Dose-Dependent Effects of Histamine on Growth, Immunity and Intestinal Health in Juvenile Grouper (Epinephelus coioides)

A 56 day feeding trial was conducted to examine the effects of different levels dietary histamine on growth performance, immune response, and intestinal health grouper ( Epinephelus coioides ). Seven isonitrogenous (46%), isolipidic (10%) diets were prepared with supplement 0 (T0), 0.05% (T1), 0.1% (T2), 0.15% (T3), 0.2% (T4), 0.25% (T5), 0.3% (T6), respectively. The results showed that supplementation had no significant weight gain rate (WGR), specific (SGR), feed conversion (FCR), hepatosomatic index (HSI), survival (SR) at initial period (day 0–28), but WGR SGR negative linear responses level whole 0–56), a decrease observed in groups T5 T6 compared T0 P < 0.05). Supplementation decreased antioxidant capacity, contents serum interleukin-1 beta (IL-1?), intestinal-type fatty acid-binding protein (FABP2) trefoil factor (ITF), caused serious damage intestine significantly VH MFH grouper, especially fish fed supplemented high doses (0.25 0.3%). microbial communities treatments clearly control terms (?)-diversity boxplots UPGMA phylogenetic tree based unweighted unifrac distance. At phylum level, relative abundance Fusobacteria lower group T0, while Firmicutes genus uncultured_bacterium_f_ Bacteroidales _S24-7_group, Lachnospiraceae , Ruminiclostridium higher control, Cetobacterium In conclusion, present study suggested up did not result remarkable reduction growth, health; however, or more could cause E. .