| Abstrakt: |
The effect of two doses of antibiotics, chlortetracycline (200 and 400 ppm, L-CTC and H-CTC) and zinc bacitracin (50 and 100 ppm, L-BAC and H-BAC) over a control diet (no antibiotics) was studied with five groups of 8 New Zealand growing male rabbits (1455 ± 13.9 g; 49 days of age). The diets were given "ad libitum" for 21 days of the experiment, consisting of 14 d of adaptation and 7 d of a digestibility trial and urine and caecotrophs collection. At the end of the experiment, four animals per treatment were slaughtered, and caecal parameters were measured. Apparent dry matter, organic matter and neutral detergent fibre digestibilities increased with bacitracin addition compared with the control (in 0.022, 0.018 and 0.048 units; P = 0.03, 0.06 and 0.03, respectively). CTC did not affect the referred parameters. Urinary purine derivatives (PD) excretion and duodenal flow of purine bases (PB) did not evidence differences between the control and tested antibiotic although a high dose of bacitracin depressed both urinary PD and duodenal flow of PB in relation to L-BAC. Medicated diets did not affect N recycling regardless of the method of measurement. [ABSTRACT FROM AUTHOR] |
