Effects Of Different Selenium Sources On The Production Performance,meat Quality And Antioxidant Abilities Of Fattening Pigs

This experiment was conducted to evaluate the effects of different selenium sources on the production performance,meat quality,antioxidant abilities and correlative gene expression of fattening pigs.One hundred sixty 110-d-old crossbred(Duroc × Landrace × Large White)pigs with body weight(BW)of 62.06 ± 0.54(mean ± SD)kg were allocated to 16 pens(5 barrows and 5 gilts/pen),and the pens were assigned randomly to 4 treatments with 4 pens per treatment.Treatment 1 was the control group,and 0.3 mg/kg SS was added to the basic diet(without selenium,the same below);Treatments 2,3,and 4 were added 0.3 mg/kg SY,0.3 mg/kg Se-Met,and 0.15mg/kg SS + 0.15mg/kg Se-Met to the basic diet(based on selenium level),respectively.The whole test period was 50 days.The results showed as follows: Compared with group SS,each organic selenium group significantly increased(P < 0.01)ADG,final weight,kidney index,and reduced(P < 0.05)F/G;group SY and group SS + Se-Met significantly increased(P < 0.01)backfat thickness,skin thickness,and liver index;group SY significantly increased(P < 0.01)the carcass straight length and leaf fat rate;group Se-Met significantly increased(P < 0.01)the spleen index.However,no significant differences were observed in ADFI,carcass rate,carcass sloping length,eye muscle area,heart index,and lung index of fattening pigs(P> 0.05).Compared with group SS,group SY and group SS + Se-Met significantly reduced(P < 0.05)cooking loss,45 min L value,24 h L value and water content,increased(P < 0.05)protein content of longissimus dorsi;each organic selenium group significantly reduced(P < 0.01)45 min drip loss,24 h drip loss and fat content,increased(P < 0.01)selenium deposition in longissimus dorsi,liver and kidney;group Se-Met significantly reduced(P < 0.01)the shear force;group Se-Met and SS + Se-Met significantly reduced(P < 0.01)45 min b value,and group SY and Se-Met ignificantly reduced(P < 0.01)24 h b value.In addition,group Se-Met significantly reduced(P < 0.05)the TVB-N content of the longissimus dorsi on the 1st and 5th day;each organic selenium group significantly reduced(P < 0.05)the total bacterial population on the 1st,5th and 7th day,reduced(P < 0.05)the numbers of Lactobacillus on the 5th and 7th day;and also reduced(P < 0.01)the numbers of Escherichia coli on the 3rd,5th and 7th day.However,no significant differences were observed in 45 min pH,24 h pH,45 min a value and 24 h a value of the longissimus dorsi(P > 0.05).Adding different organic selenium sources to diet could improve meat quality and prolong shelf life.Compared with group SS,group SY and group Se-Met significantly reduced(P < 0.01)serum ALT activity;each organic selenium group significantly reduced(P < 0.01)AST activity,TG and MDA content,and increased(P < 0.01)ALP,T-SOD and CAT activity;group Se-Met ignificantly reduced(P < 0.01)TC content and increased(P < 0.01)GSH-Px activity and TP content.No significant differences(P > 0.05)were observed in ALB and UREA.Each organic selenium group significantly increased(P <0.01)T-SOD,GSH-Px,CAT activity and T-AOC in liver,increased(P <0.01)GSH-Px activity and T-AOC in kidney,and reduced(P <0.01)MDA content in liver and kidney;group SY and group Se-Met significantly increased(P <0.01)T-SOD activity,and group Se-Met significantly increased(P <0.01)CAT activity in kidney.Each organic selenium group significantly increased(P <0.01)the mRNA expression of GSH-Px1,GSH-Px3 and TrxR1 in liver,and increased(P < 0.01)the mRNA expression of GSH-Px1 and GSH-Px3 in kidney;and group Se-Met and SS + Se-Met significantly increased(P < 0.01)the relative expression of TrxR1 in kidney.However,no significant differences were observed in the expression of TrxR1 in kidney,but it had a tend of improvement.The immunopositive results of the three factors in liver and kidney were also consistent with the mRNA expression.Adding different organic selenium sources to the diet could improve the blood status and improve the antioxidant capacity of the body.In conclusion,diet supplemented with organic selenium could significantly improved production performance,meat quality and shelf life,serum biochemical abilities and antioxidant abilities,tissue selenium deposition,liver and kidney antioxidant abilities,distribution of related antioxidant factors and relative expression of mRNA in fattening pigs,which played a positive role in pig production.