Rabbit teeth serve as a calcium source for rabbits (Oryctolagus cuniculus)

Rabbits have hypselodont (ever-growing) teeth; dental growth constantly replaces dental tissue lost due to abrasion and attrition. It has been suggested that rabbits must have high mineral requirements, in particular for calcium, to fuel this constant tooth growth. However, this assumption ignores the fact that tooth wear represents finely ground tissue that is not lost to the body but swallowed during food processing. No studies exist regarding the possible recycling of dental enamel and dentin calcium. In this cross-over study, eight-months old intact female rabbits were fed with a complete pelleted diet containing either calcium carbonate/dicalcium phosphate (control) or ground rabbit teeth as calcium sources for 15 days each. After 11 days of adaptation, intake, urinary and faecal losses were quantified in a 4-day period in metabolism cages, and blood mineral levels were determined in a final blood sample. There were few relevant, significant differences between the treatments, with the exception of calcium digestibility (20 ±8 % on the control vs. 33 ±6 % on the tooth meal diet, P = 0.002) and total calcium retention (0.10 ±0.13 vs. 0.33 ±0.10 g/d, P = 0.004). The results suggest that rabbits are well able to recycle the minerals from dental tissue lost during dental wear.