Abstract
A total of fifty weanling New Zealand White (NZW) rabbits that were five weeks old (800 g live weight on average) were randomly allocated into five groups of 10 rabbits each and were housed in individual cages. The groups were control (12% CF and 30.08 NDF), 14% CF without enzymes (30.69 NDF), 14% CF with enzymes (30.69 NDF), 16% CF without enzymes (31.76 NDF), 16% CF with enzymes (31.76 NDF) for groups 1, 2, 3, 4, and 5, respectively. All groups received pelleted diets ad libitum for 6 weeks. Daily feed intake was recorded and total feces were collected daily and weighed individually during four days for digestibility trial. live body weight (BW), daily weight gain (WG), feed intake, feed conversion ratio (FCR) were evaluated. Apparent digestibility of nutrients [crude protein (CP), Dry matter (DM), ash], carcass traits, and some blood serum constituents (glucose, total protein, albumin, AST, and ALT) were determined. Also, the economic efficacy of this study was determined. The results showed significant reduction (P<0.05) in FBW and WG in G3 (14% CF with enzyme supplementation) compared with other treatment groups. No significant differences in feed conversion ratio (FCR) were detected among treatment groups. Also, there were no significant differences in dressed carcasses, and relative weight % of spleen and kidney. However, there was a significant difference in liver percentage. The longest cecum length (50.50 and 50.00 cm) and lowest pH (6.23 and 6.04) were recorded with rabbits in G4 and G5, respectively. However, significant increases in apparent nutrients digestibility (CP, DM, Ash) were found in G4 and G5. No significant differences were detected in serum liver enzymes (AST & ALT) between treatment groups. However, there was a significant increase in total serum protein and decrease in serum glucose in G2, G4 and G5 compared to the control group. For economic production, the study revealed that the growing rabbits fed diets containing 16% CF (G4) gave the best economic value whereas the lowest efficiency was for group 3 (14% CF plus enzymes supplementation).

Key words: Keywords: growing rabbits, dietary fiber, performance, digestibility and economic efficiency