Ridley, Australia’s largest commercial provider of high-performance animal nutrition and Australian Prawn Farms, Ilbilbie, Queensland, made a commercial-scale trial showing a new diet with lower levels of protein can produce the same sized prawns with less impact on the environment, achieving its advance in sustainable production.
In the trial, prawns were fed the novel diet called Propel Grower which has an impressive 19.5 % less protein than previous industry levels (37 vs. 46%, respectively), and contains a unique microbial biomass ingredient called NovaqPro. This product was originally developed by CSIRO and commercialized by Ridley as part of a 12-year program of research investment.
Food typically fed to farmed prawns has a high protein level −made up of fish meal, fish oils and grain− to support good prawn growth. High protein diets have a higher nutrient output which the industry is seeking to address in its focus on more sustainable production methods.
Ridley’s Customer Solutions Manager Aquaculture, Richard Smullen, said NovaqPro has been a key ingredient in allowing Ridley to reduce protein across its prawn diets by nearly 24% since 2019.
“The recent Australian Prawn Farm trial compared feeding a Propel Starter, and a Propel Grower diet, both containing NovaqPro, versus feeding a high-performing traditional Ridley program. At the end of the growth cycle the ponds recorded an 8% better feed conversion, 10% better survival rates, and a 13% improvement in yield for the prawns fed the NovaqPro –containing feeds,” Smullen explained.
“Put simply, there were greater numbers of prawns in the ponds when it came time to harvest. But most impressive of all was there was nearly a 40% reduction in nitrogen output for every tone of prawns produced which is a big win for the environmental credentials of the farm,” added the Manager.
Step towards the sustainability
In the other hand, Australian Prawn Farms General Manager Matt West says the results were impressive and a significant step towards the ongoing sustainability of the industry.
“We found there was improved water quality and pond performance, as well as less environmental impact but more than that, we also saw prawns grow at the same rate and to the same size as those on a traditional diet containing higher levels of protein, fish meal and oil.”
The results build on award winning farm-based research in 2020-1 which demonstrated with the addition of NovaqPro and other proprietary ingredients, prawn diets could include significantly less fish meal and fish oil.
Need for additional alternative raw materials
Smullen said with the global growth in aquaculture could see an increasing demand for marine resources and this creates a need for additional alternative raw materials, and this research preempted a step change for industry.
“The research demonstrated the effectiveness of Ridley’s NovaqPro containing Propel diet with reduced fish meal and protein levels in commercial ponds, and with an industry focused on sustainable production, all major prawn farmers in Australia have begun feeding some level of the diet over the past season,” he explained.
“Ridley’s Propel prawn diet allows Australian prawn farmers to meet the standards for sustainable aquaculture set by Best Aquaculture Practices and the Aquaculture Stewardship Council.”
As they detailed in a press release, sustainable seafood is measured in terms of a fish-in fish-out ratio (FIFO). This is a measure of the quantity of live fish caught in the wild for each unit of farmed fish or prawns produced. The lower the FIFO, the bigger the environmental impact. Prawns fed the Ridley Propel range meet the Best Aquaculture Practices standard for FIFO.
The diet won the Environmental award at the Queensland Seafood Industry Council 2022 Awards.
Note: FIFO of 0.5 means 0.5 kg of wild fish are used to grow 1 kilogram of prawns.