الفهرس 
Experimental animalsOnly 14 pages are availabe for public view
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Abstract
The present study was performed to investigate the influence of feeding diets containing three CF levels (12.52, 14.51 and 16.51%) with or without a probiotic supplementation on the performance, nutrient digestibility, carcass traits and blood parameters of growing New Zealand White rabbits. Seventy two 6-week-old New Zealand White (NZW) rabbits were randomly divided into 6 treatments. Each treatment had 4 replicates, each of 3 rabbits. The average weight of rabbits in all groups ranged from 972 to 1008 g. Three diets were formulated to contain crude fiber levels of 12.5, 14.5 and 16.5% (Table 1) without or with the probiotic supplementation (0.03 kg Avian Plus per 100 kg diet). Thus, six experimental diets were prepared and used during the experimental period from 6 to 12 weeks of age. All diets were formulated to meet all the essential nutrient requirements of growing rabbits (Table 1). All experimental diets were pelleted (3.5 mm diameter). Feed and fresh water were offered Ad Libitum to the experimental groups. Performance were evaluated in terms of live body weight, daily weight gain, daily feed intake, feed conversion ratio, protein efficiency ratio, efficiency of energy utilization and performance index. Digestibility of nutrients [dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), crude fiber (CF) and nitrogen-free extract (NFE)], carcass traits (relative weights of carcass, total edible parts and abdominal fat) lengths stomach, caecum and small and large intestines, and some blood plasma constituents (glucose, cholesterol, triglycerides, total protein, albumin and globulin) were also determined. Also the activities of transaminases (GOT and GPT) and alkaline phosphatase were determined in blood plasma of rabbits. The obtained results could be summarized as follows: 1 - Dietary fiber level had no significant effects on live body weight or daily weight gain at different studied ages, Dietary probiotic supplementation had no significant effect on live body weight or daily weight gain at different studied ages. 2 - Dietary fiber level, probiotic and their interaction had no significant effect on daily feed intake or feed conversion ratio throughout the experimental period. 3 - Neither dietary fiber level nor probiotic supplementation affected PER or EEU of rabbits throughout the experimental period. 4 - There were no significant differences in PI due to different dietary fiber or probiotic levels or their interaction throughout the experimental periods. 5 - Increasing dietary crude fiber level from 12.5% to 14.5 or 16.5% decreased the digestibility of DM, OM and NFE but significantly improved CF digestibility for 12-week-old NZW rabbits, while the digestibility of CP and EE was not affected Dietary supplementation with probiotic had no significant effect on the digestibility of nutrients, with the exception of a significant improvement in CP digestibility compared with that of the control rabbits. 6 - The TDN and DE values were significantly decreased for the diets containing fiber levels of 14.51 and 16.51%. On the other hand, both diets containing fiber levels of 14.51 and 16.51% had nearly similar values of DCP to that of the control diet (12.52% CF) without significant differences among them. Although the TDN and DE values were not changed by probiotic supplementation, it was found that the DCP values were significantly improved. 7 - Dietary fiber level, probiotic and their interaction had no significant effect on carcass traits of the experimental rabbits. 8 - All studied blood plasma constituents of rabbits were not significantly affected by dietary fiber level, probiotic and their interaction, except for GOT enzyme activity which was significantly decreased by probiotic supplementation. 9 -The measurements of the alimentary tract segments were not significantly affected by dietary fiber levels, probiotic and their interaction in rabbit diets. From the results of the present study. It con concluded that NZW growing rabbits can tolerate dietary fiber level up to 16.5% with no adverse effects on growth performance or carcass traits.