Question over safety of GM bacteria derived feed product

By Jane Byrne

- Last updated on GMT

© istock/Kenishirotie
© istock/Kenishirotie

Related tags Milk Cattle Efsa

EFSA was unable to conclude on the safety of a feed material produced by fermentation with Escherichia coli, a by-product of the production of l-lysine, for certain animals and for meat consumers. 

The product, which is produced by Ajinomoto Eurolysine, is targeted at pigs, ruminants and salmonids.

The amino acid company had sought authorization for the use of PL73 (LM) as a feed material, described as a dried, killed bacterial biomass produced by fermentation of the genetically modified E. coli (FERM BP-10941).

It intends PL73 (LM) to be used as a source of protein for pigs for fattening, ruminants (for meat and milk production from the beginning of rumination) and salmonids. The maximum use levels recommended in complete feed are 7% for pigs and 13% for salmonids (or replacement of 20% of fishmeal in a complete diet containing 65% fishmeal. For ruminants, the maximum recommended level is 7.3% biomass DM in complete feed DM.

Ajinomoto Eurolysine’s dossier included data on how PL73 LM is made. After removal of the l-lysine, the solids are concentrated and dried. The resulting biomass powder is granulated/pelleted, cooled and sieved to remove broken pellets and fine dust. An antifoaming agent is added during the fermentation that results in residues in the final feed material.

Safety evaluation

In its assessment of the safety and nutritional value of the material​, EFSA’s panel on Additives and Products or Substances used in Animal Feed (FEEDAP) found the molecular characterization of the E.coli​ strain in question does not indicate a safety concern. “No DNA sequences of concern including those conferring antibiotic resistances are present in the strain.

The EFSA experts found PL73 (LM) is safe for salmonids up to a dietary concentration of 13%, but they reported concerns in relation to the safety aspect of the feed material for ruminants, pigs for fattening and for consumers.

“Considering the zootechnical endpoints only, the maximum safe level for dairy cows would be 6% PL73 (LM) of feed dry matter (~ 5% in complete feed). This value could be extended to other ruminants (from the beginning of rumination).

“Complete feed for pigs for fattening may contain up to 6% PL73 (LM). These levels would not influence the sensory quality of tissues and products of animals.

Another feed material produced by Ajinomoto Eurolysine, and also targeted as a protein source for pigs, ruminants and salmonids, received a more clear-cut opinion from EFSA in relation to its use in animal diets. That assessment can be read here​. 

“However, the unexplained effects on blood coagulation, on plasma lipoproteins in dairy cows and on total plasma bilirubin and liver weight in pigs prevent a clear conclusion of safe dietary levels for ruminants and pigs for fattening. Consequently, no safe feed concentration of PL73 (LM) could be established for complete feed for ruminants and pigs for fattening.”

The panel said since the toxicological data indicate effects of PL73 (LM) on blood coagulation and liver and since the causative agent and mechanism of these effects is unknown, there is no way of determining whether residues exist in animal products sufficient to cause similar effects in consumers.

“As a consequence, the FEEDAP Panel is unable to conclude on the safety for the consumer of products derived from animals receiving feed containing PL73 (LM).”

The full opinion​ can be read here.

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