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  • GM corn 'improves animal feed, cuts pollution'


[BEIJING] Chinese scientists have developed a genetically modified (GM) corn that could help improve the nutritional value of livestock feed and reduce pollution.

The research was announced by the Chinese Academy of Agricultural Sciences (CAAS) this week (10 September). The corn has now entered pre-production field trials.

The GM corn produces seeds containing high levels of an enzyme called phytase. The enzyme helps livestock to digest phosphorus, an important nutritional element found in corn and soy feeds.

Cereal grains and oilseeds, the main ingredients of feeds, contain large quantities of phytic acid, which has adequate phosphorus content, but livestock such as pigs lack sufficient phytase in their digestive tract to absorb enough phosphorus. This means large amounts of phosphorus are released into the environment through animal waste.  

As a result, farmers add phytase to animal feed to help livestock digest phosphorus. The enzyme is a product of fermentation by microorganisms, a process which has high production costs.

The CAAS scientists — funded by the state — isolated the gene that produces phytase from a species of the fungus Aspergillus, and inserted it into corn.

Chen Rumei, of the Institute of Biotechnology under CAAS and a member of the research team, said that when compared to other corn varieties, the rate of seed germination, growth speed and yield of the GM corn were no different.

She told SciDev.Net that, under current industry criteria for feed additives, adding just a few grams of the GM corn seed per kilogram of animal feed would be enough to satisfy livestock's nutritional demand for phosphorus.

"If this technology is commercialised, we can save up to 450 million yuan (US$60 million) per year in energy costs used to produce industrial phytase enzyme additives," Chen adds.

"This could be translated into saved costs for farmers in purchasing additives," she says. And farmers who plant the GM corn rather than common corn varieties could increase their income by about 1500 yuan (US$200) per hectare.

Li Zhensheng, former vice-president of the Chinese Academy of Sciences and the chair of the Ministry of Agriculture team who evaluated the project, says phosphorus pollution caused by animal waste has been a serious problem, resulting in widespread algal blooms in the Chinese lakes (see Pollution control key to beating China's algal blooms).

"If the phytase enzyme-rich feed produced from the GM corn is widely applied, phosphorus pollution caused by animal waste will be significantly reduced, and the ecology could be largely improved," Li says. 

China has not yet approved any GM corn for commercial sale.

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