Table 2.

The evolution of the nutraceutical concept for non-ruminants and ruminants over time.

Definition	Year	Reference
Food or part of a food that provides health benefits and is used for prevention or treatment of a disease	1989	[82,83]
A nondrug substance that is produced in a purified or extracted form and administered orally to provide agents required for normal body structure and function with the intent of improving the health and wellbeing of animals	1997	[91]
Any substance that may be considered a food or part of a food which provides health benefits, including the prevention and treatment of disease	2002	[92]
A livestock feed which combines nutritional value with beneficial effects on animal health	2015	[35]
Natural compounds and/or microbes that offer potentially advantageous effects to ruminant health and productivity, including improved efficiency, milk production, and disease resistance through immune modulation or decrease disease pressure	2019	[86]