Effects of ferulic acid on the growth performance, physiological and biochemical functions, and hepato-intestinal health of blunt snout bream, Megalobrama amblycephala

To investigate the impact of dietary inclusion of ferulic acid (FA) on growth performance, physiological and biochemical functions and hepato-intestinal health, three iso-nitrogenous and iso-lipidic diets supplemented with 0 mg/kg, 100 mg/kg, and 200 mg/kg FA were fed to Megalobrama amblycephala (9.75 ± 0.04 g) for 8 weeks. The growth performance, physiological and biochemical parameters, antioxidant capacity and the expression of genes were assessed on 4th and 8th week. The results indicated that 100 mg/kg FA inclusion significantly enhanced the weight gain rate (on week 4 and 8), feed intake (on 4th week), protein efficiency ratio (on week 8) and condition factor (on week 4) (P < 0.05). In plasma biochemical index, dietary FA significantly reduced the contents of alanine aminotransferase, glucose and lactate dehydrogenase on 8th week (P < 0.05). In the antioxidant capacity, dietary FA decreased the malondialdehyde (MDA) content in hepatopancreas and intestine (P < 0.05), while increased the activities of total superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and glutathione S-transferase (P < 0.05), and the best effects were observed at 100 mg/kg FA inclusion on 8th week. On 8th week, the supplementation of 100 mg/kg FA down-regulated the expression levels of inflammation-related genes (interleukin-6, interleukin-1β (hepatopancreas only), nuclear factor-κB), pro-apoptotic gene caspase-8 and endoplasmic reticulum stress-related genes (X-box-binding protein 1 S, protein kinase R-like ER kinase, inositol requiring enzyme 1, C/EBP homologous protein, immunoglobulin binding protein (hepatopancreas only), activated transcription factor 6α, activated transcription factor 4) (P < 0.05), while the anti-apoptotic gene B lymphoblastoma-2 was significantly up-regulated (P < 0.05). In conclusion, FA enhanced the growth performance, antioxidant and anti-inflammatory properties, reduced apoptosis level, and maintained the hepato-intestinal endoplasmic reticulum homeostasis. The FA inclusion was suggested at 100 mg/kg.