An eight-week feeding trial was conducted to evaluate the effects of soy isoflavone and soy saponin on growth performance, intestinal structure, intestinal immunity and gut microbiota community of rice field eel Monopterus albus (initial weight 20.12 ± 0.15 g). Six isonitrogenous and isolipidic experimental feeds were formulated, including a positive control (55% fish meal, FM), a negative control (28.6% fish meal, 37.2% soybean meal, SBM) and basic diet group (28.6% fish meal, 22.6% soy protein concentrate, SPC), the rest was supplemented wit...