The effect of β-1,3/1,6-glucan, derived from yeast, on growth, antioxidant, and digestive enzyme performance of Pacific red snapper Lutjanus peru before and after exposure to lipopolysaccharides (LPS) was investigated. The β-1,3/1,6-glucan was added to the basal diet at two concentrations (0.1 and 0.2 %). The treatment lasted 6 weeks, with sampling at regular intervals (0, 2, 4, and 6 weeks). At the end of this period, the remaining fish from either control or β-glucan-fed fish were injected intraperitoneally with LPS (3 mg kg(-1)) or with sterile physiological saline solution (SS) and then sampled at 0, 24, and 72 h. The results showed a significant increase (P < 0.05) in growth performance after 6 weeks of feeding with β-glucan. Superoxide dismutase (SOD) activity in liver was significantly higher in diets containing 0.1 % β-glucan in weeks 4 and 6, compared to the control group. β-Glucan supplementation at 0.1 and 0.2 % significantly increased aminopeptidase, trypsin, and chymotrypsin activity. At 72 h after injection of LPS, we observed a significant increase in catalase activity in liver from fish fed diets supplemented with 0.1 and 0.2 % β-glucan; SOD activity increased in fish fed with 0.1 % β-glucan in relation to those injected with SS. Feed supplemented with β-1,3/1,6-glucan increased growth, antioxidant activity, and digestive enzyme activity in Pacific red snapper.