Feed represents a very large portion of the cost of raising a pig to market; indeed, the cost of meeting the energy specifications of a diet is the largest single item in the cost of production budget. Within this context, fibre plays a significant role as it represents a substantial but poorly utilized portion of typical commercial diets. It is therefore not surprising that enzymes attract a great deal of attention as a vehicle by which fibre can be used more effectively. Interestingly the mode of action of enzymes within the diet is poorly understood. Indeed, enzymes are providing unexpected health benefits, including but not limited to reduced mortality in the grow-finish phase. In any event, enzymes improve energy and nutrient digestibility – not always translated into faster or more efficient gain – and also impact the microbiome, gut barrier function and possibly oxidative stress. Suggestions are provided for future research topics and applications.