Effect of Dietary Seaweed Supplementation on Growth, Feed Utilization, Digestibility Co-efficient, Digestive Enzyme Activity and Challenge Study against Aeromonas hydrophila of Nile Tilapia Oreochromis niloticus

Abstract

Background: The present study aimed to determine the growth, digestibility co-efficient, digestive enzyme activity and disease resistance of juvenile GIF tilapia fed with Ulva seaweed meal supplemented diet. Methods: The study was undertaken with different inclusion levels of Ulva seaweed meal (USM) such as raw (UR) and fermented (UF) Ulva meal (UR-5, UR-10, UR-15, UF-5, UF-10 and UF-15% of diet) and control feed (C) for a period of 60 days. Result: GIFT fed with fermented Ulva meal at a 10% inclusion level in their diet exhibited the highest growth performance (41.43 g) followed by UF5 (41.07±0.43 g), UR5 (39.65±0.36 g), control (39.09±0.20 g), UF15 (38.67±0.26 g), UR10 (38.47±1.47 g) and UR15 (35.77±0.35 g) diet. The highest apparent digestibility coefficient (ADC) with crude protein (85.14±0.91%) was observed in fishes fed with fermented Ulva meal at 10% inclusion rate than that of other treatments group for dry matter, ether extract and gross energy. The digestive enzymatic activities, amylase (0.029±0.00 units/mg protein/min), protease (0.147±0.0 units/mgprotein/min) and Lipase (0.273±0.05 units/mg protein/min), showed higher level in fishes fed with diet containing 10% fermented Ulva meal compared to other treatment groups including control. Moreover, at the end of the trial, increased survival rate (86.66%) was observed with fishes fed with Ulva based diets challenged against Aeromonas hydrophila. The histopathological study showed a lower level of infection in fishes fed with 10% fermented Ulva meal supplementation. The present study concluded that the requirement of Ulva meal in fish diet shows the following trend 10% of Ulva Fermented (UF) and UF-5, Ulva Raw (UR) 5%, control (C), UF-15, UR-10 and UR-15 diet that can improve the health status of the GIF tilapia.