The current study was conducted to investigate the effect of β-Pro (probiotic-enzymes preparation) supplementation to 54 weaned rabbits (6-week-old with an average weight of 600 g) stocked at different stocking densities on some growth performance traits, carcass measurements, some blood parameters and cecal micoflora under heat stress. A factorial design arrangement with 2 diets (basal diet and basal diet + 0.2 g β-Pro/Kg from 6 to 14 weeks of age) and 3 stocking densities [2, 3 and 4 rabbits/cage (45 ´ 45 ´ 35 cm), equivalent to 10, 15 and 20 rabbits/m²] during summer season from June to August.

The results showed that, dietary inclusion of β-Pro achieved significant (P ≤ 0.05) improvements of marketing live weight and daily weight gain with no influences on feed intake, feed conversion ratio, blood variables or carcass characteristics of rabbits during the experimental period from 6 to 14 weeks of age. The incorporation of β-Pro dietary also resulted in significantly higher (P ˂ 0.01) cecal colonization of beneficial bacteria like lactobacilli, and a significant lower (P ˂ 0.05) of viable coliform counts with no changes of clostridia.
The low stocking density of 2 rabbits/cage (10 rabbits/m²) revealed higher (P < 0.01) marketing live weight, daily weight gain and feed consumption when compared with higher densities. Interactions between stocking density and dietary β-Pro supplementation exhibited significant (P ˂ 0.05) changes in daily weight gain, globulin, HDL, total bacterial, coliform and lactobacilli counts, with no influences on other evaluated measurements.
Conclusively, the present study concluded that lower cage density (10 rabbits/m²) with probiotics-enzymes inclusion is recommended for the post-weaning period of rabbits under hot environmental conditions.