干酪乳杆菌Lactobacillus casei 393在鼠消化道内定植能力及分布规律的研究

研究了干酪乳杆菌Lactobacillus casei 393在小鼠肠道中定植能力及分布规律。利用羧基荧光素二乙酸琥珀酰亚胺酯分子探针对干酪乳杆菌Lactobacillus casei 393进行标记,以每只1010mL-1的量,口服途径喂给BALB/c鼠,分别于口服后的第1,3,5,6 d取其十二指肠、空肠、回肠、结肠等肠段,通过流式细胞仪检测肠内的标记阳性菌。实验结果显示:经口服后第5 d,干酪乳杆菌Lactobacillus casei 393开始在BALB/c鼠肠道中定植,在十二指肠、空肠、回肠、结肠的定植率分别为28.70%,29.77%,15.63%,26.17%,第6 d标记的阳性菌出现明显的生长趋势,阳性检出率分别为71.77%,57.31%,65.44%,53.13%。研究表明干酪乳杆菌Lactobacillus casei 393具有良好的肠道定植能力。     

唾液乳杆菌Ls04对小鼠肠道菌群及黏膜SIgA质量浓度的影响

对唾液乳杆菌Ls04对小鼠肠道微生物区系和肠黏膜分泌型免疫球蛋白A(SIgA)质量浓度的影响及其持续作用效果进行了研究。将100只SPF雄性昆明白小鼠随机分为Ls高、中、低剂量组及对照组,进行15 d灌胃,将灌胃前、灌胃15 d各处理组小鼠,及灌胃结束后第3,7,14天Ls中剂量组小鼠断颈处死,刮取其大肠黏膜、小肠黏膜,分别进行肠道中乳杆菌、双歧杆菌、肠杆菌、肠球菌和产气荚膜梭菌的计数及肠黏膜SIgA质量浓度的测定。结果表明,灌胃Ls04能显著提高小鼠肠道中乳杆菌、双歧杆菌数量,降低肠杆菌、肠球菌、产气荚膜梭菌数量,且Ls中剂量为最适;灌胃结束后14 d,小鼠肠道中乳酸菌、双歧杆菌数量仍高于灌胃前数量,且肠杆菌仍被显著抑制;灌胃15 d,Ls中剂量组小鼠肠黏膜SIgA质量浓度显著升高,且显著高于Ls高剂量组;灌胃结束后小鼠肠黏膜SIgA质量浓度至14 d显著降低,但仍显著高于灌胃前水平。结果表明,唾液乳杆菌Ls04停用后仍可显著增殖肠道有益菌并抑制致病菌,同时能够有效提高肠黏膜SIgA含量,刺激机体免疫应答。     

复方苍术方调节肠道菌群及肠道保护作用的研究

本文探讨了复方苍术方调节肠道菌群及肠保护作用。给予复方苍术方后,中、高剂量组肠球菌及高剂量组肠杆菌菌落数(按lg CFU计)分别降低6.35%、8.17%及5.69%;中、高剂量组乳杆菌和双歧杆菌菌落数分别增加7.04%、6.74%、6.99%和8.10%,且高于阳性对照组;同时,中、高剂量组盲肠内容物p H值分别降低6.58%和5.26%;肠道组织病理结果显示复方苍术方低剂量组十二指肠、回肠及中、高剂量组十二指肠、空肠、回肠A/V比值分别增加29.84%、17.47%、56.01%、31.18%、20.09%、46.51%、30.52%和20.09%,且中、高剂量组空肠、回肠A/V比值明显高于阳性对照组。此外,复方苍术方低、中、高剂量组小肠墨汁推进率分别增加43.92%、69.93%和98.31%。研究结果表明,复方苍术方可能通过调节肠道菌群结构改善肠道微环境,且效果优于单用低聚半乳糖。     

嗜酸乳杆菌NCFM黏附定植能力的研究

采用实时定量(Real-time)PCR的方法对嗜酸乳杆菌NCFM在小鼠肠道中的定植情况进行了评价。通过研究发现,实时定量(Real-time)PCR用来菌数的评估具有非常好的线性关系和稳定性。小鼠灌胃一周的过程中,在小鼠的十二指肠、回肠、空肠、盲肠、结肠和粪便中菌体的数量并没有出现数量级上的增长或减少,说明我们灌胃的菌体浓度适当,并没有引起小鼠体内的菌群失调。而在灌胃第1 d,基本上各部分的肠组织和粪便中菌体的数量都有增加,说明灌胃初期菌体在肠道中有较好的定植。而第3、5和7 d小鼠肠道和粪便中的菌体数量上下波动,但并没有显著地增加或减少,说明小鼠体内的菌群数量达到了一个平衡,并不会因为持续灌胃就打破这个平衡。因此,嗜酸乳杆菌NCFM具有良好的定植能力。     

复方苍术方调节肠道菌群及肠保护作用研究

本文探讨了复方苍术方调节肠道菌群及肠保护作用。给予复方苍术方后,中、高剂量组肠球菌及高剂量组肠杆菌菌落数（按 lg CFU 计）分别降低 6.35%、8.17%及 5.69%;中、高剂量组乳杆菌和双歧杆菌菌落数分别增加 7.04%、6.74%、6.99%和 8.10%,且高于阳性对照组;同时,中、高剂量组盲肠内容物 p H 值分别降低 6.58%和 5.26%;肠道组织病理结果显示复方苍术方低剂量组十二指肠、回肠及中、高剂量组十二指肠、空肠、回肠 A/V 比值分别增加 29.84%、17.47%、56.01%、31.18%、20.09%、46.51%、30.52%和 20.09%,且中、高剂量组空肠、回肠 A/V 比值明显高于阳性对照组。此外,复方苍术方低、中、高剂量组小肠墨汁推进率分别增加 43.92%、69.93%和 98.31%。研究结果表明,复方苍术方可能通过调节肠道菌群结构改善肠道微环境,且效果优于单用低聚半乳糖。     

复方苍术方调节肠道菌群及肠保护作用研究

本文探讨了复方苍术方调节肠道菌群及肠保护作用。给予复方苍术方后,中、高剂量组肠球菌及高剂量组肠杆菌菌落数（按 lg CFU 计）分别降低 6.35%、8.17%及 5.69%;中、高剂量组乳杆菌和双歧杆菌菌落数分别增加 7.04%、6.74%、6.99%和 8.10%,且高于阳性对照组;同时,中、高剂量组盲肠内容物 p H 值分别降低 6.58%和 5.26%;肠道组织病理结果显示复方苍术方低剂量组十二指肠、回肠及中、高剂量组十二指肠、空肠、回肠 A/V 比值分别增加 29.84%、17.47%、56.01%、31.18%、20.09%、46.51%、30.52%和 20.09%,且中、高剂量组空肠、回肠 A/V 比值明显高于阳性对照组。此外,复方苍术方低、中、高剂量组小肠墨汁推进率分别增加 43.92%、69.93%和 98.31%。研究结果表明,复方苍术方可能通过调节肠道菌群结构改善肠道微环境,且效果优于单用低聚半乳糖。     

铁皮石斛对脾虚便秘小鼠肠道形态及肠道免疫细胞数量的影响

目的 探究铁皮石斛对脾虚便秘小鼠的肠隐窝深度、黏膜厚度、绒毛高度及淋巴细胞数的影响,从肠道形态和肠道免疫明确铁皮石斛对脾虚便秘的疗效机制。方法 18只SPF级KM小鼠随机分为正常组、模型组和治疗组。通过灌胃番泻叶水煎液7 d,控制饮食、饥饱失常8 d建立小鼠脾虚便秘模型。造模成功后,治疗组灌胃铁皮石斛汤剂,正常组与模型组灌胃等量无菌水,持续5 d。试验结束后,采集各组小鼠回肠、空肠和盲肠约2 cm肠段,分析隐窝深度、绒毛高度、黏膜厚度和淋巴细胞数。结果 与正常组和模型组相比,铁皮石斛能增加小鼠空肠淋巴细胞数和回肠肠黏膜厚度(P<0.01或P<0.05)。治疗组小鼠盲肠绒毛高度显著高于正常组(P<0.05),回肠绒毛高度虽然高于正常组,但差异不显著(P>0.05),治疗组小鼠盲肠黏膜厚度和淋巴细胞数高于模型组,二者差异显著(P<0.05)。结论 铁皮石斛通过改善脾虚便秘小鼠肠道形态,增加黏膜淋巴细胞数来治疗脾虚便秘。     

产细菌素Enterocin Y3粪肠球菌对小鼠肠道菌群及代谢功能的影响

为探讨产细菌素Enterocin Y3粪肠球菌DH9003的益生菌作用,对15只健康C57雄性小鼠进行等体积灌胃无菌生理盐水（对照组,n=7）和粪肠球菌DH9003（处理组,n=8）,4周后收集小鼠粪便,测定粪肠球菌DH9003对小鼠肠道菌群结构和代谢功能的影响。结果显示,用粪肠球菌DH9003灌胃小鼠,7 d内就可在其体内大量定植;7～28 d时,该细菌数量缓慢增加并趋近稳定。通过观察小鼠肠道和肝脏组织切片研究病理学特征,灌胃粪肠球菌DH9003不会对小鼠肠道和肝脏产生有害影响,相反会使小鼠的肠黏膜更为密集且长度增加,改善小鼠肠黏膜。用粪肠球菌DH9003灌胃使该菌株成为不同分组小鼠肠道差异的主要物种。同时,补充粪肠球菌DH9003对小鼠肠道的菌群结构具有一定的调节作用,导致门水平上的变化为拟杆菌门和厚壁菌门相对丰度的差异变化。灌胃粪肠球菌DH9003前和灌胃28 d后,从小鼠粪便中共检出254种差异代谢物,其中124种显著上调,130种显著下调。基于KEGG通路富集分析发现显著性水平较高的代谢通路有ABC转运蛋白和蛋白消化吸收通路。结论：小鼠摄入粪肠球菌DH9003后可在其体内定植...     

鱼腥草提取液对抗生素诱导小鼠肠道菌群失调的调节作用研究

为研究鱼腥草提取液(Houttuynia cordata extract,HCE)对肠道菌群失调的调节作用，使用头孢曲松钠(2 mg/g)灌胃7 d、每天2次，建立小鼠肠道菌群失调模型，再连续灌胃高、中、低剂量HCE 28 d，分析小鼠体重、摄食量、结肠长度、结肠HE染色、AB/PAS染色及肠道菌群组成与结构。结果显示，HCE对小鼠体重无影响，能够增加小鼠摄食量、缓解盲肠肿胀现象且高、中、低剂量HCE均显著改善了小鼠结肠缩短现象(P<0.05)；结肠组织病理学评分显示各HCE组均显著低于头孢曲松钠组(P<0.05)，结肠黏液层得到明显恢复；16S rDNA测序显示HCE可以缓解由头孢曲松钠灌胃导致的肠道菌群丰富度和多样性下降，显著提高了小鼠肠道拟杆菌门与乳杆菌属的相对丰度(P<0.05)，显著下调厚壁菌门与肠球菌属的相对丰度(P<0.05)，明显改善了小鼠肠道菌群失调的现象，有益于小鼠肠道健康。     

大鼠原位单向肠灌流模型研究两种多糖类药物肠道降解动力学

目的研究贻贝多糖和人参多糖在大鼠肠道内的降解特性。方法采用大鼠原位单向肠灌流模型,采用高效液相色谱法(HPLC)测定两种多糖在肠灌流液中的含量。结果贻贝多糖在十二指肠段全部降解,在空肠段的降解百分率为40.33%±15.65%,在回肠和结肠部位,贻贝多糖降解百分率较低,分别为0.70%±0.49%和0.30%±0.14%。人参多糖在各肠段均有不同程度降解,其中,回肠部位的降解百分率较大,为52.41%±13.14%,结肠部位降解较少,仅为0.68%±0.54%。十二指肠和空肠部位的降解百分率分别为25.19%±17.02%和33.04±15.26%。结论贻贝多糖及人参多糖均可在肠道发生降解。     

益生菌对断奶鼠消化酶活力、肠道运动性及粘膜形态的影响

乳双歧杆菌、副干酪乳杆菌和植物乳杆菌是常见的益生菌,本研究系统评估了3株益生菌对断奶鼠消化代谢的调控作用。将断奶1周后的大鼠和小鼠分成对照组和益生菌处理组分别饲喂5周和4周,在此期间益生菌处理组每天分别灌胃1×109 CFU的乳双歧杆菌、副干酪乳杆菌和植物乳杆菌。试验期末,小鼠用于肠运动性试验,全部大鼠剖检取样进行生化及组织学分析。结果表明,乳双歧杆菌、副干酪乳杆菌和植物乳杆菌都能够显著促进小鼠肠道的运动性。同对照组相比,灌胃乳双歧杆菌、植物乳杆菌能够显著 （P<0.05） 增加大鼠的全期体重增重和肠液中胰蛋白酶活力,其中体重增重分别增加了13.33%和8.52%,胰蛋白酶活力分别提高了28.76%和31.13%。3株益生菌对大鼠的胃蛋白酶和淀粉酶活力、肝脏、脾脏、肾脏和胰腺重量及脏器系数均无显著影响。副干酪乳杆菌、植物乳杆菌均能够显著（P<0.05） 提高大鼠血清中总蛋白和球蛋白的含量,其中总蛋白含量分别增加了6.84%和9.12%,球蛋白含量分别增加了8.80%和6.82%。乳双歧杆菌、副干酪乳杆菌、植物乳杆菌生菌都会显著（P<0.05）升高大鼠血清中总胆固醇和高密度脂蛋白的含量,其中总胆固醇含量分别增加了44.35%、28.23%和17.74%,高密度脂蛋白含量分别增加了22.92%、27.08%和12.50%,对甘油三酯和低密度脂蛋白的含量无显著影响。此外,灌胃乳双歧杆菌、副干酪乳杆菌和植物乳杆菌均能够显著（P<0.05）提高大鼠的空肠和回肠绒毛高度和隐窝深度的比值以及回肠壁厚度,其中空肠绒毛高度和隐窝深度的比值分别增加了30.65%、19.35%和21.94%,回肠绒毛高度和隐窝深度的比值分别增加了30.21%、31.25%和35.94%,回肠壁厚度分别增加了21.14%、22.35%和27.51%。因此,乳双歧杆菌和植物乳杆菌能够通过促进肠道运动性、增加胰蛋白酶活力和改善肠道组织形态来促进宿主的消化吸收功能,进而提高宿主的体重增重同时又不会带来不良影响。     

复合菌-荔枝多酚对腹泻小鼠肠道形态结构和肠道菌群的影响

为评价复合菌-荔枝多酚对肠道形态结构和肠道菌群的影响,采用蓖麻油灌胃的方法,制造小鼠腹泻模型,造模成功后灌服不同药物治疗4 d后,取小鼠十二指肠、空肠和回肠固定到福尔马林中,进行苏木精-伊红染色,倒置显微镜下观察,测量各段小肠的绒毛长度、隐窝深度,计算绒腺比。无菌采集粪便用于肠道菌群聚合酶链式反应-变性梯度凝胶电泳（denaturing gradient gel electrophoresis,DGGE）检测,对DGGE图谱上的优势条带回收、克隆并测序,对测序结果进行BLAST比对分析。结果表明,嗜酸乳杆菌和复合菌能提高十二指肠、空肠的绒毛长度与隐窝深度的比值（V/C）,复合菌-荔枝多酚能增加空肠和回肠的V/C值。整个DGGE图谱和测序结果可见,嗜酸乳杆菌、复合菌和复合菌-荔枝多酚能增加小鼠菌群的数量,增强肠道菌群的微生态稳定性,而且复合菌还能增加群落的复杂程度。各给药组条带与正常组和模型组相比,增加了优势条带,复合菌组和复合菌-荔枝多酚组还出现了新的条带,复合菌体现了最优的效果。     

Effects of ad libitum milk replacer feeding and butyrate supplementation on the epithelial growth and development of the gastrointestinal tract in Holstein calves

Intensive milk feeding and butyrate supplementation in calves stimulate body growth and affect gastrointestinal development. The aim of the present study was to investigate the synergistic effects of ad libitum milk replacer (MR) feeding and butyrate supplementation of MR on rumen and small intestinal growth and on gene expression in the small intestine related to growth and energy metabolism at weaning. Male Holstein calves (n = 32) received colostrum from birth to d 3 of age and MR either ad libitum (Adl) or restrictively (Res; 6 L of MR/d; 12.5% solids) with (AdlB+, ResB+) or without (AdlB−, ResB−) 0.24% butyrate from d 4 until wk 8 of age. From wk 9 to 10, all calves were weaned and were fed 2 L/d until the end of the trial. Concentrate, hay, and water were freely available. At d 80, calves were slaughtered, volatile fatty acids were measured in rumen fluid, and rumen and small intestine samples were taken for histomorphometric measurements. The expression of mRNA associated with the local insulin-like growth factor (IGF) system and glucose metabolism as well as lactase and maltase activities were measured in the intestinal mucosa. The small intestine was 3 m longer in Adl than in Res. In the atrium ruminis, papilla width was greater in Res than in Adl. Villus circumference, cut surface, and height in the duodenum, proximal jejunum, and ileum were greater in Adl than in Res and in the proximal, mid, and distal jejunum and ileum were greater in calves treated with butyrate. Crypt depth in the duodenum and proximal jejunum was greater in Adl than in Res and in the ileum was smaller in calves treated with butyrate. The villus height:crypt depth ratio was greatest in AdlB+ calves. In the proximal and mid jejunum, IGF1 mRNA abundance was lower in calves treated with butyrate. In the proximal jejunum, INSR mRNA abundance was greater in Res than in Adl. The abundance of PCK2 mRNA was greater in Res than in Adl in the duodenum and was greatest in ResB− in the mid jejunum. Lactase activity tended to be greater in Res than in Adl and after butyrate treatment in the proximal jejunum. The results indicated an elevated growth of the small intestinal mucosa at weaning due to intensive milk feeding and butyrate supplementation, and the local IGF system was involved in intestinal growth regulation. Rumen development was not affected by butyrate supplementation of MR and was slightly delayed due to ad libitum MR feeding.     

在体单向肠灌流模型检验大豆皂苷苷元的肠吸收特性

目的:探究大豆皂苷苷元A和B的肠吸收特性。方法:建立HPLC色谱分析方法测定灌流液的苷元浓度,基于大鼠肠段的形态学变化考察在体单向肠灌流模型的可靠性,分别研究不同肠段（十二指肠、空肠、回肠、结肠）、苷元剂量和胆汁对大豆皂苷苷元肠吸收特性的影响。结果:大豆皂苷苷元在不同肠段的表观渗透速率（P_app）和吸收速率常数（K_a）:空肠>十二指肠>回肠>结肠,苷元A在空肠段的P_app和K_a为15.34×10?5 cm/s和3.06×10?5 s?1（剂量50 mg/L）,苷元B的P_app和K_a为11.36×10?5 cm/s和2.74×10?5 s?1（剂量50 mg/L）;苷元A的吸收有显著浓度依赖性（P<0.05）,而苷元B浓度依赖性不明显（P>0.05）;有胆汁时,苷元A和B在空肠段的P_app分别为16.56×10?5和12.01×10?5 cm/s,K_a分别为3.06×10?5和2.97×10?5 s?1,均显著高于无胆汁组（P<0.05）,胆汁的存在一定程度提高了肠部上端苷元的吸收。结论:大豆皂苷苷元主要吸收部位为空肠,苷元A吸收机制为被动扩散,胆汁的参与促进了吸收作用。     

日粮补充L-亮氨酸对超早期断奶宫内发育迟缓仔猪肠道免疫功能的影响

目的:研究L-亮氨酸对超早期断奶宫内发育迟缓(intrauterine growth retardation,IUGR)仔猪肠道免疫功能的调节作用。方法:选取14日龄断奶的正常初生体质量(normal birth weight,NBW)和IUGR新生仔猪各16头,分别饲喂基础日粮或添加0.35%L-亮氨酸实验日粮,即4个处理组,每组8头猪。结果:与NBW仔猪相比,IUGR仔猪血清溶菌酶活力和补体3(complement-3,C3)水平显著降低(P0.05),空肠和回肠中杯状细胞(goblet cells,GC)和淋巴细胞(intraepithelial lymphocytes,IEL)数量显著减少(P0.05),回肠中肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)含量显著升高(P0.05),白细胞介素10(interleukin-10,IL-10)含量显著降低(P0.05)。另外,IUGR仔猪回肠TNF-αm RNA表达量显著升高(P0.05),IL-10 m RNA表达量显著降低(P0.05)。日粮添加0.35%L-亮氨酸后,IUGR仔猪血清溶菌酶活力、C3和C4水平显著升高(P0.05),回肠中GC数量及十二指肠和空肠中IEL数量显著增加(P0.05),回肠中IL-10含量显著升高(P0.05),并且IL-2和IL-10 m RNA表达量显著升高(P0.05)。结论:IUGR会引起超早期断奶仔猪肠道黏膜发生炎症反应和肠道生长发育受限。L-亮氨酸可以有效缓解IUGR引起的肠道黏膜损伤,改善仔猪肠道的免疫功能。     

壳寡糖对肉仔鸡生产性能、小肠组织结构和肌组织矿物质元素含量的影响

采用单因子试验设计,选1日龄28000只AA肉仔鸡,随机分为4组,以研究饲料中添加不同剂量(0g/t、5g/t、25g/t、125g/t)的壳寡糖对生产性能、消化器官生长发育、小肠组织结构以及胸、腿肌组织中矿物元素含量的影响。研究结果表明:随壳寡糖添加剂量增加各周龄平均体重增加, 7周龄出栏时壳寡糖组(125g/t)平均体重增加140g,提高5. 85%,料重比降低3. 93%;与对照组比较壳寡糖组(125g/t)肉仔鸡的肝脏、胆囊、胰腺、嗉囊、肌胃和腺胃的相对重量均降低,胰腺和腺胃分别降低7. 19%和10. 34%,差异显著(p<0. 05);十二指肠、空肠、回肠、盲肠和结直肠相对重量均减小,十二指肠减少14. 05%、盲肠和结直肠分别减少12. 75%和19. 59%,有显著差异(p<0. 05);空肠和回肠的绒毛高度(p<0. 05)和十二指肠、空肠、回肠的隐窝深均增加(p<0. 05),而绒毛宽度减小(p<0. 05),肠壁和粘膜厚度下降(p<0. 05);壳寡糖组(125g/t)肉仔鸡胸肌中除P元素减少外, Ca、Zn、Fe和Mn元素含量均比对照组高(p<0. 05);腿肌中Ca、P、Zn、Fe和Mn元素含量均比对照组高,除Mn外各元素差异显著(p<0. 05)。说明壳寡糖对肉仔鸡具有降低肠壁厚度、改善肠粘膜结构、提高消化器官功能,从而利于营养物质的吸收,促进生长的作用。同时,还能增加胸、腿肌中Ca、P、Zn、Fe和Mn各     

Inclusion of psyllium in milk replacer for neonatal calves. 2. Effects on volatile fatty acid concentrations, microbial populations, and gastrointestinal tract size

Fermentable fibers such as psyllium increase volatile fatty acid (VFA) concentrations in the lower digestive tract and increase the gastrointestinal tract (GIT) mass of many mammals. We reasoned that psyllium inclusion in milk replacer might produce similar effects in neonatal dairy calves, which could lead to improved growth and health. Male Holstein calves were fed a milk replacer (22% crude protein, 20% fat) either without or with psyllium (1.1% of dry matter, DM) from 2 d through 28 d of age. Milk replacer was reconstituted to 12.5% DM and fed at 12% of calf body weight, adjusted weekly. Water was offered ad libitum but no starter was fed. Three calves per treatment were harvested weekly to sample digesta from the reticulo-rumen, abomasum, jejunum, proximal colon, and distal colon, and to determine length and mass of GIT components. Psyllium in milk replacer increased the proportion of butyrate in reticulo-rumen contents from 2.4 to 3.2% of total but did not affect total VFA concentrations. Total VFA concentrations were very low in the jejunum but psyllium tended to increase total VFA, acetate, and valerate concentrations; valerate accounted for 15.9 and 16.7% of total VFA (molar basis) for control and psyllium calves, respectively. Psyllium increased total VFA concentrations in the proximal and distal colon by 104.4 and 45.6%, respectively, but had little effect on the profile of VFA. Psyllium in milk replacer increased populations of bifidobacteria (from 9.7 to 10.3 log₁₀ cfu/g of DM) and lactobacilli (from 8.2 to 9.4 log₁₀ cfu/g of DM) in the reticulo-rumen, but did not affect populations in jejunum or colon. Calves fed psyllium had 12.0% greater total GIT mass and 9.4% greater GIT as a percentage of body weight. Psyllium tended to increase mass of the reticulo-rumen and significantly increased mass of duodenum (34.2%), jejunum (14.5%), and colon (14.6%). Density of intestinal tissues from calves fed psyllium-supplemented milk replacer was 25.9% greater in the jejunum and 25.3% greater in the ileum, and tended to be greater in duodenum and colon than tissue from control calves. Supplementation of psyllium to milk replacer increased fermentation in the colon, mass of the total GIT, and populations of bifidobacteria and lactobacilli in the reticulo-rumen.     

Gastrointestinal structure and function of preweaning dairy calves fed a whole milk powder or a milk replacer high in fat

The composition of milk replacer (MR) for calves greatly differs from that of bovine whole milk, which may affect gastrointestinal development of young calves. In this light, the objective of the current study was to compare gastrointestinal tract structure and function in response to feeding liquid diets having a same macronutrient profile (e.g., fat, lactose, protein) in calves in the first month of life. Eighteen male Holstein calves (46.6 ± 5.12 kg; 1.4 ± 0.50 d of age at arrival; mean ± standard deviation) were housed individually. Upon arrival, calves were blocked based on age and arrival day, and, within a block, calves were randomly assigned to either a whole milk powder (WP; 26% fat, DM basis, n = 9) or a MR high in fat (25% fat, n = 9) fed 3.0 L 3 times daily (9 L total per day) at 135 g/L through teat buckets. On d 21, gut permeability was assessed with indigestible permeability markers [chromium (Cr)-EDTA, lactulose, and d-mannitol]. On d 32 after arrival, calves were slaughtered. The weight of the total forestomach without contents was greater in WP-fed calves. Furthermore, duodenum and ileum weights were similar between treatment groups, but jejunum and total small intestine weights were greater in WP-fed calves. The surface area of the duodenum and ileum did not differ between treatment groups, but the surface area of the proximal jejunum was greater in calves fed WP. Urinary lactulose and Cr-EDTA recoveries were greater in calves fed WP in the first 6 h post marker administration. Tight junction protein gene expression in the proximal jejunum or ileum did not differ between treatments. The free fatty acid and phospholipid fatty acid profiles in the proximal jejunum and ileum differed between treatments and generally reflected the fatty acid profile of each liquid diet. Feeding WP or MR altered gut permeability and fatty acid composition of the gastrointestinal tract and further investigation are needed to understand the biological relevance of the observed differences.