This experiment was carried out to evaluate the effect of acetic acid addition on growth and some physiological and immunological characteristics of growing rabbits. A total of 36 New Zealand White (NZW) weaning male rabbits with average live body weight of 685 ± 25 g were randomly divided into four treatment groups (9 rabbits each). The 1st group received basal untreated pelleted diet and served as a control group, while the 2nd, 3rd and 4th groups fed the basal diet with 0.5, 1.0 % and 1.5% acetic acid, respectively.
The obtained results showed that live body weight and feed intake did not significantly differed due to treatments. Mortality rate significantly (P<0.05) decreased with increasing acetic acid level than those of low level (0.5 %) and of the control group. Red blood cells (RBCs) count, hemoglobin (Hb %), packed cell volume (PCV, %), lymphocyte and heterocyte percentages of blood were significantly and white blood cells (WBCs) insignificantly differed due to acetic acid treatment. Blood plasma contents of total protein, albumin and globulin insignificantly increased and total lipids, triglycerides, totalcholesterol, uric acid and transaminase enzymes of liver (AST and ALT) were significantly (P<0.05) differed due to acetic acid treatment. Rabbits which supplemented with 1.5% of acetic acid were accompanied by the highest values of these traits than those of control group. The activities of digestive enzymes (amylase, lipase and protease) were significantly (P<0.05) increased in groups treated with different levels of acetic acid compared with control group. Number of colonies bacteria Escherichia coli and Salmonella were significantly (P<0.05) decreased in gut of rabbit groups due to acetic acid treatment compared with those of control group. Ileum and ceacum pH values were insignificantly differed due to treatments.
The obtained results indicated that addition of acetic acid showed improvement in digestive enzyme activities, some blood hemato-biochemical constituents, immunological traits and decreasing mortality rate of growing rabbits, especially in rabbits received 1.5% of acetic acid.