The effect of vitamin B complex and phosphorus on the RNA/DNA ratio and larval growth of barramundi (Lates calcarifer Bloch, 1790)

Barramundi (L. calcarifer) is a valuable fish with aquaculture potential. One of the factors determining the success of barramundi aquaculture is the availability of seeds, however larviculture success is often low. This research examined the effect of supplementation with various combinations of vitamin B complex and phosphorus on the RNA/DNA ratio and growth of captive-bred barramundi larvae. Barramundi larvae aged 2 days were stocked at a density of 25 fish/L and reared for 30 days with natural feed (Chlorella and rotifers) in 40 L containers filled with 30 L water. Commercial vitamin B complex and mineral phosphorus were dissolved in water and added to the larval rearing media. The research used a completely randomized factorial design with 2 factors, 4 levels and 3 replicates, giving 16 treatments and 48 experimental units. The factors were vitamin B complex (0, 75, 150, and 225 mg/L) and phosphorus (0, 0.5, 1.0, and 1.5 mg/L). Analysis of variance showed that the combination of vitamin B complex and phosphorus had a highly significant effect (p<0.01) on the RNA/DNA ratio. Barramundi larval growth was lowest with 0 mg/L of both supplements (control) and highest with 150mg/L vitamin B complex and 1.0 mg/L phosphorus, decreasing with higher levels of either additive.