Growth Performance of Yellow Croaker Fingerlings On Extruded Feeds in Coastal Cages at Ningbo, China
Region: Northeast AsiaDownload
Yellow croaker (Pseudosciaena crocea) growth performance in coastal cages was evaluated during the fingerling production cycle with two feeds in a two-part ASA feeding trial at Ningbo, Zhejiang Province, China. Yellow croaker were stocked in six, 2.25-m3 cages at a density of 2,500 fish per cage and fed to satiation daily for 30 days with a 47% crude protein and 15% crude fat (47/15 feed) extruded feed in the first stage of the trial. After 30 days, fish were transferred to six, 8-m3 cages and stocked at a density of 200 fish per m3 for the second stage of the trial. Fish in three of the 8-m3 cages were continued on the 47/15 feed, while fish in three other replicate cages were fed the ASA marine fish growout feed formulated to contain 43% crude protein and 12% crude fat (43/12 feed). Both feeds were fed in extruded, floating pellet form. Fish in all six cages were fed to satiation, three times daily for the first month, and twice daily thereafter. Yellow croaker grew from 2.2 g to 5.7 g in the 30-day, stage one component of the trial. Average FCR with the 47/15 feed during stage one was 1.20:1. Average fish survival was 99.6%. In the second stage, yellow croaker fed the 47/15 feed grew from 5.8 g to 42.4 g in 93 days, while yellow croaker fed the 43/12 feed grew from 5.8 g to 42.8g. Survival averaged 84.7% for fish fed the 47/15 feed, and 85.6% for fish fed the 43/12 feed. FCR averaged 1.66:1 for fish fed the 47/15 feed, and 1.63:1 for fish fed the 43/12 feed. There was no significant difference (P>0.05) in fish growth, survival or FCR for the two feed treatments. Results of the trial indicate that yellow croaker perform well on the 47/15 feed during the first 30 days of the fingerling production cycle, exhibiting excellent growth performance, survival and FCR, but that production performance is not enhanced by feeding the 47/15 feed beyond 30 days. Fish growth performance, survival and FCR were equivalent with the 47/15 and 43/12 feeds during the 93-day, stage-two trial period. At a 23% cost premium for the 47/15 feed, no benefits were demonstrated that would justify use of the higher cost feed after fish attain a size of approximately 5 g. ASA recommends use of the ASA 47/15 feed for culturing yellow croaker from 2 g to 5 g in size, followed by feeding with the ASA 43/12 feed from fish size 5 g to market size.