Effects of different dietary iron sources on growth performance, appetite regulation and intestinal health of yellow catfish Pelteobagrus fulvidraco

This research aimed to investigate the effects of five dietary iron sources on growth performance, feed utilization, appetite regulation, antioxidant capacity, endoplasmic reticulum (ER) stress and inflammatory response in the intestine of yellow catfish Pelteobagrus fulvidraco . The experimental diets were formulated with five iron sources, including ferrous sulfate (FeSO 4 ), ferrous bisglycinate (Fe-Gly), ferrous chloride (FeCl 2 ), ferric citrate (Fe-CA) and ferric oxide nanoparticles (Fe 2 O 3 NPs). Yellow catfish (initial body weight: 2.50 ± 0.01 g/fish, mean ± SEM) were fed the experimental diets for 10 weeks. Fish fed the diets with Fe-Gly and Fe 2 O 3 NPs supplementation displayed better growth performance, iron bioavailability, food intake and higher expression of appetite-related genes. Compared to inorganic iron (FeSO 4 and FeCl 2 ) and Fe 2 O 3 NPs, organic iron (Fe-Gly and Fe-CA) exhibited improved intestinal histology, upregulated expression of tight junction-related genes and enhanced antioxidant capacity. Dietary Fe 2 O 3 NPs addition damaged the intestinal antioxidation capacity of yellow catfish by down-regulating the expression and activities of related antioxidant enzymes. Besides, fish fed the Fe 2 O 3 NPs diet also showed higher mRNA and protein levels of ER stress-and inflammation-related genes. Given the above findings, Fe-Gly seems to be a better iron additive for its benefits on growth performance and intestinal health to other iron sources.