Effects Of Olive Cake Extract On Performance,Serum Indexes And Intestinal Microflora Of Weaned Piglets

The extensive use of antibiotics in feed has affected the healthy development of livestock and poultry industry,and weaning period of piglets is also the most sensitive period for digestive tract changes.Therefore,in this study,the effects of olive extract on growth performance,antioxidant and anti-inflammatory ability,intestinal health and intestinal flora of weaned piglets were evaluated by comparing olive extract with diets supplemented with antibiotics,which provided new ideas for livestock and poultry industry to find antibiotics substitutes.1.Effect of olive extract on performance and intestinal microbes of weaned pigletsThe experiment was adopted in 144 piglets with an average initial weight of（11.0±0.91kg）were randomly divided into 3 groups according to their weight,with 8 replicates in each group and 6 piglets in each replicate.The experimental group was divided into control group（Con group）:feeding basic diet;Antibiotic group（AB group）:feeding basic diet supplemented with chlortetracycline and oxytetracycline calcium;Olive extract group（OE group）feeding basic diet with 3.0‰ olive extract.The whole experiment lasted 37 days,including 7 days of pre-experiment.At the end of the experiment,after fasting for 24 hours,they were weighed,and 30 piglets were selected to collect blood from the anterior vena cava.After the blood collection,LPS（20μg/kg,BW）was injected intraperitoneally.After injection for 4 hours,these 30 piglets were sampled from the anterior vena cava again（group names were Con+LPS,AB+LPS and OE+LPS）.Collecting fresh feces of piglets one day before fasting.The experimental results showed that compared with the C group,the feed intake of piglets increased by 4.74%,the daily gain increased by 10.13%,and the feed-weight ratio decreased by 4.59%in OL group,but there was no significant difference.（P>0.05）.Before LPS stimulation,the levels of AST,ALT,SOD,T-AOC,MDA,GSH-Px,TNF-α,IL-6,D-xylose and DAO in serum of piglets were no significant difference（P>0.05）.Compared with Con group and AB group,the serum levels of TC and TG in OE group was significantly decrease（P<0.05）.Compared with Con+LPS group,the serum levels of AST,MDA,TNF-α,IL-6 and DAO in AB+LPS and OE+LPS group was significantly decrease（P<0.05）,while the levels of SOD,T-AOC and GSH-Px was significantly increase（P<0.05）.The analysis of fecal sequencing showed that the chao₁,PD_whole_tree and observed_speecies indices inα-diversity of Con group and OE group increased significantly compared with AB group（P<0.05）.From the results of β-diversity,the OTU abundance matrix of unweighted PCoA showed that Con and OE groups had higher similarity and were obviously separated from AB group.The addition of olive extract significantly increased the ratio of Firmicutes/Bacteroidetes in phylum level.The addition of olive extract also increased the relative abundance of Phascolactobacter,Oscillibacter,Roseburia,Clostridium_XlVa,Paraprevotella,Parabacteroides,Oribacterium,Eubacterium,Dorea and Collinsella,but decreased the relative abundance of Megasphaera and Desulfovibrio.Therefore,the olive extract to weaned piglets can affect the feed intake,daily gain and feed/weight of piglets to a certain extent,and can enhance the antioxidant and anti-inflammatory ability of piglets,increase the richness of beneficial bacteria in the intestinal tract of piglets,and reduce the richness of pathogenic bacteria,which is beneficial to the health of piglets.2.Effects of olive extract on lipopolysaccharide-induced oxidative stress,inflammation,intestinal villi and microbial community in pigletsThe olive extract contains compounds with antioxidant and anti-inflammatory properties.This study was designed to investigate whether olive cake extract,enriched with maslinic acid and hydroxytyrosol,alleviates the lipopolysaccharides（LPS）-induced oxidative stress,inflammation and intestinal villus damage in piglet model.Thirty weaned piglets（6.9±0.9 kg）were assigned to five groups using a randomized complete block design.Piglets were fed a basal diet before intraperitoneal（i.p.）injection of physiological saline（C）;fed a basal diet alone（CL）or fed a basal diet plus olive extract（OL）,antibiotics（AL）,or olive extract and antibiotics（OAL）before i.p.injection of LPS.The feeding lasted for 2 weeks.Piglets were euthanized 4h after LPS injection.Systemic anti-oxidant and inflammation levels were measured and villus morphology in the intestine was examined.Compared with those in the C group,piglets in the CL group had significantly lower GSH-Px,SOD,ALB levels and higher MDA,NO,LDH,ALT and AST levels in the serum（P<0.05）.Compared with the CL group,piglets in OL,AL,and OAL groups had significantly higher serum GSH-Px,SOD and ALB levels and lower MDA,NO,LDH,ALT and AST levels（P<0.05）.LPS administration significantly increased the serum concentration of TNF-α,IL-6,DAO and D-xylose in the CL group compared with the control group（P<0.05）.Piglets in OL,AL,and OAL groups had significantly lower serum TNF-α,IL-6,DAO and D-xylose levels and higher IL-10 level（P<0.05）.In the duodenum and ileum of piglets,LPS challenge led to significantly lower villus height,higher crypt depth and lower villus height/crypt depth compared with the control group（P<0.05）,whereas,OL,AL,and OAL groups had significantly lower crypt depth and higher villus height/crypt depth compared with the CL group（P<0,05）.Compared with group C,the expression of Claudin-3 and Occludin in ileum of Cl group was significantly decrease（P<0.05）;compared with CL group,the expression of Claudin-3 and Occludin in ileum tissue of OL group,AL group and OAL group was significantly increase（P<0.05）.Dietary inclusion of olive extract increased the relative abundance of intestinal Lactobacillus and Clostridium at genus level.Therefore,dietary supplementation with olive extract can improved anti-oxidative and anti-inflammatory capacity,intestinal structure morphology,and increased the abundance of beneficial intestinal bacteria in weaned piglet model challenged by LPS,which is beneficial to the health of piglets.Above all,we explored the application of olive extract in weaned piglets.The experimental results showed that supplementation of olive extract in diet could increase the feed intake（4.74%）and daily gain（10.13%）of piglets and reduce the feed-weight ratio（4.59%）.And can enhance the liver function,antioxidant capacity and anti-inflammatory capacity of weaned piglets,and weakening the stimulation of LPS;guarantee the steady state of digestive tract;ensure the integrity of intestinal villi of weaned piglets,increase the villus height of duodenum,ileum and jejunum,and reduce the crypt depth;enhance the intestinal barrier function and increase the expression of Claudin-3 and Occludin in ileum.Improve the diversity and richness of intestinal flora,increase the abundance of beneficial bacteria and reduce the abundance of pathogenic bacteria in weaned piglets.