The interactive effects of dietary protein and energy on feed intake, growth and protein utilization of juvenile mulloway (Argyrosomus japonicus).
Pirozzi I, Booth MA and Allan GL (2010) The interactive effects of dietary protein and energy on feed intake, growth and protein utilization of juvenile mulloway (Argyrosomus japonicus). Aquaculture Nutrition, 16, 61-71.
Available online: http://dx.doi.org/10.1111/j.1365-2095.2008.00641.x
Mulloway, Argyrosomus japonicus, are considered a good candidate for aquaculture in Australia due to their wide distribution, ease of adaptation to different culture systems and good growth rates. To date, however, there is no published information on the nutritional requirements for dietary protein and energy for this species and, as a consequence, no specifically formulated diets are currently available. The objectives of this study were to determine the optimal dietary digestible protein (DP) content and the optimal DP to digestible energy ratio (DP:DE ) for juvenile mulloway by testing the effects of diets containing one of four different DP levels (25 - 55% ) at two DE levels (16 or 21 MJ kg-1) on feed intake, growth, protein utilization and carcass composition. Juvenile mulloway were stocked into 200 l tanks at each of two different sizes (70 or 200 g) in triplicate groups for each dietary treatment and fed twice daily to apparent satiation over 58 days. The results indicate that feed intake was not governed solely by energy demands but was also influenced by the DP content of the diet. Increasing dietary energy did not improve protein utilization indicating that mulloway have a limited capacity to spare dietary protein. Optimal dietary DP content was found to be 44-49% depending on the DE content of the diet and the size of mulloway and is within the range reported for other sciaenid species. The use of formulated diets with 28.6 g DP MJ DE-1 will achieve optimal growth and protein deposition for 70 275g mulloway.