Abstract:In order to investigate the effects of grass carp diets,which were added with stickwater meal and fish oil to supplement fish required part of growth factor,on grass carp growth,liver fat content and serum indicators.In practical formulation mode,six experimental diets added 6% pork powder meal(6P),3% pork powder meal +3% stickwater meal(3P3SW),6% stickwater meal(6SW),3% pork powder meal +3% stickwater meal +2% fish oil(3P3SW2O),6% stickwater +2% fish oil(6SW2O),6% fish meal(6F control)were prepared.All the experimental diets were isonitrogenous and isoenergetic.The diets were fed to grass carps[mean initial body weight of(80.0±0.2)g]in pond cages for 72 d.The results showed that,there were no significant differences in SGR,FCR,PRR,ERR and HSI between 6F and 6P.After adding stickwater meal,SGR of 3P3SW and 6SW improved by 9.1%-9.6% compared with 6F,when it comes to FCR,it decreased by 8.5%-11.2%,the differences were significant(P<0.05),but there were no significant differences between 3P3SW and 6SW(P>0.05),while in PRR,FRR and ERR terms,3P3SW,6SW have some improvements.After adding fish oil,compared 3P3SW2O,6SW2O with 3P3SW,6SW,the SGR decreased by 9.7%,15.4%,the FCR increased by 6.9%,31.1%,the differences were significant(P<0.05),except the FCR of 3P3SW2O and 3P3SW.In terms of 3P3SW2O and 6SW2O,PRR and ERR declined;at the same time,FRR and liver fat content increased,and HSI,TBA,CHOL,HDL and LDL with liver fat showed the same trend,and the highest group of these indicators was 6SW2O which had significant differences(P<0.05),compared with all other groups.In the correlation analysis of free amino acids,biogenic amines with FCR and SGR,Pearsion correlation coefficients of free lysine,taurine and putrescine were all greater than 0.8,and presented a quadratic function.So,in the effect of promoting growth,stickwater meal is better than fish meal.Adding small amount of stickwater meal to diets which have no fish meal can not only meet the needs of grass carp but also save the amount of fish meal,and this growth-promoting effect is closely related with free Lys,Tau and Put.Fish oil promotes fat deposition in the body and liver,burdens the lipid metabolism.Together with its easily oxidized characteristics,its use in aquaculture feed is limited.