Top Spec Fibre Plus is non-heating and low in sugar and starch. Soya and linseed are added to balance the calories with protein and help to avoid... TopSpec FibrePlus Cubes are an excellent highly digestible fibre source with added ingredients to allow a little muscle development and function. They are ideal for Good-Doers because they have a DE of only 9MJ/kg and when soaked they are a perfect hay replacer for elderly horses and ponies. ‘Non-Heating’.