New Research Shows Feeding Brassicas May Reduce E.coli O157 in Sheep

Feeding turnips or other brassicas to sheep could be an effective and practical method to reduce the shedding of E.coli O157 in sheep, according to trials undertaken in a research project co-funded by Quality Meat Scotland, the NFUS, FSA Scotland and Biotechnology and Biological Sciences Research Council (BBSRC).

The latest results of the three-year project were revealed today (11 September 2012) at an event to launch Quality Meat Scotland’s Research and Development Report 2011/12.

The research, being undertaken by Eilidh Fraser at Aberdeen University, suggests that sheep grazing on brassicas (the plant family including turnips, swedes and kale) in spring appear to have a significantly lower prevalence of shedding of E.coli O157 in their faeces. In addition the results showed that sheep excreted significantly more E. coli O157 in summer than in winter when at grass.

“The results of this on-going project look promising and we hope bring us a step closer to a simple, cheap means to reduce the shedding of the organism in sheep,” said Prof Charlotte Maltin, QMS Science and Innovation Manager.

E.coli O157 is a bacterium which can cause health problems for humans. Infection can occur as a result of people not washing their hands after being in, or working in, environments exposed to ruminant dung or other infected people, or from eating contaminated food (both meat and vegetables).  It is generally agreed that cattle and sheep are the main source of the organism and E. coli O157 is found in the hind gut of cattle and sheep and is excreted in their dung.

“Farmers can’t tell whether their animals are carrying E.coli O157 as the animals don’t show signs of being unwell. This means that treating infected individual animals is not practically possible so it makes sense to look at alternative ways of reducing the prevalence of this organism,” added Prof Maltin.

“Further work is needed to try to confirm and extend this work to assess whether turnip feeding could be a means of reducing the shedding of E. coli O157 in dung but certainly these initial results look interesting.”

Sixteen farms in Grampian were recruited to be studied in winter. “The flock sizes ranged from 100 – 600 sheep with 50 faecal samples per flock collected and tested for E. coli O157 at pasture from November to January and when grazing on brassicas from March to April,” explained PhD student Eilidh Fraser of Aberdeen University who is leading the project.

The same 16 farms were revisited during the next two years when animals were at pasture and again when they were grazing brassicas. Over the three years 4,450 fresh faecal grab samples were collected. A further 19 different farms with sheep grazing on pasture were recruited to be studied in the summer between June and September.

“What we found during the three years of testing - 2009/10, 2010/11 and 2011/12 - was that while some sheep on the farms tested positive for E. coli O157 whilst grazing on pasture, they all went back to testing negative when being fed brassicas. In fact we found no E.coli O157 at all among sheep grazing brassicas on the 16 farms.”

“The control of E. coli O157 throughout the foodchain is a priority for the FSA, but there are still evidence gaps in relation to how this pathogen can be tackled at its key source which is the ruminant gut,” said Dr Jacqui McElhiney, FSA Scotland Senior Policy Adviser.

“We welcome the results produced by this research, which could help in the development of practical and cost effective measures for reducing the shedding of E. coli O157 by sheep.”

NFU Scotland's Animal Health and Welfare Policy Manager, Penny Johnston said: "E. coli O157 is a real problem for livestock farmers and, given the dangers E. coli O157 can present, any research into simple ways in which it can be fought is very welcome. "The results of this study are very interesting and I hope that they can be developed easily into practical advice for livestock farmers."

The new QMS Research & Development Report is available to download by visiting www.qmscotland.co.uk to download a copy. Alternatively you can request a print copy by emailing info@qmscotland.co.uk or calling 0131 472 4040