Fuente: PubMed "industrial biotechnology" Microb Pathog. 2026 Mar 7:108432. doi: 10.1016/j.micpath.2026.108432. Online ahead of print.ABSTRACTThe non-protein amino acid L-theanine derived from Camellia sinensis may enhance animal productivity. Its elevated bioavailability and rapid metabolism address contemporary animal husbandry challenges. In the central nervous system, it regulates neurotransmission and promotes alpha-wave activity, which is associated with relaxation. It diminishes glutamatergic excitability and enhances gamma-aminobutyric acid (GABA)-mediated inhibition. This modulation reduces stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis and cortisol levels in animals. L-theanine promotes the proliferation of T lymphocytes known as gamma delta (γδ) T-cells and natural killer (NK) cells, while regulating neuroactivity and inflammatory cytokine responses. Elevated levels of tight junction proteins and gut microbiota such as Lactobacillus and Bifidobacterium enhance intestinal health. These effects ultimately enhance the growth, feed efficiency, and meat quality of poultry, swine, and aquaculture. Previous ruminant studies indicate a decrease in heat stress and an enhancement in nutritional digestibility. This review synthesizes available literature on L-theanine to address knowledge gaps in species-specific mechanisms and long-term safety, providing recommendations for researchers and industry. Commercializing these advantages necessitates species- and stage-specific dose protocols, efficient production and delivery, as well as long-term safety and multi-generational efficacy assessments. Future research must concentrate on enhanced delivery mechanisms, synergistic combinations with other functional feed components, and extensive field trials to establish L-theanine as a fundamental element of natural, health-enhancing animal nutrition.PMID:41802656 | DOI:10.1016/j.micpath.2026.108432