High GABA-producing Lactococcus lactis ZFM559 and its derived GABA alleviates chronic unpredictable mild stress (CUMS)-induced depression via the “microbiota-brain” axis

γ-aminobutyric acid (GABA) is a crucial inhibitory neurotransmitter with recognized benefits in alleviating depression. However, the ability of exogenous GABA to cross the blood-brain barrier remains debated, and the underlying...