control. Moreover, tissues cultured in presence of 1,000 pM melatonin showed a higher percentage of normal follicles when compared to follicles cultured in the presence of 250 pM melatonin. It was observed a similar profile of stromal density in both uncultured tissues and those cultured in vitro in the presence of melatonin. In conclusion, melatonin (1,000 and 2,000 pM) promotes bovine primordial follicles activation and maintains the stromal cell density during in vitro culture of ovarian cortical tissue.     

Reproductive disruption in Fasciola hepatica associated with incomplete efficacy of a new experimental formulation of triclabendazole

The objective of the present study was to analyse the reproductive viability (using histopathologic studies) of Fasciola hepatica from cattle artificially infected and treated subcutaneously with a new experimental formulation of triclabendazole (8mg/kg b.w.). The results of the efficacy controlled test, which only takes into account the presence of live adult flukes, indicated that, whilst in the control group (n=7) 533 live specimens were recovered, in the test groups (doses of 8 and 12mg/kg b.w.) only 195 and 47 adults were recovered, respectively. These numbers indicate efficacies of 69% and 95.6%, respectively. It was observed in that dose of 8mg/kg b.w. some specimens remained viable, but they were infertile, which severely compromises the biological cycle of the trematode. In the testis tubules of flukes treated with the low dose of TCBZ (8mg/kg), very few cells were present and the vitelline follicles were markedly reduced in size and each follicle contained very few cells. This would have direct implications for the pathogenesis of the parasitosis since the remaining parasites would produce little clinical-productive manifestations, would stimulate the immune response and would find it difficult to establish future re-infestations/re-infections. Consequently, these observations will also prompt a review of certain methodological and interpretative aspects related to efficacy tests, where the only discriminative factor is the reduction of the adult parasite load. On one hand, histopathological studies could be complementary to the efficacy controlled test for TCBZ or other BZD formulations.     

Pharmacokinetics of enrofloxacin HCl‐2H2O (ENRO‐C), PK/PD,and Monte Carlo modeling vs. Leptospira spp. in cows

The pharmacokinetics, PK/PD ratios, and Monte Carlo modeling of enrofloxacin HCl‐2H₂O (Enro‐C) and its reference preparation (Enro‐R) were determined in cows. Fifty‐four Jersey cows were randomly assigned to six groups receiving a single IM dose of 10, 15, or 20 mg/kg of Enro‐C (Enro‐C₁₀, Enro‐C₁₅, Enro‐C₂₀) or Enro‐R. Serial serum samples were collected and enrofloxacin concentrations quantified. A composite set of minimum inhibitory concentrations (MIC) of Leptospira spp. was utilized to calculate PK/PD ratios: maximum serum concentration/MIC (C_max/MIC₉₀) and area under the serum vs. time concentration of enrofloxacin/MIC (AUC_0‐24/MIC₉₀). Monte Carlo simulations targeted C_max/MIC = 10 and AUC_0‐24/MIC = 125. Mean C_max obtained were 6.17 and 2.46 μg/ml; 8.75 and 3.54 μg/ml; and 13.89 and 4.25 μg/ml, respectively for Enro‐C and Enro‐R. C_max/MIC₉₀ ratios were 6.17 and 2.46, 8.75 and 3.54, and 13.89 and 4.25 for Enro‐C and Enro‐R, respectively. Monte Carlo simulations based on C_max/MIC₉₀ = 10 indicate that only Enro‐C₁₅ and Enro‐C₂₀ may be useful to treat leptospirosis in cows, predicting a success rate ≥95% when MIC₅₀ = 0.5 μg/ml, and ≥80% when MIC₉₀ = 1.0 μg/ml. Although Enro‐C₁₅ and Enro‐C₂₀ may be useful to treat leptospirosis in cattle, clinical trials are necessary to confirm this proposal.     

Carcinocythemia: First report in a cat and literature review

A 6‐year‐old female neutered European Shorthair cat was presented with a 2‐day history of lethargy and hyporexia. On physical examination, the cat was slightly depressed and had a 2.5 cm nodule in the left 3^rd mammary gland. The hemogram revealed mild leukocytosis with mature neutrophilia and moderate thrombocytopenia. On blood smear evaluation, rare pleomorphic cells, possibly of epithelial origin, were observed mainly at the feathered edge. The animal died about 12 hours after presentation, and a necropsy was performed. On histopathology, the mammary nodule was diagnosed as a tubulopapillary adenocarcinoma with vascular invasion and widespread metastases. Immunocytochemical tests for cytokeratins (AE1/AE3) confirmed the epithelial phenotype of the neoplastic cells observed on the blood smear. The present report describes a feline mammary carcinoma with widespread metastases and the presence of malignant epithelial cells in the peripheral blood referred to as carcinocythemia. This condition has been previously described in people and dogs. To the author's knowledge, this is the first reported case of feline carcinocythemia. As in other species, the phenomenon was associated with a terminal phase of systemic malignancy.     

Anatomical description of arterial segments of the spleen of deer

With 2 figures SUMMARY: The anatomosurgical segmentation of the arteries of the spleen was studied in 31 deer of the species Mazama gouazoubira and Blastocerus dichotomus by means of vascular injection with latex and vinyl acetate and radiographic examination. The arteria lienalis penetrated through the hilus lienis in 87% of the cases, whereas an extrahilar artery was present in the other cases. An extraparenchymal division of the lineal artery into two, three or four segmental arteries was observed in 74% of the cases. Anastomoses between intraparenchymal arterial branches were rare and of a reduced calibre.     

Use of topical mitomycin C in myoplasty of the medial rectus muscle of rabbits

To possibly reduce postoperative adhesions that occur after ocular myoplasties, we investigated the topical effects of 0.04% mitomycin C on the repaired areas of the medial rectus muscle using an equine renal capsule preserved in 98% glycerin for reinforcement of the sutures. Twenty-four rabbits, divided into two groups of 12 animals each [untreated (control) and treated group (MMC)], were submitted to surgical rupture of the medial rectus muscle of one eye and repair of the defect 24 h later with sutures and an equine renal capsule. Post-operative prophylactic treatment of the two groups consisted of the administration of eye drops containing neomycin, polymyxin B and dexamethasone at regular 6-h intervals for eight consecutive days and daily rinsing with physiological saline. MMC animals received additional treatment with topical 0.04% mitomycin C every 6 h for 14 consecutive days. Slit lamp biomicroscopy showed greater irritation of the ocular surface in MMC animals during the first days post operatively. Adhesions were observed at 15 and 30 days of assessment in the two groups, but were more extensive in control animals at 60 days. Histopathology revealed inflammatory exudation in both groups, which was greater in MMC animals. Mitomycin C (0.04%) instilled at 6-h intervals for 14 consecutive days reduced the occurrence of fibrosis in the myoplastic areas. However, the equine renal capsule was found to be of little benefit for the reinforcement of myoplasties.     

Electrocardiographic parameters in the clinically healthy Zamorano-leones donkey

Limited information exists regarding electrocardiographic parameters in clinically healthy donkeys. The study was carried out in 75 healthy adult animals (40 females and 35 males) using the Einthoven standard II and base-apex leads. The P wave showed usually a bifid shape deflection. The QRS complex of the donkeys appeared in several forms: QR and R were the most frequent in limb lead II, and QS and QR in the base-apex lead. Most T waves presented a simple negative configuration in lead II and biphasic shape in the base-apex one. Mean heart rate value was 52 beats per minute. The direction of the QRS vector in lead II had a mean value of 91.4°. We observed a lack of detected arrhythmias. Statistically significant differences were observed between sexes for several parameters. The electrocardiogram of Zamorano-leones donkey differs in several duration, amplitude and morphologic parameters from that of several breeds of horses and donkeys. This fact justifies obtaining values for a specific breed against which to compare values for the same breed.     

Supplementation strategies for Nellore female calves in creep feeding to improve the performance: nutritional and metabolic responses

The objective of this study was to evaluate the effects of supplementation strategy on performance, nutritional and metabolic characteristics of Nellore suckling female calves, on grazing Urochloa decumbens during the rainy-dry transition period. Forty-four Nellore female calves, averaging 147.6?±?1.34 kg (4 months), were used. A single supplement 20% of crude protein of dry matter was provided, consisting of daily supplement at 0.0, 0.2, 0.4, or 0.6% of body weight. A positive linear effect (P?<?0.05) on final body weight and average weight gain of female calves was observed with increased supplementation. Supplementation increased consumption, in kilograms per day, of dry matter (DM), organic matter (OM), crude protein (CP), digested dry matter, and total digestible nutrients (TDN), all calculated as % of dry matter. There was no effect of supplementation on the consumption in kilograms per day of neutral detergent fiber corrected for ash and protein (apNDF) (P?>?0.05). Supplementation increased, in a quadratic way, the total apparent digestibility coefficient of DM, OM, CP, apNDF, and TDN (P?<?0.05). There was no effect of supplementation (P?>?0.05) on non-esterified fatty acid concentrations. There was a positive linear effect (P?<?0.05) of supplementation on insulin concentrations. In this study, it is concluded that linearly increasing the feeding level of a supplement with 20% crude protein (% of DM) in the range of 0.2–0.6% of body weight improves the performance, nutritional and metabolic characteristics of the animals, considering these pasture characteristics.