Growth Performance of Yellow Croaker Fed Extruded Feed and Fresh Fish Rations in Cage Trials at Ningbo and Wenzhou, China
Region: Northeast AsiaDownload
Yellow croaker (Pseudosciaena crocea) growth in cages was evaluated from fingerling to sub-market size with extruded pellet and fresh fish rations in ASA feeding trials at Xiangshan, Ningbo and Nanji Island, Wenzhou. The extruded feed was a soymeal-based ration containing 43% crude protein and 12% fat and was fed in extruded, floating pellet form. Fresh fish was fed in chopped form. Yellow croaker fingerlings were stocked in 8.0-m3 cages at 200 fish per m3 in the Ningbo trial and 175 fish per m3 in the Wenzhou trial. In the Ningbo trial, yellow croaker grew from 3.2 g to 37.9 g in 103 days on the extruded feed, with an FRC of 1.69:1, and from 3.4 g to 44.0 g in 103 days on the fresh fish ration, with an FCR of 9.92:1. Net income and ROI were 27% and 82% higher, respectively, for fish fed the extruded feed than for fish fed the fresh fish ration in the Ningbo trial. In the Wenzhou trial, yellow croaker grew from 5.4 g to 23.4 g in 62 days on the extruded feed, with an FCR of 1.53:1, and from 5.6 g to 25.4 g in 62 days on the fresh fish ration, with an FCR of 4.98:1. Net income and ROI in the Wenzhou trial were nearly identical for the two feed treatments, but any increase in the cost of fresh fish above the RMB 1.0/kg rate that prevailed during the trial would favor the use of the extruded feed. Results of both trials demonstrated good growth performance, feed conversion and economic return with the soymeal-based extruded feed and ASA cage technology. The added benefits of quality consistency, less nutrient loading of the aquatic environment, ease in shipping and storing, and absence of potential pathogens make manufactured feed a better choice than fresh fish for feeding yellow croaker.