QUERCETIN AND ALLICIN AS PROPHYLACTIC HERBS FOR BRACKISHWATER TILAPIA IN PERIPHYTON NURSERY SYSTEM

Ibnu Sahidhir*, Abdul Razaq, M. Yasir, Hasanuddin, Abidin Nur and Kevin Fitzsimmons
 
Brackishwater Aquaculture Development Center of Ujung Batee, Aceh, Indonesia
ibnusahidhir@yahoo.com

 

Disease prevention by regularly delivering antibiotics in feed is discouraged due to emergence of resistant bacteria. Quercetin and allicin are bioactive substances in onion and garlic respectively that posses anti-microbial properties. The objective of this study is to test allicin and quercetin as prophylactic in feed for tilapia fingerlings cultured in a periphyton system. The studies were conducted the first two times with quercetin and then with allicin. Each test was conducted with 5 treatments and 3 replications. Quercetin and allicin were applied to feed by top dressing, each test with 0 ppm, 100 ppm, 200 ppm, 300 ppm, 400 ppm (w/w). To promote growth of the periphyton community a cylinder-formed of small mesh size hapa with dimension 60 cm in diameter and 90 cm high was used as a unit of replication. Each unit of hapa contained 45 brackishwater-adapted tilapia fingerlings sized +0.5 gr. The tilapia was reared in brackishwater (10-12 ppt) and fed 4% of body weight/day with feeding frequency twice a day.

The result revealed that allicin increased survival rate of tilapia from 81% at 0 ppm to 93-98% in 100-400 ppm (p<0.05) (Table 1). No significant differences in survival rate were found in any of dose range 100-400 ppm with quercetin addition in the diet (p>0.05) (Table 2). Though quercetin seemed to have reduced weight gain significantly, the specific growth rate and feed conversion ratios with quercetin were not different.  The FCRs in both trials were very low, which implies that the fish consumed the feed efficiently and probably grazed a considerable amount of periphyton.  Confirmation came from evaluation of intestinal content of the fish with abundant remains of periphytic organisms. The study showed that dietary allicin was able to improve survival rate of tilapia fingerlings and that quercetin had no significant effect on survival rate.