Effects of vaccination against brucellosis and clostridia on the intake, performance, feeding behavior, blood parameters, and immune responses of dairy heifers calves.

The aim of this study was to identify possible effects of different vaccination strategies (concomitantly or not) against brucellosis and clostridia on intake, performance, feeding behavior, blood parameters, and immune responses of dairy heifers calves. Fifty heifers calves were enrolled [38 Gyr (Zebu, Bos taurus indicus) and 12 5/8 Holstein × Gyr]. At 120 d of age, animals were randomly distributed among 3 groups: B (n = 18), vaccinated against brucellosis; C (n = 14), vaccinated against clostridia and CB (n = 18), vaccinated concomitantly for both. Rectal and thermographic temperatures were evaluated on days -1, 0, 1, 2, 3, 5, 7,10, 14, and 28 relatives to the vaccination day. Feed and water intake, body weight (BW), and feeding behavior were monitored daily by an electronic feeding system. Blood was sampled on days 0, 3, 7, 14, and 28, relative to the vaccination day for determination of glucose and ß -hydroxybutyrate (BHBA) concentrations. Blood sampled on day 0 (prevaccination) and on days 28 and 42 were used to evaluate the immune response against Brucella abortus and clostridia. There was an increase in rectal temperature between the first and the third day postvaccination in the 3 groups. The thermography revealed an increase of local temperature for 7 d on groups B and CB. Group C had increased local temperature for a longer period, lasting for up to 14 d. Dry mater intake was reduced for groups B and CB, but no alteration was observed for group C. No alterations regarding initial BW, final BW, average daily weight gain, and feed efficiency were observed. No differences were observed for the 3 vaccination groups for blood parameters throughout the evaluation period. The concomitant vaccination against brucellosis and clostridia led to lower neutralizing antibody titers against epsilon toxin of Clostridium perfringens and botulinum toxin type C of C. botulinum (C > CB > B). When cellular proliferation assay and serological tests to B. abortus were evaluated, no differences were observed between groups B and CB. The present results indicate that the concomitant vaccination against brucellosis and clostridia has no relevant impact on the intake, performance, and feeding behavior of dairy calves. However, the concomitant vaccination of vaccines against these 2 pathogens impacts animal immunity against clostridial infections.

Necrohemorrhagic enteritis outbreak in a cattle feedlot in Nova Crixás, Goiás, Brazil / Surto de enterite necro-hemorrágica em um confinamento de bovinos no município de Nova Crixás, Goiás, Brasil

This study described an outbreak of necrohemorrhagic enteritis in a beef cattle feedlot in Nova Crixás, State of Goiás, Brazil, with emphasis on epidemiological, lesional, and laboratory aspects. Visits to the property were carried out and a necroscopic examination was performed on the bovine cadavers (N=57), which presented similar macroscopic alterations. Epidemiological data were collected, mainly referring to the feeding management of animals, and tissue samples were submitted to histopathological examination. Samples of feces and intestinal contents were also collected for bacterial isolation and PCR genotyping to detect the etiological agent, being confirmed Clostridium perfringens type A strains in 100% of the samples. Furthermore, 33.3% of strains isolated from intestinal contents and 40% of those isolated from feces were positive for beta-2 encoding gene. Considering the history, macroscopic and microscopic findings, as well as bacterial isolation and PCR, the diagnosis of bovine necrohemorrhagic enteritis was determined.(AU)

Descreve-se um surto de enterite necro-hemorrágica em um confinamento de bovinos de corte no município de Nova Crixás, Estado de Goiás, Brasil, com ênfase nos aspectos epidemiológicos, lesionais e laboratoriais. Foram realizadas visitas à propriedade e todos os cadáveres bovinos (N=57) foram submetidos ao exame necroscópico, os quais apresentaram alterações macroscópicas semelhantes. Foram compilados dados epidemiológicos, sobretudo referentes ao manejo alimentar dos animais e amostras de tecido foram submetidas a exame histopatológico. Foram colhidas, também, amostras de fezes e conteúdo intestinal para isolamento bacteriano e genotipagem por PCR para detecção do agente etiológico, sendo confirmadas estirpes de Clostridium perfringens tipo A em 100% das amostras. Ainda, 33,3% das cepas de Clostridium perfringens isoladas no conteúdo intestinal e 40% daquelas isoladas nas fezes foram positivas para o gene codificador da toxina beta-2. Considerando o histórico, os achados macroscópicos e microscópicos, o isolamento bacteriano e o PCR, foi estabelecido o diagnóstico de enterite necro-hemorrágica por C. perfringens tipo A.(AU)

Mucoadhesive chitosan films as a potential ocular delivery system for ofloxacin: preliminary in vitro studies.

OBJECTIVE: The objective of the study is to evaluate the physical properties, in vitro release profile, and antibacterial efficiency of chitosan films prepared with ofloxacin. PROCEDURE: Mucoadhesive films were prepared by means of a casting and solvent evaporation technique performed in a 2 wt% acetic acid solution and distilled water. Physical properties were characterized by release and swelling studies, differential scanning calorimetry (DSC) analysis, and attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR) analysis. The in vitro evaluation of the films was performed by inhibiting Staphylococcus aureus and Pseudomonas aeruginosa through activity studies. RESULTS: Circular ofloxacin-loaded chitosan-developed films with 0.3 mg of drug weighed 7 mg were 110 µm thick and 5 mm in diameter. The DSC curve of ofloxacin-loaded chitosan films suggests an amorphous dispersion of ofloxacin within these films. ATR-FTIR analysis showed that ofloxacin is indeed present in the matrix film. The drug was released in vitro over a 1-h period. No statistical difference could be observed between the ofloxacin-loaded chitosan films and sterile disk soaked for 1 min in 0.3% commercial ofloxacin ophthalmic solution for S. aureus and P. aeruginosa (P = 0.1686, P = 0.1172, respectively).The films presented a significantly larger mean bacterial inhibition zone of S. aureus than did the commercial ciprofloxacin control disk (P = 0.0002) and a significantly larger mean bacterial kill zone of P. aeruginosa than did the commercial enrofloxacin control disk (P < 0.0001). CONCLUSIONS: Ofloxacin was successively incorporated onto chitosan films and was not inactivated during the process of manufacturing, thus preserving antibacterial proprieties.

Production and evaluation of a recombinant chimeric vaccine against clostridium botulinum neurotoxin types C and D.

Bovine botulism is a fatal disease that is caused by botulinum neurotoxins (BoNTs) produced by Clostridium botulinum serotypes C and D and that causes great economic losses, with nearly 100% lethality during outbreaks. It has also been considered a potential source of human food-borne illness in many countries. Vaccination has been reported to be the most effective way to control bovine botulism. However, the commercially available toxoid-based vaccines are difficult and hazardous to produce. Neutralizing antibodies targeted against the C-terminal fragment of the BoNT heavy chain (HC) are known to confer efficient protection against lethal doses of BoNTs. In this study, a novel recombinant chimera, consisting of Escherichia coli heat-labile enterotoxin B subunit (LTB), a strong adjuvant of the humoral immune response, fused to the HC of BoNT serotypes C and D, was produced in E. coli. Mice vaccinated with the chimera containing LTB and an equivalent molar ratio of the chimera without LTB plus aluminum hydroxide (Al(OH)3) developed 2 IU/mL of antitoxins for both serotypes. Guinea pigs immunized with the recombinant chimera with LTB plus Al(OH)3 developed a protective immune response against both BoNT/C (5 IU/mL) and BoNT/D (10 IU/mL), as determined by a mouse neutralization bioassay with pooled sera. The results achieved with guinea pig sera fulfilled the requirements of commercial vaccines for prevention of botulism, as determined by the Brazilian Ministry of Agriculture, Livestock and Food, Supply. The presence of LTB was essential for the development of a strong humoral immune response, as it acted in synergism with Al(OH)3. Thus, the vaccine described in this study is a strong candidate for the control of botulism in cattle.

Viabilidade de Tritrichomonas foetus após congelamento com diferentes crioprotetores / Viability of Tritrichomonas foetus after freezing with diferents cryoprotectors

Este trabalho teve como objetivo avaliar a viabilidade de um isolado de Tritrichomonas foetus criopreservada com glicerol e dimetilsulfóxido (DMSO) a -196ºC. Isolados do protozoário foram descongeladas dois dias após o congelamento e 6, 12, 18 e 26 meses, para avaliação de sua viabilidade. Em todos os tempos analisados, o congelamento foi viável em 60 por cento e 90 por cento das amostras congeladas com glicerol a 10 por cento e DMSO a 12 por cento, respectivamente.

The aim of this work was to evaluate the viabilitity of Tritrichomonas foetus cryopreservated with glycerol and dimethilsulphosyde (DMSO) at -196ºC. Samples of the protozoa were thaw two days and 6, 12, 18, and 26 months after freezing to be evaluated. In the time analyzed, the freezing was viable in 60 percent and 90 percent of freeze samples with glycerol at 10 percent and DMSO at 12 percent, respectively.

[Viability of Tritrichomonas foetus after freezing with diferents cryoprotectors]. / Viabilidade de Tritrichomonas foetus após congelamento com diferentes crioprotetores.

The aim of this work was to evaluate the viabilitity of Tritrichomonas foetus cryopreservated with glycerol and dimethilsulphosyde (DMSO) at -196 degrees C. Samples of the protozoa were thaw two days and 6, 12, 18, and 26 months after freezing to be evaluated. In the time analyzed, the freezing was viable in 60% and 90% of freeze samples with glycerol at 10% and DMSO at 12%, respectively.