* FTSEurofirst 300 up 0.5 pct, Euro STOXX 50 up 0.6 pct
* ECB seen keeping rates unchanged at 0.25 pct
* Metro and ProSieben rise after updates
* European equities to outperform in May -UBS strategists
By Sudip Kar-Gupta
LONDON, May 8 (Reuters) - European stock markets rose on Thursday after reassuring updates from top companies, such as the German supermarket chain Metro, and better-than-expected Chinese trade figures.
Investors were also focusing on the European Central Bank's interest rate decision later on Thursday. Most expect the ECB to leave rates on hold at a record low of 0.25 percent.
The pan-European FTSEurofirst 300 index, which rose to near a six-year high of 1,357.05 points earlier this month, climbed 0.5 percent to 1,350.94 points in mid-session trading.
The euro zone's blue-chip Euro STOXX 50 index rose 0.6 percent to 3,178.74 points. Germany's DAX gained 0.5 percent to 9,573.04 points.
Metro AG rallied 5.1 percent as better-than-expected profits at its cash and carry business offset a weaker contribution from the Media-Saturn division. German media group ProSiebenSat.1 rose 4.8 percent after posting a 9.5 percent increase in first-quarter core earnings.
Data on Thursday also showed that China's exports and imports returned to slight growth in April, sending a positive signal for the world's second-biggest economy after a weaker-than-expected start to 2014.
According to Thomson Reuters StarMine, 50 percent of the companies on the pan-European STOXX 600 index that have reported quarterly earnings so far have beaten or met market expectations with those results.
"Generally speaking, the first-quarter results so far have seemed pretty good," said Berkeley Futures associate director Richard Griffiths.
The ECB was expected to take heart from signs of life in the euro zone economy and leave interest rates at 0.25 percent, resisting pressure to act in the face of a stronger euro and persistently low inflation.
"I'm going in neutral into the ECB meeting. I took profits on the DAX yesterday, but I'm expecting bullish reverberations from the ECB meeting," said JNF Capital investment manager Edward Smyth.
UBS equity strategists said on Thursday they expected European equities to outperform in May and beat the UK market.
"The region continues to benefit from a recovery in growth particularly the peripheral countries, easing credit spreads and subdued inflation," they wrote in a note.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (Additional reporting by Blaise Robinson; Editing by Larry King)