Effects of propolis and thyme essential oil as a biofumigants on microbiological load of hatching eggs, incubation and growth performance parameters

This research was conducted to determine the effects of propolis and thyme essential oil on microbiological load of hatching eggs, incubation and growth performance parameters which could be an alternative to chemicals used at disinfection. Two thousand and one hundred sixty unwashed, non broken-cracked, normal sized, (uninfected with feces and pad) clean hatching eggs from 29 wk aged of Ross 308 were divided into seven treatment groups, disinfected by dipping method with 2 doses (10% and 20%) of Propolis (P1-P2), 2 doses (8 and 16 ml/L) of Thyme essential oil (Origanum onites L., T1-T2), ethyl and isopropyl alcohol (Negative Control), Formaldehyde (Positive Control, F) and untreated group (Control). The levels of initial total mesophilic microorganism (6.59) Coliform (5.30), Escherichia coli (3.66), Staphylococcus aureus (7.10), Pseudomonas (2.78) and mold-yeast (2.71) decreased significantly after application of propolis and thyme (log CFU/ml). Salmonella, was detected on the application day (0th day) at P1 and P2 groups and not detected in any group on 1st and 18th day of embryonic development. Egg weight loss (%) values were determined as 10.13 at T1, 9.96 at T2, 10.11 at E, 10.42 at P, 10.61 at F, 8.91 at P1 and 8.69 at P2 groups (P<0.05). At the end of incubation period, 630 chicks were taken into fattening program about 5 weeks. The overall mortality rate has been detected as 4.13% and highest loss was 1.27% at P group. 5th live weight values were obtained as T2 (2468.51gr), P1 (2453.24gr), P2 (2445.12gr), T1 (2367.44gr), P (2359.45gr), E (2340.06gr) and F (2298.10gr) respectively (P<0.05). The best results at feed conversion ratios were 1.420 at T1 and 1.429 at T2 group. Significant differences between application groups were found in inedible viscera, heart (female), gizzard, right leg, back and carcass weight values (P<0.05). Key Words: Hatching egg, disinfection, propolis, thyme oil, carcass parameters