27
Insights on hatchery feed for Penaeus monodon postlarvae: custard diets supplemented with microbial biomass NovacqTM improve survival and enhance growth of larger animals Artur N. Rombenso, Ha Truong, Cedric Simon, CSIRO
The use of microbial biomass as a complimentary ingredient or feed additive has been highlighted as a promising strategy to promote growth and health of Penaeid prawns (Litopenaeus vannamei and Penaeus monodon) and sustainability of aquafeeds (Burford et al., 2004; Kuhn et al., 2008, 2009; Glencross et al., 2013, 2014, 2015; Arnold et al., 2016; Qiu and Davis, 2018). Currently, there is a variety of microbial origin products including pro- and pre-biotics, immune-stimulants, and proteins, among others. Their distinct microbial composition and manufacturing procedures generally result in different nutritional characteristics used in aquafeeds and aquaculture systems. NovacqTM, a microbial biomass-based dry ingredient, has been successfully applied in juvenile (3-8g) P. monodon diets at inclusion rates ranging from 5-10 percent supporting better growth (up to 50 percent increase), increasing feed intake, and improving performance on suboptimal diets (lower protein content or with no marine products like fishmeal) (Glencross et al., 2013, 2014, 2015; Arnold et al., 2016). However, there is no report on the usefulness of microbial biomass in P. monodon postlarvae. Egg custard diets have been investigated in the freshwater prawn Macrobrachium rosenbergii larval rearing and postlarvae due to their excellent nutritional
profile and high digestibility (Alam et al., 1995, Nair et al., 2007; Shailender et al., 2012; Sin and Shapawi 2017). However, there is a lack of nutritional studies evaluating the suitability of formulated custard diets in P. monodon postlarvae. Accordingly, we assessed the suitability of custard diets (experiment 1) and the effects of NovacqTM supplementation in custard diets (experiment 2) on P. monodon postlarvae survival and growth performance.
Material and methods Experiment 1 Two dietary treatments were tested, a control custard and a commercial diet (Frippak, INVE). For the control custard diet, all ingredients (Table 1) were mixed using a food processor and cooked in the microwave for approximately 15 minutes until a spongy texture was achieved. The dough was then spread evenly onto a tray and oven dried for 12 hr at 60°C. Once cooled, the diet was ground and sieved to three crumble size-ranges (125-250 µm, 250-350 µm, 350-500 µm). Approximately 3,840 postlarvae (PL3) were individually counted and randomly allocated to sixteen 6-L tanks at a stocking density of 40 PL/L (240PL/tank) at Bribie Island Research Centre (BIRC, Queensland, Australia). The experimental system was set up with a flow-through system with continuous aeration and
Hatcheryfeed Vol 7 Issue 3 2019