Laboratory Animals - June Issue - 238

238

Laboratory Animals 53(3)

Figure 3. Gnotobiotic animals as a tool for analysing the effects of the microbiome.
Gnotobiotic and germ-free animal models evolved into a potent tool addressing mechanistic questions regarding the
impact of the microbiome on host physiology and pathology. Several different strategies can be utilized to address
respective causal and functional questions ranging from analyses of the effects of candidate, defined communities and
complex communities. Particular germ-free animal models that can be associated with various microorganisms are the
foundation of gnotobiotic experiments. The model complexity increases with the number of colonized species. Association
with single (monocolonization) or a few microorganisms at the same time can provide insights into the protective or
detrimental effect of a respective candidate microorganism. Furthermore, by colonizing germ-free mice with minimal
bacterial consortia, the effect of a respective microbial population can be studied under highly standardized conditions,
and the application of defined bacterial communities reduces interindividual variability and the complexity of the microbiome to a manageable level. Germ-free animals can also be associated with a complex microbiota by faecal transplantation using healthy or diseased individuals as donors. This strategy can reveal pathophysiological effects of the particular
complex microbiota and reveal microbiota-transferable phenotypes.

Salmonella
enterica
serovar
Typhimurium.51
Furthermore, two different simplified human microbial
consortia (SIHUMI) were developed. One community
comprises human IBD-related enteric bacteria52. This
community could induce colitis in susceptible IL10deficient mice, presenting a proof-of-concept for the
multi-hit model of colitis induction.7,53 The composition of the second SIHUMI was based on the numerical importance and fermentative abilities of human
intestinal bacteria.54 Dietary intervention studies involving fat and fibre content in SIHUMI-colonized
rodents have shown that diet influences the community
composition and numbers of particular community
members.54 However, researchers need to keep the limitations of these model communities in mind. Minimal
bacterial consortia consist of only a few bacterial species and, therefore, have limited diversity. Additionally,
these model communities usually lack the functional
redundancy and metabolic capacity of complex microbiota.46 Furthermore, the time point of colonization

can have a profound impact on the immune system.
Specifically, exposure to the intestinal microbiota
during early life is crucial for the normal development
of the mucosal immune system.55 However, these limitations can be overcome by colonization of mice before
weaning or by using the offspring of inoculated
mice.56,57
Furthermore, gnotobiotic mice can be associated
with complex human or rodent microbiota. Though
alterations in the composition may occur during xenogenic microbiome transfer,58 the transfer of complex
communities from healthy or diseased donors into
gnotobiotic animal models can reveal pathophysiological effects of the respective microbiota. Several
human or human-like disorders such as obesity, irritable bowel syndrome, Crohn's disease-like inflammation or resistance to cancer therapy were shown to be
transmissible by the transfer of dysbiotic microbial
communities.59-64 This approach allows the impact
and function of microbiota in human diseases to be



Laboratory Animals - June Issue

Table of Contents for the Digital Edition of Laboratory Animals - June Issue

Contents
Laboratory Animals - June Issue - Cover1
Laboratory Animals - June Issue - Cover2
Laboratory Animals - June Issue - Contents
Laboratory Animals - June Issue - 214
Laboratory Animals - June Issue - 215
Laboratory Animals - June Issue - 216
Laboratory Animals - June Issue - 217
Laboratory Animals - June Issue - 218
Laboratory Animals - June Issue - 219
Laboratory Animals - June Issue - 220
Laboratory Animals - June Issue - 221
Laboratory Animals - June Issue - 222
Laboratory Animals - June Issue - 223
Laboratory Animals - June Issue - 224
Laboratory Animals - June Issue - 225
Laboratory Animals - June Issue - 226
Laboratory Animals - June Issue - 227
Laboratory Animals - June Issue - 228
Laboratory Animals - June Issue - 229
Laboratory Animals - June Issue - 230
Laboratory Animals - June Issue - 231
Laboratory Animals - June Issue - 232
Laboratory Animals - June Issue - 233
Laboratory Animals - June Issue - 234
Laboratory Animals - June Issue - 235
Laboratory Animals - June Issue - 236
Laboratory Animals - June Issue - 237
Laboratory Animals - June Issue - 238
Laboratory Animals - June Issue - 239
Laboratory Animals - June Issue - 240
Laboratory Animals - June Issue - 241
Laboratory Animals - June Issue - 242
Laboratory Animals - June Issue - 243
Laboratory Animals - June Issue - 244
Laboratory Animals - June Issue - 245
Laboratory Animals - June Issue - 246
Laboratory Animals - June Issue - 247
Laboratory Animals - June Issue - 248
Laboratory Animals - June Issue - 249
Laboratory Animals - June Issue - 250
Laboratory Animals - June Issue - 251
Laboratory Animals - June Issue - 252
Laboratory Animals - June Issue - 253
Laboratory Animals - June Issue - 254
Laboratory Animals - June Issue - 255
Laboratory Animals - June Issue - 256
Laboratory Animals - June Issue - 257
Laboratory Animals - June Issue - 258
Laboratory Animals - June Issue - 259
Laboratory Animals - June Issue - 260
Laboratory Animals - June Issue - 261
Laboratory Animals - June Issue - 262
Laboratory Animals - June Issue - 263
Laboratory Animals - June Issue - 264
Laboratory Animals - June Issue - 265
Laboratory Animals - June Issue - 266
Laboratory Animals - June Issue - 267
Laboratory Animals - June Issue - 268
Laboratory Animals - June Issue - 269
Laboratory Animals - June Issue - 270
Laboratory Animals - June Issue - 271
Laboratory Animals - June Issue - 272
Laboratory Animals - June Issue - 273
Laboratory Animals - June Issue - 274
Laboratory Animals - June Issue - 275
Laboratory Animals - June Issue - 276
Laboratory Animals - June Issue - 277
Laboratory Animals - June Issue - 278
Laboratory Animals - June Issue - 279
Laboratory Animals - June Issue - 280
Laboratory Animals - June Issue - 281
Laboratory Animals - June Issue - 282
Laboratory Animals - June Issue - 283
Laboratory Animals - June Issue - 284
Laboratory Animals - June Issue - 285
Laboratory Animals - June Issue - 286
Laboratory Animals - June Issue - 287
Laboratory Animals - June Issue - 288
Laboratory Animals - June Issue - 289
Laboratory Animals - June Issue - 290
Laboratory Animals - June Issue - 291
Laboratory Animals - June Issue - 292
Laboratory Animals - June Issue - 293
Laboratory Animals - June Issue - 294
Laboratory Animals - June Issue - 295
Laboratory Animals - June Issue - 296
Laboratory Animals - June Issue - 297
Laboratory Animals - June Issue - 298
Laboratory Animals - June Issue - 299
Laboratory Animals - June Issue - 300
Laboratory Animals - June Issue - 301
Laboratory Animals - June Issue - 302
Laboratory Animals - June Issue - 303
Laboratory Animals - June Issue - 304
Laboratory Animals - June Issue - 305
Laboratory Animals - June Issue - 306
Laboratory Animals - June Issue - 307
Laboratory Animals - June Issue - 308
Laboratory Animals - June Issue - Cover3
Laboratory Animals - June Issue - Cover4
https://www.nxtbookmedia.com