Tabs gone when i navigate to a page by sidemenu

Hi there,
When i press on some option in my sidemenu, tabs gone. Ive something like that:

  templateUrl: 'app.html'
export class MyApp {

  @ViewChild(Nav) nav: any;
  rootPage:any = TabsPage;
  activePage: any;

  pages: any;
constructor(platform: Platform, statusBar: StatusBar, splashScreen: SplashScreen) {
    platform.ready().then(() => {
      this.pages = [
        {title: 'Página Principal', component: HomePage},
        {title: 'Veg', component: VegetablesPage},
        {title: 'Herbs', component: HerbsPage},
        {title: 'Pests', component: PestsPage},
        {title: 'Definições', component: SettingsPage},
        {title: 'Reportar Erros', component: HelpPage},
        {title: 'Termos e Condições', component: TermsPage},
        {title: 'Politica de Privacidade', component: PrivacyPage},
        {title: 'Acerca', component: AboutPage},

      this.activePage = this.pages[0];

      // Okay, so the platform is ready and our plugins are available.
      // Here you can do any higher level native things you might need.

    this.activePage = page;

    return page == this.activePage;