Considering both growth performance and feed intake, we find that GW can
serve as an alternative source of protein for monosex tilapia fry up to 20%
inclusion. We observed significantly better water quality and comparatively
better weight gain of fry in tanks supplied with 20% GW protein diet than
0% and 10% GW protein diets. Therefore, 20% fishmeal replacement (or
12.54% GW in the diet) can be recommended for monosex male tilapia
culture. Inclusion of 5% Ulva sp. (another seaweed) meal increased growth
performance in the Nile tilapia (Ergün et al. 2009). In another study, 10%
Ulva sp. diets improved growth in sea bass (Dicentrarchus labrax) juveniles
(Valente et al. 2006). El-Tawil and Amer (2010) reported reduced growth
performance of Nile tilapia fed a diet replacing 15% fish meal with Ulva sp.
Since we managed to successfully replace 20% of fishmeal with GW protein,
it may be that the GW is a better protein source than Ulva sp. for tilapia fry
growth and feed intake.