* U.S., European stocks decline, Treasuries gain
* U.S. private sector employment, services data disappoint
* Investors await ECB, BOJ meetings, U.S. payrolls data
By Wanfeng Zhou
NEW YORK, April 3 (Reuters) - Major stock markets and the U.S. dollar fell on Wednesday after weaker-than-expected growth in U.S. private-sector jobs and services dented some optimism about the world's largest economy, while investors awaited policy meetings by central banks in the euro zone and Japan.
Brent crude slipped below $110 a barrel as oil stockpiles swelled in the United States, the top oil consumer, where a struggling economy is limiting demand for fuel.
U.S. private employers added 158,000 jobs in March, the smallest gain in five months and falling short of economists' expectations. The report by ADP injected caution among investors about Friday's all-important government jobs data.
"The disappointing headline did dent some of the recent optimism surrounding the U.S. recovery and the overall improvement in labor markets," said Omer Esiner, chief market analyst at Commonwealth Foreign Exchange in Washington.
"While the ADP and broader non-farm payroll numbers have not had the closest correlation over recent months, investors are likely to go into Friday's jobs report a bit more cautious."
Analysts forecast U.S. non-farm payrolls hit 200,000 in March, with the unemployment rate seen holding steady at 7.7 percent.
A separate release showed the pace of growth in the vast U.S. services sector slowed in March to the lowest level in seven months as new orders and employment measures pulled back.
The MSCI world index slipped 0.2 percent to 359.42 points.
The Dow Jones industrial average dropped 26.45 points, or 0.18 percent, to 14,635.56. The Standard & Poor's 500 Index fell 6.01 points, or 0.38 percent, to 1,564.24. The Nasdaq Composite Index shed 8.72 points, or 0.27 percent, to 3,246.15.
European shares lost 0.5 percent after surging 1.3 percent the previous day, with heavy falls in the telecoms and mining sectors.
The dollar index, which measures the greenback versus a basket of currencies, dropped 0.3 percent to 82.697.
The euro rose 0.3 percent to $1.2856, while the dollar fell 0.5 percent to 92.92 yen.
The European Central Bank and the Bank of Japan are both expected to make monetary policy announcements on Thursday.
Analysts said a recent run of weak euro zone data, political turmoil in Italy, and concerns over Cyprus could lead ECB President Mario Draghi to strike a dovish tone in his comments after the meeting.
The BOJ is widely expected to ramp up its bond buying and extend the maturities of the bonds it purchases, although some traders have pared back bets against the yen lately given the already hefty short positions.
Expectations of further easing drove Japan's Nikkei average up 3 percent for its biggest one-day rise in almost two months.
The benchmark 10-year U.S. Treasury note was up 9/32, with the yield at 1.8296 percent.
Brent shed 97 cents to trade at $109.72 a barrel, while U.S crude slid 75 cents to $96.44.
Further pressure came from concern a prolonged oil pipeline outage in the U.S. Midwest would cause inventories to build up near the delivery point of the benchmark contract in Cushing, Oklahoma.