乳化植物甾醇对福建白兔生长性能、肠道形态及盲肠菌群与代谢物的影响

Effects of Emulsified Phytosterol on Growth Performance,Intestinal Morphology,Cecal Microbial Communities and Metabolites of Fujian White Rabbits

本试验旨在研究乳化植物甾醇对福建白兔生长性能、肠道形态及盲肠菌群与代谢物的影响。选取健康、体重相近的40日龄福建白兔150只,随机分为5组,每组30只(公母各占/1/2),单笼饲养。对照组饲喂基础饲粮,试验组A在基础饲粮中添加20 mg/kg的普通植物甾醇,试验组B、C、D在基础饲粮中分别添加10、20和40 mg/kg的乳化植物甾醇,试验期为60 d。饲养试验结束后采样,测定各组的生长性能和肠道形态、盲肠菌群组成与代谢物组成及相对含量。结果显示:1)与对照组和试验组A相比,试验组B、C、D福建白兔的腹泻率和死亡率明显下降,平均日采食量、平均日增重、料重比等各项生长性能指标均有一定程度的改善,其中试验组C的平均日增重、料重比与其他各组的差异达到显著水平(P<0.05)。2)与对照组相比,试验组C的十二指肠绒毛长度与试验组B、C的空肠绒毛长度显著提高(P<0.05),试验组A、B、C、D十二指肠的隐窝深度与试验组B、C、D空肠的隐窝深度显著降低(P<0.05),试验组A、B、C、D十二指肠和空肠的绒毛长度与隐窝深度比值(V/C值)与试验组B、C、D回肠的V/C值显著增加(P<0.05);试验组A空肠、回肠的V/C值显著低于试验组B、C、D(P<0.05);试验组C十二指肠的绒毛长度、试验组C、D十二指肠的V/C值显著高于其他各组(P<0.05)。3)试验组B、C、D盲肠菌群组成与对照组和试验组A相差较大,试验组B、C、D在门水平上以厚壁菌门(Firmi-cutes)、拟杆菌门(Bacteroidota)为主,厚壁菌门/拟杆菌门随着乳化植物甾醇添加剂量的增加呈现先增加后略微下降的趋势;在属水平上,Muribaculaceae、瘤胃球菌科NK4A214组(Ruminococ-caceae_NK4A214_group)、阿克曼氏菌属(Akkermansia)、梭菌纲UCG014(Clostridia_UCG-014)、梭菌纲vadinBB60组(Clostridia_vadinBB60_group)为各组优势菌属。4)添加植物甾醇的各试验组盲肠中糖和醇、有机酸、氨基酸等代谢物的相对含量比对照组增加,部分脂类和类脂类的相对含量下降,类激素物质的相对含量增加。Spearman相关性分析表明,这些代谢物与产粪甾醇真杆菌属(Eubacterium_coprostanoligenes)和瘤胃球菌科V9D2013组(Ruminococcaceae_V9D2013_group)密切相关。综上所述,饲粮中添加乳化植物甾醇可降低福建白兔的腹泻率和死亡率,提高平均日采食量和平均日增重,降低料重比,有利于改善肠道形态和盲肠菌群组成,增加盲肠中代谢物的相对含量,特别是短链脂肪酸;乳化植物甾醇添加剂量为20 mg/kg时对福建白兔生长性能和肠道黏膜形态完整性的改善效果最好,此剂量为福建白兔饲粮中的乳化植物甾醇的最佳添加剂量。

This study aimed to investigate the effects of emulsified phytosterol on the growth performance,in⁃testinal morphology,cecal microbial communities and metabolites of Fujian white rabbits.A total of 150 healthy and similarly weighted 40⁃day⁃old Fujian white rabbits were selected and randomly divided into 5 groups with 30 rabbits in each group(half male and half female),and the rabbits were fed separately.The control group was fed a basal diet,and test group A added 20 mg/kg of ordinary phytosterol to the basal diet,while test groups B,C and D added 10,20 and 40 mg/kg of optimized emulsified phytosterol,respectively.The experimental period was 60 days.The growth performance,intestinal morphology,the composition of ce⁃cal microbial communities,and the composition and relative contents of cecal metabolites in each group were measured.The results showed as follows:1)compared with the control group and test group A,the diarrhea rate and mortality of Fujian white rabbits in test groups B,C and D obviously decreased,and various growth performance indicators such as average daily feed intake,average daily gain,and feed to gain ratio improved to a certain extent.The average daily gain and feed to gain ratio of test group C were the best,and the difference between the test group C and the other groups was significant(P<0.05).2)Compared with the control group,the duodenal villi length in the test group C and the jejunal villi length in the test groups B and C were signifi⁃cantly increased(P<0.05),the duodenal crypt depth in the test groups A,B,C,D and the jejunal crypt depth in the test groups B,C,D were significantly decreased(P<0.05),the duodenal and jejunal villus length/crypt depth(V/C value)in the test groups A,B,C,D and the ileal V/C value in the test groups B,C,D were significantly increased(P<0.05).The jejunal and ileal V/C value in the test group A was signifi⁃cantly lower than that in the test groups B,C,D(P<0.05);the duodenal villi length in the test group C and the duodenal V/C value in the test groups C,D were significantly higher than those in the other groups(P<0.05).3)There are large differences on the composition of cecal microbial communities between the test groups B,C,D and the control group and the test group A.At the phylum level,Firmicutes and Bacteroidota were the main phyla in test groups B,C,D;Firmicutes/Bacteroidota(F/B)showed a trend of first increasing and then slightly decreasing with the increase of emulsified phytosterol additive dosage.At the genus level,Muribaculaceae,Ruminococcaceae_NK4A214_group,Akkermansia,Clostridia_UCG⁃014 and Clostridia_vad⁃inBB60_group were the dominant microbial genus of each group.4)The relative contents of metabolites such as sugars,alcohols,organic acids and amino acids in the cecum of rabbits in each test group with emulsified phytosterol were increased,while the relative contents of some lipids and lipid substances decreased,and the relative contents of hormone like substances increased compared with the control group.Spearman correlation analysis indicated that these metabolites were closely related to the Eubacterium_coprostanoligenes and Rumino⁃coccaceae_V9D2013_group.In summary,adding emulsified phytosterol to the diet of Fujian white rabbits can reduce the diarrhea rate and mortality,increase the average daily feed intake and average daily gain,reduce the feed to weight ratio,improve the intestinal morphology and cecal microbial community composition,and in⁃crease the relative contents of metabolites in cecum,especially the short chain fatty acids.When the additive dosage of emulsified phytosterol is 20 mg/kg,the growth performance and intestinal mucosal morphological in⁃tegrity of Fujian white rabbits are best,that is the suitable additive dosage of emulsified phytosterol in the diet for Fujian white rabbits.