Effects Of Lactobacillus Delbrueckii And Xylo-oligosaccharides On Growth Performance And Meat Quality Of Huanjiang Mini-pigs And The Mechanism

This study was conducted to investigate the effects of Lactobacillus delbrueckii（LD）and xylo-oligosaccharides（XOS）on growth performance,carcass traits,and meat quality of Huanjiang mini-pigs.A total of 128 Huanjiang mini-pigs with average body weight of 9.5 kg were randomly divided into four groups,and reared in eight pens with four pigs per pen（male:female=1:1）.The control group was fed basal diet;and LD group,XOS group,and LD+XOS group were added with 0.05% LD,0.02% XOS,and 0.05% LD+0.02% XOS,respectively,in the basal diet.During the experimental period,the feed intake was recorded daily,and the fasting body weights were weighed on the 28^th,56^th,and 84^thdays of the test.The ADFI,ADG,and F/G were calculated.Blood samples were collected and used for measuring plasma biochemical indexs,oxidant/antioxidant indexs and cytokines.The carcass traits were determined by slaughter,and the longissimus dorsi muscle was taken to determine the meat quality and nutrient content.The pre-test period is 3 days and the trial period is 84 days.The results showed that:1)Effects of LD and XOS on growth performance of Huanjiang mini-pigs.Compared with the control group,the ADG of LD group and LD+XOS group significantly increased（P<0.05）,the F/G of LD+XOS group decreased（P>0.05）,on days 29-56 of the experiment;the ADG of LD group and LD+XOS group increased,while F/G decreased（P>0.05）on days 1-84 of the experiment.2)Effects of LD and XOS on carcass traits and meat quality of Huanjiang mini-pigs.Compared with the control group,on day 28 of the experiment,the dorsum thickness of LD group significantly decreased（P<0.05）,and the eye muscle area of LD+XOS group significantly increased（P<0.05）;the pH_45minof LD group,XOS group,and LD+XOS group significantly increased,and the marbling score significantly decreased（P<0.05）.On day 56 of the experiment,the skin rate of XOS group significantly increased（P<0.05）.On day 84 of the experiment,the skin thickness and brightness value of LD group significantly decreased（P<0.05）;the backfat thickness,skin thickness,and brightness value of XOS group and LD+XOS group significantly decreased（P<0.05）,and redness value significantly increased（P<0.05）;the pH_45minof XOS group significantly decreased（P<0.05）,and slaughter rate significantly increased（P<0.05）.3)Effects of LD and XOS on nutrition content of the longissimus dorsi muscle of Huanjiang mini-pigs.Compared with the control group,on day 28 of the experiment,the IMF,C18:0 and SFA contents of the longissimus dorsi muscle of LD group significantly decreased（P<0.05）;the DM,IMF,and EAA contents of the longissimus dorsi muscle of XOS group significantly decreased（P<0.05）;the CP content of the longissimus dorsi muscle of LD+XOS group significantly increased,and the IMF content significantly decreased（P<0.05）.On day 56 of the experiment,the C16:1 content of the longissimus dorsi muscle of LD group significantly increased（P<0.05）;the DM,His,and EAA contents of the longissimus dorsi muscle of XOS group significantly increased（P<0.05）;the DM,CP,C20:0,Gly,Met,Phe,His,EAA,NEAA,FAA,and TAA contents of the longissimus dorsi muscle of LD+XOS group significantly increased（P<0.05）.On day 84 of the experiment,the Ser,Tyr,EAA,NEAA,FAA,TAA,and C22:6n3 contents of the longissimus dorsi muscle of XOS group significantly increased（P<0.05）;the C22:6n3 and SFA contents of the longissimus dorsi muscle of LD+XOS group significantly increased（P<0.05）.4)Effects of LD and XOS on plasma biochemical indices of Huanjiang mini-pigs.Compared with the control group,on day 28 of the experiment,the plasma TG concentration of LD group significantly increased（P<0.05）;the plasma UN and TG concentrations and ALP activity of XOS group significantly increased,and HDL-C concentration significantly decreased（P<0.05）;the plasma ALB,UN,and TG concentrations and ALP activity of LD+XOS group significantly increased（P<0.05）.On day 56 of the experiment,the plasma NH₃ concentration and AMS activity of LD group significantly increased（P<0.05）;the plasma NH₃ concentration of XOS group significantly increased,and LDH activity significantly decreased（P<0.05）;the plasma TP,ALB,UN,GLU,TG,CHO,and LDL-C concentrations and LIPC activity of LD+XOS group significantly increased,and AST and LDH activities significantly decreased（P<0.05）.On day 84 of the experiment,the plasma AST,AMS,and LDH activities and TG concentration of LD group significantly decreased（P<0.05）;the plasma AST and LDH activities and NH₃ concentration of XOS group significantly decreased（P<0.05）;the plasma TP concentration of LD+XOS group significantly increased,and AST and LDH activities and NH₃ concentration significantly decreased（P<0.05）.5)Effects of LD and XOS on plasma oxidant/antioxidant indices of Huanjiang mini-pigs.Compared with the control group,on day 28 of the experiment,the plasma H₂O₂ concentration of LD group and LD+XOS group significantly increased（P<0.05）;the plasma HR concentration of LD group,XOS group,and LD+XOS group significantly increased,and GSH-Px activity significantly decreased（P<0.05）;the plasma SOD activity of LD group significantly decreased（P<0.05）;the plasma CAT activity and T-GSH concentration of XOS group significantly increased（P<0.05）.On day 56 of the experiment,the plasma MDA concentration of LD group and XOS group significantly decreased（P<0.05）;the plasma T-GSH concentration of the XOS group significantly decreased（P<0.05）.On day 84 of the experiment,the plasma H₂O₂ concentration of LD group,XOS group,and LD+XOS group significantly decreased（P<0.05）;the plasma GSH-Px activity of XOS group and LD+XOS group significantly increased（P<0.05）.6)Effects of LD and XOS on plasma cytokine concentration of Huanjiang mini-pigs.Compared with the control group,the plasma IL-1β,IL-2,and TNF-α concentrations of XOS group and LD+XOS group significantly increased（P<0.05）on day 28 of the experiment;the plasma IL-1β,IL-2 and IL-6 concentrations of XOS group and LD+XOS group significantly increased（P<0.05）on day 84 of the experiment.In summary,dietary supplementation with LD or XOS can affect the body’s biochemical parameters related to nitrogen metabolism and glycolipid metabolism,and weaken the body’s oxidative damage,as well as improve carcass traits and meat quality.And the addition of LD and XOS had a better effect on carcass traits and meat quality.