肠道菌群变化对实验小鼠肠黏膜免疫的影响

目的探讨肠道菌群变化对肠黏膜相关淋巴组织的影响。方法通过变性梯度凝胶电泳（Denatu-ring gradient gel electrophoresis,DGGE）法研究了三种不同级别实验小鼠即清洁级小鼠、SPF小鼠和普通小鼠肠道菌群的组成,并用免疫组织化学（immunohistochemistry,IHC）方法研究了此三种不同级别的实验小鼠肠黏膜相关淋巴组织sIgA阳性细胞分布情况。结果普通小鼠肠道细菌种类最多,其sIgA阳性细胞分布最多,肠道不同部位之间sIgA分布情况差异有显著性（P〈0.05）,小肠和大肠之间的阳性细胞分布差异极显著（P〈0.01）;其次是清洁级小鼠,其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异有显著性（P〈0.05）;SPF小鼠肠道细菌种类最少,故其sIgA阳性细胞分布最少,且其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异无显著性（P〉0.05）。结论随着动物微生物控制级别的增高,肠道微生物多样性递减;sIgA阳性细胞与肠道细菌种类正相关。     

Effect of the probiotic Enterococcus faecium NCIMB10415 on cell numbers of total Enterococcus spp., E. faecium and E. faecalis in the intestine of piglets

Sows and their piglets were fed a diet supplemented with or without the probiotic E. faecium NCIMB10415 (also known as SF68). Piglets were sacrificed 14, 28, 35 and 56 days after birth and DNA from intestinal segments was extracted and purified. A real time PCR assay was used to distinguish Enterococcus spp. (16s rDNA based), E. faecium (Efaafm gene), E. faecalis (Efaafs gene) as well as the probiotic strain (unique plasmid sequence). Extracts of autoclaved sow feces inoculated with E. faecium and E. faecalis cultures were used to calibrate real time PCR results. The probiotic strain was detected in 14 day old suckling piglets before the piglets had access to the starter diet. In piglets of the probiotic group, probiotic E. faecium cell counts were always a significant proportion of total E. faecium cells in stomach digesta (4-20%), however only a small fraction of the total Enterococcus spp. cell number on day 14 and 28 in all intestinal segments (0.1-0.7%). Compared to control samples, the probiotic E. faecium strain significantly (p < or = 0.05) decreased the amount of total Enterococcus spp. and E. faecalis cells in the colon of 14 day old suckling piglets as well as in jejunum and colon samples one week after weaning. E. faecium cell counts were not modified on any sampling day or intestinal segment. This study showed that the presence of probiotic E. faecium NCIMB10415 coincided with reduced total E. faecalis, but not total E. faecium cell numbers in the intestine of piglets. In view of unchanged cell numbers and ratios in sow feces, modifications must have taken place within the intestine of suckling piglets.     

不同生长性能苏姜猪保育猪肠道菌群差异分析

【背景】苏姜猪是优质瘦肉型新品种猪,断奶仔猪受到多方面应激影响会出现生长性能差异。【目的】研究不同生长性能的苏姜猪保育猪肠道菌群结构的异同。【方法】试验选取了同日龄、体重相近、健康情况良好的的保育仔猪100头,在相同的饲养条件下饲养42 d,试验结束选取体重较轻的为弱仔猪,3头弱仔猪体重为18.43±2.37 kg;体重较大的为健康仔猪,3头健康仔猪体重为27.37±1.36 kg。屠宰后,采集其空肠和盲肠内容物,提取微生物基因组DNA进行高通量测序分析其菌群结构。【结果】苏姜猪仔猪空肠和盲肠在菌群丰度、多样性上有极显著的差异(P<0.01)。苏姜猪仔猪空肠菌群优势菌群为变形菌门(Proteobacteria)假单胞菌属(Pseudomonas)的非致病性菌株,占比超过90%。苏姜猪仔猪盲肠优势菌门依次为拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)。门水平组成结构存在差异,弱仔猪厚壁菌门丰度低于健康仔猪、变形菌门丰度高于健康仔猪。苏姜猪盲肠中普雷沃氏菌属(Prevotella)、疣微菌科UCG-005 (Ruminococcaceae_UCG-005)、拟普雷沃菌属(Alloprevotella)等与纤维消化有关的菌属丰度较高。弱仔猪与健康仔猪盲肠菌群在属水平结构存在显著差异(P<0.05),弱仔猪盲肠中普雷沃氏菌-9 (Prevotella_9)、埃希菌-志贺菌属(Escherichia-shigella)、疣微菌科UCG-005 (Ruminococcaceae_UCG-005)、Norank_f_普雷沃氏菌(norank_f_ Prevotellaceae)高于健康仔猪,健康仔猪盲肠中乳酸杆菌属(Lactobacillus)、普雷沃氏菌-2 (Prevotella_2)、土孢杆菌属(Terrisporobacter)、狭义梭菌属1 (Clostridium_sensu_stricto_1)高于弱仔猪。其中乳酸杆菌属和土孢杆菌属与仔猪健康相关,埃希菌-志贺菌属与疾病相关。【结论】不同生长性能仔猪肠道菌群构成存在显著差异,研究结果为进一步研究苏姜猪肠道菌群的功能提供依据。     

Prebiotic oligosaccharides and the enterohepatic circulation of bile salts in rats

Human milk contains prebiotic oligosaccharides, which stimulate the growth of intestinal bifidobacteria and lactobacilli. It is unclear whether the prebiotic capacity of human milk contributes to the larger bile salt pool size and the more efficient fat absorption in infants fed human milk compared with formula. We determined the effect of prebiotic oligosaccharides on bile salt metabolism in rats. Rats were fed a control diet or an isocaloric diet containing a mixture of galactooligosaccharides (GOS), long-chain fructooligosaccharides (lcFOS), and acidified oligosaccharides (AOS) for 3 wk. We determined synthesis rate, pool size, and fractional turnover rate (FTR) of the primary bile salt cholate by using stable isotope dilution methodology. We quantified bile flow and biliary bile salt secretion rates through bile cannulation. Prebiotic intervention resulted in significant changes in fecal and colonic flora: the proportion of lactobacilli increased 344% (P < 0.01) in colon content and 139% (P < 0.01) in feces compared with the control group. The number of bifidobacteria also increased 366% (P < 0.01) in colon content and 282% in feces after the prebiotic treatment. Furthermore, pH in both colon and feces decreased significantly with 1.0 and 0.5 pH point, respectively. However, despite this alteration of intestinal bacterial flora, no significant effect on relevant parameters of bile salt metabolism and cholate kinetics was found. The present data in rats do not support the hypothesis that prebiotics naturally present in human milk contribute to a larger bile salt pool size or altered bile salt pool kinetics.     

Heat shock protein 70 is upregulated in the intestine of intrauterine growth retardation piglets

The objective of this study is to investigate the expression and distribution of heat shock protein 70 (Hsp70) in the intestine of intrauterine growth retardation (IUGR) piglets. Samples from the duodenum, prejejunum, distal jejunum, ileum, and colon of IUGR and normal-body-weight (NBW) piglets were collected at birth. The results indicated that the body and intestine weight of IUGR piglets were significantly lower than NBW piglets. The villus height and villus/crypt ratio in jejunum and ileum of IUGR piglets were significantly reduced compared to NBW piglets. These results indicated that IUGR causes abnormal gastrointestinal morphologies and gastrointestinal dysfunction. The mRNA of hsp70 was increased in prejejunum (P < 0.05), distal jejunum (P < 0.05), and colon in IUGR piglets. However, the hsp70 mRNA in ileum of piglets with IUGR was decreased. Similar to hsp70 mRNA, the protein levels of Hsp70 in prejejunum (P < 0.05), distal jejunum, and colon (P < 0.05) in IUGR piglets were higher than those in NBW piglets. These results indicated that the expression of Hsp70 in the intestinal piglets was upregulated by IUGR, and different intestinal sites had different responses to stress. Meanwhile, the localization of Hsp70 in the epithelial cells of the whole villi and intestinal gland rather than in the lamina propria and myenteron suggested that Hsp70 has a cytoprotective role in epithelial cell function and structure.     

Gastrointestinal dysfunction induced by early weaning is attenuated by delayed weaning and mast cell blockade in pigs

Our previous work has demonstrated that weaning at 19 days of age has deleterious effects on mucosal barrier function in piglet intestine that are mediated through peripheral CRF receptor signaling pathways. The objectives of the present study were to assess the impact of piglet age on weaning-associated intestinal dysfunction and to determine the role that mast cells play in weaning-induced breakdown of mucosal barrier function. Nursing Yorkshire-cross piglets were either weaned at 19 days of age (early-weaned, n = 8) or 28 days of age (late-weaned, n = 8) and housed in nursery pens. Twenty-four hours postweaning, segments of midjejunum and ascending colon from piglets within each weaning age group were harvested and mounted on Ussing chambers for measurements of transepithelial electrical resistance and serosal-to-mucosal [(3)H]mannitol fluxes. Early weaning resulted in reductions in transepithelial electrical resistance and increases in mucosal permeability to [(3)H]mannitol in the jejunum and colon (P < 0.01). In contrast, postweaning reductions in intestinal barrier function were not observed in piglets weaned at 28 days of age. Early-weaned piglet intestinal mucosa had increased expression of CRF receptor 1 protein, increased mucosal mast cell tryptase levels, and evidence of enhanced mast cell degranulation compared with late-weaned intestinal mucosa. Pretreatment of piglets with the mast cell stabilizer drug cromolyn, injected intraperitoneally 30 min prior to weaning, abolished the early-weaning-induced intestinal barrier disturbances. Our results indicate that early-weaning stress induces mucosal dysfunction mediated by intestinal mast cell activation and can be prevented by delaying weaning.     

酶解乳蛋白对初生仔猪小肠组织学结构及隐窝细胞增殖的影响(英文)

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Effects of a bovine colostrum-supplemented diet on some gut parameters in weaned piglets

The present study investigated the effects of a bovine colostrum-supplemented diet on gut post-weaning adaptation and health in piglets. Thirty-six 21-d-old piglets were allocated to one of the three following dietary treatments: sow-reared (SR), weaned on a control starter diet (WCtrl) or on a starter diet supplemented with bovine colostrum (WCol) until slaughter at 28 d or 35 d of age. Gastric pH and intestinal bacteriological, structural and functional parameters were determined. Compared to WCtrl, the gastric pH was lower (P < 0.05) and the duodenal lactobacilli:coliform ratio was higher (P = 0.05) in WCol piglets. The relative small intestine weight was 18% (P < 0.05) higher in WCol piglets than in SR piglets. Duodenal villous height was lower (P < 0.01) in WCtrl than in SR piglets, whereas the value for WCol piglets was intermediate. The weaning-increased crypt cell proliferation was not affected by bovine colostrum supplementation. The mucosal ribosomal capacity was higher (P < 0.05) in W than in SR piglets. In conclusion, a diet supplemented with colostrum induced, although not always significantly, variations of gut parameters, suggesting that globally, colostrum may limit weaning-induced gut structural and microbial alterations. The observed effects occurred early and were maintained throughout the post-weaning adaptive phase.     

Effect of Streptococcus faecalis BIO-4R on intestinal flora of weanling piglets and calves

The effect of oral administration of Streptococcus faecalis BIO-4R, an antibiotic-resistant lactic acid bacterium, on the intestinal flora of weanling piglets and cows reared on antibiotic-containing diet was investigated. Fourteen days after administration of the bacteria, the intestinal flora of the piglets was examined. Animals of the administered group had stabilized lactic flora such as bifidobacteria, streptococci, and lactobacilli, whereas most animals of control group had reduced lactic flora. On the other hand, abundant yeasts were detected from the cecum, colon, and feces of the control animals, but the levels were significantly lower in the animals given strain BIO-4R. The density of Salmonella in the intestine appeared to be reduced after the administration of strain BIO-4R. The number of BIO-4R cells was shown to be 10 times lower in the duodenum and jejunum than in the ileum, suggesting that strain BIO-4R might have grown transiently in the ileum. The similar trend toward stabilization of the lactic flora was also observed in cows after administration of BIO-4R. In addition, an antagonistic effect of the strain against yeasts and Salmonella was suggested. These findings indicate that the oral administration of strain BIO-4R is one of the useful methods whereby the potentially deleterious effect of antibiotics on the intestinal flora of farm animals may be minimized.     

Effect of Streptococcus faecalis BIO-4R on intestinal flora of weanling piglets and calves.

The effect of oral administration of Streptococcus faecalis BIO-4R, an antibiotic-resistant lactic acid bacterium, on the intestinal flora of weanling piglets and cows reared on antibiotic-containing diet was investigated. Fourteen days after administration of the bacteria, the intestinal flora of the piglets was examined. Animals of the administered group had stabilized lactic flora such as bifidobacteria, streptococci, and lactobacilli, whereas most animals of control group had reduced lactic flora. On the other hand, abundant yeasts were detected from the cecum, colon, and feces of the control animals, but the levels were significantly lower in the animals given strain BIO-4R. The density of Salmonella in the intestine appeared to be reduced after the administration of strain BIO-4R. The number of BIO-4R cells was shown to be 10 times lower in the duodenum and jejunum than in the ileum, suggesting that strain BIO-4R might have grown transiently in the ileum. The similar trend toward stabilization of the lactic flora was also observed in cows after administration of BIO-4R. In addition, an antagonistic effect of the strain against yeasts and Salmonella was suggested. These findings indicate that the oral administration of strain BIO-4R is one of the useful methods whereby the potentially deleterious effect of antibiotics on the intestinal flora of farm animals may be minimized.     

Proton NMR Spectra of Peracetylated Derivatives of α,α-Trehalose and Sucrose in the Presence of a Europium Shift Reagent

The possibility of using recombinant human lactoferrin from rice (rhLF) makes it necessary to study its differences from the protein of milk. In this work, the binding of different iron-saturated forms of rhLF to Caco-2 cells was studied. Iron-saturated rhLF bound in higher proportion than the apo-form, but, the data obtained for specific binding were not compatible with receptor-mediated binding. Competition assays showed the same binding capacity for human milk lactoferrin as for rhLF to Caco-2 cells. Another basic protein of milk, lactoperoxidase, was found to compete with rhLF for binding to Caco-2 cell membranes, suggesting an electrostatic interaction. The transport of iron (⁵⁹Fe) bound to rhLF and to citrate and the transport of rhLF (¹²⁵I-labeled) were studied on Caco-2 monolayers. Transport of iron was found to be significantly greater when bound to citrate than to rhLF. The amount of intact lactoferrin that traversed the Caco-2 monolayers was very low, suggesting degradation of it across these cells.     

高通量测序方法分析两种草食性淡水螺肠道菌群多样性

淡水螺是水生态系统中重要的生物类群，也是多种寄生虫的中间宿主。肠道菌群在动物能量代谢和抵抗病原体方面起着重要作用。本文分析了耳萝卜螺Radix auricularia和三旋卷丽螺Planorbella trivolvis肠道菌群的多样性。结果表明：在门水平上，耳萝卜螺有23个菌门，以变形菌门 (Proteobacteria，33.63%)、蓝细菌门(Cyanobateria，15.33%)、绿弯菌门 (Chloroflexi，13.95%) 和放线菌门 (Actinobacteria，12.99%)为主；三旋卷丽螺有13个菌门，以变形菌门 (54.88%)、拟杆菌门 (Bacteroidetes，28.49%) 和放线菌门 (7.65％) 为主。属水平上，耳萝卜螺有厚皮藻属Pleurocapsa、硫网菌属Thiodictyon、纤毛菌属Leptotrichia及类诺卡氏菌属Nocardioides等445个属；三旋卷丽螺有Cloacibacterium、OM60NOR5_clade、假单胞菌属Pseudomonas及红杆菌属Rhodobacter等238个属。有93个菌属为两种螺的共有核心菌群 (所有样本中都存在)，其中27个菌属丰度大于0.5%。两种螺肠道菌群结构差异显著 (P=0.027)。PICRUSt功能预测分析表明，两种螺肠道菌群KEGG功能组成相似，氨基酸代谢、碳水化合物代谢及膜转运丰度较大。综上，两种草食性淡水螺肠道菌群多样性较高且差异显著，但有数量较多的共有核心菌群。     

不同来源乳铁蛋白对幼鼠肠道发育的影响

目的 探究哺乳期乳铁蛋白（lactoferrin，LF）的缺失及不同来源LF补充后对幼鼠肠道发育的影响。方法 以LF基因敲除型雌鼠作为哺乳母鼠造成幼鼠哺乳期无LF的摄入，且从幼鼠出生第3~21天每日人工饲喂100 mg/kg 牛血清白蛋白（BSA）、牛源乳铁蛋白（bovine Lactoferrin，bLF）及重组人源乳铁蛋白（recombinant human Lactoferrin，rhLF），于幼鼠21日龄取样，测定各组小鼠小肠发育指标。结果 在本实验周期下，哺乳期rhLF的补充显著性增加小鼠回肠绒毛长度/隐窝深度值（P<0.05），且上调回肠Occludin和ZO-1基因的表达（P<0.05），增加小鼠十二指肠、空肠和回肠麦芽糖酶酶活/乳糖酶酶活比值（P<0.05），表明哺乳期rhLF的补充能够增强小鼠肠道消化吸收能力和肠屏障功能；哺乳期bLF的补充显著增加小鼠十二指肠及回肠麦芽糖酶活性/乳糖酶活性比值（P<0.05）。结论 对于哺乳期无LF摄入的乳鼠来说，哺乳期间LF的补充能够增强乳鼠肠道对营养物质的消化吸收能力、促进肠道的发育成熟、增强肠道屏障功能，并且，本实验中rhLF表现出比bLF更加有效的作用。     

Effects of Recombinant Human Lactoferrin on Osteoblast Growth and Bone Status in Piglets

Lactoferrin (LF), an ~80?kDa iron-binding glycoprotein, modulates many biological effects, including antimicrobial and immunomodulatory activities. Recently, it was shown that LF also regulates bone cell activity, suggesting its therapeutic effect on postmenopausal bone loss. However, a minimal amount is known regarding the effects of recombinant human LF (rhLF) supplementation on bone status in young healthy infants. We found osteoblast cell differentiation was significantly promoted in vitro. Furthermore, treatment of human osteoblast cells with rhLF rapidly induced phosphorylation of p44/p42 mitogen-activated protein kinase (p44/p42 MAPK, ERK1/2). In order to investigate the effects of rhLF on bone status in vivo, we used a piglet model, which is a useful model for human infants. Piglets were supplemented with rhLF milk for 30 days. Bone formation markers, Serum calcium concentration, bone mineral density (BMD), bone mineral content (BMC), tibia bone strength, and the overall metabolite profile analysis showed that rhLF was advantageous to the bone growth in piglets. These findings suggest that rhLF supplementation benefits neonate bone health by modulating bone formation.     

七味白术散对菌群失调腹泻小鼠肠道细菌多样性的影响

【背景】肠道微生物与人体多项生理功能密切相关,我们课题组前期研究表明七味白术散对菌群失调腹泻有较好的疗效。【目的】探讨与七味白术散疗效相关肠道微生物,比较传统中药饮片与超微中药饮片的疗效,进一步明确七味白术散治疗菌群失调腹泻的机理,为临床应用提供科学依据。【方法】应用抗生素建立菌群失调小鼠腹泻模型,分别灌胃给药七味白术散传统汤剂和超微50%量七味白术散汤剂。治疗结束后,提取肠道内容物微生物宏基因组DNA,建立16S rRNA基因文库进行测序。【结果】肠道微生物中的群落由乳酸菌(Lactobacillus spp.)、屎肠球菌(Enterococcus feacium)、梭状芽孢杆菌(Clostridium spp.)、黏液真杆菌(Blautia producta)、毛螺旋菌(Anaerostipes spp.)、腐生性葡萄球菌(Staphylococcus saprophyticus)和不能培养的细菌组成,其中乳酸菌为优势菌,占全部细菌DNA克隆数的61.90%。经抗生素造模后Lactobacillus spp.数量明显减少,Enterococcus feacium成为优势菌种,Clostridium spp.、Blautia product、Anaerostipes spp.和Staphylococcus saprophyticus等在数量上开始有增长的趋势,而治疗结束后,传统七味白术散治疗组和超微50%量七味白术散治疗组的Lactobacillus spp.比例均有所恢复,且超微50%量七味白术散治疗组的乳酸菌比例与正常组最接近;通过建立聚类树和计算各组中各菌群的多样性(H)、丰富度(S)、均匀度(E)及优势度指数(D)可知,超微50%量七味白术散治疗组可与正常组聚为一类,且超微50%量七味白术散治疗组各项指数与正常组最为接近,说明超微50%量七味白术散治疗组肠道微生物的基因文库及多样性与正常组最接近,超微50%量七味白术散汤剂的治疗效果优于七味白术散传统汤剂。【结论】应用16S rRNA基因克隆文库技术进一步明确了正常小鼠肠道中细菌群落的组成,以及七味白术散对菌群失调腹泻小鼠肠道细菌群落的恢复效果,超微50%量七味白术散汤剂的治疗效果优于七味白术散传统汤剂。     

Zinc availability and digestive zinc solubility in piglets and broilers fed diets varying in their phytate contents, phytase activity and supplemented zinc source

The study was conducted to evaluate the effects of dietary zinc addition (0 or 15 mg/kg of Zn as inorganic or organic zinc) to three maize-soybean meal basal diets varying in their native Zn, phytic P contents and phytase activity (expressed in kg of feed: P- with 25 mg Zn and 1.3 g phytic P, P+ with 38 mg Zn and 2.3 g phytic P or P+/ENZ being P+ including 500 units (FTU) of microbial phytase per kg) in two monogastric species (piglets, broilers). Measured parameters were growth performance, zinc status (plasma, and bone zinc) and soluble zinc in digesta (stomach, gizzard and intestine). The nine experimental diets were fed for 20 days either to weaned piglets (six replicates per treatment) or to 1-day-old broilers (10 replicates per treatment). Animal performance was not affected by dietary treatments (P > 0.05) except that all P- diets improved body weight gain and feed conversion ratio in piglets (P < 0.05). Piglets fed P- diets had a better Zn status than those fed P+ diets (P < 0.05). In both species, Zn status was improved with supplemental Zn (P < 0.05), irrespective of Zn source. Phytase supplementation improved piglet Zn status to a higher extent than adding dietary Zn, whereas in broilers, phytase was less efficient than supplemental Zn. Digestive Zn concentrations reflected the quantity of ingested Zn. Soluble Zn (mg/kg dry matter) and Zn solubility (% of total Zn content) were highest in gizzard contents, which also presented lower pH values than stomach or intestines. The intestinal Zn solubility was higher in piglet fed organic Zn than those fed inorganic Zn (P < 0.01). Phytase increased soluble Zn in piglet stomach (P < 0.001) and intestine (P = 0.1), but not in broiler gizzard and intestinal contents. These results demonstrate (i) that dietary zinc was used more efficiently by broilers than by piglets, most probably due to the lower gizzard pH and its related higher zinc solubility; (ii) that zinc supplementation, irrespective of zinc source, was successful in improving animal's zinc status; and (iii) suggest that supplemented Zn availability was independent from the diet formulation. Finally, the present data confirm that phytase was efficient in increasing digestive soluble Zn and improving zinc status in piglets. However, the magnitude of these effects was lower in broilers probably due to the naturally higher Zn availability in poultry than in swine.     

Profiling of composition and metabolic activities of the colonic microflora of growing pigs fed diets supplemented with prebiotic oligosaccharides

It is evident that quantitative information on different microbial groups and their contribution in terms of activity in the gastrointestinal (GI) tract of humans and animals is required in order to formulate functional diets targeting improved gut function and host health. In this work, quantitative information on levels and spatial distributions of Bacteroides spp, Eubacterium spp, Clostridium spp, Escherichia coli, Bifidobacterium spp and Lactobacillus/Enterococcus spp. along the porcine large intestine was investigated using 16S rRNA targeted probes and fluorescent in situ hybridisation (FISH). Caecum, ascending colon (AC) and rectum luminal digesta from three groups of individually housed growing pigs fed either a corn-soybean basal diet (CON diet) or a prebiotic diet containing 10 g/kg oligofructose (FOS diet) or trans-galactooligosaccharides (TOS diet) at the expense of cornstarch were analysed. DAPI staining was used to enumerate total number of cells in the samples. Populations of total cells, Bacteroides, Eubacterium, Clostridium and Bifidobacterium declined significantly (P < 0.05) from caecum to rectum, and were not affected by dietary treatments. Populations of Lactobacillus/Enterococcus and E. coli did not differ throughout the large intestine. The relative percent (%) contribution of each bacterial group to the total cell count did not differ between caecum and rectum, with the exception of Eubacterium that was higher in the AC digesta. FISH analysis showed that the sum of all bacterial groups made up a small percentage of the total cells, which was 12.4%, 21.8% and 10.3% in caecum, AC and rectum, respectively. This supports the view that in swine, the diversity of GI microflora might be higher compared to other species. In terms of microflora metabolic activity, the substantially higher numerical trends seen in FOS and TOS treatments regarding total volatile fatty acid, acetate concentrations and glycolytic activities, it could be postulated that FOS and TOS promoted saccharolytic activities in the porcine colon.     

The dominant expression of functional human lactoferrin in transgenic cloned goats using a hybrid lactoferrin expression construct

Human Lactoferrin (hLF) is an iron-binding protein with multiple physiological functions. As the availability of natural hLF is limited, alternative means of producing this biopharmaceutical protein have been extensively studied. Here we report on the dominant expression of recombinant human lactoferrin (rhLF) in transgenic cloned goats using a novel optimised construct made by fusing a 3.3kb hLF minigene to the regulatory elements of the β-casein gene. The transgenic goat produced more than 30mg/ml rhLF in its milk, and rhLF expression was stable during the entire lactation cycle. The rhLF purification efficiency from whole goat milk is approximately 70%, and its purity is above 98%. Compared with natural hLF, the rhLF from transgenic goats has similar biological characteristics including molecular mass, N-terminal sequence, isoelectric point, immunoreactivity and digestive stability. More importantly, the purified rhLF showed specific anti-tumour activity in the mouse model of melanoma experimental metastasis. Therefore, our study shows that the large-scale production of functional rhLF in transgenic goat milk could be an economical and promising source of human therapeutic use in the future.