The Effects And Mechanism Of Dietary Supplementation With A Combination Of Linseed And Palm Oils Or Linseed Grain On The Synthesis Of N-3 Long-chain Polyunsaturated Fatty Acids In Body Tissues Of Cashemere Goats

Overgrazing contributes to a decrease in grassland productivity and damages to the ecological balance.Therefore,indoor feeding insteads of traditional grazing is becoming important in Albas white cashmere goat husbandry,which leads to a decreased contents of C18:3n3 and n-3 LCPUFA?C20:5n3 and C22:6n3 etc.?in mutton,thereby decreasing the meat quality.The n-3 LCPUFA content in meat can be increased by including oils rich in C18:3n3 in ruminant diet.The aim of this study was to investigate the effects of dietary supplementation with oils?linseed oil vs.linseed grain;a combination of liseed and palm oils vs.linseed oil alone?on the content of n-3 LCPUFA in muscles and adipose tissues of Albas white cashmere goats,and used the molecular biology technology?qPCR and activity of enzymes?and bioinformatics technology?rumen bacteria diversity?to investigate the processes involved.All these provide a theoretical basis for regulating the FA composition in mutton and improving mutton quality by manipulating the diets.The study included two parts.The first part includes experiments 1-4.Sixty four-month-old castrated male kids were selected and randomly allocated among three groups in a randomized block design,with each group comprising four units of five kids.Three dietary treatments were used:?i?basal diet without supplementation?Control?,?ii?basal diet supplemented with linseed oil?LSO?,?iii?basal diet supplemented with heated linseed grain?HLS?.HLS and LSO provided similar amount of C18:3n3 to the goats.The second part included experiments 5-8.Sixty four-month-old castrated male kids were selected and randomly allocated among three groups in a randomized block design,with each group comprising four units of five kids.Three dietary treatments were used:?i?basal diet supplemented with palm oil?CON?,?ii?basal diet supplemented with linseed oil?LSO?,?iii?basal diet supplemented with a combination of linseed and palm oils?MIX,W/W=2:1?.The length of both the two trails were 90 d.Growth profermance was measured.At the end of the experiment,two kids from each unit were randomly selected and slaughtered.Dressing profermance,serum composition,FA profiles in body tissues,FA profiles and bacteria diversity in rumen,FA profiles in liver and serum,activity and mRNA expression of transcription factors and enzymes involved lipid metabolism in liver,longissimus thoracis muscle and subcutaneous adipose tissue were measured.The results of the first trail show that LSO kids had better growth and slaughter performance as well as fat deposition than HLS kids.Compared with the Control group,the contents of C18:3n3 and n-3 PUFA in all muscles and adipose tissues were increased;C20:5n3 and n-3 LCPUFA in some muscles and adipose tissues were increased;but n-6/n-3 value was decreased in LSO and HLS groups.HLS was more efficient in promoting the contents of C18:3n3,n-3 LCPUFA and n-3 PUFA in muscles and adipose tissues,and decreasing the n-6/n-3 value than LSO.HLS but not LSO can promote the content of C22:6n3 in various tissues.norank_fBacteroidales_RF16_group and norank_fBacteroidales_BS11_gut_group were involved in the hydrogenation of C18:2n6c;Selenomonas₁was involved in the hydrogenation of C18:3n3.Relative abundance of the bacteria related to the hydrogenation of C18:2n6c was increased,but relative abundance of the bacteria related to the hydrogenation of C18:3n3 was decreased in HLS rumen compared to LSO rumen.This indicated that HLS promoted the hydrogenation of C18:2n6c,while decreased the hydrogenation of C18:3n3.HLS increased the mRNA expression of enzymes and transcription factors involved in the synthesis of n-3 LCPUFA in liver and body tissues,and also increased the amount of n-3 LCPUFA transported to body tissues from liver.The results of the second trail show that LSO kids had better growth and slaughter performance as well as fat deposition than MIX kids.Compared to CON group,contents of C18:3n3,C20:5n3 and n-3 PUFA were increased,but the n-6/n-3 value was decreased in muscles and adipose tissues of LSO and MIX groups.MIX was more efficient in promoting the contents of C20:5n3,C22:6n3 and n-3 LCPUFA in muscles and adipose tissues than LSO.Pseudobutyrivibrio was the genus which hydrogenate Cl8:3n3;Succinivibrio,Succinivibrionaceae UCG-002 and unclassified genus in Bacteroidete were the genus which hydrogenate C18:ln9c.Relative abundance of the bacteria related to the hydrogenation of C18:ln9c was increased,but relative abundance of the bacteria related to the hydrogenation of C18:3n3 was decreased in MIX rumen compared to LSO rumen.This indicated that MIX promoted the hydrogenation of C18:ln9c,while decreased the hydrogenation of C18:3n3.MIX increased the mRNA expression of enzymes and transcription factors involved in the synthesis of n-3 LCPUFA in liver and body tissues,and also increased the amount of n-3 LCPUFA transported to body tissues from liver.In conclusion,dietary supplementation with a combination of linseed and palm oils or linseed grain on the synthesis of n-3 PUFA in body tissues of cashemere goats was more effenciency that linseed oil,the processes involved in FA hydrogenation in rumen,FA metabolism in liver and body tissues.