DISINFECTION OF HATCHING EGGS WITH CHEMICAL AND NATURAL AGENTS: EFFECTS ON HATCHABILITY AND SEX RATIO IN LAYING HENS

Abstract

In this study, the effects of six disinfectants (Ecocid^® S, ethanol, formaldehyde, propolis, salt and hydrogen peroxide) and distilled water (as a negative control) applied to hatching eggs on hatchability, embryonic development, chick quality and the sex ratio of the resulting chicks were investigated. In addition, an untreated control group was included to establish baseline values without any application. Hydrogen peroxide achieved the highest hatchability (79.4% of eggs set; 85.7% of eggs fertilised), followed by formaldehyde, Ecocid^® S (Krka, d.d. Novo mesto, Slovenia) and ethanol. Compared to these four treatments, which formed a statistically homogeneous group (p>0.05), the groups with salt and propolis had a significantly lower hatchability (p<0.05). Propolis significantly reduced the hatchability (16.2 %; p<0.05) and egg weight loss (7.6 %; p<0.05), probably due to pore blockage and impaired gas exchange. A significantly higher ratio of early to late dead embryos (ED/LD) was observed in the propolis group (0.49) compared to all other experimental groups (0.05– 0.24; p<0.05). A significant effect on the sex ratio was found (p<0.05): the propolis and distilled water groups showed a male-biassed ratio (1.20), while the salt group showed a female-biassed trend (0.78). Although no significant differences were found among three concentrations of Ecocid^® S (0.5%, 1.0%, 2.0%) and hydrogen peroxide (3.0%, 5.0%, 7.0%) in terms of hatchability or sex ratio (p>0.05), the control group had a significantly higher ED/LD ratio (1.26) than all Ecocid® S and hydrogen peroxide treated groups (0.11–0.39; p<0.05). The  study confirms the efficacy and safety of hydrogen peroxide and Ecocid® S and emphasise the importance of considering sex ratio effects when evaluating the embryotoxicity of disinfectants in hatching poultry.

Razkuževanje valilnih jajc s kemičnimi in naravnimi sredstvi: vplivi na valilnost in razmerje med spoloma pri nesnicah

Izvleček: V tej študiji so bili na valilnih jajcih kokoši preučeni učinki šestih razkužil (Ecocid® S, etanol, formaldehid, propolis, sol in vodikov peroksid) ter destilirane vode (kot negativne kontrole) na parametre valjenja, razvoj zarodkov, kakovost piščancev ter razmerje med spoloma ob izvalitvi. Vključena je bila tudi kontrolna skupina, v kateri jajca niso bila tretirana z nobenim razkužilom. Najvišja valilnost je bila dosežena v skupini z vodikovim peroksidom (79,4 % glede na vložena jajca; 85,7 % glede na oplojena jajca), sledile so skupine s formaldehidom, Ecocidom® S (Krka, d. d., Novo mesto, Slovenija) in etanolom. Te štiri skupine so tvorile statistično homogeno skupino (p>0,05), medtem ko je bila valilnost v skupinah, tretiranih s soljo in propolisom, statistično značilno nižja (p<0,05). V skupini s propolisom sta bili valilnost (16,2 %; p<0,05) in izguba mase jajc (7,6 %; p<0,05) značilno manjši, verjetno zaradi zamašitve por v lupini in otežene izmenjave plinov. V isti skupini je bilo opaženo najvišje razmerje med zgodaj in pozno zamrtimi zarodki (ZZ/PZ = 0,49) v primerjavi z vsemi drugimi skupinami (0,05–0,24; p<0,05). Prav tako je bil ugotovljen značilen vpliv na razmerje med spoloma (p<0,05): v skupinah, tretiranih s propolisom in destilirano vodo, je bilo razmerje premaknjeno v korist petelinčkov (1,20), medtem ko je bila v skupini s soljo izražena tendenca v korist jarčk (0,78). Med tremi koncentracijami Ecocida® S (0,5 %, 1,0 %, 2,0 %) in vodikovega peroksida (3,0 %, 5,0 %, 7,0 %) niso bile ugotovljene statistično značilne razlike v valilnosti ali razmerju med spoloma (p>0,05), je pa bilo v kontrolni skupini ugotovljeno značilno višje razmerje ZZ/PZ (1,26) v primerjavi z vsemi skupinami, tretiranimi z Ecocidom® S in vodikovim peroksidom (0,11–0,39; p<0,05). Z raziskavo sta bili potrjeni učinkovitost in varnost vodikovega.

Ključne besede: valilna jajca; vodikov peroksid; Ecocid® S; embrionalna umrljivost; razmerje med spoloma piščancev