| With a combined strategy comprising of feeding trials,digestion and metabolism experiments,slaughter experiment and molecular biology,the study was conducted to investigate the effects of tryptophan(Trp)level on production performance,nutrient digestibility,serum biochemical parameters,amino acid digestibility and fur quality for white minks in growth period.And this thesis aims to estimate the optimum dietary tryptophan requirement for white minks.This study also investigated the regulatory mechanism of tryptophan though the transcriptome on jejunum,which lays the foundation for perfecting the ideal amino acid requirement model.Part 1: Effects of dietary tryptophan supplemental levels on growth performance,nutrition digestibility and serum biochemical indices on growing white mink(Mustela Vison).This study was designed a single factorial experiment.120 healthy 60-day white minks were randomly divided into 6 groups with 20 replicates each,male and female in half.The minks in 6 groups were fed either a basal diet(Trp 0.22 and CP 34%)supplemented with 0(groupI),0.1%(group II),0.3%(groupIII),0.5%(groupIV)and 0.7%(groupV)Trp or a diet contained 36% protein with no supplementation with Trp(group VI),respectively.The pretest period lasted for 7 days and the trial lasted for 60 days.The results were as follows:No differences were detected in ADG,ADFI among the groups(P>0.05),the ADG in groupIII,group IV,group VI of male minks were higher than other groups and the ADG in groupII of female minks was higher than that of other groups.The N retention in groupIII of male minks was the highest,which had a significantly higher than groupIV.The N retention in groupII of female minks was the highest.The CHOL、ALT、AST in groupII and groupIII of female had a great significantly lower than those of groupIV(P<0.01 or P<0.05).The IgM was great significantly higher from male minks in group II than other groups(P<0.01).The IgA and IgG were great significantly higher in groupI,group II than groupV,groupVI(P<0.01).The IgG in groupII of female minks was great significantly than that of group III(P<0.01)and the IgM in groupII,groupIII had a great significantly higher than that of groupIV and group VI(P<0.01).Summary:(1)The diet of Trp levels in 0.52% of male minks is favorable for a growth performance and protein,fat,dry matter digestibility to meet the cask theory demand.Compared with the male minks,the diet Trp supplementation of 0.1%(diet Trp 0.32%)from female minks can get the best growth performance.(2)The best amino acid deposition could be obtained by the level of tryptophan supplementation of 0.1%(diet Trp 0.32%).(3)The diet with tryptophan supplementation level 0.5%(diet Trp 0.72%)might hurt liver function.The level of CHOL,AST and ALT increased significantly,which affected the immune function of mink.In summary,the suitable level of tryptophan for white mink was 0.32%~0.52%.Part 2: Effects of dietary tryptophan supplemental level on growth performance,nutrient digestibility,serum biochemical indices and fur quality of white mink during winter fur-growing season.There were 120 healthy 120-day white minks in the experiment.The Part 2 designed the same as the Part 1.The pretest period lasted for 5 days and the trial lasted for 70 days.The results were as follows:The IGF-1 in groupI of male minks was the highest,the IGF-1 in group I of female minks had great significantly higher than other groups(P<0.01).No differences were detected in ADG,ADFI among the groups(P>0.05).When the dietary Trp level was increased,the ADFI of male minks had a downward trend.The N retention in groupII of female minks was the highest.The amino acid digestibility in group VI of male minks had great significantly than that of other groups besides Cys and Trp(P<0.01),the Cys digestibility and Trp digestibility in group I had no difference to groupVI(P>0.05).The amino acid digestibility in groupVI of female minks was the highest as well.The ALT in groupII was the lowest.The CHOL in groupII,group III and IV of male minks was significantly lower than that of group VI(P<0.01).The TG level of female minks in groupI,group VI was significantly lower than that in group II(P<0.05).The ALT in groupIV was significantly higher than that of groupVI(P<0.05).The immune indicators and the index of immune organs in groupIV were the highest of female mink.The IgA in group I of female minks had a significant difference than that of group II,group IV,group V(P<0.05).The IgG,IgM and immune organ index in groupIII and IV were higher than others.Compaired with other groups,fur quality in group II was the best quality.Summary: When the dietary tryptophan levels reached 0.26%,it can fulfil the basic needs of white mink in winter fur-growing period.The growth performance,nutrient digestion was the ideal.So,the dietary tryptophan level in 0.26%~0.36% is more appropriate for winter fur-growing period.When dietary tryptophan levels reached 0.76%,the amino acid metabolism out of balance and liver was damaged.Part 3: Transcriptomic study of jejunum tissue fed with different tryptophan levels on white male minks.Sequencing and sequence assembly of the jejunum for male white minks,which fed with different levels of tryptophan.The total number of all-unigenes was 97332 and the total length was 124 017345 nt.It’s the first time establish a database of transcriptome for white mink jejunum tissue.Unigene annotations were obtained by database comparison with NR,Swiss-Prot,GO,COG,KOG,eggNOG4.5 and KEGG.The annotated unigene in the groups that added tryptophan test group(Group II,III,IV,V)compared with group I.GroupI compared with groupII,65 unigenes.GroupI compared with groupIII,we received 122 unigenes.GroupI compared with groupIV,a total of 132 differentially expressed unigenes.GroupI compared with groupV,we received 55 unigenes.As the group IV had the most unigenes,which combined with the Part 2,and the high content of tryptophan in group IV has a certain effect on the jejunum tissue.Differential gene alignment under GO classification,there are some great differences in immunesystem process,reproductive process,growth function,signaling,biological attachment,extracellular and receptor activity function from the three functions classification(BP,CC,MF).Nine related unigenes were found from the above functional classification.They are HSPA8(Heat shock 71 kDa Protein),Heat shock 70 kDa Protein1,rpl 22,rpl 13 a,48s ribosomal protein SA,ATP2A1,RBP4(Retinol-binding protein 4),ACTB,FGA1.Combined with the results of Part 2,the FGA1 affects the complement system and immune system. |
PDF Full Text Request