Effects Of Replacing In-feed Antibiotics With Plant Essential Oil And Tremella Fuciformis Fermentation On Growth Performance And Immunological Functions Of Weaning Piglets

Experiment 1:Effect of replacing in-feed antibiotics with different proportions of coated Plant Essential Oil on growth performance and immunological functions of weaning pigletsThis study was conducted to determine the effects of replacing in-feed antibiotics with different proportions of coated Plant Essential Oil（PEO）on growth performance and immunological functions of weaning piglets.A total of 144 weaned piglets（Duroc×Landrace×Yorkshire,aged 21±2 d,initial body weight 6.50±0.25 kg,half male and female）,were randomly allocated to 6 groups with 6 pens and 4 piglets per pen,respectively.The piglets received control（Based diet,CON）diet or control diet supplement antibiotic（colistin sulfate 20 mg/kg+virginiamycin 25 mg/kg,ANT）,PEO1（uncoated PEO,200 g/T）,PEO2（25%coated PEO,200 g/T）,PEO3（50%coated PEO,200 g/T）and PEO4（100%coated PEO,200 g/T）for 21 days.The basal diet formulation referenced to NRC（2012）.At 8 days,one piglet was selected from each pen and then challenged with 100 ml of L-Broth（Luria Broth）containing 1×10⁹ cfu/mL Enterotoxigenic Escherichia coli（ETEC）.The selected piglets were healthy with BW near the average BW of each pen.During the challenge period,all piglets had free access to feed and water.After 2 days of challenge,36 piglets were slaughtered,the antioxidant capacity,inflammation and immunological index in plasma,the content of volatile fatty acids in hindgut were determined.The results showed that:1.Growth performance and diarrhea score:The results showed that dietary supplementation with ANT or PEO not affect growth performance and diarrhea score（P<0.05）.However,after 12h of ETEC challenge,the groups of CON,PEO2 and PEO4had higher value of diarrhea score.Besides,piglets in CON,PEO2,PEO3 and PEO4groups had higher diarrhea frequency than other groups.The diarrhea score was similar between ANT and PEO1 groups.2.Blood indexes:After challenged with ETEC,compared to ANT diet,PEO1 had no significantly effects on Pig-Major Acute Phase Protein（Pig-MAP）but that was increased（P<0.05）in PEO4 group.Additionally,PEO1 significant decreased C-reactive protein（CRP）and IL-6 compared to the CON group（P<0.05）;Tumor necrosis factor-α（TNF-α）was lower in PEO1 group compared to ANT group（P<0.05）.In addition,compared to the CON,ANT supplementation singnificantly decreased（P<0.05）CD³⁺CD⁴⁺and the PEO1and PEO2 supplementation showed the similar response and the level of CD³⁺CD⁴⁺in PEO4 was similar to the CON.3.Volatile fatty acids:In the colon digesta,PEO4 supplementation decreased the concentration of butyrate compared with CON,ANT and PEO3 groups（P<0.05）.In the cecum,PEO4 supplemtation also showed lower concentration of propionate compared to CON and PEO1 groups（P<0.05）.The above results show that dietary treatments had not significant effects on piglet growth performance.However,after ETEC challenge,piglets in the PEO1 group showed similar inflammation response and diarrhea score with ANT group.These results may suggest that uncoated PEO may supress ETEC poisonousness.However,the lower concentrations of SCFAs in PEO4 suggesting that full-coated essential oil could transport to hindgut and inhibit microbial metabolism.Experiment 2:Effect of replacing in-feed antibiotics with Tremella fuciformis fermentation on growth performance and immunological functions of weaning pigletsThis study was conducted to investigate the effects of replacing antibiotics with Tremella fuciformis fermentation（TFF）on growth performance and immunological functions of weaning piglets.A total of 200 weaned piglets（Duroc×Landrace×Yorkshire,aged 21±2 d,initial body weight 6.50±0.25 kg,half male and female）,were randomly allocated to 5 groups with 8 pens and every pen have 5 piglets,respectively.The piglets received control（Based diet,CON）diet or control diet with antibiotic（ANT）or 0.1%TFF（TFF,1 kg/T）,0.2%TFF（TFF,2 kg/T）,PEO（PEO 300 g/T）for 28 days.The based diets were formulated by referring to NRC（2012）.At 8 days,two piglets were selected per-pen of CON and 0.2%TFF groups to be challenged or not with ETEC（100 ml per pig）,resulting in a 2×2 factorial arrangement of treatments design.Six piglets were selected from per groups challenged with ETEC or sterile medium and slaughtered after 24h.The results showed that:There were no significant differences for the body weight（BW）,ADG and Feed:Gain（F:G）（P>0.05）,but in the second week（8-14d）,the 0.2%TFF group had higher ADFI than ANT,0.1%TFF and PEO groups（P<0.05）.As for overall phases（1-28 d）,the 0.1%TFF group showed lower ADFI than CON,ANT and 0.2%TFF groups（P<0.05）.In addition,the CON group showed higher diarrhea index compared with other groups（P<0.05）.After challenged with ETEC,the plasma concentrations of albumin（ALB）（P=0.09）and glucose（GLU）decreased（P<0.05）,and IL-1βsignificantly increased（P<0.05）.Dietary treatment significantly decreased the concentration of haptoglobin（HPT）（P<0.05）.The above results show that there were no significant differences among treatments on piglet growth performance,but the ANT,TFF and PEO groups had lower diarrhoea score than CON group（P<0.05）.After ETEC chanllenge,the plasma concentration of IL-1βincreased significantly（P<0.05）,but the concentration of ALB and GLU decreased（P<0.05）.These results may imply that ETEC chanllenge has an impact on nutrition metabolism and inflammatory response.However,0.2%TFF group significantly reduced the concentration of HPT after ETEC chanllenge,suggesting TFF may alleviate the stress reaction.Conclusion:In present study,uncoated PEO can achieve similar growth performance with antibiotic group.After challenged with ETEC,piglets in the PEO1 group could relieve the stress and inflammation,and the diarrhea was relieved.These results may suggest that uncoated PEO can benefit to supress ETEC poisonousness.In addition,piglets in the coated PEO groups can preserve more PEO to the hindgut and regulate microbial metabolism.Compared with antibiotic and plant essential oil groups,piglets in the 0.2%TFF group has the similar ability to control diarrhea.Furthermore,0.2%TFF can alleviate the stress response of piglets.