Effects of blood meal as a substitute for fish meal in the culture of juvenile Silver Pompano Trachinotus blochii (Lacepède, 1801) in a circulating aquaculture system

A feeding trial was conducted for 12 weeks to evaluate the nutritive value of fermented and un-fermented blood meal as a possible protein source for diets of juvenile silver pompano, Trachinotus blochii. The experiments were carried out concurrently in a completely randomized design. A total of 330 fish (10.98 ±0. 5g and 12. 52±0. 01 cm) were stocked in 33 tanks (1000 L) for 8 weeks and fed one of the experimental diets at 10% body weight per day in 3 equal feedings. Eleven isonitrogenous experimental diets (45% crude protein and 12% crude lipid) were prepared by replacing fish meal levels from 5, 15, 25, 35 and 45% with) fermented and unfermented blood meal, and a 100% fish meal based diet was used as a control diet. Fish fed a 35% experimental diet of fermented blood meal and unfermented blood meal exhibited significantly higher growth performance compared to fish fed the control diet of 100% fish meal and 5, 15, 25 and 45% experimental diets replaced with both fermented and unfermented blood meal (weight gain 88.06 – 67.33 g; FCR 1.14 - 1.65; SGR 3.2 - 3.11; and PER 1.94 -1.34) respectively. The overall performance was significant higher in fermented diets (88.06 g at 35%) than unfermented diets (67.33 g). The levels of lipid and ash in the whole body carcass increased as both fermented and un-fermented blood meal substitution in diets increased, whereas protein and moisture decreased in all treatment groups compared with the control. These results showed that approximately 35% of fish meal protein could be replaced by both fermented and unfermented blood meal for juvenile silver pompano without compromising growth performance and feed efficiency, potentially leading to significant cost saving.