Development of the cellulolytic microflora in the rumen of lambs transferred into sterile isolators a few days after birth

Abstract

Seven lambs, separated from their dam 24 h after birth, were kept in a conventional environment until transferred to sterile isolators between 1 and 9 days of age: two on day 1 (IA and IB), two on day 4 (IVA and IVB), one on day 8 (VIIIA), and two on day 9 (IXA and IXB). The lambs were reared in these isolators until 120 days of age. Lambs IA, IB, IXA, and IXB were free of cellulolytic bacteria when they were placed in the isolators. They were then inoculated with Bacteroides succinogenes S85 which became established in the four lambs. Until the age of 2 months, the population of this strain fluctuated and then stabilized at a high level (10(8)-10(9) cells/mL). Cellulolytic bacteria were present in the rumen of lambs IVA, IVB, and VIIIA when they were transferred to the isolators. In IVA, and IVB, the cellulolytic population slowly increased with the animal age. In contrast, in VIIIA, the cellulolytic bacteria disappeared within a few days. Bacteroides succinogenes S85 inoculated thereafter became established rapidly and reached a level comparable to that observed in lambs IA and IB. The total number of viable rumen bacteria in the isolated lambs was similar to that observed in conventionally raised animals, but differences were observed in the selective enumeration of bacteria utilizing specific energy sources.

Development of the rumen digestive functions in lambs placed in a sterile isolator a few days after birth

“…In a previous study (Fonty et al, 1989), we showed that cellulolytic bacterial species, F succinogenes in IA, IB, VIIIA, IXA and IXB, and a mixed population in IVA and IVB, can establish and remain stable whereas it is extremely difficult, if not impossible, for these same species to become established in gnotoxenic lambs, whose rumen microflora is too simplified (Mann and Stewart 1974;Lysons et al, 1976;Hobson et al, 1981;Fonty et al, 1983a;Fonty et al, 1988a). The microflora harboured by the lambs at the time they were isolated was also sufficiently diversified to allow uneventful weaning and satisfactory feed intake.…”

“…Le développement des fonctions digestives du rumen a été étudié chez des agneaux conventionnels placés en isolateurs stériles à l'âge de 1, 4, 8 et (Fonty et al, 1987) and calves (Bryant et al, 1958 (Fonty et al, 1987(Fonty et al, , 1988c 2), to compare the development of rumen digestive functions and the digestive utilization of the feed and of its main components in the isolated lambs with those of conventional animals. The establishment of cellulolytic bacteria has previously been described (Fonty et al, 1989). In the present paper results on the digestive parameters are reported and discussed.…”

“…The slight differences observed in the centesimal composition of the VFA of the different groups may be linked to differences in the qualitative composition of the microflora (Fonty et al, 1989). The kinetics of establishment of cellulolytic bacteria were much more irregular and slower in isolated lambs than in the conventionally-reared lambs.…”

“…The kinetics of establishment of cellulolytic bacteria were much more irregular and slower in isolated lambs than in the conventionally-reared lambs. In the latter, cellulolytic bacteria were present in high numbers from the end of the first week onward while in all isolated animals their number varied considerably during the first 2 months (Fonty et al, 1989 (Fonty et al, 1989). Differences in the qualitative composition of the dominant rumen flora between isolated and conventionally reared lambs were observed when several bacterial populations were enumerated on specific culture media containing a single energy source (Fonty et al, 1989).…”

“…While lambs IIIA and IVB naturally harboured a cellulolytic microflora, lambs IA, IB, IXA and IXB which were free of cellulolytic bacteria when placed in sterile isolators, and lamb VIIIA, in which cellulolytic bacteria had disappeared soon after entry, were then inoculated with a pure culture of Fibrobacter (Bacteroides) succinogenes S.85 as previously described (Fonty et al, 1989 The digestive utilization of the feed and of its main components was studied in lambs lA, IB, IVA, IVB, and VIIIA by control of the feed intake and total collection of feces during 2 periods of 7 days. The analytic methods used for feed and feces have been described previously (Fonty et al, 1983b (fig 2).…”