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"Focus on food poisoning, seed selection, diet and productivity"

1st April 2013


In the UK, scientists are using the beneficial bacteria known as probiotics to destroy food poisoning bacteria in poultry before it enters the food chain.

Based at the Institute of Food Research (IFR), the scientists have discovered that the probiotic Lactobacillus johnsonii clears the pathogenic bacterium Clostridium perfringens from the gut of chicks. This bacterium can cause lesions in chicks as well as causing food poisoning in humans.

"Some poultry feed already contains probiotic bacteria, but an undefined mixture that gives inconsistent results. This research is exciting because we have used a single strain and shown that it can be targeted to eliminate a specific pathogen,“ said IFR research scientist Arjan Narbad.

The probiotic also reduced colonisation of the small intestine by E.coli, but did not clear it completely.

The scientists screened thousands of acommensal' bacteria from the adult chicken gut to identify strains that might competitively exclude abad' bacteria. Commensal bacteria have also been described as afriendly' or agood'. One of these, Lactobacillus johnsonii showed particular promise, and the IFR teamed up with the Veterinary Laboratories Agency to test its potential.

"For decades we have known that naturally-occurring bacteria in adult chickens can prevent pathogens from colonising in younger birds, whose gut flora is not yet well developed. But we have not known which bacteria are most effective“, said Narbad. "We are particularly pleased to have identified a strain to combat Clostridium perfringens because it can not only cause food poisoning in humans, but can cause illness in chicks.“

Clostridium perfringens is naturally present in the chicken gut, normally without causing disease. Sometimes the bacteria produce toxins, and scientists believe these are what cause the disease necrotic enteritis. Necrotic enteritis has a number of symptoms in poultry, including poor weight gain and ulcers. In humans it causes intense abdominal cramps and diarrhoea, sometimes accompanied by vomiting.

British and European farmers are being encouraged to reduce their use of antibiotics in animal feed, and this research provides one viable alternative.

The next stage of research with Lactobacillus johnsonii will be to conduct a field trial of this probiotic strain. Preliminary studies have shown that it may also have a protective effect against Campylobacter jejuni in poultry.

More generally, the IFR scientists will investigate how competitive exclusion works, in order to improve on the process and find other competitive exclusion products. There are three current theories: probiotics produce antimicrobials that destroy or inhibit the growth of bacteria; they force pathogenic bacteria to compete for nutrients; they occupy sites in the chick's intestinal tract where pathogens would normally attach and grow.

Best seeds found by X-ray

The spring sowing of sugar beet has just been completed in central Europe. Even if as many plants as possible germinate and thrive, crop yield and sugar content ­ and hence financial reward ­ will not be known until the autumn. As well as soil and climate conditions, seed quality is a major factor in the success of the sugar beet crop. And leading seed producer Strube-Dieckmann is pioneering new methods of quality control.

"Germination tests are the only officially accepted procedure, and that of course takes time,“ explained Antje Wolff, head of the company's seed research unit. "Standard X-ray speeds up analysis. But as we constantly strive for higher quality, we decided to install a new facility two years ago. Now we can measure up to 20 geometric seed parameters.“

The X-ray microtomography device scans the tiny rotating seed grain. A software program creates cross-sectional images of the seeds and then reconstructs a 3D picture. It distinguishes different types of tissue ­ for instance the embryonic with nutritive and outer shell ­ and measures the volume of each.

The seed is automatically graded by comparing these results with germination test data. Up to 100 seeds can be analysed in a few minutes. With the results, the operators can quickly adjust the sorting machines to meet the required quality standards.

The cabinet-sized machine was developed in close cooperation with the development centre for X-ray technology, EZRT, jointly run by two Fraunhofer institutes in Germany.

Dutch low-fat breakthrough

In the Netherlands, researchers at TNO have shown that a diet of low-fat food is better than small portions of high-fat food for preventing diabetes in obese people.

Mice put on a low-fat diet were found to be more sensitive to insulin than mice that received the same amount of energy in the form of high-fat food: so a low-fat diet is a more effective remedy for diabetes than eating less calories.

Researcher Martin Muurling also discovered that in mice the consumption of fish oil had no positive effects whatsoever on reduced insulin sensitivity. From this he concluded that a diet with fish oil cannot prevent or remedy diabetes in the case of somebody who is already less sensitive to insulin due to a high-fat diet.

A genomic approach to grapes

In Spain, Genoma España has teamed up with the Department of Vegetable Physiology of the Faculty of Sciences at the University of Navarre to develop a genomic approach to the identification of genetic and environmental components underlying grape quality.

Over the next three years the Fundación Genoma España will provide E2 million to identify the genes responsible for the quality of grapes.

Six research teams are working on the Hamburg Moscatel dessert variety. In a parallel effort, scientists in Canada will carry out the same study on a grape variety grown for wine production ­ Cabernet Sauvignon.





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