Effect of Three Plant Oils on Aeromonas hydrophila Infection, Immune-Related Renal Gene Expression, and Serum Biochemical Parameters in the Common Carp

      Medicinal plants can be cost-effective, more productive, and alternative anti-bacterial agents in aquaculture, exhibiting many biological effects as anti-stress action and immune stimulation against various diseases. The present study aimed to evaluate the effect of three types of plant oils, namely mint, chamomile, and ginger on some serum biochemical parameters, Aeromonas hydrophila infection, as well as immune performance and mRNA levels of some renal immune-related genes (il-1β, il-8, il-10, and tnf-α) in common carp. We used for this purpose 120 fish with an average weight of 250 ± 4 g. Fish were fed on an experimental diet of 5% of the weight divided into two meals per day. The experiment continued for 120 days with adaptation. The results showed that mint oil had a superior effect on the serum total protein, ginger oil treatment induced the highest serum alkaline phosphatase activity, and chamomile oil treatment induced the highest serum alanine aminotransferase activity. Both ginger and mint oil treatments recorded the highest serum aspartate aminotransferase activity. The mint treatment proved effective at treating experimentally-induced Aeromonas hydrophila infection, reducing the infection rate to 0%. Mint oil treatment caused a significant elevation in the expression of renal il-8, il-10, and tnf-αmRNA, chamomile oil treatment caused a significant elevation in the expression of renal il-8 and il-10 mRNA, and ginger oil treatment caused a significant change in the expression of renal il-1β, il-8, and tnf-α. The results showed that these three oils improved production performance and enhanced the expression of some immune-related genes against bacterial infections.