SAO PAULO, March 21 (Reuters) - JBS SA, the world's biggest meatpacker, reported a nearly 64% fall in net profits for the fourth quarter, blaming its U.S. beef operations and an oversupplied global market for chicken meat that affected its Pilgrims Pride unit.

JBS's U.S. beef operations is its biggest unit by sales, followed by Pilgrims Pride. Both recorded a fall in net revenue over the fourth quarter, with the U.S. beef unit selling some 12% less, at almost 29 billion reais ($5.53 billion).

Pilgrims sales dropped almost 4% to just below 22 billion reais, JBS said.

Overall, quarterly net profit was 2.35 billion reais, while adjusted earnings before interest, tax, depreciation and amortization (EBITDA) was 4.6 billion reais, 65% below the result in the fourth quarter of 2021.

"We note that the challenging market conditions that pressured our performance in the fourth quarter of 2022 remains in the first quarter of 2023, traditionally a weaker period for the protein industry globally," said CEO Gilberto Tomazoni in a note addressing investors.

China, always an important driver for growth, remained the main destination of JBS' meat exports in 2022, accounting for 26.2% of the company's total sales internationally. In 2021, that share was a higher 27.1%, the company said.

On a brighter note, JBS said sales to the affluent Middle Eastern market were 12.1% of total exports last year, up from 10.7% in 2021.

In its home market, JBS posted healthy results at its Seara division, which processes pork and chicken, driven by its ability to raise average domestic product prices.

Seara also benefited from a 15.4% jump in dollar-denominated export sales, JBS said.

But while Seara's overall revenue jumped 9% from the same quarter in 2021, margins suffered because of cost inflation, in particular higher livestock feed prices in Brazil.

JBS said extreme volatility in the international market affected its results in 2022, citing the global increase in the supply of poultry, as well as avian flu and the conflict between Russia and Ukraine.

Still, the company had net sales of 375 billion reais in 2022, a 7% rise from 2021.

($1 = 5.2340 reais) (Reporting by Ana Mano; Editing by Lincoln Feast)