Two experiments were designed on buck and doe rabbits. In the 1st experiment, a total of 25 New Zealand White (NZW) rabbits bucks (9 months of age with a mean live body weight of 3400±173 g) were allotted into 5 treatments to study the effect of additive citric, lactic acids and propylene glycol on nutrients digestibility coefficients, blood picture, sexual urge, physical semen and spermatozoa characteristics, feed intake and live body weight changes. In the 2nd experiment, a total of 40 nulliparous does (8 months of age with an average live body weight of 3100±188 g) were allotted into 5 treatments. Does were inseminated with semen from untreated bucks. Does performance including:- blood picture, litter size and weight at birth and at weaning, milk yield, feed intake and body gain were studied.
First group in both experiments received plain water and severed as a control group, while water for the 2nd ,3rd ,4th and 5th groups for the two experiments supplemented with citric, lactic acids (Concentration of citric and lactic acid 98%) or propylene glycol (2% propylene glycol, as an energy source) at 0.5 ml/liter drinking water and mixture of them with 0.75 ml/liter at 0.25 ml, each, respectively.
Results showed in first experiments significant improvement in buck's nutrients digestibility of OM, CP and NFE were significantly increased with mixture of (citric , lactic acid and propylene glycol ) group than in other groups. There was also a significant increase in CP and NFE in the group that received citric acid in the drinking water. There was no significant effect on CF and EE digestibility coefficient. Hematocrit, red blood cells counts and white blood cells counts increased significantly in all treated groups compared to control while hemoglobin values, increased significantly in all treated group (except lactic acid group) than control. Total protein, globulin, triiodothyronine and testosterone, were significantly increased due to supplemented of citric, lactic acids, propylene glycol individual or a mixture of them compared to the control group. Significantly improvements in each of sexual urge (libido) and all the semen and sperm characteristics in treated group compared to control group. In second experiments Does performance with using individual citric, lactic acids or propylene glycol or mixture of them to drinking water was improvements. Hematocrit, red blood cells counts, white blood cells counts and triiodothyronine increased significantly in all treated groups compared to control while hemoglobin values, increased significantly in all treated group (except lactic acid group) than control. Total protein, albumin, globulin and A/G ratio significantly affected by supplemented citric, lactic acids or propylene glycol and mixture of them and tended to increase by group received propylene glycol or group received mixture of them. The changes in weight gain of does in the four groups across the experimental period were significant in citric acids or propylene glycol group. organic acids or propylene glycol supplemented achieved improvement in litter weight at birth. At weaning day, all treated groups had heavier kits' weight than those in control. Litter size increased obviously due to supplemented water by citric, lactic acids or propylene glycol and mixture of them than that in control group during the all experimental days. Mortality rate reduced by supplemented water by citric, lactic acids or propylene glycol and mixture of them. Milk yield in 3rd week of lactation was increased significantly in all treated group compared to control.
In conclusion, this study demonstrated the effectiveness of citric acid, lactic acid and propylene glycol and its ability to improve the performance of rabbits, by improving reproductive performance as a result role for additives in improved blood metabolites and improving available energy, improving nutrition digestion as well as improving milk quality, and thus affecting reproduction in farm animals