Veterinary Science Collected Works - Research Publications

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    Insights into physiological roles of unique metabolites released from Plasmodium-infected RBCs and their potential as clinical biomarkers for malaria
    Beri, D ; Ramdani, G ; Balan, B ; Gadara, D ; Poojary, M ; Momeux, L ; Tatu, U ; Langsley, G (NATURE PUBLISHING GROUP, 2019-02-27)
    Plasmodium sp. are obligate intracellular parasites that derive most of their nutrients from their host meaning the metabolic circuitry of both are intricately linked. We employed untargeted, global mass spectrometry to identify metabolites present in the culture supernatants of P. falciparum-infected red blood cells synchronized at ring, trophozoite and schizont developmental stages. This revealed a temporal regulation in release of a distinct set of metabolites compared with supernatants of non-infected red blood cells. Of the distinct metabolites we identified pipecolic acid to be abundantly present in parasite lysate, infected red blood cells and infected culture supernatant. Further, we performed targeted metabolomics to quantify pipecolic acid concentrations in both the supernatants of red blood cells infected with P. falciparum, as well as in the plasma and infected RBCs of P. berghei-infected mice. Measurable and significant hyperpipecolatemia suggest that pipecolic acid has the potential to be a diagnostic marker for malaria.
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    Digesta passage and nutrient digestibility in Boran steers at low feed intake levels.
    Ali, AIM ; Wassie, SE ; Korir, D ; Goopy, JP ; Merbold, L ; Butterbach-Bahl, K ; Dickhoefer, U ; Schlecht, E (Wiley, 2019-09)
    The present study evaluated the effects of energetic undernutrition on liquid and solid digesta passage and on nutrient digestibility as well as their interdependencies. Using a 4 x 4 Latin square design, 12 growing Boran steers (183 ± 15.2 kg live weight) were allocated to four levels of metabolizable energy (ME) supply fixed at 100, 80, 60 and 40% of individual maintenance energy requirements (MER) during four experimental periods. Each period comprised three weeks of adaptation, two weeks of data collection and two weeks of recovery. Diets MER80, MER60 and MER40 only consisted of Rhodes grass hay (RGH), whereas diet MER100 contained (as fed) 83% RGH, 8% cotton seed meal and 9% sugarcane molasses. Feed intake differed between treatments (p < .001) and ranged from 40 ± 0.6 g dry matter (DM) per kg of metabolic weight (kg0.75 ) in MER40 to 81 ± 1.3 g DM in MER100. Digestibility of neutral and acid detergent fibre (NDF, ADF) was highest at MER80, whereas rumen retention time of liquid and solid digesta was longest at MER40. The correlation of rumen retention time of liquid and solid digesta with the digestibility of proximate diet components was weak but positive, whereas the correlation of liquid and solid rumen retention time with quantitative feed and nutrient intake was strong (p < .01) and negative. Our results suggest that tropical cattle are able to buffer a moderate energy deficit by prolonging rumen retention time of digesta and hence improve diet digestibility. Conversely, a severe energy deficit cannot be buffered by digestive adaptation mechanisms and will inevitably lead to productivity losses.
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    A modified approach to recover and enumerate Ascaris ova in wastewater and sludge
    Ravindran, VB ; Surapaneni, A ; Crosbie, ND ; Schmidt, J ; Shahsavari, E ; Haleyur, N ; Soni, SK ; Ball, AS ; Morassutti, A (PUBLIC LIBRARY SCIENCE, 2019-02)
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    Editorial: Working Dogs: Form and Function
    Otto, CM ; Cobb, ML ; Wilsson, E (FRONTIERS MEDIA SA, 2019-10-18)
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    Supplementing Tropical Cattle for Improved Nutrient Utilization and Reduced Enteric Methane Emissions.
    Ali, AIM ; Wassie, SE ; Korir, D ; Merbold, L ; Goopy, JP ; Butterbach-Bahl, K ; Dickhoefer, U ; Schlecht, E (MDPI AG, 2019-04-30)
    Given their high nitrogen (N) concentration and low costs, sweet potato vine silage (SPVS) and urea-molasses blocks (UMB) are recommended supplements for tropical regions; therefore, they were investigated in this study. Six heifers were allocated to three diets: the roughage diet (R) consisted of wheat straw (0.61) and Rhodes grass hay (0.39; on dry matter (DM) basis); R + SPVS combined R (0.81) and SPVS (0.19); and with R + UMB animals had access to UMB. During two experimental periods, feed intake, feces and urine excretion, digesta passage, and rumen microbial protein synthesis were determined during seven days and methane emissions during three days. There was no treatment effect (p > 0.05) on DM and N intake. Apparent DM digestibility of R + SPVS (510 g/kg) was higher (p < 0.05) than of R (474 g/kg). Digesta passage and duodenal microbial N flow were similar for all diets (p > 0.05), while N retention was highest with R + SPVS (p > 0.05). Methane emissions per unit of digested feed (g CH4/kg dDM) were lower (p < 0.05) for R + SPVS (55.2) than for R (64.7). Hence, SPVS supplementation to poor-quality roughage has the potential to increase diet digestibility and N retention while reducing CH4 emissions.
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    Are We Objective? A Study into the Effectiveness of Risk Measurement in the Water Industry
    Kosovac, A ; Davidson, B ; Malano, H (MDPI, 2019-03-01)
    A survey of 77 water practitioners within Melbourne, Australia, highlighted the lack of objectiveness within current risk scoring processes. Each water authority adopted similar processes, all of which adhere to the ISO31000 standard on Risk Management, and these were tested within this study to determine the “objective” nature of technical risk assessments such as these. The outcome of the study indicated that current risk measurement approaches cannot be seen as objective. This is due to the high variation in risk scores between individuals, which indicates a level of subjectivity. The study confirms previous research that has been undertaken in assessing the effectiveness of risk matrices. This research is novel in its testing of the water sector’s risk measuring practices and may be of value to other industries that utilize similar risk approaches. This research posits whether this subjectivity is due to inherent bias of either a psychological or cultural risk nature that could produce the varied scores.
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    Survival Mechanisms of Campylobacter hepaticus Identified by Genomic Analysis and Comparative Transcriptomic Analysis of in vivo and in vitro Derived Bacteria
    Thi, THV ; Lacey, JA ; Vezina, B ; Phung, C ; Anwar, A ; Scott, PC ; Moore, RJ (FRONTIERS MEDIA SA, 2019-02-05)
    Chickens infected with Campylobacter jejuni or Campylobacter coli are largely asymptomatic, however, infection with the closely related species, Campylobacter hepaticus, can result in Spotty Liver Disease (SLD). C. hepaticus has been detected in the liver, bile, small intestine and caecum of SLD affected chickens. The survival and colonization mechanisms that C. hepaticus uses to colonize chickens remain unknown. In this study, we compared the genome sequences of 14 newly sequenced Australian isolates of C. hepaticus, isolates from outbreaks in the United Kingdom, and reference strains of C. jejuni and C. coli, with the aim of identifying virulence genes associated with SLD. We also carried out global comparative transcriptomic analysis between C. hepaticus recovered from the bile of SLD infected chickens and C. hepaticus grown in vitro. This revealed how the bacteria adapt to proliferate in the challenging host environment in which they are found. Additionally, biochemical experiments confirmed some in silico metabolic predictions. We found that, unlike other Campylobacter sp., C. hepaticus encodes glucose and polyhydroxybutyrate metabolism pathways. This study demonstrated the metabolic plasticity of C. hepaticus, which may contribute to survival in the competitive, nutrient and energy-limited environment of the chicken. Transcriptomic analysis indicated that gene clusters associated with glucose utilization, stress response, hydrogen metabolism, and sialic acid modification may play an important role in the pathogenicity of C. hepaticus. An understanding of the survival and virulence mechanisms that C. hepaticus uses will help to direct the development of effective intervention methods to protect birds from the debilitating effects of SLD.
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    Strategies to increase adoption of animal vaccines by smallholder farmers with focus on neglected diseases and marginalized populations
    Donadeu, M ; Nwankpa, N ; Abela-Ridder, B ; Dungu, B ; Rupprecht, CE (Public Library of Science, 2019-02-07)
    Background Most smallholder farmers (SHFs) and marginalized populations (MPs) in Africa, Asia, and Latin America depend on livestock for their livelihoods. However, significant numbers of these animals do not achieve their potential, die due to disease, or transmit zoonotic diseases. Existing vaccines could prevent and control some of these diseases, but frequently the vaccines do not reach SHFs, especially MPs, making it necessary for specific vaccine adoption strategies. Principal findings Several strategies that have the potential to increase the adoption of animal vaccines by SHFs and MPs have been identified depending on the type of vaccines involved. The strategies differed depending on whether the vaccines were aimed at diseases that cause economic losses, government-controlled diseases, or neglected diseases. The adoption of vaccines for neglected diseases presents a major challenge, because they are mostly for zoonotic diseases that produce few or no clinical signs in the animals, making it more difficult for the farmers to appreciate the value of the vaccines. Strategies can be aimed at increasing the availability of quality vaccines, so that they are produced in sufficient quantity, or aimed at increasing access and demand by SHFs and/or MPs. Some of the strategies to increase vaccine adoption might not provide a definite solution but might facilitate vaccine uptake by decreasing barriers. These strategies are varied and include technical considerations, policy components, involvement by the private sector (local and international), and innovation. Conclusions Several strategies with the potential to reduce livestock morbidity and mortality, or prevent zoonoses in SHFs communities and MPs through vaccination, require the involvement of donors and international organisations to stimulate and facilitate sustainable adoption. This is especially the case for neglected zoonotic diseases. Support for national and regional vaccine manufacturers is also required, especially for vaccines against diseases of interest only in the developing world and public goods.
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    Faecalibacterium diversity in dairy cow milk.
    Savin, KW ; Zawadzki, J ; Auldist, MJ ; Wang, J ; Ram, D ; Rochfort, S ; Cocks, BG ; Staley, C (Public Library of Science (PLoS), 2019-08-16)
    The bacterial species, Faecalibacterium prausnitzii, beneficial to humans and animals and found in mammalian and avian gut, is also occasionally found in dairy cow milk. It is one of the butyrate-producing bacteria of the colon, has anti-inflammatory properties and its abundance in the gut is negatively correlated with obesity in humans. Several strains differing in their functional capability, have been identified. It is important therefore, milk being a potential source of F. prausnitzii as a novel probiotic, to investigate the diversity of this species in bovine milk. Using 16s rRNA gene amplicons we find 292 different dereplicated Faecalibacterium-related amplicons in a herd of 21 dairy cows. The distribution of the 20 most abundant amplicons with >97% identity to a Greengenes OTU varies from cow to cow. Clustering of the 292 pooled sequences from all cows at 99.6% identity finds 4 likely Faecalibacterium phylotypes with >98.5% identity to an F. prausnitzii reference sequence. Sequence alignment and phylogenetic analysis shows these phylotypes are distinct from 34 other species from the Ruminococcaceae family and displaying the sequence clusters as a network illustrates how each cluster is composed of sequences from multiple cows. We conclude there are several phylotypes of Faecalibacterium prausnitzii (the only species so far defined for the genus) in this dairy herd with cows being inoculated with a mixture of several strains from a common source. We conclude that not only can Faecalibacterium be detected in dairy cow milk (as noted by others) but that there exist multiple different strains in the milk of a dairy herd. Therefore milk, as an alternative to faeces, offers the opportunity of discovering new strains with potential probiotic application.
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    Perceptions of Responsible Cat Ownership Behaviors among a Convenience Sample of Australians
    Elliott, A ; Howell, TJ ; McLeod, EM ; Bennett, PC (MDPI, 2019-09)
    Responsible cat ownership is important for keeping pet cats and wildlife safe. Much research investigating levels of compliance with and attitudes towards responsible cat ownership practices has focused on cat owners. Non-owner attitudes are relevant because their opinions may encourage cat-owning friends and family to engage (or not) in a cat management practice. The aim of this study was to determine levels of compliance with responsible cat ownership practices among cat owners, as well as attitudes towards those behaviors by owners and non-owners alike. An online survey was completed by 6808 people living in Australia who were recruited via companion animal or wildlife interest groups on social media. Frequency data were used to measure owner compliance with responsible cat ownership behaviors and t-tests were used to determine whether owners and non-owners differed in their attitudes towards these behaviors. Owner compliance with responsible practices ranged from 46.5% (complete cat containment all day and night) to 76.9% (cat is de-sexed). Owner attitudes towards these practices were generally more positive than the reported levels of management practices implemented for their own cat. For example, 47.3% of owners agreed or strongly agreed that cats should always be contained and 88.6% agreed that cats should be contained at night. Non-owners were more likely than owners to agree that cats should be contained during the day, but there was no difference for containment at night. Owners were more likely to report that cats should be de-sexed. These results can be used to inform campaigns aimed at increasing compliance with responsible cat ownership behaviors.