UPDATE 1-Brasil Foods profit down 99 pct on currency swing, grain costs

* Weaker currency drives up financial expenses over 400 pct

* EBITDA down on feed costs; in line with forecasts

SAO PAULO Aug 13 (Reuters) - Brasil Foods, the world's largest poultry exporter, posted a 99 percent drop in quarterly profit on Monday, hurt by rising feed costs and a currency swing that drove up debt-servicing costs.

The company posted net income of 6 million reais ($3 million) for the second quarter, down from 498 million reais a year earlier. The result missed forecasts for profit of 90 million reais in a Reuters poll of six analysts.

Brazil's currency, the real, slid 10 percent against the U.S. dollar in the quarter, bolstering the company's exports but driving up the cost of its foreign debts. Financial expenses grew more than 400 percent from a year ago to 288 million reais.

Revenue rose 9 percent, driven by export growth, but profitability suffered as operating costs jumped 17 percent on surging grain prices.

"We registered a positive trend in sales volumes, but with insufficient price increases so far to make up for accelerating grain prices," said Chief Executive Jose Antonio do Prado Fay in the earnings filing.

Earnings before interest, taxes, depreciation and amortization, a gauge of operating profit known as EBITDA, fell 28 percent to 565 million reais, in line with an average estimate of 568 million reais in the Reuters survey.

EBITDA as a share of revenue, a measure of profitability known as the EBITDA margin, slipped to 8.3 percent in the second quarter from 12.5 percent a year earlier.