Not all aquafeed supplements are created equal
High quality meals like krill and squid have traditionally been the main supplements used to promote growth of farmed prawns. Although cost-effective, these meals use precious marine resources harvested from finite reserves.
NovacqTM, our patented microbial biomass developed at CSIRO, is an environmentally friendly product. It is made by converting carbon waste, like bagasse and molasses, into a growth enhancing aquaculture supplement. Our recent study published in Aquaculture shows that NovacqTM is even more effective than traditional products. The efficacy and mode of action of NovacqTM was directly compared with traditional supplements.
In our study, juvenile tiger prawns were fed diets containing equal amounts of NovacqTM, krill meal, krill hydrolysate, and whole squid. These test ingredients improved prawn growth, however NovacqTM generated much faster gains. Efficiency was also improved with NovacqTM by converting more of the macronutrients from the diet into body weight. The NovacqTM diet also influenced the microbiome of the prawns reducing the relative abundance of Vibrio bacteria that can cause disease in farmed prawns.
Interestingly, by restricting feed intake, the growth effect of the test ingredients was limited, particularly for NovacqTM fed prawns. On restricted feed rations all prawns became more efficient at converting macronutrients into body weight due to a heightened digestive capacity, however all animals grew much slower compared to those fed to their appetite. Changes were also observed in the microbiome of prawns fed the restricted diet with comparatively lower levels of potentially detrimental bacteria.
In essence the growth effect from feeding NovacqTM is maximised when prawns are allowed to consume as much food as they want. Prawns fed NovacqTM converted more energy into body weight and retained more nutrients than other animals. Comparatively, prawns fed the other diets ate a similar amount but grew slower and did not use the food as well as NovacqTM fed prawns.
The outcomes from this study highlight the need to manage feeding judiciously on farm so that good quality feeds achieve maximum benefits.
CSIRO Aquaculture contact
Dr Cedric Simon – Principal Research Scientist