'Normalization' of germfree mice with anaerobically cultured caecal flora of 'normal' mice

Abstract

Germfree (GF) mice were inoculated with a cultured flora from 10-1, 10-3, 10-5, and 10-7 dilutions of caecal contents from a 'normal' mouse. GF mice associated with a flora of a 'normal' mouse served as controls. The following intestinal parameters were determined: Colonization resistance (CR), Relative caecal weight (RCW), villus:crypt ratio (jejunum and ileum), IgA-producing cells (jejunum and ileum), ß-aspartyl glycine (faeces), volatile and non-volatile fatty acids (caecum) and bile acids (faeces). Only the 10-1 culture was able to induce similar changes in the GF mice to a 'normal' flora. The GF + 10-5 and GF + 10-7 groups deviated markedly from the controls while the GF + 10-3 group showed in general intermediate values between GF + SPF and GF + 10-1 on the one hand and GF + 10-5 and GF + 10-7 on the other hand. ß-aspartyl glycine was present only in the GF + 10-7 group. Scanning electron microscopy (SEM) of ileal contents revealed segmented filamentous organisms in the ileum of controls and the GF + 10-1 group. The faecal flora consisted mainly of fusiform organisms. In the faeces of the 10-5 and 10-7 groups increasing amounts of non-bacterial matter were found, while in the faeces of the other groups virtually only bacteria were seen.

The gastrointestinal microbiota and its role in monogastric nutrition and health with an emphasis on pigs: Current understanding, possible modulations, and new technologies for ecological studies

“…Many studies have demonstrated that germ-free animals are far more susceptible to colonization by pathogens than are conventionally grown animals (Gordon et al 1966;Nurmi and Rantala 1973;Rantala and Nurmi 1973;Koopman et al 1984). This is consistent with the finding that chickens are much more susceptible to Salmonella infection at 1 d of age, when their microbiota is immature, than when they are 4 days of age and older (Milner and Schaffer 1952).…”

Comparison of the Intestinal Bacteria in Specific Pathogen Free Mice from Different Breeders

“…In practice SPF animals are established from hysterectomy derived or germfree animals by allowing them to acquire microflora naturally contaminated in a barrier environment [16], by association with pure cultures of microorganisms [6], by infecting them with diluted culture of intestinal contents [11] , or by association with SPF microflora obtained from other animal species [10]. SPF animals are also established by selective decontamination with antibiotics [18].…”

“…Experimental results can possibly be influenced by variation in gastrointestinal microflora of mice employed, e. g., survival of mice following total body irradiation varied among mice from different SPF units [15]. Moreover, it is considered that composition of microbial flora could play a key role in the development of both humoral and cellular immunity of the hosts [11] .…”

Influence of Conventionalization on Small-Intestinal Mucosa of Germ-Free Wistar Rats: Quantitative Light Microscopic Observations

“…The studies on the conventionalized G F animals, which are inoculated with the microbial flora or which are transferred to the CV environment, have revealed that the mucosal appearance of the small intestine [Khoury et al. 1969: Syed etal.. 1970: Koopman et al, 1984 and the migration rate of the epi thelial cells [Khoury et al. 1969: Savage et al.…”