Abstract

Corn silks are threads found in the maize plant (Zea mays) and traditionally used to treat urological infections and disorders. Corn silk is also known to possess nutrients and volatile compounds. However, this material is often disregarded and unused. This study therefore investigated the potential use of corn silk in aquaculture through its protective capacity in matured Nile tilapia (Oreochromis niloticus (L.) by measuring some nonspecific immune parameters (phagocytosis, production of reactive oxygen species, and plasma lysozyme level) in experimental Aeromonas hydrophila-challenged fish. The anti-oxidative property of corn silk was also investigated using paracetamol-induced hepatic toxicity in order to measure oxidative stress (malondialdehyde or MDA). Based on the results, phagocytosis was significantly higher in A. hydrophila infected fish fed with corn silk-coated feeds than in fish from the negative (PBS-injected) and positive control (Aeromonas hydrophila infected) treatments. Lysozyme level was also higher in corn silk-fed fish, but it was not significantly different from the positive control fish (A. hydrophila infected fish). Reactive oxygen species (ROS) was higher in corn silk-fed fish than the positive control fish but it was not statistically significant. MDA levels were significantly higher in paracetamol-treated fish than paracetamol-corn silk treated group. The results showed the potential immunostimulatory and antioxidant role of corn silk in Nile tilapia, but further studies are required to fully understand its mechanism of action and its full use in aquaculture.

Key words: Corn silk, lipid peroxidation, Aeromonas hydrophila, Oreochromis niloticus, immunostimulation.