EGG WEIGHT AFFECTS HATCHING RESULTS, BODY WEIGHT AND FEAR-RELATED BEHAVIOR IN JAPANESE QUAILS

Abstract

This study was conducted to determine effect of egg weight on hatching results, chick performance and tonic immobility duration in Japanese Quails. Eggs were weighed individually and divided by weight into four groups: group 1 = 11.0 - 11.9 g, group 2 = 12.0 - 12.9 g, group 3 = 13.0 - 13.9 g and group 4 = 14.0 - 14.9 g. Egg weight loss during incubation and hatching parameters were recorded. Additionally, hatching weight and body weight were measured until 5 weeks and tonic immobility (TI) test was performed at the end of the experiment. Results revealed that egg weight loss during incubation decreased as egg weight increased. Group 2 was determined as the best suitable egg weight group in terms of fertility and group 2 and 3 in terms of hatchability of incubated eggs and hatchability of fertile eggs. Body weight increased as the egg weight increased and the heaviest chicks were hatched from heaviest egg group. Significant differences in TI duration between birds were noticed, as higher body weight birds had longer TI duration than birds with lower body weight. Thus, birds of high body weight were more fearful than birds of low body weight. It was concluded that the medium to heavy weight eggs are better eggs for hatching results and chick weight. Therefore, we recommend the selection of medium and heavy weight eggs for hatching implementations in Japanese quail. Key words: body weight; egg weight; fertility; hatchability; tonic immobility TEŽA JAJC VPLIVA NA NESNOST, TELESNO TEŽO TER VEDENJE POVEZANO S STRAHOM PRI JAPONSKIH PREPELICAH Povzetek: Študija je bila izvedena z namenom določanja vpliva teže jajc na rezultate izvalitve, uspešnost piščancev in trajanje tonične negibnosti pri japonskih prepelicah. Jajca smo posamezno stehtali in jih po teži razdelili v štiri skupine: skupina 1 = 11,0 - 11,9 g, skupina 2 = 12,0 - 12,9 g, skupina 3 = 13,0 - 13,9 g in skupina 4 = 14,0 - 14,9 g. V času valjenja so bile zabeležene izgube teže jajc ter parametri valjenja. Izmerili smo tudi težo valilne mase in telesno maso do 5 tednov starosti, na koncu poskusa pa izvedli test tonične negibnosti (TI). Rezultati so pokazali, da se je izguba teže jajca med inkubacijo zmanjševala s povečanjem teže jajc. Skupina 2 je bila kot najbolj primerna skupina jajc glede plodnosti, skupini 2 in 3 pa glede na valilnost inkubiranih jajc in valilnost plodnih jajc. Telesna teža se je povečevala, ko se je povečala teža jajc in najtežji piščanci so se izvalili iz najtežje skupine jajc. Opažene so bile pomembne razlike v trajanju TI med pticami, saj so imele ptice z višjo telesno težo daljše trajanje TI kot ptice z nižjo telesno težo. Tako je bilo ptice z veliko telesno težo bolj strah kot ptice z nizko telesno težo. Ugotovljeno je bilo, da so jajca srednje do višje teže boljša jajca glede valjenja in teže piščancev. Zato priporočamo izbiro jajc srednje in višje teže za valjenje japonskih prepelic. Ključne besede: telesna teža; teža jajc; plodnost; valilnost; tonična negibnost