Effects Of Methionine Source And Level On Hepatic Methionine Metabolism And Lipid Metabolism Of Laying Hens

Four studies were carried out to investigate the effects of methionine source and level on hepatic one-carbon metabolism and lipid metabolism for broiler breeder hens and commercial laying hens.Exp.1.Effects of methionine source and level on hepatic methionine and lipid metabolism of broiler breeder hensThe aim of this study was to investigate the effects of methionine source and level on hepatic one-carbon and lipid metabolism in broiler breeder hens.A total of 2184 Da Hen 699 broiler breeder hens(30 wk,a local color-feathered breed in China)were assigned to 13 dietary treatments in a 2 × 6 + 1 completely randomized design,with 8 replicate per treatment.The 13 treatments included 1 diet without any DL-methionine(DLM)or DL-2-hydroxyl-4-methylthio-butiric acid(HMTBA)supplementation plus 12 additional treatments employing 2 methionine sources(DLM and HMTBA)and 6 supplementation levels(0.05,0.10,0.15,0.20,0.25,and 1.00%)in a 2 × 6 factorial arrangements.No significant effects were observed between methionine source and level on breeder performance criterion(P > 0.10).Hepatic TG content increased linearly or quadratically as dietary DLM or HMTBA supplementation level increase(P ? 0.05).Methinonine source and level had no effect on plasma E2 contcentration(P > 0.10).Plasma Met concentration linearly increased as dietary methionine supplementation level increased(P < 0.01),but higher Met concentration was measured in the plasma obtained from DLM supplemented hens than those from HMTBA supplemented.Plasma Ala concentration linearly increased as DLM(P = 0.03)or HMTBA(P = 0.02)supplementation level increased.There was a linear increase in concentrations of Tyr(P = 0.02),Val(P = 0.03),Gly(P = 0.05)and Ser(P < 0.01)as dietary DLM supplementation level increased.No significant effects were observed between methionine source and level on plasma concentration of Cys,Tau and Cysthi(P > 0.10).Methionine source and level had no effects on expression of ACC,FAS,DAGT2 and LPL(P > 0.10).The expression of MAT2A(P = 0.06)and ADA(P = 0.07)was tend to be affected by HMTBA supplementation level linearly.As dietary HMTBA supplementation level increased,the expression of MSR(P = 0.09),MS(P = 0.02),ADA(P = 0.08),SAHH(P = 0.08)and MAT2A(P = 0.06)changed quadratically(goes down first and then goes up),while the expression of GNMT(P = 0.04),MSR(P = 0.06)and SAHH(P = 0.07)changed quadratically(goes down first and then goes up)as DLM supplementation level incerased.The expression of hepatic pro-inflammation cytokines such as IL-1?(P = 0.04),IL-10(P = 0.05)and TNF-?(P = 0.08)was increased linearly as dietary HMTBA level increased.In conclusion,adding HMTBA at high level could enhance Hcy remethylation to generate methionine and methyl group metabolism by upregulating the expression of MS and MAT2 A and increase the risk of FLHS by increasing the liver fat content and expression of IL-1?,IL-10 and TNF-?.Exp.2.Effects of methionine source and level on hepatic methionine and lipid metabolism of commercial laying hens fed with low nutrient level or moderate nutrient level diets under restricted feedingThe aim of this study was to investigate the effects of methionine source and level on hepatic methionine and lipid metabolism of commercial laying hens fed with low nutrient level(LN)or moderate nutrient level(MN)diets under restricted feeding.A completely randomized design with 2 dietary nutrient level(MN:AMEn,2700 kcal/kg,Dig.Lys 0.66%;LN:AMEn,2580 kcal/kg,Dig.Lys,0.61%)was used.Within each dietary nutrient level,there were 2 methionine source(DLM and HMTBA)and 3 supplementation level(LN: 0,0.091 and 1%;MN: 0,0.113 and 1%).A total of 2000 Lohmann laying hens was allocated to 10 dietary treatments with 10 replicates for each.Under the condition of feeding LN diets: when compared with negative group,adding methionine at 1% significantly reduced average daily feed intake(ADFI)and FCR(P ? 0.05);adding methionine at 0.091% significantly increased egg weight(P ? 0.05).Under the condition of feeding MN diets: adding methionine at 1% significantly reduced ADFI and adding methionine at 0.113% significantly increased egg weight when compared with negative group(P ? 0.05).During 33-37 wk and 28-37 wk,adding methionine resulted in a higher egg weight than negative group,but the egg weight was lower from treatment adding methionine at 1% than those from treatment adding methionine at 0.113%(P ? 0.05).Adding methionine significantly increased egg mass(33-37wk)(P ? 0.05)and reduced FCR when compared with negative group(P ? 0.05).For hens fed with LN diets,adding methionine at 0.091% significantly reduced relative liver weight compared with negative group,while adding methionine at 0.113% or 1% significantly increased plasma TG concentration of hens fed with MN diets(P ? 0.05).Regardless of dietary nutrient level,methionine source and level had no effects on plasma estradiol(E2)and Hcy concentration and live Hcy content(P > 0.10).Under the condition of feeding LN diets: plasma Met and Tau concentration of hens treated with DLM was higher than those treated with HMTBA(P ? 0.05).The concentrations of Met and Tau significantly increased whent methionine was supplemented at 0.091% or 1%.Under the condition of feeding MN diets: plasma Tau concentration of hens treated with DLM was higher than those treated with HMTBA(P ? 0.05).When compared with negative group,plasma Met concentration significantly increased with methionine supplementation(P ? 0.05)and plasma Tau concentration significantly increased with methionine at 1%(P ? 0.05).Under the condition of feeding LN diets: compared with negative group,adding methionine(HMTBA source)at 0.091% or 1% markedly increased the expression of GNMT(P ? 0.05),and adding methionine(DLM source)at 1% significantly increased the expression of BHMT(P ? 0.05).Under the condition of feeding MN diets: adding methionine(HMTBA source)at 0.113% or 1% significantly increased the expression of ADA and adding methionine(HMTBA source)at 0.113% significantly increased the expression of MS when compared with negative group(P ? 0.05).Without methionine supplementation,hens fed with LN diets had a higher expression of BHMT and MS than hens fed with MN diets(P ? 0.05).When adding methionine at 1% as a source of HMTBA,hens fed with LN diets had a higher expression of SAHH,MTHFR,CEBP? and AdipoR2(P ? 0.05).Compared with negative group,adding methionine(DLM source)at 1% significantly increased the expression of TNF-?of hens fed with LN diets(P ? 0.05).No significant was observed for the expression of hepatic pro-inflammatory cytokines of hens fed with MN diets(P > 0.10).Hens fed LN diet had higer expression of INF-? and IL-1? than hens fed MN diet when methionine was provided at 1% as a source of HMTBA.In conclusion,(1)methionine deficiency could promote the regeneration of methinonine by upregulating the expression of MS and BHMT,but did not affect expression of genes involved in hepatic methionine metabolism and pro-inflammatory cytokines.(2)when using HMTBA as a source of methionine and adding methionine at 1%,feeding hens with low nutrient level diets could enhance Hcy remethylation to generate methionine and methyl group metabolism by upregulating the expression of SAHH and MTHFR and increase the risk of FLHS by increasing the expression of CEBP? to promote the fat synthesis of liver and upregulating the expression of hepatic pro-inflammatory cytokinesExp.3.Effects of bio-efficacy of HMTBA on hepatic methionine and lipid metabolism of commercial laying hens fed with low nutrient level diets or moderate nutrient level diets under restricted feedingThe objective of this study was to investigate the effects of HMTBA supplemented at various bio-efficacy on hepatic methionine and lipid metabolism of commercial laying hens fed with low nutrient level diets or moderate nutrient level diets under restricted feeding.A completely randomized design was used.There were 2 dietary nutrient level(MN:AMEn,2700 kcal/kg,Dig.Lys 0.66%;LN: AMEn,2580 kcal/kg,Dig.Lys,0.61%).Within each dietary nutrient level,there were 5 Met-treatments(D: negative control;DLM-R: positive control;HMTBA-R80: added at 80% bio-efficacy;HMTBA-R84: added at 84% bio-efficacy;HMTBA-R88: added at 88% bio-efficacy)was used.A total of 2000 Lohmann laying hens was allocated to 10 dietary treatments with 10 replicates for each.Adding DLM or HMTBA at 84% bio-efficacy significantly increased egg weight(33-37 wk and 28-37wk)of hens fed LN diets when compared with negative group(P ? 0.05).When fed with MN diets,adding DLM or HMTBA at various bio-efficacy significantly increased the egg weight compared with negative group(P ? 0.05).There was no significant difference between DLM and HMTBA at various bio-efficacy for egg weight(P > 0.10).Under the condition of feeding LN diets: plasma Met concentration of hens treated with DLM or HMTBA at various bioefficacy was higher and plasma Tau concentration of hens treated with DLM was higher than that of negative group(P ? 0.05).When fed with MN diets,adding DLM or HMTBA at 88% bioefficacy significantly increased the concentration of Met(P ? 0.05),but adding DLM or HMTBA had no significant effect on plasma Tau concentration(P > 0.10).When adding HMTBA at 80% bio-efficacy,hens fed LN diets had a higher expression of SREBP1,ACC,LPL and AdipoR1 than those of hens fed MN diets(P ? 0.05),and the expression of CEBP?(P = 0.07)and AdipoR2(P = 0.07)also tend to increase for hens fed LN diets.Comparing with hens fed MN diets,hens fed LN diet had higher expression of BHMT and MS when no methionine was added to the diet(P ? 0.05),while the expression of SAHH,ADK,BHMT and PEMT increase when HMTBA was added to the diet at 80% bio-efficacy(P ? 0.05).In conclusion,adding HMTBA at 88,84 or 80% bio-efficacy did not affect the production performance of laying hens significantly,but when adding HMTBA at 80% bio-efficacy,hepatic methionine metabolism of hens fed low nutrient level diets could be affected and hepatic lipid synthesis could be promoted by upregulating the expression of CEBP? and SREBP1.Exp.4.Effects of dietary nutrient level and bio-efficacy of HMTBA on egg performance and hepatic lipid metabolism of commercial laying hens under ad libitum feedingThe objective of this study was to investigate the dietary nutrient level and HMTBA supplemented at various bio-efficacy on egg proformance and hepatic lipid metabolism of commercial laying hens under ad libitum feeding.A completely randomized design was used and there were 2 dietary nutrient levels(MN:AMEn,2700 kcal/kg,Dig.Lys 0.67%;LN: AMEn,2460 kcal/kg,Dig.Lys,0.61%)and 5 Met-treatments(D: negative control;DLM-R: positive control;HMTBA-R80: added at 80% bio-efficacy;HMTBA-R84: added at 84% bio-efficacy;HMTBA-R88: added at 88% bio-efficacy).A total of 1500 Lohmann laying hens was allocated to 10 dietary treatments with 10 replicates for each.Under the condtion of feeding LN diets: comparing with negative group,adding DLM or HMTBA at 84% or 88% bio-efficacy significantly increased egg production rate during 36-41wk(P ? 0.05);adding DLM or HMTBA at various bio-efficacy significantly increased ADFI during 30-35 wk and 36-41 wk,egg weight,egg mass and significantly improved FCR(36-41 wk and 30-41wk)(P ? 0.05).Under the condition of feeding MN diets: comparing with negative group,adding DLM or HMTBA significantly increased egg production rate(36-41wk),ADFI,egg weight and egg mass(P ? 0.05),and also significantly improved FCR(36-41 wk and 30-41wk)(P ? 0.05).Regardless of dietary nutrient level,there was no significant differenc between DLM and HMTBA adding at various bio-efficacy(P > 0.10).Under the condition of feeding LN diets: comparing with negative group,adding HMTBA significantly decreased relative liver weight(P ? 0.05);adding HMTBA at 80% bio-efficacy increased abdominal fat weight(P ? 0.05).There was no significant difference between DLM and HMTBA at various bio-efficacy for liver index,liver TG and plasma TG content(P > 0.10).Under the condition of feeding MN diets: comparing with negative group,adding DLM or HMTBA did not affect liver index,abdominal fat weight and concentrations of liver TG,plasma TG and plasma E2(P > 0.10).When compared with DLM,adding HMTBA at 80% bio-efficacy significantly increased live weight,abdominal fat weight and abdominal fat percentage(P ? 0.05).In conclusion,adding HMTBA at 88%,84% or 80% bio-efficacy did not affect production performance of hens under ad libitum feeding,but adding HMTBA at 80% bio-efficacy may increase the liver fat content.ConclusionFor broiler breeder hens: adding HMTBA at high level could enhance Hcy remethylation to generate methionine and methyl group metabolism by upregulating the expression of MS and MAT2 A and increase the risk of FLHS by increasing the liver fat content and expression of IL-1?,IL-10 and TNF-?.For commercial laying hens:(1)methionine deficiency could promote the regeneration of methinonine by upregulating the expression of MS and BHMT,but did not affect expression of genes involved in hepatic methionine metabolism and pro-inflammatory cytokines.(2)when using HMTBA as a source of methionine and adding methionine at 1%,feeding hens with low nutrient level diets could enhance Hcy remethylation to generate methionine and methyl group metabolism by upregulating the expression of SAHH and MTHFR and increase the risk of FLHS by increasing the expression of CEBP? to promote the fat synthesis of liver and upregulating the expression of hepatic pro-inflammatory cytokines.(3)from the perspective of liver health,bio-efficacy of HMTBA relative to DLM would better be set to 88%(on weight basis),because the liver fat synthesis and risk of liver inflammation may be reduced compared with adding HMTBA at 80% bio-efficacy when hens fed with low nutrient level diets.