An index of Asian shares gained on Thursday while the dollar eased slightly after the Federal Reserve signaled that interest rates would rise more slowly than markets had expected. After a closely-watched two-day meeting, the Fed said the economy was likely strong enough to support an interest rate increase by the end of the year. MSCI’s broadest index of Asia-Pacific shares outside Japan climbed about 0.3 percent, while Japan’s Nikkei (.N225) skidded 0.8 percent to a one-week low as the yen gained against the dollar.