SEAWEED (HYPNEA SP.) SUPPLEMENTATION IN FEED PLAY ROLE IN BOOSTING IMMUNITY OF NILE TILAPIA (OREOCHROMIS NILOTICUS)

Abstract

Hypnea sp. is the most common economically potential seaweed species in
Bangladesh. In this experiment, an initiative was taken to formulate fish feed
using seaweed (Hypnea sp.) that can improve the immunity of Nile Tilapia,
Oreochromis niloticus. Seaweed was supplemented in different percentages with
commercial feed to evaluate their effects on their serum bactericidal activities. A
90-days experiment was conducted under five treatments – T1 (5% seaweed), T2
(10% seaweed), T3 (15% seaweed), T4 (20% seaweed) and C (only commercial
feed) with a replica for each. Fish blood was collected, serum was separated from
blood and serum bactericidal activity was tested. Blood serum of 10% seaweed
treated fish showed the highest sensitivity against three bacteria (Bacillus cereus,
Salmonella typhimurium, Shigella flexneri) followed by 5% seaweed which showed
sensitivity against Bacillus cereus and slightly against Salmonella typhimurium and
Shigella flexneri and 15% seaweed showed slight bactericidal activity against
Bacillus cereus only, whereas, no bactericidal activity was observed for control
and 20% seaweed treated fishes. The result indicates that the use of an optimum
amount of seaweed supplements can improve the immunity system of Nile
tilapia which can prevent the growth of bacteria and likely make fishes safe for
human consumption.