The experiment was conducted to investigate the effects of monosodium glutamate on protein、lipid metabolism of suckling piglets.A total of 24(6 nests,4 piglets/nest) crossbred (Duroc×Large White×Landrace) newborn pigs were selected,each nest were randomly divided to four treatments: The doses of MSG were 0.06(Low-MSG,n=6),0.5,(Medium-MSG,n=6),and lg (High-MSG,n=6)per kg of body weight per day.The MSG was dissolved in 2 ml water per kg of body weight before gavage.Control piglets (CN,n=6) received the same amount of sodium as NaCl in the middle group(0.24g NaCl).Monosodium glutamate was dissolved in water based on weight,force-feeding at 8:00 and 18:00 everyday.The results showed that,concentration of total protein(TP)in the serum of the middle dose group was significantly higher than that in the control group (P<0.05);the there was no significant difference(P>0.05)of serum urea nitrogen(UN、UREA) between each group; compared with the control group,serum triglyceride(TG),total cholesterol (TC),low density lipoprotein cholesterol(LDL-C)concentration had no significant difference(P>0.05);high density lipoprotein cholesterol(HDL-C)concentrations in serum of the middle dose group were significantly higher than those in the control group(P<0.05).Compared with the control group,low and middle dose of MSG could significantly improve the protein content(P<0.01) in the longissimus muscle of suckling piglets; middle dose of MSG can improve the fat content in the longissimus muscle of suckling piglets significantly(P<0.05).Compared with the control group,There was significant difference(P<0.01 )expression of IGF-1、GOT、GPT in liver of middle dose group; there was no significant diflference(P>0.05)expression of IGF-1 of middle and high dose group; GOT mRNA expression of low and high dose group significantly(P<0.05)higher than the control group; GPT mRNA expression of middle dose group raise significantly(P<0.05),whereas reduced significantly (P<0.05)of high dose group.With the additional dose increased.Compared with the control group,0.25g/kg/time monosodium glutamate significantly(P<0.05)raise the ACC、FAS mRNA expression in liver,whereas no significant diflference(P>0.01 )was observed in low and high dose group; MSG supplementation did not affect mRNA expression for HSL or CPT-1(P>0.05).These results suggest that 0.25g/kg/time monosodium glutamate additive improve the protein synthesis and sediment of suckling pig;0.25g/kg/time monosodium glutamate additive increase the lipid sediment through promote lipid synthesis and maintain the break level previously.