3.5. Nutritional composition and fodder potentials
The nutritional composition of the seaweeds in this study and the three most common seaweeds used as holothuria feed (Laminaria japonica, Entermorpha prolifera and S. thunbergii) are summarized in Table 5. The ash contents of S. hemiphyllum in the control site and fish farm were 17.16% and 15.85%, respectively, which were lower than those of S. henslowianum, L. japonica and E. prolifera, but higher than that of S. thunbergii. The crude protein contents of the seaweeds in this study ranged from 11.7% to 14.0%, which were higher than those of L. japonica and E. prolifera but lower than that of S. thunbergii. The crude fat contents of the seaweeds in this study ranged from 2.2% to 2.7%, with the maximum and minimum values observed in S. hemiphyllum grown in the control site (2.7%) and fish farm (2.2%), respectively. Both Sargassum spp. in this study contained higher crude fat contents than those of the other three seaweeds used as holothuria feed (ranging from 0.2% to 0.41%), suggesting higher nutritional value. However, as indicated previously, the heavy metal contents (Cr, Pb or Cd) of S. henslowianum exceeded the MAC of aquatic feed. Hence, its fodder potential was lower than that of S. hemiphyllum.