Opinion of the Scientific Panel on Additives and Products or Substances used in Animal Feed on the safety of the micro-organism preparation of Duddingtonia flagrans, for use as a feed additive for calves in accordance with Council Directive 70/524/EEC

Duddingtonia flagrans belongs to a group of nematophagous fungi that physically entrap nematodes by means of a specialised adhesive hyphal net. Deliberate introduction of nematophagus fungi into pasture offers an alternative biological means of controlling pathogenic nematodes (eelworm) in ruminants and horses, avoiding the use of chemical anthelminthics. Such infections cause major economic losses to the agricultural industry world-wide. Chlamydospores from cultures of the fungus are fed to the target species. Ingested spores pass through the digestive tract without germinating and are deposited on pasture with the faeces where they germinate and produce mycelium with its hyphal traps. This in turn reduces the number of nematodes able to migrate to herbage and re-infect the grazing animals. The Commission has asked the European Food Safety Authority to deliver an opinion on the safety of the preparation of Duddingtonia flagrans, for the target animals, the consumer, the user of the product and the environment, when used for the control of gastro-intestinal nematodes under the conditions proposed by the Applicant. Duddingtonia flagrans in the product consists largely of chlamydospores (1 x 107 spores g-1 additive). Any metabolites produced during the initial production of the fungus on the grain substrate also would be carried through to the final product which consists of the whole solid-substrate fermentation. No treatment-related adverse effects were seen when the product was given to calves for 100 days at up to ten times the recommended dose. Therefore the FEEDAP Panel considers safety for the target species to have been demonstrated. Very little is known about the metabolism of this organism other than that related to its nematophagous activity. Although the acute oral toxicity study (limit test) classifies the product as of very low toxicity, there remains a degree of concern that chronic toxicity might arise from metabolites carried over from the production process and absorbed by the host animal. Consequently the FEEDAP Panel is unable to conclude on the safety of the product for the consumer (and user) in the absence of data from a 90 day repeat oral dose toxicity study. In common with many proteinaceous materials, the FEEDAP Panel would expect this product to have a potential for sensitisation via a respiratory (and ocular) route but to be unlikely to be a skin irritant or to cause dermal sensitisation. The FEEDAP Panel recognises that the product is formulated to minimise respiratory risks for those handling the product. Duddingtonia flagrans is widely distributed in the environment. Published data indicates that the organisms deposited with faeces remain localised and has no detectable impact on other non-target nematodes or earthworms. The FEEDAP Panel concludes that use of the product would not have an adverse effect on the wider environment.