Effect of weaning age and diet on growth performance, caecal characteristics and potential pathogenetic microflora in rabbits

The aim of this study was to investigate the effect of age and diet at weaning on growth performances, caecal characteristics and development of potential pathogenetic microflora. The trial was carried out on 64 litters from 18 to 45 days of age comparing two weaning age (25 vs. 34 d) and two weaning diets (HF and LF) characterized, especially, by different energy, fat and starch concentration (HF: DE=11.5 MJ/kg, EE=6.2%, Starch=8.7%; LF: DE=10.1 MJ/kg DM, EE=3.1%, Starch=11.3%). At 45 d, early weaning determined a significant reduction of growth (1219 vs. 1282; P<0.01), although the solid feed intake resulted significantly higher, from 25 to 34 days of age, in early weaned rabbits (50.0 vs. 29.8 g/d; P<0.001). The age at weaning did not modify caecal traits, with the exception of pH value, that was lower in rabbits early moved to the mothers (5.53 vs. 5.83; P<0,05). Independently by age of weaning, the administration of diet HF promoted growth performance in rabbits at 45 d (1280 vs. 1222; P<0.01). Diet composition did not influence mortality rate at 34 days of age, while early weaning determined values significantly higher than those found in rabbits weaned later. The data of microbial analysis, carried out on 10 animals per diet (at 25 and 34 days of age), showed potential pathogenetic microflora development depended by the age of animal and was not affected by the composition of diets.