Thiamphenicol is a chloramphenicol homologue. Thiamphenicol (TAP) serum and egg concentrations in breeder اhens were investigated in this study. with special reference to the fertility percent. One hundred-Twenty breeder hens and fifteen cockerels were used for the purpose of the experiment The hens were divided into three equal groups of 40 hens at random each and 5 cockerel the 1st and 2nd experimental groups received Thiamphenicol (30 mg/kg, 60 mg/kg orally for 5 days) was given to the first two groups, while the third was held as a control. TAP concentrations in serum and eggs were measured at 1, 3and 6 days post administration by using HPLC. Ten eggs were randomly collected for fertility detection at 1,
3and 6 days post administration. Thiamphenicol was distributed to serum and egg on the first day after the last dose, reaching (0.12± 0.06 mg/dL and 0.65±0.02 mg/gm) in the 30 mg/kg BW treated group and (0.63±0.03) mg/dL and 1.80±0.17 mg/gm) in the 60 mg/kg BW treated group. According to the previous findings, the maximum concentration was found in egg in the 60 mg/kg BW group. On the3rd day after last dosage, the measured level was not detected in serum in 30mg/kg comparison with groups Thiamphenicol detected only in serum of group 60 by 0.22±0.09 mg/dL but on egg it was detected as 1.4±0.19 mg/gm and 4.0±0.29 mg/gm in group 30 and group 60 respectively. On the 6 day, the level of Thiamphenicol was still detectable only in the eggs of 60 mg/kg bw treated group (0.48±0.02) mg/gm. It is clear from the study that, the concentration of Thiamphenicol in eggs was higher than the concentration in serum. In the 60 mg/kg groups, there was evidence of decreased fertility; on the third day, the fertility percentage was 0%. The control group, on the other hand, had a fertility rate of 70%. Fertility was poor until the sixth day following treatment. In this treatment group, no chicks were hatched. There were no problems in hatching chicks once hatchability was returned to normal. While no abnormalities were discovered at necropsy on any of the hens, egg breakouts revealed that fetal deaths happened around day 5 of
development.