Austral Journal of Veterinary Sciences
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Aquatic pollution from anthropogenic discharges modulates gene expression in liver of rainbow trout (Oncorhynchus mykiss)
Get PDFWith the aim to characterise the biological impact of anthropogenic discharge in a river, gene expression in fish was evaluated as a biomarker for mixture effects of potential toxic compounds in the aquatic environment. Adult male rainbow trout (Oncorhynchus mykiss) were used as monitoring organisms. Within the German experimental set up, trout were exposed actively for 28 days in biologically purified sewage as well as in river water up- and downstream of the sewage treatment plant (STP) effluent. In a different approach, wild trout were captured in southern Chile near anthropogenic discharges. Fish were taken from river Maullin receiving sewage from a settlement and from river Pescado influenced by effluents from a fish farm. In vivo effects were assessed by RT-qPCR analyses of biomarker gene expression, vitellogenin (vg), metallothionein (mt) and cytochrome 1A (cyp1A) in liver samples with primers amplifying specific sequences previously confirmed by cloning and sequencing. The modulation of expression of marker genes involved in metal stress, reproduction and detoxifying systems in the liver of male rainbow trout revealed organismal response to anthropogenic contamination in two different study areas, such as Chile and Germany, thereby indicating a potential risk on the aquatic ecosystems
Vaccination of nulliparous gilts against porcine epidemic diarrhoea can result in low neutralising antibody titres and high litter mortality
Get PDFPorcine epidemic diarrhoea (PED) is a disease caused by an alphacoronavirus and the symptoms include watery diarrhoea and vomiting, with more than 80% mortality amongst newborn piglets. The placentation in sows hinders the transference of antibodies to the foetus, therefore, the vaccination of pregnant females and transference of antibodies to piglets through colostrum are essential to protect them against virus particles. The aim of the study was to determine whether vaccination of nulliparous gilts could induce a high colostrum antibody titre and lower litter mortality, in comparison with vaccinated multiparous sows previously exposed to the virus. Samples of colostrum were obtained from 11 nulliparous gilts with two previous vaccinations (inactivated vaccine) and from 9 multiparous sows with three or more vaccinations (inactivated vaccine) that had been exposed to the virus. The IgG antibody titre was determined through anti-PED enzyme-linked immunosorbent assays (ELISA) and the neutralisation of antibodies was evaluated through plaque reduction neutralisation tests (PRNT). The colostrum of nulliparous gilts, when compared to the multiparous sows, presented a lower anti-PED IgG antibody titre as well as fewer neutralising antibodies. Furthermore, the piglets of multiparous sows experienced higher survival in comparison with those of nulliparous gilts (P<0.01), and mortality was dependent on the ‘farrowing’ variable (P<0.01). In conclusion, these results show that vaccinating nulliparous gilts does not increase the survival of their piglets in comparison with multiparous sows and that the IgG titres and neutralising antibodies are significantly lower in the former. These results suggest that a modified vaccine strategy is needed for nulliparous gilts to increase piglet protection
The magic number
Get PDFSince the novel of Douglas Adams, The Hitchhiker’s Guide to the Galaxy (1979), where the answer of a supercomputer to “the most important question”, including life and the universe, is the number 42, no one has been so attached to a single number as scientists.This is the purpose that we often assigned to P-values, an arbitrary threshold delimiting “statistical significance”. Recently, more than 800 scientists from 50 countries signed a letter requesting the withdrawal of all concepts of Statistical Significance1. The dichotomized discussion involves the terms statistically “significant” and “non-significant”, which depend on whether the P-value falls below or above this “magic” number, giving the idea that the items evaluated are categorically different.Unfortunately, the false belief that crossing the threshold of statistical significance is enough to show that a result is ‘real’ has led scientists and us (journal editors) to privilege such results, thereby distorting the literature. Some could argue that an arbitrary but clear limit is better than an unclear one. Additionally, if we do not use statistical significance, then what should we be doing instead? Whatever the discussion might lead to in the future, what seems relevant now is to educate ourselves about statistical misconceptions, but further, we should consider the logic, the background knowledge, and the experimental design along with P value to conclude.Austral Journal of Veterinary Sciences is not considering changing how it considers the statistical analysis in evaluation of papers at this time, but we are aware of this discussion in the scientific world since the conclusions will necessarily have an impact on what is currently considered suitable for publication.
Editorial CommitteeAustral Journal of Veterinary Science
Editorial
Get PDFThis is the second number of the “Austral Journal of Veterinary Sciences” formerly “Archivos de Medicina Veterinaria”. The name differs, but the aim of the Journal remains the same: “to divulgate the latest developments and discoveries in Veterinary Sciencesand to inform about advances in veterinary medicine among universities, research centers, industries, government agencies, biologists, agronomists and veterinarians”. Today, as always, we face many complexes challenges and we do our best to tackle them. In this editorial we would like to honor two veterinarians who reached the top on their specific fields: Peter Doherty, Nobel Prize winner in Physiology and Medicine in 1996, for his discoveries with Rolf M. Zinkernagel concerning the “specificity of the cell mediated immune defense” and Miguel Cerda, rowing world champion in lightweight men’s pair, Seville 2002. In an interview for nobelprize.org, Dr. Doherty, describes himself as “my characteristics as a scientist stem from a non-conformist upbringing, a sense of being something of an outsider, and looking for different perceptions in everything from novels, to art toexperimental results. I like complexity, and am delighted by the unexpected. Ideas interest me”. Dr. Cerda is an alumnus of Universidad Austral de Chile who practiced rowing most of his life, in parallel to his veterinary medicine studies. During his whole rowing career, he has experienced many values associated with the practice of rowing and also with the veterinary practice such as passion, will, perseverance, effort, and patience, all of which translate into a constant, progressive, fine, delicate, and endless work. The path of these two successful veterinarians towards the top in their own fields differs but there is something they had in common, they had to face many difficulties and failures but that never stopped them. It was only preparation for the challenges ahead. The same spirit flows in our journal from the beginning of “Archivos de Medicina Veterinaria” and we expect that it will flow forever in “Austral Journal of Veterinary Sciences”
Methane production: Where should we focus our attention?
Get PDFThe UN recently called for reducing meat consumption due to its contribution to global warming. However, from my perspective as a researcher, the role of livestock greenhouse gas emissions is often exaggerated.The annual reports of greenhouse gas (GHG) emissions from the EU1 and the USA2 reveal that the contribution of agriculture, particularly the livestock sector, is of little relevance compared to that of other industries. Thus, focusing attention and efforts to decrease emissions in those sectors would have a greater influence on GHG than the reduction of meat consumption.The May 2019 EU report indicates that 4,330 tons of CO2 equivalent were emitted in 2017, almost 80% of which were from the energy industry and only 10% (440ton) were from agriculture. Of those 440 tons, less than 40% corresponds to enteric fermentation methane. Furthermore, all GHG producing sectors have decreased their production of CO2 equivalent since 1990, except for transportation and air conditioning, which together have increased by more than 260 tons in the same period. The equivalent CO2 production of cattle in Europe was 190 tons and has decreased by 50 tons in 27 years. Transport, on the other hand, produces 880 tons of CO2 equivalent (2017) and in the same 27 years has increased its production by 180 ton, which is roughly equivalent to emission from cattle in 2017.The numbers are similar for the United States, however, GHG production has not decreased since 1990. Total GHG emissions in the USA in 2017 were 5700 tons of CO2 equivalent and, at 5400 tons of CO2 equivalent, the energy sector was the greatest contributor. Agriculture emitted 540 tons of CO2 equivalent, which represents 8.4% of the total production. Enteric fermentation by cattle was 175 tons. In contrast, from 1990-2017, fossil fuel combustion increased from 4740 tons to 4910 tons (170 tons), which is almost equivalent to all enteric fermentation. Although animal scientists should continue to search for ways to reduce GHG emissions, the facts prompt the question, where should we really focus our attention
Detection of antimicrobial resistant Salmonella enterica strains in samples of ground hedgehogs (Atelerix albiventris) reared as pets in the urban area of Santiago, Chile
Get PDFThe breeding of exotic pets has become a popular practice in Chile and, within this group of animals, small mammals such as guinea pigs and hedgehogs have gained importance due to their docile behaviour. The most common exotic hedgehog species in Chile is the African pygmy hedgehog (Atelerix albiventris). It has been reported that these pets are reservoirs of some zoonotic pathogens, among which Salmonella enterica constitutes an important threat for the owners. This study aimed to detect the presence of Salmonella strains in faeces from hedgehogs (Atelerix albiventris) admitted to a veterinary clinic in Santiago, Chile, and to characterise the antimicrobial susceptibility of the isolated strains. From 200 animals sampled, S. enterica was detected in 5 hedgehogs, corresponding to serotypes Muenchen (2), Infantis (2) and IV43:z4,z23:- (1). Furthermore, phenotypic antimicrobial resistance was determined in all subsp. enterica isolates. These results suggest that in Chile these exotic pets constitute a potential hazard for public health, therefore, supporting educational campaigns about basic biosecurity measures is necessary, mostly aimed at pet owners and risk groups
In search of a combined brucellosis and tuberculosis vaccine for cattle
Get PDFBovine brucellosis is caused by Brucella abortus. The bacterial pathogen causes economic losses because it induces abortion in cattle. Vaccination of calves with live B. abortus strain 19 induces a certain level of protection but induces persistent antibodies against cell envelope lipopolysaccharide that make it difficult to Distinguish Infected from Vaccinated Animals (DIVA). Live vaccine B. abortus strain RB51 was developed to eliminate such interfering antibodies and therefore, facilitate the differentiation of infected from vaccinated animals and help in the eradication of the disease. Vaccination with strain RB51 induces levels of protection similar to strain 19 but neither of the two vaccines give complete protection. We have been working to enhance protection induced by strain RB51 vaccine. Protective Brucella antigens can be over-expressed in strain RB51 by introducing a plasmid containing the leuB gene and the genes encoding such antigens. To avoid the expression of antibiotic resistance genes, we produced a leuB deficient strain RB51 and introduced a plasmid containing the leuB gene and the genes to be over-expressed. This new strain maintains the plasmid and has induced significantly high protection levels in mice. In addition, it allowed the construction of an RB51 vaccine strain able to express Mycobacterium bovis protective antigens so that the vaccine could protect against brucellosis and tuberculosis simultaneously
Equine strangles: An update on disease control and prevention
Get PDFStreptococcus equi spp. equi (SEE) causes a disease in horses commonly referred to as strangles. Carrier or reservoir equids are important for the maintenance of the bacteria between epizootics and the initiation of outbreaks on premises, they also make the control and prevention of the disease more difficult. Disease outbreaks are common in many countries, affecting negatively equine health and causing major economic losses to the equine industry. This review describes general aspects of the disease caused by SEE in horses (clinical signs, pathogenesis, epidemiology, treatment, complications) and then focuses on prevention, control and eradication mechanisms
