(Reuters) -Mars Inc has stopped supplying some petcare products to Britain’s Tesco, less than a week after U.S. packaged foods company Kraft Heinz pulled several brands from its shelves. European retailers are locked in extended price negotiations with giant food companies as they fight to retain shoppers and protect their profits. Britain’s largest supermarket chain said the impacted products were limited to Mars’ petcare brands and that it hoped to resolve the issue soon. “With household budgets under increasing pressure, now more than ever we have a responsibility to ensure customers get th…