| Se(Selenium)is an essential micronutrient for the growth,development and metabolism of human and animal.As an essential component of selenoprotein and selenase,selenium plays an important role in antioxidation,scavenging excessive free radicals,protecting the structure and function of biological membrane,promoting growth and enhancing immunity.Selenium yeast,as an organic raw material for selenium supplement,is often used in livestock and poultry diets to produce selenium-rich products.it is widely used in livestock and poultry industry because of its high absorption rate,strong biological activity,low toxicity and low environmental pollution.The purpose of this study was to study the effects of different levels of yeast selenium on production performance,meat quality and lipid metabonomics of fattening pigs,so as to provide a new theoretical basis for the application of nutrient selenium in healthy breeding of pigs.at the same time,it also provides new ideas for the improvement of meat quality in pork production.Experiment 1: effects of different levels of yeast selenium on production performance,tissue selenium deposition,antioxidation,immune performance and serum biochemical indexes of finishing pigs.Sixty "du × Landrace × Landrace" finishing pigs were randomly divided into 5 groups with 6replicates in each group and 2 pigs in each group.The pigs were fed with basal diet(no selenium,SD group)and basal diet supplemented with yeast selenium 0.3mg/kg(CT group),1mg/kg(SY1group),3mg/kg(SY3 group)and 5mg/kg(SY5 group)for 78 days.The results showed that: 1)There was no significant difference in ADG,ADFI and F/G among finishing pigs(P>0.05).2)The selenium deposition of yeast in various tissues of fattening pigs from small to large is as follows:Subcutaneous fat→serum→dorsal longissimus→kidney→liver.Compared with SD group,selenium deposition in liver,kidney and longissimus dorsi was significantly increased in finishing pigs(P<0.01).Selenium deposition in serum and fat was significant when the addition of selenium was higher than that of 1 mg/kg and 3 mg/kg,respectively(P<0.01).3)Compared with SD group,the contents of Ig A and Ig M in serum of finishing pigs in CT,SY1,SY3 and SY5 groups increased significantly(P<0.05).4)Compared with SD group,CT,SY1,SY3 and SY5 groups significantly increased the contents of liver T-SOD and GSH-Px(P < 0.05)and CAT content(P < 0.01).Compared with SD group,SY3 group significantly increased the content of serum GSH-Px(P<0.05).5)Different levels of yeast selenium had no significant effect on serum biochemical indexes(P>0.05).Experiment 2: effects of different levels of yeast selenium on meat quality traits,nutritional composition of longissimus dorsi and m RNA level of related selenoprotein gene in finishing pigs.The experimental design is the same as that of experiment 1.The results showed that: 1)compared with CT group,the liver index of SD group and SY5 group decreased significantly(P<0.01),the average backfat thickness of SY3 group decreased significantly(P<0.05).2)Compared with CT group,marbling in SD group decreased significantly(P<0.05).Compared with CT group,meat color 24 h L * value of SY5 group was significantly lower(P<0.05).Compared with SD group,45 min a * value of SY1 group increased significantly.3)Compared with CT group,the content of tyrosine in SY1 group and SY5 group increased significantly(P<0.05),taurine and alanine in SY3 group decreased significantly(P<0.05),and threonine decreased significantly(P<0.01),and alanine in SD group decreased significantly(P<0.05),and taurine decreased significantly in SY5group(P<0.05).4)Compared with SD group,CT,SY1,SY3 and SY5 groups significantly upregulated the m RNA expression level of selenoprotein Sel W(P<0.05).Compared with SD group,SY1 and SY3 groups significantly up-regulated the m RNA expression level of SBP1(P<0.05).Experiment 3: effects of different levels of yeast selenium on lipid metabonomics of longissimus dorsi muscle in finishing pigs.The experimental design is the same as that of experiment 1.Thirty samples of longissimus dorsi muscle of fattening pigs were collected for non-targeted absolute quantitative analysis of lipid metabonomics.The results showed that: 1)based on the high throughput technology of UPLC mass spectrometry system,35 kinds of lipid subclasses and 1179 kinds of lipid molecules were detected by positive and negative ion pattern identification.2)through the comparative analysis of the total content of lipid subclasses in each test group,the results showed that the overall lipid content in the SY5 group was higher than that in the control group.The results showed that: ○1 at the level of lipid subclasses,compared with the CT group,the contents of PG,PIP and PIP2 in the SY5 group were significantly lower than those in the CT group(P<0.05),while the content of SQMG was significantly higher in the SY5 group(P<0.05).○2 at the lipid molecular level,35 kinds of lipid molecules were obtained by SY5 vs CT,18 kinds of PE molecules including PE(18:1e-18:1),PE(18:1e-20:4),PE(18:1e-22:5),etc.and 5 kinds of PS molecules including PS(18:0-18:2)、PS(16:1e-22:5),etc.and 5 kinds of PC molecules including PC(16:0e-18:1)、 PC(18:0e-18:2),etc.and PG(32:2e)、PG(29:2e)and CL(78:6)、DG(36:4e)、PI(16:0-20:4)、PIP(17:1-18:0)、PIP2(37:2e).Interestingly,18 kinds of PE were significantly up-regulated in molecular cluster analysis(VIP>1,P<0.05).In summary,dietary addition of appropriate amount of yeast selenium can improve the immune function and antioxidant capacity of fattening pigs,and improve the color and marbling of the longest back muscle of fattening pigs,as well as increase the amino acid content and selenoprotein gene expression,so as to improve the quality of fattening pork..Lipid metabolomics revealed that high-dose yeast selenium caused up-regulation of 18 PE lipid molecules.. |
