Effects And Mechanism Of Different Methionine Sources On Lipid Metabolism In Broilers

The effect and mechanism of methionine source and level on lipid metabolism of broilers during different growth phase were studied with 3 trails,and the relative bio-efficacy of different Met sources in broiler during different growth phase.Exp.1.Relative effectiveness of different methionine in broilers during different growth phase and effect of different methionine on liver weight and antioxidantThis trail was aimed to evaluate the relative effectiveness of different methionine in broiler during different growth phase and explore the effect of different methionine on liver weight and antioxidant.A 3×5+1 randomly design was used in the trail,contained 3methionine sources?LM,L-methionine;DLM,DL-methionine;MHA-Ca,DL-methionine hydroxyl analogue calcium salt?and 5 levels?0.03,0.06,0.10,0.15 and 0.21%?.A negative control without supplementation of Met was set to form 16 treatments with 8 replication of20 birds each.Experimental period was 10-42d.The result showed:Met source had no significant effect on growth performance except that LM and DLM got a better feed conversion?FCR?than MHA-Ca?P=0.015,P=0.017?with a significant interaction?P=0.011?on 10-42d and 22-42d.Supplementation of Met in a Met deficient diet significantly increased growth performance in broilers.Met source had no significant effect on carcass performance except half-eviscerated weight?P=0.03?;however Met level significantly increased effect on carcass weight,eviscerated weight,percentage of eviscerated weight,half-eviscerated weight,breast meat weight/yield,leg meat weight,liver weight,leg weight and percentage of half-eviscerated weight?P<0.05?;and significantly decreased leg meat yield while no effect on percentage of carcass weight and percentage of liver weight?P>0.05?.Based on equal mass,the relative bio-efficacy of DLM and MHA-Ca to LM was 99.2%and 82.0%,respectively based on 10-21d growth performance;148.1%and 79.1%,respectively based on 22-42d growth performance;132.2%and 84.8%,respectively based on 10-42d growth performance;112.4%and 78.7%,respectively based on 42d carcass performance.Effect on liver oxidative stress showed:when compared to LM,DLM and MHA-Ca significantly increased liver H₂O₂ on 42d?P<0.0001?,increased activity of CAT?P=0.001?and decreased MDA concentration?P<0.0001?.When compared with the control group,Met supplementation increased liver H₂O₂ and decreased malondialdehyde?MDA?concentration.Effect on redox state showed:LM and DLM got a higher total glutathione?TGSH?in liver on 42d than MHA-Ca?P=0.001?,and DLM got a higher reduced glutathione?reGSH?than MHA-Ca?P=0.005?,Met level significantly increased all kinds of GSH?P<0.0001?.Met source and level had no significant effect on the ratio of reGSH/TGSH and reGSH/GSSG?oxidized glutathione??P=0.221,P=0.304 and P=0.408,P=0.226?.The result of oxidative damage on DNA showed:LM got a higher 8-hydroxy guanosine?8-OHDG?than MHA-Ca?P=0.004?,Met level significantly decreased the concentration of 8-OHDG?P=0.004?with an interaction?P=0.003??In conclusion,addition of Met in a methionine deficient diet resulted in a better growth and carcass performance,while no difference among Met sources.The optimum addition level was 0.12%?LM?,0.15%?DLM?and 0.15%?MHA-Ca?,respectively for 10-21d broilers.Met supplemented birds presented a better liver oxidative status in comparison to the deficient birds.Exp.2.Effect and mechanism of different methionine on lipid metabolism in broilers during1-21dThis trail was aimed to study the effect and mechanism of different Met source and level in 1-21d broilers.In 1-21d broilers,a 3×3 randomly experiment design was set with 3 Met sources?LM,DLM and MHA-Ca?and 4 level?0.10,0.22 and 0.32%?,a negative control without Met supplementation was set to form 11 treatments.Experiment period was 1-21d.The result showed:Met source had a significant effect on 14dBW,1-14d average daily gain?ADG?,1-7dADFI and 1-21dADFI?P=0.049,P=0.029,P=0.015 and P=0.021?with a better growth performance in LM compared to MHA-Ca,Met level significantly increased growth performance of 1-21d?P<0.05?.Chickens fed a Met deficient basal diet?basal group?got the highest liver EE content,with the supplementation of Met liver EE decreased and reached a significant difference at an addition level of 0.32%?P=0.027?.Addition of three Met sources significantly increased liver weight on 21d,while had no effect on percentage of liver weight,abdominal fat weight and percentage of abdominal fat?P>0.05?.Serum TG on 21d was lower in DLM than LM and MHA-Ca?P=0.005?,LDLC linearly increased with the increase of LM?P<0.0001?.Compared with DLM and MHA-Ca,supplementation of LM decreased liver MDA on 21d?P=0.005?,addition of 3 Met sources increased plasma Hcy content on 21d,MHA-Ca got a higher plasma Hcy?P=0.002?.With the increase of Met supplemental level,the 21d Liver H₂O₂ concentration decreased at first and then increased,but was still lower than control.The effect on expression of lipid metabolism relative genes showed:MHA-Ca got a higher relative expression of ApoB and Cpt1a than LM and MHA-Ca?P=0.007?;Met level significantly decreased relative expression of liver Adipor2,ACOX1,FASN on 14d and ACOX1,Cpt1a on 21d,significantly increased relative expression of 14d ApoB and 21d Chrebp.The effect on expression of Hcy metabolism relative genes showed:LM and DLM showed higher expression of liver SAHH and betaine-homocysteine methyltransferase?BHMT?on 14d than MHA-Ca?P<0.05?,14d C?S mRNA expression showed significant difference among Met sources:MHA-Ca>DLM>LM,relative expression of 21d BHMT mRNA in LM was higher than in DLM and MHA-Ca,while 21d C?S mRNA expression in LM and DLM was higher than MHA-Ca.The effect on relative expression of liver inflammatory cytokines and VCAM1 showed:DLM and MHA-Ca got a lower expression of liver IL8 on 14d than LM?P<0.05?,LM and DLM had a higher expression of liver interleukin1??IL1??and IL8 on 21d than MHA-Ca?P<0.05?.Addition of Met significantly decreased expression of liver VCAM1 and TNF-?.Compared to negative control,low level Met?0.10%?increased expression of liver IL1?,low Met also increased expression of IL8,while high level Met decreased.In conclusion,during1-21d,addition of Met in a methionine deficient diet resulted in a better growth,while LM had a higher ADFI?1-21d?than DLM and MHA-Ca.Within the supplementation level of 0-0.32%on starter broilers?1-21d?,liver lipid deposited was highest in Met deficient basal diet,and the increased liver deposited may mainly mediated by regulation on lipid metabolism relative genes and inhibition on lipid transport mediated by Hcy may be a cofactor.Exp.3.Effect and mechanism of different methionine on lipid metabolism of broilers during22-42dThis trail was aimed to study the effect and mechanism of different Met source and level on lipid metabolism in 22-42d broilers,and evaluate the relative effectiveness of different methionine in 22-42d broilers.A 3×4+1 randomly experiment design was set on 22-42d with3 Met sources?LM,DLM and MHA-Ca?and 4 levels?0.05,0.10,0.14 and 0.24%?.A negative control without supplementation of Met was set to form 13 treatments with 8replication of 20 birds each.During 1-21d,the negative control was feed a Met deficient diet without supplementation of Met,and other treatments feed a Met sufficient diet?DLM,0.22%;Met,0.50%?.Experimental period was 22-42d.The result showed:supplementation of LM and DLM significantly increased 22-42d average daily feed intake?ADFI??P=0.002?than MHA-Ca with no difference between LM and DLM.Met level had significant effect on growth performance on 22-42d?P<0.0001?.Met source had no significant effect on carcass?P>0.05?,carcass weight,eviscerated weight,half-eviscerated weight,breast meat weight,leg meat weight and breast meat yield increased with the increase of Met supplementation level?P<0.05?.On an equal mass base,the relative effectiveness of DLM and MHA-Ca to LM was 100.1%and 85.1%on average.Supplementation of DLM increased liver weight and percentage of liver weight than LM and MHA-Ca?P=0.009 and P=0.011?,Met level elicited linear and quadratic effect on liver weight and percentage of liver weight?P<0.05?.Met source had no significant effect on abdominal fat weight and percentage of abdominal fat,Met level elicited quadratic effect on abdominal fat weight;Met level also had a linear effect on percentage of abdominal fat.LM deficiency or excess both increased the 42d liver EE content,DLM had a similar effect as LM.While MHA-Ca supplementation decreased the 42d liver EE concentration.Met level tended to significantly affect low density lipoprotein cholesterol?LDLC??P=0.051?,Met level showed a linear effect on LDLC.Supplementation LM got a higher plasma Hcy concentration than DLM and MHA-Ca?P<0.001?.Met source had a significantly effect on liver MDA and H₂O₂?P<0.05?,Met level elicited linear and quadratic effect on plasma MDA and H₂O₂?P<0.05?.MHA-Ca increased the relative expression of Carnitine palmitoyltransferase 1a?Cpt1a?in 42d liver?P=0.009?,while LM increased Fatty acid synthase?FASN?and apolipoprotein B?ApoB?relative expression?P=0.014 and P=0.002?;Met level decreased expression of adiponectin receptor 2?Adipor2?,acyl-coenzyme A oxidase 1?ACOX1?,Cpt1a,Carbohydrate response element-binding protein?Chrebp?,FASN and ApoB?P<0.05?.DLM decreased S-adenosylhomocysteine hydrolase SAHH expression and LM increased methionine synthase?MS?expression?P<0.0001?;Met level significantly decreased MS and increased cystathionine?-synthase?C?S?mRNA?P<0.0001?.LM got a higher tumor necrosis factor-??TNF-??expression than DLM and MHA-Ca?P=0.012?,Met level significantly decreased vascular cell adhesion molecule-1?VCAM1?and TNF-?relative expression?P<0.0001?,while increased interleukin 8?IL8?expression?P=0.022?.In conclusion,during22-42d,addition of Met in a methionine deficient diet resulted in a better growth and carcass performance,decreased leg meat yield,while no difference among Met sources.However,the growth performance of MHA-Ca during the first two weeks of grower phase was lower than DLM and LM.Within the supplementation level of0-0.24%on grower broilers?22-42d?,0.24%DLM significantly decreased abdominal fat deposited,Met deficiency or LM and DLM excess increased 42d liver lipid content while the supplementation of MHA-Ca decreased liver lipid deposited.The increased liver deposited of different Met source and level may mainly mediated by regulation on lipid metabolism relative genes and inhibition on lipid transport mediated by Hcy.However,DLM and LM had a regulation on lipid hydrolysis,synthesis and transport,MHA-Ca had a main effect on lipid transport.Conclusion?1?A supplementation of LM,DLM or MHA-Ca on a Met deficient basal diet in starter or grower broiler chicks could significantly increased growth without difference between Met sources.?2?On 22-42d broilers,Met sources didn't affect abdominal fat deposited while addition of Met increased abdominal fat weight and decreased percentage of abdominal fat,0.22%DLM significantly decreased abdominal fat deposited.Within the supplementation level of Met in this trail,addition of LM and DLM during 1-21d decreased liver lipid deposited while LM and DLM excess during 22-42d increased liver lipid content in broilers.Supplementation of MHA-Ca decreased liver lipid eposited no matter in starter or grower broilers.?3?Increased liver deposited of different Met source and level may mainly mediated by egulation on lipid metabolism relative genes and inhibition on lipid transport mediated y Hcy may be a cofactor.However,DLM and LM had a regulation on lipid ydrolysis,synthesis and transport,MHA-Ca had a main effect on lipid transport.