Evaluation of tea and spent tea leaves as additives for their use in ruminant diets

Abstract

Animal scientists have been challenged to improve animal production systems with respect not only to competitiveness and efficiency but at the same time producing products which are healthy for the consumers and friendly to the environment. Plant secondary metabolites such as tannins, saponins, and essential oils have been investigated for their advantageous outcomes as ‘natural’ additives to manipulate rumen fermentation via decreased ammonia (NH3) and methane (CH4) production, improved animal health and vitality, and increased meat quality. Tea leaves is one of native plants being rich in secondary metabolites and widely known to have health benefits for human consumption. However, the information on chemical characteristics of tea leaves and their spent tea leaves (STL) as residues along with their prospective as additives for ruminants is still inadequate. Therefore, a series of four studies aimed to evaluate chemical characteristics of tea and their STL as additives for their use in ruminant diets through in-vitro and in-vivo experiments.It can be concluded that tea leaves can be potentially used as additives for ruminants to improve the degradability of low quality forage and to decrease in-vitro rumen NH3 and CH4 productions but their ability to do so by their STL depends upon their tannin and saponin contents. In addition, GTL can improve some mineral digestibility and meat fatty acids quality without affecting animal performance.