| Intramuscular fat content is a key index for meat quality evaluation,to explore fat deposition mechanism and nutrient regulating agent is a focus of research and production.Intramuscular fat deposition is comprehensive effect of lamb growth,fat distribution,fat metabolism in blood,fatty acid composition,key gene associate with fat metabolism and transcription factor.Choline has important function in fat distribution of monogastric animals,but there has no system research on lamb growth,fatty acid metabolism regulating effect and mechanism in different adipose tissue.This study taking rumen protected choline(RPC)as nutrient regulator,using animal feeding experiment,metabonomics,molecular biology technique and bio-informatics,to explore regulate effect and mechanism on fat metabolism and intramuscular fat formation in lambs.There are 4 parts as follow:Trail 1.Effect of RPC on growth performance and fat deposition of lambDorper X Hu lambs with 3-5 month old and 10-12 month old lambs were chosen for experiment,and each period has 24 lambs,devided into 4 groups equally with no significant difference in body weight.Four groups were control,0.25%RPC,0.50%RPC,0.75%RPC respectively each experiment last 60d.The results showed that:For 3-5-month old lamb,RPC improved DMI,ADG and F/G ratio in 3-5-month lambs(P<0.05).RPC has no significant effect on blood TAG,cholesterol,HDL,LDL levels(P>0.05).RPC decreased blood FFA levels(P<0.01),has no significant effect on cortisol,leptin,adiponectin and insulin blood levels(P>0.05).RPC has no significant effect on slaughter rate,loin muscle areas,intercostal thickness,back fat thickness(P>0.05),decrease abdominal fat rate,kidney fat rate and pelvic fat rate with no significant difference(P>0.05).RPC group has higher liver,kidney,spleen,stomach,intestine weight than control(P>0.05),has no significant effect on intramuscular fat content(P>0.05),but has significant effect on pH value of Longissimus Dorsi muscle and foreleg muscle(P<0.05).RPC decreased water loss rate of foreleg muscle and rear leg muscle(P<0.05),has no effect on Longissimus Dorsi muscle(P>0.05).RPC decreased muscle tissue shear force of Longissimus Dorsi muscle,foreleg muscle and rear leg muscle compared to control(P>0.05).For 10-12-month old lamb,RPC has no effect on DMI,ADG and F/G ratio(P>0.05)in fattening 10-12-month lambs.RPC has no significant effect on TAG,cholesterol,HDL,LDL levels(P>0.05).RPC has elevate FFA level and decreased at high RPC level,decreased insulin significantly(P<0.05),RPC has tendency for decline resistin,adiponectin with higher RPC adding levels(P>0.05).RPC has improved loin muscle areas,back fat thickness values with no significant difference but without slaughter rate(P>0.05),decrease abdominal fat rate,kidney fat rate and pelvic fat rate with no significant difference(P>0.05),and has higher weight of liver,kidney,stomach and large intestine than control(P>0.05),elevated spleen weight,intestine weight significantly(P<0.05).RPC decreased intramuscular fat content compared to control(P=0.73),with no significant difference among pH values of Longissimus Dorsi muscle,foreleg muscle and rear leg muscle(P>0.05),decreased water loss rate,shear force of Dorsi muscle,foreleg muscle and rear leg muscle(P>0.05),and has no significant modulation effect on meat color(P>0.05).RPC improved PUFA content in subcutaneous fat,Longissimus Dorsi muscle of 10-12-month lambs,decreased SFA,elevate n-3,n-6 fatty acid content with no significant difference(P>0.05).RPC improveed C18:0,C18:1trans,C18:1cis,C18:2cis levels in Longissimus Dorsi muscle(P>0.05).RPC decreased adipocyte diameters of subcutaneous fat,abdominal fat,perirenal fat and pelvic fat by 33.52%,18.23%,17.47%,5.10%compared to control in 10-12-month lambs(P<0.01).The order of fat tissue that sensitity to RPC is perirenal fat>abdominal fat>pelvic fat>subcutaneous fat.Trial 2.Effect of RPC on urine metabomomic of lambs36 lambs with similar body weight were allocated into 3 groups randermly(P>0.05),12 lambs for each group.adding 0%,0.25%RPC,0.75%RPC in the basis diet as control group and experiment groups.There are 10 days for pre-experiment,and 5 days for experiment,urine sample collection at third to fifth day of experiment,for the measurement of urine metabomomic,during these days,keeping the same management for the lambs.Urine determination using NMR and results were analysised using PCA analysis,PLS DA analysis,OPLS-DA analysis.Theresults showed that RPC affect lambs metabolic profiling,there are significant differenc between 0.25%,0.75%RPC adding level,and the main different metabolites are pyruvate,trimethylamine oxide(TMAO),p-cresol,phenylacetylglycine(PAG)and hippurate(Hipp).Pyruvate has lower level in 0.25%,0.75%RPC group than control,but TMAO,p-cresol,PAG,Hipp has higher levels in 0.25%,0.75%RPC groups than control.These different metabolites mainly associated with energy,fat,protein and amino acid metabolism,intestinal microbes metabolism.The main metabolites associated with fatty and carbohydrate metabolism is PAG and pyruvate,adding RPC ameliorated metabolism of fat and carbohydrate.Trial 3.Effect of RPC on key function gene associated with fatty acid metabolismTaking tissue samples from lambs of 3-5-month and 10-12-month,for 3-5-month lambs taken samples from control,0.25%RPC,0.75%RPC group,for 10-12-month lambs taken samples from control and 0.25%RPC group,mainly analysis adipocyte diameter and key genes expression associated with fatty acid metabolism of each adipose tissue.Results showed that:For 3-5-month old lamb,RPC elevated LPL,CD36,ACC,FASN,AGPAT1 and ACADVL mRNA level in Longissimus Dorsi muscle(P<0.05),has no significant effect on DGAT1,DGAT2,ATGL,HSL and CPT-1?(P>0.05).RPC mainly through promote fatty acid uptake,synthesis,esterification and enhance oxidation to elevate fatty acid deposition in Longissimus Dorsi muscles.RPC decreased pelvic fat LPL,FASN and AGPAT1 mRNA expression(P<0.05),elevated CD36,GPAT1 and CPT-1? mRNA expression(P<0.05).had no significant effect on DGAT1,DGAT2,ATGL,HSL,MGLL and ACADVL mRNA expression in pelvic fat(P>0.05),RPC mainly through decrease fatty acid uptake,synthesis and esterification,enhance oxidation key gene mRNA expression associate with fatty acid metabolism,wholly decrease fatty acid diposition in pelvic fat of 3-5-month lambs.RPC decreased perirenal fat LPL,FASN,GPAT1 and AGPAT1 mRNA expression(P<0.01),elevated CPT-1? and ACADVL mRNA expression(P<0.05),has no significant influence onCD36,ACC,DGAT1,DGAT2,ATGL HSL and MGLL mRNA expression,mainly through decrease fatty acid uptake,synthesis and esterification,promote fatty acid oxidation key gene expression associate with fatty acid metabolism,decrease fatty acid deposition of perirenal fat.RPC decreased subcutaneous fat CD36,ACC,GPAT1 and ACADVL mRNA expression(P<0.05),elevated LPL,FASN,AGPAT1,DGAT1,ATGL and CPT-1? mRNA expression(P<0.05),mainly through decrease uptake,synthesis esterification and oxidation,and enhance hydrolysis key genes associate with fatty acid metabolism,decreased fatty acid deposition in subcutaneous fat.RPC decreased abdominal fat CD36,ACC,FASN,GPAT1,DGAT2 and ACADVL mRNA expression(P<0.05),elevated LPL,AGPAT1,DGAT1 and CPT-1? mRNA expression(P<0.01),mainly through decrease fatty acid uptake,synthesis,esterification and oxidation,decreased fatty acid deposition in abdominal fat.For 10-12-month old lamb,RPC decreased Longissimus Dorsi muscle LPL and CD36,mRNA expression(P<0.01),promote HSL,MGLL and CPT-1? mRNA expression(P<0.01),but has no significant effect on ACC,FASN,GPAT1,AGPAT1,DGAT1,DGAT2,ATGL and ACADVL mRNA expression(P>0.05),RPC mainly through decrease fatty acid uptake,enhance fatty acid hydrolysis and oxidation,decreased fatty acid deposition in Longissimus Dorsi muscle of 10-12-month lambs.RPC decreased pelvic fat LPL,ACC and FASN mRNA expression(P<0.01),elevated CD36,GPAT1,AGPAT1,ATGL and ACADVL mRNA expression(P<0.05),had no significant effect on ATGL,DGAT1,DGAT2,HSL and CPT-1? mRNA expression(P>0.05),RPC mainly through decrease fatty acid uptake and synthesis,enhance esterification,hydrolysis and oxidation key gene expression,wholly decrease fatty acid diposition in pelvic fat of 10-12-month lambs.RPC decreased perirenal fat LPL,ACC,FASN,GPAT1,AGPAT1,DGAT2,ATGL and ACADVL mRNA expression(P<0.05),promote MGLL mRNA expression(P<0.05),RPC mainly through decrease pelvic fat fatty acid uptake,synthesis,esterification and hydrolysis key gene expression,wholley decreased perirenal fat deposition.RPC decreased subcutaneous fat CD36,GPAT1 and ACADVL mRNA level(P<0.05),promote FASN and ATGL mRNA expression(P<0.05),RPC mainly through decrease pelvic fat fatty acid uptake,synthesis,esterification and oxidation key gene expression,wholley decreased subcutaneous fat deposition.RPC decreased abdominal fat CD36,ACC,FASN,GPAT1,DGAT2,ATGL and ACADVL mRNA expression(P<0.05),elevated LPL,DGAT1 and MGLL mRNA expression(P<0.05),RPC mainly through decrease fatty acid uptake synthesis,esterification hydrolysis and oxidation,wholly decreased fatty acid deposition in abdominal fat of 10-12-month lambs.Trial 4.Effect of RPC on intramuscular fat depositionRPC has no significant effect on LXR?,LXR? mRNA expression in longissimus dorsi muscle of 3-5-month lambs(P>0.05),but PPARa mRNA has a little elevate,this illustrate RPC modulate fatty acid deposition through keep LXRa expression and elevate PPARa pathway,and modulate key gene expression downstream of LXRa and PPAR?,promote lipid deposite.RPC inhibit LXRa and PPARa gene expression in longissimus dorsi muscle of fattening anaphase lambs,decrease fat deposition. |
PDF Full Text Request