Dietary Supplementation with <i>Eucommia ulmoides</i> Leaf Extract Improved the Intestinal Antioxidant Capacity, Immune Response, and Disease Resistance against <i>Streptococcus agalactiae</i> in Genetically Improved Farmed Tilapia (GIFT; <i>Oreochromis niloticus</i>)

Abstract

A 7-week rearing trial was designed to investigate the effects of Eucommia ulmoides leaf extract (ELE) on growth performance, body composition, antioxidant capacity, immune response, and disease susceptibility of diet-fed GIFT. The results showed that dietary ELE did not affect growth performance or whole-body composition (p > 0.05). Compared with the control group, plasma ALB contents increased in the 0.06% dietary ELE group (p p CAT and SOD (p Hsp70 (p TLR2, MyD88, and NF-κB mRNA levels (p TGF-β and IL-10 were upregulated by supplementation with 0.04% and 0.06% dietary ELE (p FADD mRNA (p S. agalactiae showed that 0.06% dietary ELE could inhibit bacterial infection, and significantly improve the survival rate of GIFT (p Streptococcus agalactiae.

Keywords

• <i>Eucommia ulmoides</i> leaf extract
• antioxidant capacity
• immune response
• apoptosis
• disease resistance
• GIFT