Transcriptome analysis revealed both the potential damaging and benefiting effects of long-term Phellodendri Cortex supplementation on the intestine of tiger grouper (Epinephelus fuscoguttatus)

Previous study has shown that short-term (2-week) supplementation of Phellodendri Cortex (PC) significantly decrease the cumulative mortality of Epinephelus fuscoguttatus (tiger grouper) after Vibrio harveyi infection and exhibited significant anti-inflammatory effects in the head-kidney of tiger grouper. In this study, we explored the long-term (8 weeks) effect of PC supplementation on tiger grouper' s growth, non-spectic immunity, disease resistance and intestine gene expression. Results showed that 8-week PC diet did not affect the growth or vibrio disease resistance of tiger grouper. Serum biochemical analysis revealed that the ALP and LZM activities were significantly increased in the fish serum. Transcriptome analysis suggested that long-term PC supplementation to grouper diet may potentially damage the structural and functional integrity of healthy grouper intestine. On the other hand, long-term PC supplementation also exhibited potential anti-inflammatory and cathepsin inhibition effects, which would be helpful for prevention and therapy of fish enteritis. In summary, long-term PC supplementation in grouper culture should be applied with caution.