administration aminoacids animalnutrition animals biologicalavailability chemistry composition dosage drugdeliverysystems drugeffects drugs food fruit functionalfood functionalfoods gastrointestinalagents gastrointestinalmotility intestinalabsorption metabolism methods minerals nutrition pharmaceuticalpreparations physiologicaleffect phytotherapy plantextracts ra784 research statisticalmethods statisticsastopic therapeuticequivalency veterinarymedicine vitamins wb430 wi102d7931989