This study aims to present the different effects produced by a post-weaning intake limitation strategy without or with early probiotic supplementation (Lacobacillus lactis 2.5 x 108 CUF, Bacillus subtilis 1.8 x 109 CUF/g) from 3 to 12 weeks of age on growth performance, digestibility, viability, and economic efficiency of growing rabbits. A total number of 54 local growing Black Balady rabbits, divided into six dietary treatment groups three replicates each. The dietary levels of feed restriction (FR) and probiotic (PR) included 3x2 factorial design as follow: T1: Rabbits fed basal diet ad libitum ,T2: Rabbits fed basal diet with early fed 0.4g probiotic/ kg diet (PR), T3 : Rabbits fed restricted by 120% from the energy requirements for maintenance (FR120), T4: Rabbits fed restricted by 120% from the energy for maintenance with early fed 0.4g probiotic/ kg diet, T5: Rabbits fed restricted by 140% of the energy requirements for maintenance (FR140) and T6: Rabbits fed restricted by 140% of the energy requirements for maintenance with early fed 0.4g probiotic/ kg diet from 6 to 14 weeks of age.
The results showed that feeding probiotic (PR) early supplementation from 3 weeks of age to weaning (6 weeks of age) did not affect on body weight (BW) and viability % at weaning compared to the control groups.
Post weaning the rabbits fed ad libitum with early PR 0.4g/ kg diet at 3 weeks of age recorded significantly higher daily weight gain than control diet. Feed conversion was improved due to adding PR to the diet by about 10.8% compared to the control diet. Also, the Ad libitum diet with PR resulted in increase the performance index.
The growing rabbits fed ad libitum had the highest daily weight gain compared to those fed restricted diet. The best value of feed conversion ratio (FCR) achieved by fed sever feed restriction (FR120) and moderate feed restriction (FR140) compared to ad libitum diet. The FR120 resulted in decrease all digestibility traits except for the digestibility of crude fiber compared to ad libitum feeding. The FR140 did not cause any detrimental effect on digestibility of nutrients. Viability % was significantly improved by about 5.7% as a result of FR120 compared to ad libitum group. The greatest value of economic efficiency produced by fed FR either FR120 or FR140.
Also all interaction treatments tend to significantly decrease daily feed intake and improve FCR except for the ad libitum with adding PR and FR120 without PR. The FR120 with PR and FR140 with or without PR increased PI. The ratio N/L increase significantly due to feeding on FR120 with PR early from 3 weeks of age compared to ad libitum feeding. Also, the most interaction dietary treatments improved V%. All interaction treatments except for ad libitum with probiotic resulted in a significant higher economic efficiency than caused by feeding on ad libitum diet.
The current study illustrated that rabbit's start fed PR product early from 3 to 6 weeks of age pre weaning and feeding PR continued to 12 weeks of age with FR120 post- weaning immediately or rabbits fed FR140 with or without PR product showed be taken with considerable in the commercial exploitation of rabbits production for its high economically value, under the Egyptian environmental condition.