Relationships between microflora and caecal fermentation in rabbits before and after weaning.
Some microbiological and biochemical parameters of caecal content were studied in 15- to 49-d-old rabbits that were slaughtered sequentially. The ammonia level did not differ before weaning (11.5 mmol/L on average) (P = 0.41) or after weaning (7.4 mmol/L on average) (P = 0.19) but decreased by 40% (P < 0.001) between days 29 and 32. The level of pH decreased linearly (P < 0.001) throughout the period studied. The Escherichia coli counts decreased up to weaning (P < 0.001) and was then not significantly affected by age (P = 0.12). The total volatile fatty acid (VFA) concentration increased between days 15 (8.2 mmol/L) and 25 (33.9 mmol/L) (P < 0.05) and then levelled off below 40 mmol/L. Molar proportions in propionate and in branched-chain fatty acid (BCFA) and valeric acid were high at day 15 but decreased when the animals began to eat solid feed. The C3/C4 ratio reversed at weaning (3.8 on day 15 and 0.5 on day 49) whereas the acetic acid proportion was not affected by age (P = 0.19). High counts of anaerobic microflora were found between 15 and 22 d of age (10(11) bacteria/g of caecal content, on average) and did not change significantly according to the age (at about 10(10) bacteria/g), from day 29 until the end of the experiment (P = 0.29). Amylolytic flora had a similar evolution at a slightly lower level. In contrast, under our breeding conditions cellulolytic microflora slowly colonized the caecum and remained at a low level. The discriminant analysis revealed relationships between ages, intestinal microflora and fermentation parameter; the colibacilli flora was associated with mother-fed animals and amylolytic flora which was linked to BCFA and valeric acid, while the cellulolytic flora was associated with animals older than 4 weeks and linked to the production of C2, C3, C4 and ammonia.
Padilha
M T
MT
UFSC, Université Fédérale, Santa Catarina, Brazil.
Licois
D
D
Gidenne
T
T
Carré
B
B
Fonty
G
G
D000375:Aging; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000254:growth & development* / Q000302:isolation & purification; D002432:Cecum / Q000378:metabolism* / Q000382:microbiology*; D015169:Colony Count, Microbial; D016002:Discriminant Analysis; D004926:Escherichia coli / Q000302:isolation & purification; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008297:Male; D011817:Rabbits / Q000502:physiology*; D014886:Weaning
D005232:Fatty Acids, Volatile; D000641:Ammonia