SAO PAULO/BRASILIA, Aug 21 (Reuters) - When Brazil's notoriously private President Dilma Rousseff showed up in her kitchen cooking pasta in a campaign TV ad this week, it was one of the clearest signs yet that the country's October election is up for grabs.
Rousseff and other candidates are shifting strategies and showing rarely seen sides of their personalities in what suddenly looks like a tight three-way race following this week's late entry of popular environmentalist Marina Silva.
Popular with young voters for her authenticity and tough stance on corruption, Silva joined the field following the death of her party's previous candidate in a plane crash.
Her presence forces Rousseff and other contenders to show a more human side of themselves - as in the kitchen scene - while also doubling down on the message that Brazilian voters most want to hear in this election: Change.
About two-thirds of Brazilian voters have said in polls they want change from their next government, reflecting broad disenchantment with a stagnant economy, corruption, and poor public services such as healthcare and education.
Silva's anti-establishment record, including her resignation from the ruling Workers' Party in 2009 following a dispute over Amazon deforestation, gives her enormous appeal for disgruntled voters, many of whom participated in huge street protests against the political elite last year.
A poll this week showed Rousseff in first place ahead of the Oct. 5 vote and Silva neck-and-neck for second with Senator Aecio Neves, a business-friendly candidate.
But Silva held a slight lead over Rousseff in the event of a second round runoff on Oct. 26, which polls show is likely.
Even before Silva's candidacy, Rousseff was trying to harness or at least acknowledge public dissatisfaction, as seen in her official campaign slogan: "More Changes, More Future."
Some Workers' Party officials privately acknowledge it's not easy for a party that has run Brazil for 12 years to present itself as an enemy of the status quo.
But they say they will continue to do so, by arguing in TV ads that Rousseff's experience, sober demeanor and broad party support make her better positioned to address Brazil's complex problems than Silva, who has a reputation for unpredictability and fighting with even her own allies.
"You'll hear 'change, change, change,' even more than before," one party official said, speaking on condition of anonymity to discuss strategy. "We cannot allow Marina or Aecio to be the owners of that word."
In many ways, Rousseff's campaign seems to be trying to rebrand "change" in voters' minds as the progress the party made in reducing poverty and inequality over the past decade, a period that saw a long, commodities-fueled economic boom.
"Don't allow change to stop. Don't let Brazil stop changing," Rousseff's popular predecessor and political mentor, Luiz Inacio Lula da Silva, said in a TV ad for her campaign that aired on Thursday.
Rousseff's other ads have featured an off-screen announcer who cited a litany of flattering statistics - 36 million Brazilians lifted out of poverty, 12 million jobs created - and then declared it was the country in the world that has "most changed its socioeconomic profile."
Meanwhile, the ads have shown a humility that was often missing from the party's rhetoric during the boom years - a move one adviser said was geared to reassure voters that "we understand they're mad."
Rousseff recognized that the economy has slowed "a bit," which she blamed on crises in Europe and elsewhere. "We're not an island," she said.
Many economists say her left-leaning policies are also to blame for scaring investors and reducing average growth to just under 2 percent during her rule, half the pace Brazil enjoyed last decade.
In another implicit recognition of recent problems, Lula began one ad by saying: "My second term was better than my first. With Dilma, I'm certain it will be the same way."
Neves, the candidate for the centrist Brazilian Social Democracy Party (PSDB), is also modifying his approach to capture dissatisfied voters following Silva's entry to the race, while combating his own reputation in some circles as a bon vivant who lacks the gravitas to be president.
Neves' first TV ad featured him in a dark suit and tie, giving a speech that mentioned the word "change" at least six times and featured soaring, patriotic rhetoric that would not have been out of place at a party convention.
A PSDB source said Neves would concentrate more in coming weeks on building his support among poorer Brazilians since Silva is likely, at least in the short term, to attract educated, richer voters who had previously been undecided.
Sources with both the Rousseff and Neves campaigns say they will wait to see what kind of messages Silva embraces, and whether she continues to rise in polls, before deciding whether to "go negative" and attack her.
Diego Brandy, an Argentine who is helping with the political strategy for Silva's campaign, said her team is still trying to figure out its next moves following the death of the Brazilian Socialist Party's previous candidate, Eduardo Campos.
Whatever happens, the campaign will continue the broad, non-aggressive approach seen under Campos, Brandy said. "We will not hit back." (Writing by Brian Winter; Editing by Todd Benson and Kieran Murray)