The first genetically modified animal aimed at consumers' dinner plates faces an uncertain future following a federal advisory panel on Monday that gave a mixed assessment on whether such food -- a salmon -- is safe to eat.

A number of the Food and Drug Administration's panelists raised concerns about the fast growing fish, made by Aqua Bounty Technologies Inc, saying there was not enough data to answer key questions about allergens and other potential risks.

There are questions that have not been answered by the data that has been presented, panelist James McKean, a veterinarian and professor at Iowa State University, said.

But other panel members argued there was no difference between the altered salmon and its natural counterpart.

I would not feel alarmed about eating this kind of fish, said Gary Thorgaard, a professor and fish researcher at Washington State University.

Aqua Bounty is seeking U.S. approval to market its engineered Atlantic salmon, which contains a gene from another fish species to help it grow twice as fast as normal.

If approved, Aqua Bounty's salmon would be the first genetically altered animal for human consumption in the United States. The FDA has already allowed modified animals as pets or to help produce biologic medicines. Genetically engineered vegetables such as corn have been on the market for years.

Both FDA staff and the company have said the genetically spliced fish appears to be the same as normal Atlantic salmon and poses little threat to the environment or diners.

But nearly a dozen consumer advocates, environmentalists and others protested the move, citing tens of thousands of people who signed petitions or letters backing them up. They say there is not enough data to show that eating the modified salmon does not cause side effects such as allergic reactions or that accidental escape will not harm other fish.

This is not what the public wants, American Anti-vivisection Society Research Analyst Nina Mak testified.

Overcoming advocates' complaints and winning the panel's support is critical for Aqua Bounty, whose shares have more than tripled this year ahead of the FDA's potential green light.

The company has no other approved products and is eyeing the genetic technology for use in other fish like tilapia and trout.

Aqua Bounty Chief Executive Officer Ronald Stotish told the FDA's panel of outside experts that approval could help provide the healthy kind of diet that Americans are used to amid threats from overfishing and increased demand. Without it, it's hard to imagine how we'll meet the protein needs of the developing population over the next 20 to 30 years.

The small Massachusetts-based biotechnology company first sought U.S. approval of the salmon in 1995 and reported a $4.8 million net loss for last year after restructuring in 2008 to preserve cash and focus on approval.

Its shares were unchanged on the London Stock Exchange ahead of the panel's recommendation.

After 11 hours of deliberation, FDA's panelists did not hand down a clear verdict on whether the salmon was safe to eat, and many said Aqua Bounty's trials could be better designed. Most panelists did say the company appeared to take appropriate steps to prevent the modified fish from escaping and possibly causing harm.

The FDA will weigh the comments before making its final decision, but officials declined to say when that could be.

INCREASED RISK?

Critics, including groups like Consumers Union, the Center for Food Safety and Food & Water Watch, also said Aqua Bounty has not done sufficient studies to prove its fish is safe. They also criticize the FDA for allowing just 14 days for the public to review the data even though the company submitted its bid more than a decade ago.

Last week, various groups protested in front of the White House, urging President Barack Obama to postpone the public meeting or block the potential approval.

Consumers Union is particularly concerned that this salmon may pose an increased risk of severe, even life-threatening allergic reactions to sensitive individuals, it said in a statement. It added that fish are already a major allergen and that this salmon could make the problem worse.

After the meeting, Stotish said the company has already submitted extensive data and that there was confusion among panelists about much of the company's research.

Aqua Bounty has said its fish is the same in every way to other salmon and that taste tests showed no difference.

Stotish said Aqua Bounty plans to sell the eggs to inland fish farmers. The product could eventually boost the United States' meager domestic salmon farms, he said, even though the company's first application seeks approval to grow the fish at facilities in Canada and Panama.

The United States imports more than $1 billion of Atlantic salmon a year after industrialization knocked out most wild populations in its Northeast region.

Steven Vaughn, director of the Office of New Animal Drug Evaluation at the FDA's Center for Veterinary Medicine, said it took the FDA so long to make Aqua Bounty's bid public because it had to grapple with how to handle the complex science.

This has been very challenging for us as a new technology, he said.

But other genetically altered food animals, including pigs and cows, are in the works. One other engineered fish, Yorktown Technologies LP's GloFish, is already sold in the United States as a pet.

One concern is whether consumers will know when they are buying genetically modified salmon, if it is approved.

On Tuesday, the agency will hear public comments on the labeling issues.

Current FDA rules only call for special labels for altered food when there is a material difference in the product's end result. Aqua Bounty and FDA staff both say tests show the salmon's composition appears similar to normal fish.

The company and the industry trade group that represents it, the Biotechnology Industry Organization, do not want products with the fish to point out its genetic differences.

People will perceive a label as some sort of warning, Stotish told reporters.