Investigating in vitro biohydrogenation of rumen-protected long chain n-3 fatty acids to assess suitability for use as supplements for dairy cows
Department: Animal Dairy & Food Chain Sciences
Supervised by: Dr Kirsty Kliem
Supplementary feeding of oils high in polyunsaturated fatty acids (PUFA) to dairy cows decreases milk saturated fatty acid (SFA) content, but transfer of these dietary PUFA to milk is poor due to the action of rumen microorganisms, which change PUFA structure. For optimal transfer efficiency rumen protection technology of the oil is required, but protection effectiveness can vary immensely in commercially available supplements. Recently, there has been interest in assessing the effect of such supplements on cow health in addition to milk quality. Directly post-calving cows are in a state of heightened inflammation which can contribute to increased disease incidence. Inflammatory mediators can be altered by circulating PUFA (n-6 or n-3; n-3 PUFA being mainly anti-inflammatory), some of which are absorbed from the cow’s digestive tract. A new research project is being prepared which will assess the effect of dietary n-3 PUFA on cow health. This requires an n-3 PUFA supplement which delivers optimal amounts of PUFA to the cow, so it is first necessary to analyse a range of commercially available long chain n-3 supplements. This placement study aims to investigate the in vitro biohydrogenation of PUFA in commercially available “rumen protected” n-3 PUFA supplements for dairy cows. Supplements will be incubated with rumen fluid using established methods, with subsamples of fermentation medium analysed for fatty acid (FA) composition using gas chromatography at various time points. Disappearance of selected PUFA will be compared with an unprotected source of the same FA, in order to identify the most “protected” supplement.
The student will work under the supervision of the School of Agriculture Policy and Development (SAPD)/ADFCS academics and researchers, in order to investigate in vitro biohydrogenation of rumen-protected long chain n-3 fatty acids. The placement will be performed in three steps: (i) literature review on the effectiveness of rumen protection of long chain n-3 PUFA on transfer from diet to the cow, using peer-reviewed publications and electronic resources provided by the University of Reading library (week 1), ii) planning and conducting the in vitro study, which will involve preparation of fermentation vessels, incubating vessels for 24 hours in the presence of rumen fluid (obtained from dairy cows at CEDAR), then FA analysis of the in vitro fermentation fluid by wet chemistry and identification of FA using the gas chromatography facilities within SAPD/ADFCS (weeks 2-5), and (iii) data organisation and statistical analysis, including an introduction to in silico biomathematical modelling software to support biological interpretation of the data (week 6). Selection of supplements to be investigated will take place prior to commencement of the placement, and supervision will be available throughout.
The student should have: an interest in dairy production, dairy cow health and nutritional physiology; good laboratory analytical skills and attention to detail; very good knowledge of MS Excel and MS Word; very good time-management and organisation skills; ability to work independently and as part of a team; reasonable knowledge of statistics.
In undertaking this work, the student will develop a broad range of strong research skills, such as experimental planning, reviewing scientific literature, performing laboratory analyses, dataset preparation, biomathematical modelling and statistical analysis. The student will work as part of a team alongside scientists of several disciplines, who have excellent knowledge of fatty acid metabolism and nutritional physiology of dairy cows, statistical analysis and experience of supervising research projects. This will provide the student with employment skills such as research planning, team working, independent working, time-management, report writing, critical evaluation, organisation and laboratory competency. Work experience and undertaking responsibilities within highly advanced research teams and analytical environments, as well as co-authorship of future publications will increase employability of the student, both in an academic and industry career path, and will allow an understanding of what research careers are like. The student will receive appropriate training in all laboratory and statistical analyses. To ensure the success of the placement, the student will be encouraged to plan their time in advance.
School of Agriculture, Policy and Development, University of Reading
9:00-17:00 with an hour for lunch The supervisor works part-time Wednesday-Friday so lab work will need to be conducted on these days
Wednesday 14 June 2017 - Wednesday 26 July 2017
A CV and cover letter should be submitted to Dr Kirsty Kliem (k.e.kliem@reading.ac.uk). Applicants will subsequently be shortlisted for interview after the closing date. During the interview the candidates will be asked to lead a 5 minute presentation discussing: “n-3 PUFA in dairy cow diets”. Please submit this directly to k.e.kliem@reading.ac.uk by Friday 5th May.