How fish oils can stifle greenhouse gases

March 25, 2003

Brussels, 24 Mar 2003

Farm animals produce around 22% of global emissions of the greenhouse gas methane. But Belgian scientists found a drop of fish oil in animal fodder could nearly halve that amount.

Does this smell fishy to you?

The US Environmental Protection Agency estimates farm animal belching accounts for some 22% of worldwide emissions of the greenhouse gas methane. What's more, on a volume for volume basis, it traps almost 20 times as much heat as carbon dioxide. This makes it a powerful contributor to global warming.

Researchers around the world have investigated various ways of reducing the harmful effects of animal gas emissions. In June 2001, New Scientist reported on a programme, led by the CSIRO, Australia's national science agency, to vaccinate sheep and cattle to reduce their gaseous production. The vaccine targets the methane-producing bacteria that reside in the animals' stomachs.

Earlier, in 2000, a team of Scottish scientists from the Rowett Research Institute in Aberdeen used a powdered bacterial additive to suppress methane production. But they reported disruptions to the animals' normal digestion process. Belgian researchers think they have the solution.

Something fishy in Belgium

Working out of the Department of Animal Production in Ghent University, the Belgian team assessed the effects of adding a mixture of fish oil and fluid from a sheep's fore-stomach to animal fodder. Remarkably, they found just 4% of fish oil added cut back the bacteria's methane output by 80%. The results were less effective when the oil was fed directly to the sheep, but still managed a 25 to 40% reduction.

Both the Australian and Belgian research suggests decreasing the animals' methane production can also boost its growth. Somewhere between 2 and 12% of a cow or sheep's energy intake is used for methane production by the bacteria, reports the New Scientist. Fish oil could have other benefits too.

The Belgian team discovered high levels of omega-3 fatty acids, and other polyunsaturated fats thought to reduce cholesterol, in the stomachs of the sheep fed this fishy diet. Further tests will be done to assess if there will be any effects on the meat or milk flavour of animals fed with fish oil. In view of depleting stocks of some varieties of fish, the team are also investigating fish alternatives such as using extracts from algae and oil-rich crustaceans.

Source: Press article, Journal of Animal Feed & Technology


More information on this subject:

Animal Feed Science & Technology (vol. 104)

New Scientist article

Greenhouse Gases and Animal Agriculture

DG Research ndex_en.html

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