Freshwater pompano (piaractus brachypomus) performs well when raised on soybean meal-based feed

The American Soybean Association (ASA), in cooperation with the Nanjing Jiangpu County Aquatic Technology Extension Station, the Jiangpu Fish Breeding Farm, the Jiangsu Provincial Aquatic Technology Extension Station, and the National Extension Center for Aquatic Technology (NEC), carried out a 2-month pond trial on the culture of freshwater pompano. The aim was to demonstrate the growth and economic performance of the ASA 32/6 soybean-maximized feed and its 80:20 pond culture model in growing large-size freshwater pompano fingerlings to marketable fish.

Materials and Methods The trial was conducted in 3 fish ponds averaging 4.0 mu (0.27 ha) at the Jiangpu County Fish Breeding Farm in Nanjing, Jiangsu Province. The average water depth of the ponds was about 1.5 m. All ponds were equipped with water exchange and aeration equipment. The bottom of each pond was clean and free of organic matter. The freshwater pompano used in the trial had a size of 149 g/fish and was produced by the Nanjing Jiangpu County Fish Breeding Farm. The fingerlings were stocked in early June 2004 at a stocking density of 800 fish/mu (or 12,000 fish/ha), together with silver carp fingerlings stocked at 100 fish/mu (1,500 fish/ha). The fingerlings stocked in the 3 fish ponds were uniform in size and age. The target size for grow-out was 500 g/fish. The freshwater pompano were fed the American Soybean Association's 32/6 all-plant-protein extruded floating pellet grow-out feed (Table 1). The feed was formulated by the American Soybean Association, using maximized dehulled soybean meal in the formulation, and was produced by the Fushou Feed Mill in Xiamen, Fujian Province. The cultured fish were fed twice a day, each time to satiation, and the amount of feed given to each of the 3 ponds was the same each time. The daily management of the culture trial followed the American Soybean Association 80:20 pond culture model. All fish ponds were sampled once on the same day each month. At the end of the trial, all ponds were drained, and all the black carp and silver carp were counted and weighed, and the average fish body weight, gross yield and net yield, feed conversion ratio and survival rate were calculated accordingly. The various production costs invested during the trial were recorded, and net income and return on investment (ROI) were calculated at the end of the trial. Results From June 3 to July 26, 2004, the freshwater pompano were cultured for a total of 54 days, growing from 149 g/fish to an average of 628 g/fish (Table 2). The average gross yields from the culture were 496 kg/mu (7,440 kg/ha) for freshwater pompano and 108 kg/mu (1,620 kg/ha) for silver carp (Table 2). The average survival rates of freshwater pompano and silver carp were 98.7% and 100%, respectively. The average feed conversion ratio of freshwater pompano on the 32/6 soybean-maximized feed was 1.12:1. The harvested freshwater pompano were uniform in size, bright in color, and well-proportioned in body shape. The feed cost per kilogram of fish produced was 4.59 yuan (0.56 USD). Based on the local market price of 8.8 yuan/kg for freshwater pompano (or 1.07 USD/kg) and 4.3 yuan/kg for silver carp (or 0.52 USD/kg), the net income for the 54-day culture cycle was 1,809 yuan/mu (3,285 USD/ha). The average return on investment for the 3 trial ponds was 59.9%. Summary and Conclusions When cultured with the 32/6 soybean meal-based feed and the American Soybean Association 80:20 pond culture model, freshwater pompano showed excellent growth performance and high feed conversion efficiency. In only 54 days, the freshwater pompano grew from 149 g at stocking to 628 g, exceeding the target market size of 500 g by 25%, thus demonstrating the great potential of culturing freshwater pompano with soybean feed. The short culture cycle demonstrated by the trial shows that freshwater pompano can produce two crops in one production season in ponds in the temperate regions of China. That is, in the first year of a 2-year culture cycle, 150 g large-size freshwater pompano fingerlings are produced, and then these 150 g large-size fingerlings are stocked, with a 55-day culture cycle, allowing 2 harvests, with an interval of 10 days for harvesting the first crop and preparing for the second crop of culture. Such a production cycle can be completed within the relatively short period from June 1 to September 30 in the central region of China.