President Reagan moved to prevent "serious disruption" in the nation's meat and poultry inspection system yesterday by asking Congress to release $5.7 million to offset effects of the Gramm-Rudman-Hollings balanced-budget act.

The Department of Agriculture had proposed furloughing all 9,000 of its meat and poultry inspectors for nine days to meet its Gramm-Rudman-Hollings target for this fiscal year. The action would have required a simultaneous industry shutdown because inspectors must be present whenever a slaughterhouse is operating.

The new money will mean the inspectors face only a three-day unpaid furlough to be taken on three holidays when the industry wouldn't be operating.

The meat and poultry industries have conducted a full-court press to try to head off the furloughs.

Six weeks ago, the American Meat Institute and the National Broiler Council met with Randall Davis, associate director of the Office of Management and Budget, to oppose the furlough plan.

Since then, "We've visited by phone with the agency and members of Congress," said George Watts, president of the American Broiler Council.

The $5.7 million Reagan requested yesterday was appropriated by Congress last year in the belief that the administration's annual budget request for the Food Safety and Inspection Service was not sufficient.

It is therefore a fairly simple procedure to release the money now, requiring only the request the president made yesterday.

Some saw Reagan's move as a vindication of congressional wisdom.

"Occasionally there are accounts where the administration doesn't ask for the amount they need," a congressional staff aide said. "If Congress appropriates the money they need, the administration points the finger at Congress for overspending . . . . In this case we called the bluff of the administration on meat inspection."

Gramm-Rudman-Hollings went into effect Saturday, and the Department of Agriculture furloughs, the most dramatic result of the act to come to light so far, received widespread publicity.

Facing a 4.3 percent Gramm-Rudman-Hollings cut and having little else to trim but personnel, the food safety service proposed the nine-day inspectors' furlough.

At about 10 a.m. yesterday, Reagan formally requested the $5.7 million, and it was automatically released under the law.

"The industry case was a strong case," said OMB spokesman Edwin L. Dale Jr.

The role in the furlough matter of the Department of Agriculture, which has an acting secretary filling in for another acting secretary who quit, is unclear.

Secretary of Agriculture-designate Richard E. Lyng, testifying during his Senate confirmation hearing yesterday, alluded to the furloughs without giving any sign of knowing that extra funds would soon be available.

"The final say is always OMB," Dale said. The Agriculture Department "doesn't normally go over our head to the president."