日粮能量源结构对小鼠生长、血清生化指标及肠道健康的影响

Effects of dietary energy source structure on growth performance,serum biochemical parameters and intestinal health in mice

为了探讨日粮能量源结构对小鼠血清生化指标、肠道黏膜形态、屏障功能及盲肠菌群结构的影响,试验将72只健康且体重相近的21日龄雄性C57BL/6J小鼠分为CON组(79%蜡质玉米淀粉组)、LSB组(70%蜡质玉米淀粉+9%大豆油组)、MSB组(61%蜡质玉米淀粉+18%大豆油组)、HSB组(52%蜡蜡质玉米淀粉+27%大豆油组),每组18只,分别饲喂4种能量源结构的等能等氮日粮(蜡质玉米淀粉和大豆油提供定量蛋白之外的所有能量),试验期为36 d。试验结束时通过测定小鼠的生长性能、血清生化指标、肠道黏膜形态、屏障功能及盲肠菌群结构研究日粮能量源结构的影响。结果表明:与CON组相比,MSB组、HSB组小鼠的终末体重分别提高5.61%、7.69%(P<0.05)。与CON组相比,LSB组、MSB组、HSB组血清中的白蛋白含量均显著降低(P<0.05);HSB组小鼠血清中尿素氮含量升高了20.11%,差异显著(P<0.05);LSB组与MSB组总蛋白含量分别降低了4.10%、3.82%,差异不显著(P>0.05)。与CON组相比,MSB组小鼠十二指肠隐窝深度显著降低(P<0.05)。LSB组小鼠回肠紧密连接蛋白-1(Claudin-1)mRNA相对表达量与其他三组比较均显著降低(P<0.05);HSB组小鼠十二指肠、空肠的闭锁连接蛋白-1(ZO-1)mRNA相对表达量与LSB组比较显著增加(P<0.05)。在门水平上,厚壁菌门与拟杆菌门比值的相对丰度呈先降低后升高的趋势,与CON组相比,LSB组和MSB组降低,HSB组升高,但均差异不显著(P>0.05)。在属水平上,MSB组、HSB组布劳特氏菌属、毛螺菌属、颤螺菌属等产酸菌属的相对丰度显著提高(P<0.05)。说明适当调整日粮中能量源结构可促进小鼠生长、影响小鼠血清生化指标、提高肠道屏障功能、改善小鼠肠黏膜形态,并提高小鼠盲肠中产酸菌群的相对丰度,进而增强小鼠肠道黏膜机械性屏障作用。

The purpose of this study was to investigate the effects of dietary energy source structure on serum biochemical indices,small intestinal tissue morphology,barrier function and cecal flora structure in mice.Seventy-two healthy 21-day-old male C57BL/6J mice with similar initial body weight were randomly divided into CON group(79%waxy corn starch),LSB group(70%waxy corn starch+9%soybean oil),MSB group(61%waxy corn starch+18%soybean oil)and HSB group(52%waxy corn starch+27%soybean oil),with 18 animals in each group,which were fed four kinds of isoenergetic and isonitrogen diets(waxy corn starch and soybean oil provided all energy except quantitative protein).The experiment lasted for 36 days.Growth performance,serum biochemical indices,intestinal mucosal morphology,barrier function and cecal microflora structure of mice were measured to study the influence of dietary energy source structure.The results showed that compared with the CON group,the final body weight of mice in MSB group and HSB group was increased by 5.61%and 7.69%,respectively(P<0.05).Compared with CON group,serum ALB content in LSB group,MSB group and HSB group was significantly decreased(P<0.05).Serum BUN content in HSB group was significantly increased by 20.11%,which was a significant difference(P<0.05).The TP content of LSB group and MSB group was decreased by 4.10%and 3.82%,respectively without significant difference(P<0.05).Compared with CON group,the depth of duodenal recess in MSB group was significantly decreased(P<0.05).The mRNA relative expression of Claudin-1 in the ileum of LSB group was significantly decreased compared with the other three groups(P<0.05).The mRNA relative expression of atresia connexin-1(ZO-1)in duodenum and jejunum of mice in HSB group was significantly increased compared with that in LSB group(P<0.05).In terms of the structure of cecum flora,the relative abundance of Firmicutes/Bacteroidetes decreased first and then increased;compared with CON group,the relative abundance of Firmicutes/Bacteroidetes was significantly decreased in LSB and MSB groups(P<0.05),while it was increased in HSB group but not significantly(P>0.05).At the genus level,the relative abundance of Brautella,Trichospirillum and Tremillum in MSB and HSB groups was significantly increased(P<0.05).These results indicated that proper adjustment of the energy source structure in the diet could promote the growth of mice,affect the serum biochemical indexes of mice,improve the intestinal barrier function,the intestinal mucosal morphology,and the relative abundance of acid bacteria in the cecum of mice,thus enhancing the mechanical barrier effect of the intestinal mucosa.