Even prawns like custard, and more so when baked with Novacq™
Custard tarts, crème brûlée and English trifle – everyone likes custard, and prawns are no exception. Egg custard feeds have been investigated in the freshwater prawn Macrobrachium rosenbergii larval rearing and postlarvae (PLs) due to their particle size, soft format, high water stability, excellent nutritional profile and high digestibility. Supplementation of NovacqTM, a microbial biomass-based ingredient, has been successful in juvenile P. monodon feeds increasing growth, health and feed efficiency.
Custard diets have not been used widely to feed larval penaeids, but may offer an experimental method for effective delivery of NovacqTM in hatcheries. Accordingly, we assessed the suitability of a modified custard feed formulation (experiment 1) and the effects of NovacqTM supplementation (experiment 2) on P. monodon PLs survival and growth performance.
After a 21-day feeding trial (Control custard vs. commercial PL feed), PLs readily accepted the Control custard feed performing equivalent to the commercial feed. Despite the differences in dietary proximate composition, PLs were able to maintain suitable growth with 20% less protein in the custard diets, suggesting the increased availability of better-quality protein may have improved digestibility and nutrient utilisation.
In the following experiment, custard feeds (Control vs. NovacqTM) were accepted and utilised by PLs with no differences in average growth. However, PLs fed the NovacqTM custard feed had higher survival (7% increase) than those fed the Control custard feed, and the faster growing PLs were significantly bigger on the NovacqTM custard feed.
Our findings demonstrate the suitability of custard diets in P. monodon PLs for hatchery nutrition research and that NovacqTM appears to be a beneficial ingredient in PL nutrition, improving survival and enhancing the growth of better-performing PLs.
For more information, read Hatcheryfeed, Vol 7 Issue 3 2019.
CSIRO Aquaculture contact
Dr Artur Rombenso – Research Scientist
Dr Ha Truong – Research Scientist
Dr Cedric Simon – Principal Research Scientist