Shares are expected to open slightly lower as traders digest a raft of trading updates and await first quarter economic growth data later this morning.Controversial oil colossus BP saw its first quarter profit advance to $7,124m from $6,079m the year before. Replacement cost profit dipped to $5,481m from $5,598m, however. Including the impact of the Gulf of Mexico oil spill, net cash provided by operating activities for the first quarter was $2.4bn, compared with $7.7bn in the same period of last year.Banking giant Barclays saw adjusted profit before tax rise 10% in the first quarter of 2011, despite a 15% slide in top-line income at Barclays Capital, its high profile investment banking arm. Adjusted profit before tax grew to £2,004m from £1,822m in the first quarter of 2010. Net operating income dipped 1% to £6,478m from £6,557m a year earlier.British Sugar and Primark owner Associated British Foods saw adjusted earnings per share grow by 7.9% year on year at the interim stage, ahead of some brokers' expectations, but warned full year results will only be roughly on a par to last year. Group revenue rose 9% to £5,207m in the 24 weeks to 5 March, up from £4,976m in the corresponding period a year earlier and ahead of the £5.16bn predicted by broker Charles Stanley.Carpet and floor coverings retailer Carpetright warned underlying pre-tax profit for the year is expected to be slightly below the level of profits achieved in the 2009 as tough trading conditions continued in the fourth quarter. Group sales for the 11 weeks ended 16 April 2011 fell by 6.5%. UK and Republic of Ireland sales declined 6.5% during the quarter, with like-for-like sales down 6.3%.