When Rex was so sick if I could just get him to take one bite of anything we were home free as he'd go on and progressively eat other things, like hamburger and rice and sometimes even kibble.
With him I never knew what would stoke his engine...hot dog, braunswager, sardine (usually worked cuz he loved them and they were smelly) freeze dried liver, cheese in a can (another fav), cream cheese, cheddar..if I could just get him to take that first bite he'd go on.