Fat sources and levels in growing rabbit diets [electronic resource].

Includes references.

A total number of 80 post weaning male New Zealand White (NZW) rabbits of 6 weeks old with an average body weight of 804.6 g were used in this study. Animals were divided randomly into 10 similar groups to study the effects of adding three levels (2.5, 5.0 and 7.5%) of either cotton seed oil (CSO) or poultry fat (PF) or their combination (1:1) on the performance of growing rabbits fed isocaloric and isonitrogenous diets. Growth performance was studied over 8 weeks, at the end of the growing period (14 weeks of age) five randomly selected rabbits from each treatment were slaughtered and carcass traits, bone mineralization and some blood components were measured. At the end of 14 weeks of age the digestibility trails were conducted for 6 days using 3 rabbits from each treatment. The results could be summarized as follows: 1-The final live body weight at 14 weeks of age ranged from 2323.3 g (7.5% PF) to 2801.8 g (2.5% CSO + PF combination) compared with the control (2533.9 g). While, feed conversion ratio varied from 4.30 (7.5% PF) to 3.73 (7.5% CSO) compared with the control (4.20). Highly significant effect (P<0.01) was observed due to fat sources, levels and their interactions on final body weight and feed conversion.2- The apparent digestibility coefficients (ADC) of crude protein ,ether extract, crude fiber and nitrogen-free extract for the different experimental diets showed significant differences (P<0.05) due to sources, levels and their interactions of dietary fat. 3-The calculated energy and protein retention percentages showed significant differences (P<0.05) between sources, levels and interactions of dietary fat. Rabbits fed experimental diets supplemented with plant oil (CSO) reflected the highest significant figures in both energy and protein retention compared with those fed animal fat (PF). By feeding diets containing 2.5% CSO + PF (1:1) experimental animals utilized their energy and protein contents in feed with higher efficiency (15.42 and 34.78%) respectively than other tested treatments. 4- The dressing percentage values were 54.6 % (control), 54.4% (Average CSO), 53.5 % (Average PF) and 54.0% (Average CSO+PF 1:1combination) without significant differences. 5-The calculated bone mineralization grade values showed inconsistent figures and did not follow a definite trend as a direct effect of feeding different sources, levels and their interactions (SxL) of dietary fat and differences failed to be significant .6- Neither dietary source nor level of fat had a significant effect on erythrocyte sedimentation rate (ESR) and hematocrit values (HV). No significant differences were found among sources, levels and interactions (SxL) of dietary fat regarding total protein, albumen, globulin and glucose in blood serum. While, the total lipids and cholesterol clearly significantly (P< 0.01) affected by using different sources, levels and their interactions of dietary fat. By feeding experimental diets supplemented with CSO resulted in the lowest content of total lipids and cholesterol, while rabbits fed diets containing PF showed the highest values compared with those fed diets supplemented with CSO+PF (1:1). Conclusively, it could be concluded that NZW-rabbits at 6-14 weeks of age can be fed diets containing 18% crude protein, 15% crude fiber and 2500 Kcal digestible energy lkg diets throughout partial replacement of cereals such as imported yellow corn and barley by using 2.5 – 5.0 % (1:1) combination of plant oil (CSO) and animal fat (PF) without any adverse effect on the production performance.

Summary in Arabic.

1