Desinfetantes alternativos ao uso de formaldeído para desinfecção de ovos férteis

Abstract

The present study examined the effect of different disinfection procedures as an alternative to formaldehyde fumigation on eggshell microbial load, eggshell quality, hatching parameters, neonate chick quality and yolk sac contamination of day-old chicks. A total of 10,080 nest clean eggs were collected from a 42-wk-old Cobb commercial breeder flock and randomly distributed in a complete block design composed by the following treatments: paraformaldehyde fumigation (13.33 g/m3/20 min; FF); ozone fumigation (5-10 ppm/20 min; OZF); UV-C light irradiation (254nm ; 6.36 mW/cm2; 60 s; UVI); spraying with hydrogen peroxide (1.56%; 0,69 ml/egg; H2O2), with peracetic acid (0.13%; 0,69 ml/egg; PAA), with water (0,69 ml/egg; wet control; H2OCONT) and no disinfection procedure (dry control; DCONT) Eight samples (pool of four eggs each one) from each treatment were collected to enumerate the presence of Enterobacteriaceae and total aerobic bacteria on the eggshell before and after the disinfection procedure. A total of 24 eggs per group were collected to evaluate the eggshell resistance and thickness. A total of 1,152 eggs per treatment were placed in twelve 96-egg trays to evaluate eggs weight loss during incubation, hatchability, hatchability of fertile eggs, embryo mortality (initial, medium and late), chick weight and percentage of saleable chicks at hatch. The counts of Enterobacteriaceae and total aerobic bacteria present in the yolk sac were performed in thirteen day-old chicks originated from each treatment. No significant reductions were observed in Enterobacteriaceae and total aerobic bacteria population on eggshell between groups before the disinfection (P>0.05). After disinfection, Enterobacteriaceae count on eggshell was not affected by treatments (P>0.05). Only eggs from UVI and FF groups showed significant reduction (P<0.05) on total aerobic bacteria count on eggshell when compared to DCONT after disinfection, and compared to the same groups before the treatments; however, FF group showed greater reduction (P<0.05) than UVI group. It was observed an increase in egg weight loss in eggs from H2O2, PAA and H2OCONT (P<0.05) and no statistical difference (P>0.05) for this variable in eggs from FF, OZF, UVI and DCONT groups. The other variables evaluated in this study were not affected by treatments (P>0.05). It can be concluded that UVI is a potential alternative to disinfect hatching eggs, since it decreased bacterial load on eggshell without affecting hatchability, the percentage of saleable chicks and bacterial load on yolk sac from day-old chick.