Administration of meloxicam to improve the welfare of mice in research: a systematic review (2000 – 2020)

Veterinary Research Communications - Although laboratory animals experience pain as a necessary component of the objectives of experimental protocols, the level of pain should be minimized through...     

Identification of genomic regions related to age at first calving and first calving interval in water buffalo using single-step GBLUP

In Brazil, water buffaloes have been used to produce milk for mozzarella cheese production. Consequently, the main selection criterion applied for the buffalo genetic improvement is the estimated mozzarella yield as a function of milk, fat and protein production. However, given the importance of reproductive traits in production systems, this study aimed to use techniques for identifying genomic regions that affect the age at first calving (AFC) and first calving interval (FCI) in buffalo cows and to select candidate genes for the identification of QTL and gene expression studies. The single-step GBLUP method was used for the identification of genomic regions. Windows of 1 Mb containing single-nucleotide polymorphisms were constructed and the 10 windows that explained the greatest proportion of genetic variance were considered candidate regions for each trait. Genes present into the selected windows were identified using the UOA_WB_1 assembly as the reference, and their ontology was defined with the Panther tool. Candidate regions for both traits were identified on BBU 3, 12, 21 and 22; for AFC, candidates were detected on BBU 6, 7, 8, 9 and 15 and for first calving interval on BBU 4, 14 and 19. This study identified regions with great contribution to the additive genetic variance of age at first calving and first calving interval in the population of buffalo cows studied. The ROCK2, PMVK, ADCY2, MAP2K6, BMP10 and GFPT1 genes are main candidates for reproductive traits in water dairy buffaloes, and these results may have future applications in animal breeding programs or in gene expression studies of the species.     

Immunological changes in canine peripheral blood leukocytes triggered by immunization with first or second generation vaccines against canine visceral leishmaniasis

In this study, we summarized the major phenotypic/functional aspects of circulating leukocytes following canine immunization with Leishvaccine and Leishmune?. Our findings showed that Leishvaccine triggered early changes in the innate immunity (neutrophils and eosinophils) with late alterations on monocytes. Conversely, Leishmune(?) induced early phenotypic changes in both, neutrophils and monocytes. Moreover, Leishvaccine triggered mixed activation-related phenotypic changes on T-cells (CD4+ and CD8+ and B-lymphocytes, whereas Leishmune(?) promoted a selective response, mainly associated with CD8+ T-cell activation. Mixed cytokine profile (IFN-γ/IL-4) was observed in Leishvaccine immunized dogs whereas a selective pro-inflammatory pattern (IFN-γ/NO) was induced by Leishmune? vaccination. The distinct immunological profile triggered by Leishvaccine and Leishmune? may be a direct consequence of the distinct biochemical composition of these immunobiological, i.e. complex versus purified Leishmania antigen along with Bacillus Calmette-Guérin (BCG) versus saponin adjuvant. Both immunobiologicals are able to activate phagocytes and CD8+ T-cells and therefore could be considered as a putative vaccines against canine visceral leishmaniasis (CVL).     

Caenorhabditis elegans as a model to screen plant extracts and compounds as natural anthelmintics for veterinary use

The most challenging obstacles to testing products for their anthelmintic activity are: (1) establishing a suitable nematode in vitro assay that can evaluate potential product use against a parasitic nematode of interest and (2) preparation of extracts that can be redissolved in solvents that are miscible in the test medium and are at concentrations well tolerated by the nematode system used for screening. The use of parasitic nematodes as a screening system is hindered by the difficulty of keeping them alive for long periods outside their host and by the need to keep infected animals as sources of eggs or adults when needed. This method uses the free-living soil nematode Caenorhabditis elegans as a system to screen products for their potential anthelmintic effect against small ruminant gastrointestinal nematodes, including Haemonchus contortus. This modified method uses only liquid axenic medium, instead of agar plates inoculated with Escherichia coli, and two selective sieves to obtain adult nematodes. During screening, the use of either balanced salt solution (M-9) or distilled water resulted in averages of 99.7 (± 0.73)% and 96.36 (± 2.37)% motile adults, respectively. Adult worms tolerated DMSO, ethanol, methanol, and Tween 80 at 1% and 2%, while Labrasol (a bioenhancer with low toxicity to mammals) and Tween 20 were toxic to C. elegans at 1% and were avoided as solvents. The high availability, ease of culture, and rapid proliferation of C. elegans make it a useful screening system to test plant extracts and other phytochemical compounds to investigate their potential anthelmintic activity against parasitic nematodes.     

Geotrichum candidum as etiological agent of horse dermatomycosis

Fungi of the genus Geotrichum are commonly found in the environment and, in some circumstances, they may cause diseases in humans and animals. Although these fungi have been isolated from skin lesions of some animal species, their pathogenic role in horses remains uncertain. With the aim to investigate the role of Geotrichum candidum as etiological agent of dermatomycoses, a retrospective study of 64 horses presenting skin lesions and suspected to have fungal infections was carried out. For each animal, anamnestic data were recorded and fungal culture were performed using hair. Out of 64 cases, 18 (28.1%) were positive for G. candidum and only two (3.1%) for dermatophytes (i.e., one for Microsporum equinum and the other for Microsporum canis). Alopecia, desquamation, and pruritus localized mainly on head and neck were frequently observed in G. candidum infected animals. Most of G. candidum infections were recorded during spring (44.4%). Out of the 18 animals presenting G. candidum infections, eight were treated using a disinfectant with antifungal properties. After one month of treatment, the clinical lesions were healed and fungal cultures resulted negative. The high prevalence of G. candidum in skin lesions of horses and the clinical recover following antifungal treatment indicated that these yeast-like fungi might play a role as etiological agents of horse cutaneous mycoses.     

Mango and acerola pulps as antioxidant additives in cassava starch bio-based film

The objective of this study was to investigate the feasibility of incorporating mango and acerola pulps into a biodegradable matrix as a source of polyphenols, carotenoids, and other antioxidant compounds. We also sought to evaluate the efficacy of mango and acerola pulps as antioxidants in film-forming dispersions using a response surface methodology design experiment. The bio-based films were used to pack palm oil (maintained for 45 days of storage) under accelerated oxidation conditions (63% relative humidity and 30 °C) to simulate a storage experiment. The total carotenoid, total polyphenol, and vitamin C contents of films were evaluated, while the total carotenoid, peroxide index, conjugated diene, and hexanal content of the packaged product (palm oil) were also monitored. The same analysis also evaluated palm oil packed in films without antioxidant additives (C1), palm oil packed in low-density polyethylene films (C2), and palm oil with no package (C3) as a control. Although the film-forming procedure affected the antioxidant compounds, the results indicated that antioxidants were effective additives for protecting the packaged product. A lower peroxide index (36.12%), which was significantly different from that of the control (p<0.05), was detected in products packed in film formulations containing high concentration of additives. However, it was found that the high content of vitamin C in acerola pulp acted as a prooxidant agent, which suggests that the use of rich vitamin C pulps should be avoided as additives for films.     

Tissue distribution of Leishmania chagasi and lesions in transplacentally infected fetuses from symptomatic and asymptomatic naturally infected bitches

Visceral leishmaniasis (VL) is primarily transmitted by an invertebrate vector, but transmission in the absence of the vector has been reported. Vertical transmission of VL has been described in man and dogs. The aim of this study was to evaluate the distribution of Leishmania amastigotes in fetal organs and histopathologic changes associated with parasitism and to determinate the frequency of transplacental transmission and potential of vertical transmission by symptomatic and asymptomatic pregnant bitches. Symptomatic (n = 4) and asymptomatic (n = 4) pregnant bitches, serologically and parasitologically positive for Leishmania sp., carrying a total of 53 fetuses (26 from symptomatic and 27 from asymptomatic bitches) were selected at the Veterinary Hospital of the National University of Asuncion, Paraguay. Samples of placenta and fetal organs such as liver, spleen, lymph nodes, bone marrow, kidney and heart were histologically evaluated and processed for immunodetection of amastigotes and PCR. There were no lesions compatible with VL in fetal tissues in spite of the presence of amastigotes, particularly in lymphoreticular tissues. However, fetal hepatocytes had marked degenerative changes that were independent of the presence of amastigotes in liver. Twenty-six out of 53 placentas (13 symptomatic and 13 asymptomatic) and a total of 17 fetuses out of 53 (nine symptomatic and eight asymptomatic) were PCR positive. Together these findings indicate a high frequency of transplacental transmission and no differences in the potential of transmission when symptomatic were compared to asymptomatic pregnant bitches.     

Short-Term Effects of Duodenocecostomy on Body Weight,Glucose Absorption,Serum Components,and Intestinal Histopathology in Four Normal Horses

The objective of this study was to evaluate duodenocecostomy in horses performed through a ventral midline laparotomy and report its influence on body weight, glucose absorption, serum components, and characteristics of jejunum, cecum, and large colon histology. Four horses were submitted to the duodenocecostomy technique through a ventral midline laparotomy with animals in dorsal recumbency under inhalation anesthesia, followed by abdominal exploration. A side-to-side anastomosis was performed between the duodenojejunal flexure and the base of the cecum with two simple continuous suture lines of the serosal and muscular layers. The size of the opening created was approximately 2 cm in diameter. The mucosa layer was not sutured. After 30 days, animals were submitted to a second laparotomy to check the patency of the duodenocaecal fistula. During both laparotomy procedures, excisional biopsies of different segments of the gastrointestinal tract were performed. Information on physical examination findings, results of hematologic and histopathologic evaluations, and oral glucose absorption test were recorded. The horses did not have significant weight loss from baseline, and absorption curve of glucose did not significantly vary from baseline. Only triglycerides had significant alterations. Histologic evaluation of jejunum, cecum, and large colon did not show alterations of intestinal structure and morphology. We concluded that the proposed technique, principally in relation to the fistula size and not suturing the mucosa layer, allowed partial or total occlusion of the fistulae without the necessity of a second surgery and avoided the permanent bypass of ingesta and weight loss.     

Cell proliferation and expression of connexins differ in melanotic and amelanotic canine oral melanomas

Melanoma is a malignant neoplasm occurring in several animal species, and is the most frequently found tumor in the oral cavity in dogs. Melanomas are classified into two types: melanotic and amelanotic. Prior research suggests that human amelanotic melanomas are more aggressive than their melanotic counterparts. This study evaluates the behavior of canine melanotic and amelanotic oral cavity melanomas and quantifies cell proliferation and the expression of connexins. Twenty-five melanomas (16 melanotic and 9 amelanotic) were collected from dogs during clinical procedures at the Veterinary Hospital of the School of Veterinary Medicine and Animal Science of the University of São Paulo, Brazil. After diagnosis, dogs were followed until death or euthanasia. Histopathology confirmed the gross melanotic or amelanotic characteristics and tumors were classified according to the WHO. HMB45 or Melan A immunostainings were performed to confirm the diagnosis of amelanotic melanomas. Cell proliferation was quantified both by counting mitotic figures and PCNA positive nuclei. Expressions of connexins 26 and 43 were evaluated by immunohistochemistry, qRT-PCR and Western blot. Dogs bearing amelanotic melanomas presented a shorter lifespan in comparison to those with melanotic melanomas. Cell proliferation was significantly higher in amelanotic melanomas. Expressions of Connexins 26 and 43 were significantly reduced in amelanotic melanomas. The results presented here suggest that oral cavity melanotic and amelanotic melanomas differ regarding their behavior, cell proliferation and connexin expression in dogs, indicating a higher aggressiveness of amelanotic variants.