(Adds shares, analyst comments) By Ana Mano and Gabriel Araujo SAO PAULO, Aug 30 (Reuters) - Brazilian food processor BRF SA said on Tuesday that chief executive Lorival Luz has resigned and will be replaced by Miguel Gularte, a top executive at meatpacker Marfrig Global Foods SA. Shares in poultry and pork processor BRF were around 6% higher in early trading in Sao Paulo after the announcement. BRF said the move does not reflect an intention to merge the two companies. Marfrig, which owns 33.27% of BRF, has said it is only interested in a passive stake in BRF. "We see the appointment of Miguel Gularte as CEO of BRF as unexpected," XP analysts said in a note, highlighting the fact his experience comes from the beef sector. Still, XP believes Gularte "should be able to make BRF more agile, removing discomforting inertia that was responsible for lost opportunities in BRF's past."