LYSOZYME ACTIVITY IN JUVENILE TIGER GROUPER, Epihnephelus fuscoguttatus FOLLOWING ADMINISTRATION OF BIO-ENCAPSULATED VIBRIOSIS VACCINE

Firdaus-Nawi, M.*, Zamri-Saad, M., Nik-Haiha, N.Y., Shuhada,
A. and Shaharah, M.I.
 
Faculty of Veterinary Medicine
University Putra Malaysia
43400, UPM Serdang
Selangor, Malaysia
firdausnawi_18@yahoo.com

Fish lysozyme is an enzyme with antibiotic properties that is released by leucocytes. It has a broader activity compared to the mammalian lysozyme (Demers and Bayne, 1997). Lysozyme is frequently used as an indicator for non-specific immune functions, which is of primary importance in combating infections in fish (Murray and Fletcher 1976; Lie et al. 1989). Fish lysozyme is principally distributed in the head kidney, skin, gastrointestinal tract and eggs, where the probability of bacterial invasion is high. Furthermore, lysozyme has been detected in the peripheral blood, cutaneous mucus and certain tissues of both marine and freshwater fishes (Fletcher and Grant, 1968; Ebran et al., 2000; Fagan et al., 2003). Similarly, lysozyme activity has been identified in monocytes and neutrophils of plaice, Pleuronectes platessa L., (Fletcher and White, 1973). This study describes the detection of lysozyme activity in the body mucus and intestinal tract of juvenile tiger grouper, Epeniphelus fuscoguttatus.

This is a 120-day study that determines the level of lysozyme in body mucus and intestinal lavage of juvenile tiger grouper. Vaccination was by oral administration of bio-encapsulated rotifer at 15 and artemia salina at 30 days of age. Samples of body mucus and intestinal lavage were collected from 30, 45, 60, 75, 90, 105 and 120 days old grouper before the lysozyme activity was determined by measuring the ability to lyse Micrococcus lysodeikticus. Lysozyme activity was highest in the body mucus and intestinal lavage of grouper at 30 days old and decreased at day-45. However, it's started to increase gradually with the increasing of age at 60 days old and above (Fig.1). Similar pattern was observed in the intestine. Highest activity was observed in posterior followed by mid and anterior intestine. Lowest activity was recorded in the body mucus. High activity at 30 days old was due to administration of booster dose. In general, vaccinated grouper showed significantly (p<0.05) higher activity than the unvaccinated grouper. This finding suggests that vaccination against vibriosis can start as early as 15 days and booster at 30 days old.