Veterinary and Agricultural Sciences Collected Works - Research Publications
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ItemShort-term heat stress and vitamin E supplementation affect carcass weight, mucle omega-6 fatty acid and meat quality in lambs(Elsevier, 2016)The effect of short term-heat stress and -vitamin E supplementation on carcass traits and muscle quality – vitamin E, nutritional value and retail colour of lambs was investigated. Forty-eight lambs (crossbred; 42 ± 2 kg body weight, 7 mo age) were randomly allocated by body weight to one of three groups (n = 16) and fed 3 different doses of Vitamin E and Se. The doses of Vitamin E and Se for control (CON), moderate (MOD), and supranutritional (SUP) diets were 28, 130, 228 mg/kg DM as α-tocopherol acetate and 0.16, 0.66, 1.16 mg Se as SelPlex™ kg/DM, respectively. Lambs were fed for 4 weeks followed by a week of exposure to heat treatment. After 4 weeks feeding in individual pens, including 1 week of adaptation, lambs were moved to metabolism cages for 1 week and allocated to one of 2 heat regimes (8 per feeding group): thermoneutral (TN) (18–21◦C and 40–50% relative humidity) or heat stress (HS) (28–40◦C and 30–40% relative humidity) conditions. Final body weight (P = 0.05, 44.1 vs 46.6 kg) and hot carcass weight (P = 0.01, 21.1 vs 22.5 kg) were significantly affected by diet such that lambs supplemented with SUP levels of antioxidants had a higher FBW and HCW as compared with lambs fed MOD and CON antioxidant diets, respectively. Vitamin E concentration in the longissimus lumborum (LL) muscle tended to be higher in lambs fed moderate or supranutritional levels of antioxidants compared with control lambs and values from all treatments were below the threshold (3.2 mg/kg muscle) for optimal maintenance of retail colour. Vitamin E supplementation also reduced lipid oxidation of aged meat, as assessed by thiobarbituric acid reactive substances (TBARS) formation after 72 h of display. One week of heat stress to lambs significantly increased muscle linoleic acid concentration, which in turn increased total n-6 concentration compared with the control group. Results demonstrate that 4 weeks of vitamin E supplementation or 1 week heat stress might not have been adequate to make significant changes in muscle vitamin E concentration and fatty acid composition, which in turn can influence retail colour stability of meat.
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ItemAMP is a more potent activator of phosphofructokinase-1 activity than fructose 2,6-bisphospate in porcine skeletal muscle under simulated postmortem conditions(Wageningen Academic Publishers, 2017)Phosphofructokinase-1 (PFK-1) is a key regulatory enzyme of postmortem glycolysis. PFK-1’s activity is regulated antemortem by a number of compounds including adenosine monophosphate (AMP) and fructose 2,6-bisphosphate (F-2,6-BP). However, PFK-1’s postmortem regulation by AMP and F-2,6-BP is still unclear. Therefore, a study was conducted where porcine longissimus lumborum samples were collected to determine PFK-1 activity as affected by various concentrations of AMP and F-2,6-BP at buffered pH. Both compounds increased PFK-1 activity. However, at physiological concentrations, 50 and 150 μM AMP increased PFK-1 activity compared to 1 and 2 μM F-2,6-BP. Thus, AMP may play a greater role in dictating the rate and extent of postmortem glycolysis and pH decline than F-2,6-BP.
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ItemImpacts Of Heat Stress On Retail Meat Quality Of 2ND Cross And Dorper Lambs(ICoMST 2019, 2019)
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ItemIntestinal Small Cell Lymphoma: Are Dogs Big Cats?(ACVIM, 2019-06-08)Previously T-cell lymphomas of the gastrointestinal tract in human were classified as enteropathy-associated T-cell lymphoma (EATL) type I and type II. Type I is associated with celiac disease and characterized by large lymphocytes, whereas type II is not associated to enteropathies and characterized by small lymphocytes. In view of these differences, the nomenclature has been changed and EATL currently refers only to type I and type II has been renamed monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL).1 EATL has an aggressive clinical course and tumor cells most commonly have an αβ T-cell receptor phenotype. In comparison MEITL tumour cells express CD8, CD56, and megakaryocyte-associated tyrosine kinase. T-cell lymphoproliferative disorder (TLPD) is another type of small cell lymphoma described in the intestinal tract. This lymphoma has typically an indolent clinical course and commonly express CD8 and is negative for CD4 and CD56, Markers of T-cell lymphomas of the gastrointestinal tract have been much less extensively studied in cats and dogs and for this reason for the purpose of this lecture small cell lymphoma (SCL) will be used for neoplastic cells with nuclei smaller than 2 red blood cells in diameter and large cell lymphoma (LCL) for larger neoplastic cells. SCL characterized by infiltration of the intestinal mucosa by mature T-cells with variable epitheliotropism has been described for more than 10 years in cats. SCL has better outcome than other types of lymphoma in this species, with median survival times over 1.5 years.3 Although criteria have been described in cats to diagnose SCL, these are not as well defined in dogs. However, several recent studies support that SCL is also present in dogs and the clinical findings and outcome will be described in this presentation.
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ItemMetabolic profiling of cytotoxic steroidal saponins in five Australian Panicum species(ISOPP, 2018-09-18)Up to 500 species of Panicum (panic grasses) are recognised worldwide, of which 24 species are indigenous to Australia and nine introduced. Recently, some of the introduced summer-growing annual Panicum spp. have been identified with high prevalence across southern Australia. Certain Panicum species have also been implicated in severe outbreaks of hepatogenous photosensitization in livestock, characterized by crystal-associated cholangiohepatopathy. The causal compound(s) responsible for liver dysfunction in livestock ingesting Panicum spp. have been previously identified as steroidal saponins. Although metabolic profiling of Panicum spp. has been undertaken in the USA and NZ, the saponins implicated in toxic outbreaks in Australia have not yet been identified. In this study, fresh shoot tissue from three introduced (P. capillare,P. hillmanii and P. gilvum) and two native (P. decompositumand P. effusum) species were extracted in methanol and analysed by UPLC/QTOF mass spectrometry. The relative abundance of key steroidal saponins was determined based on specific molecular features including retention time, mass spectra and fragmentation pattern when compared to saponin analytical standards. Distinct qualitative and quantitative differences were observed in the saponin profiles of the Panicum species evaluated, including in the type, number and abundance of the saponins detected, such as protodioscin and pseudoprotodioscin.. In vitro cytotoxicity assays of shoot extracts collected from Panicumrelated photosensitization outbreaks will be performed to further identify key steroidal saponins and saponin profiles associated with hepatogenous photosensitization in grazing livestock.
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ItemIdentification of eight Panicum species in Riverina region of NSW using DNA sequence analysisDNA sequence analysis(Council of the Australasian Weed Societies/ The Weed Society of New South Wales Inc., 2018-09-12)Australia has over 30 Panicum spp. (panic grass) including several non-native species that cause crop and pasture loss due to competition. To develop appropriate management strategies for each species, it is critical to correctly identify panic grass species encountered. Currently, panic grass identification relies on microscopic examination of the inflorescence and spikelets, an approach that is only useful for flowering specimens and requires significant taxonomic expertise. To overcome this limitation, we applied both morphological and molecular techniques for identification of Panicum spp. in the Riverina region of New South Wales. We identified three molecular markers: one nuclear gene region (ITS) and two chloroplast gene regions (matK and trnL intron-trnF) capable of differentiating eight Panicum spp. Concatenation of sequences from ITS, matK and trnL intron-trnF gene regions provided clear separation of eight species collected regionally and identified a maximum intraspecific distance of 0.22% and minimum interspecific distance of 0.33%. Based on comparison with verified voucher specimens, P. hillmanii Chase was prevalent and constituted 78.9% of all samples collected and identified. DNA barcoding represents an accurate and potentially cost effective tool for distinguishing Panicum spp. at the species level regardless of growth stage. Molecular markers may also be useful for accurate demographic analysis of Panicum grass invasion in Australia and abroad. http://caws.org.nz/old-site/awc_contents.php?yr=2018#v_p125
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ItemMaking “middle managers”: workforce development for agricultural industries in transition(International Farming Systems Association, 2018)The availability of suitably skilled people is being increasingly recognised as a critical element for success in agriculture, yet this can be challenging to achieve. The perennial fruit industry in Australia’s Goulburn-Murray region is an example of this. In 2015, employers in this industry identified a shortage of people for ‘middle management’ roles as a particular current concern. This paper outlines the findings of a scoping study focused on developing a better understanding of the issues affecting the ability of fruit growers in this region to attract, retain and develop appropriately skilled ‘middle managers’. The study was informed by a ‘systemic’ approach to workforce development, according to which the availability of suitably-skilled workers arises from the dynamic interactions of elements in the workforce system. Based on structured interviews with the managers of twenty fruit growing businesses, we developed a typology of four typical workforce structures that are found in businesses of different sizes, including identification of the most common job titles and typical duties for these jobs. We discuss the approaches that employers used to recruit workers, including both internal and external recruitment pathways. The findings of this study allow us to begin identifying the range of entry points to jobs, and the career progression pathways, that currently exist for workers in the perennial fruit industry, and to identify opportunities for industry collective action to address current workforce challenges. As employed workers come to play increasingly important roles in family farm businesses, systemic understandings of workforce development will become increasingly important within the field of farming systems research.
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ItemChronic enteropathy: Faecal microbiota transplant or antibiotic trial?(Australian Institute of Professional Intelligence Officers,, 2018-07-06)
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ItemOptimization of immunotherapy(Australian and New Zealand College Of Veterinary Scientists Small Animal Chapter, 2018-07-05)
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ItemImmune suppressive drugs: Do we need more than prednisolone?(Australian Veterinary Association, 2018-05-14)