China claimed the first gold medal of the world aquatics championships Saturday as the sport\'s chiefs tightened their doping crackdown in the wake of a major scandal. Divers Wu Minxia and He Zi got the hosts off to a roaring start as they bagged the women\'s 3m springboard synchro in stunning style in a sunset final at Shanghai\'s open-air Crescent Lagoon venue. Wu and He totalled 356.40 points, more than 40 points ahead of Canada\'s Emilie Heymans and Jennifer Abel, with Australians Anabelle Smith and Sharleen Stratton third. It was China\'s sixth successive victory in the event, equalling diving\'s longest ever winning streak set by the United States between 1973 and 1991, and underlining their years of dominance in the sport. China missed only one gold medal at the 2008 Beijing Olympics and won seven out of 10 at the 2009 world championships in Rome, raising hopes they can take the lot even without \"diving queen\" Guo Jingjing, who retired in January. Meanwhile governing body FINA said blood testing, along with urine testing, would be used for the first time since 2005 at the biennial world championships, which open just days before Brazilian star Cesar Cielo learns his fate over a positive test. Executive director Cornel Marculescu said the decision to reintroduce blood tests, which were not considered necessary in Melbourne in 2007 and Rome in 2009, had been taken on the advice of experts. \"It\'s nothing new in our life. We have done the blood tests before,\" he said. \"It\'s a matter for the scientific world. We have to follow what the scientific world is telling us.... I don\'t see anything unusual,\" Marculescu added. The decision comes before Wednesday\'s hearing by the Court of Arbitration for Sport into Cielo and three other Brazilians who tested positive for a banned diuretic but were let off with warnings by the national federation. FINA took the case to the international body, calling for bans and for the swimmers to be stripped of all their results since they failed the tests in May. A ban would rule Cielo, who blamed a contaminated vitamin supplement for the failed test, out of the ongoing world championships and would threaten his defence of his Olympic 50m title next year in London. The risk of failed tests appears especially high in Shanghai after Chinese officials acknowledged the risk of athletes eating meat contaminated with banned fat-burner clenbuterol, which farmers sometimes feed to pigs and cattle. Officials drew up a list of designated restaurants which were safe to visit after team officials raised concerns. Reports said one study found 22 out of 28 travellers leaving China tested positive for clenbuterol. In Saturday\'s other action, Li Shixin came out on top in his battle with Chinese team-mate He Min in the men\'s individual 1m springboard preliminaries, raising expectations of another home win in Monday\'s final. The world championships, featuring 2,200 swimmers, divers and water polo players from a record 181 countries, will formally begin later on Saturday with an opening ceremony at 8:00 pm (1200 GMT). The swimming competition starts on July 24 with all eyes on whether 14-time Olympic champion Michael Phelps can dominate as he did at the 2008 Beijing Games, where he won eight golds. But the swimming events are likely to see few if any world records after the banning of high-tech polyurethane swimsuits which helped set a whopping 43 new marks at the last edition in Rome.