Studies On Dietary Protein And Lipid Requirement Of Sepiella Maindroni

The experiment was conducted to study the dietary protein and lipid requirement oncuttlefish Sepiella maindroni. Firstly，fishmeal and casein were used as dietary protein source toformulate five kinds of experimental diets at different protein levels (30%、35%、40%、45%and50%). A60-day feeding trial was conducted to investigate the effects of the dietary protein levelson growth performance, feed utilization, biochemical parameters in hepatopancreas, proximatecompositions and acid amino compositions in muscles of Sepiella maindroni whose initialweight were1.59~1.81g, at the temperature of20~23℃and salinity of23~26. Base on theexperimental results, the optimal dietary protein level in diet of Sepiella maindroni wasdetermined. Then a60-day feeding trail was also conducted to determine dietary lipidrequirement of Sepiella maindroni whose initial weight were1.28~1.50g, at the temperature of22~25℃and salinity of24~27. Fishmeal was used as main protein source and fish oil was usedas main lipid source to formulate five kinds of isonitrogen experimental diets at different lipidlevels (6%,8%,10%,12%and14%). Results of the present study were showed as following:1. Studies on dietary protein requirement of cuttlefish, Sepiella maindroniAfter feeding cuttlefish with different protein levels diets for60days, cuttlefish fed dietswith45.9%and51.5%dietary protein had significantly higher WGR, SGR, CF, FCR, PCR, SRand protein content of muscle than those groups with other dietary protein level (P<0.05). Therewere no significant difference in crude lipid and crude ash contents of muscle of cuttlefishamong groups. The activities of protease, GPT, GOT, SOD, AKP and ACP in hepatopancreas ofcuttlefish fed45.9%and51.5%dietary protein were significantly higher than other groups. Thevalues of MDA in hepatopancreas of cuttlefish fed45.9%and51.5%dietary protein weresignificantly lower than those fed diets with36.0%and41.6%dietary protein. The total aminoacid and total essential amino acid contents in muscle of cuttlefish did not change markedly withincreasing dietary protein level (from31.3%to41.6%)(P>0.05). cuttlefish fed diets with45.9%and51.5%dietary protein levels showed significantly higher contents of total amino acid andtotal essential amino acid in muscle than those fed diets with lower dietary protein level(P<0.05)。2. Studies on dietary lipid requirement of cuttlefish, Sepiella maindroniAfter feeding cuttlefish with different lipid levels diets for60days. Cuttlefish fed diets with8.09%and10.05%dietary lipid had significantly higher WGR, CF, HIS, SGR, FCR, PCR, SR and protein contents of muscle (P<0.05) than those groups with other dietary lipid level (P<0.05).The crude lipid contents in8.09%and10.05%dietary lipid level was significantly lower thanthose of in the groups with other dietary lipid level (P<0.05). There was no significant differencein crude ash contents of muscle among all groups. The activities of protease, SOD, AKP andACP in hepatopancreas of cuttlefish fed diets with8.09%and10.05%dietary lipid weresignificantly higher than those of other groups. The values of MDA in hepatopancreas and thecontents of UFA and PUFA in muscle of cuttlefish fed8.09%and10.05%dietary lipid were alittle lower than those fed12.09%and14.08%dietary lipid.In conclusion, the results suggested that the optimal dietary protein level and dietary lipidlevel for cuttlefish were45.9~51.5%and8.09%~10.05%respectively.