Effects of Common Duckweed on Growth Performance, Survival and Intestinal Morphology of Rohu, Labeo rohita(Hamilton, 1822) Fry in Biofloc System

This study investigated the effects of incorporating varying levels of fermented common duckweed, Lemna minor (FLM), on the growth performance, survival, and intestinal morphology of rohu, Labeo rohita fry, in a biofloc system for 90 days. The fry (2.6 ± 0.12 cm and 0.3 ± 0.03 g) were reared at a stocking density of 15 fry 100 L-1 in circular tanks following a completely randomised design. Five isonitrogenous (25% crude protein) diets were formulated by incorporating fermented common duckweed, viz., Control (0%), FLM10 (10%), FLM20 (20%), FLM30 (30%), and FLM40 (40%). No significant differences (p > 0.05) were observed in the growth performance of fish among treatments, and survival ranged from 96% to 98%. The FLM40 group showed significantly greater villus length (p < 0.05), which was similar to the control. No significant differences (p > 0.05) were observed in villus width, crypt depth, and muscularis thickness of rohu fed experimental diets. Incorporating higher levels of duckweed progressively reduced the cost of formulatedfeed. The study concluded that 5% wet yeast fermented common duckweed can be incorporated up to 40% in the diet of rohu fry without adversely affecting growth performance or survival in a biofloc system.