The sanitization of hatching eggs is the backbone of the hygienic–sanitary management of eggs on farms and extends to the hatchery. Poultry production gains depend on the benefits of sanitizers. Obtaining the maximum yield from incubation free of toxic sanitizers is a trend in poultry farming, closely following the concerns imposed through scientific research. The toxic characteristics of formaldehyde, the primary sanitizer for hatching eggs, are disappointing, but it is a cheap, practical and widely used antimicrobial. To overcome this shortcoming, multiple synthetic and natural chemical sanitizers have been, and continue to be, tested on hatching eggs. This review aims to evaluate the effects of different sanitizers on the microbiological quality of hatching eggshells and poultry health during embryogenesis and early stages after hatching.

The aim of this study was to evaluate an ethanolic extract of propolis and clove essential oil as a substitute for paraformaldehyde for the sanitation of fertile eggs. In total, 1,800 hatching eggs (from 40-week-old CPK [Pesadão Vermelho] breeder hens) were randomly distributed among the treatments (grain alcohol, clove essential oil, ethanolic extract of propolis, and paraformaldehyde). Spraying was the application method for all treatments except for paraformaldehyde, for which fumigation was used. The experimental design was a randomized block design with 4 treatments. Analysis of the incubation parameters was based on 6 replications per treatment. The egg weight loss was lower in the eggs treated with ethanolic extract of propolis (8.59 ± 3.34%) than in the eggs treated with grain alcohol (13.40 ± 2.87%), clove essential oil (12.96 ± 3.33%), and paraformaldehyde (13.05 ± 3.24%). The hatchability of the fertile eggs (51.39 ± 5.81%) and the hatchability of the set eggs (44.74 ± 6.79%) were negatively affected by the application of ethanolic extract of propolis. Late mortality of eggs treated was higher than early mortality in the grain alcohol (12.14 ± 4.72%; 2.86 ± 3.30%), clove essential oil (4.60 ± 5.95%; 3.03 ± 3.50%), and ethanolic extract of propolis (36.63 ± 6.60%, 11.98 ± 4.30%) treatments. The eggs treated with clove essential oil (67.90 ± 1.87%), paraformaldehyde (67.80 ± 1.85%), or grain alcohol (67.50 ± 1.92%) presented chick yields as expected. However, despite the ideal yield of eggs treated with ethanolic extract of propolis (69.25 ± 1.68%), its application at the concentration used in the present research is not recommended. Clove essential oil, when sprayed on fertile eggs as a sanitizing agent, did not differ from paraformaldehyde in relation to hatchery performance parameters.

The aim of this study was to evaluate the efficacy of sanitizing fertile eggs with clove essential oil as an alternative to paraformaldehyde; effects on the reduction in eggshell microbial count, incubation yield, and neonatal chick quality were measured. A total of 1,460 brown fertile eggs with a mean weight of 58.64 ± 0.49 g (from 37-wk-old CPK [Pesadão Vermelho] breeder hens) were collected under aseptic conditions and randomly distributed into 4 treatments (nonsanitized and sanitized with grain alcohol, clove essential oil, and paraformaldehyde) before incubation. The count of total aerobic mesophilic bacteria was significantly lower after spraying with clove essential oil (2.30 ± 0.24 log10 CFU/mL) than on nonsanitized eggs (3.49 ± 0.34 log10 CFU/mL) or on eggs sprayed with grain alcohol (3.09 ± 0.14 log10 CFU/mL) but did not differ significantly from the count in the paraformaldehyde group (2.23 ± 0.29 log10 CFU/mL). The hatchability of fertile eggs differed significantly between the studied treatments. The mean values for the eggs treated with clove essential oil (84.69 ± 1.65%) and paraformaldehyde (81.87 ± 3.92%) were statistically similar but were higher than the negative control (74.03 ± 3.58%) and grain alcohol (73.59 ± 2.87%) values. In the Pasgar© score assessment, it was determined that the clove essential oil (9.21 ± 0.89%) had a superior effect on the physical quality of the chicks compared with the effects of the other treatments. Clove essential oil is effective and safe for eggs intended for incubation. Its use as an alternative to paraformaldehyde in the sanitation of fertile eggs is strongly recommended.

This study aimed to evaluate the effects of different egg turning frequencies on incubation efficiency parameters. Nine hundred sixty brown fertile eggs, with an average weight of 52.20 ± 0.85 g, from 38-week-old CJD (Carijó Pesadão) breeder hens were randomly distributed among 4 treatments before incubation. Each treatment corresponded to a turning frequency, being 24 (control), 12, 6, or 3 times per day, at an angle of 45°, until day 18 of incubation. The experimental design was a randomized complete block design with 4 treatments. Analysis of the incubation parameters was based on 6 replications per treatment. The eggs that were turned 12, 6, and 3 times per day exhibited a decrease in hatchability of the fertile eggs of 6.61, 15.51, and 19.70%, respectively, when compared with the control group (91.84 ± 2.73%). With a decrease in turning frequency, there was a gradual increase in early (2.84 ± 1.89 to 14.31 ± 1.82%) and late (3.57 ± 1.39 to 8.05 ± 1.24%) mortality rates. An egg turning frequency of 24 times per day during incubation provided high hatchability rates. In contrast, the turning frequencies of 12, 6, and 3 times per day showed significant losses in hatchability.

This study aimed to evaluate the effect of a pectin biofilm on the preservation of refrigerated and unrefrigerated eggs during 5 wk of storage based on egg weight loss, albumen height, Haugh unit (HU), and the yolk index (YI). A total of 1,200 nonfertile eggs from GLK Bankiva laying hens (40 wk of age), which were freshly laid and came from a single collection, were obtained from a model poultry rearing system (Planaltina, Federal District, Brazil) that meets all animal welfare criteria. The experimental outline was entirely randomized, with 20 treatments in a factorial scheme of 2 × 2 × 5, with 2 biofilm treatments (with and without) × 2 storage temperatures (refrigeration: 5°C and ambient: 25°C) × 5 storage periods (7, 14, 21, 28, and 35 d), with 12 repetitions per treatment. Starting from the third storage week, increased weight loss (%) was observed in noncoated eggs (4.46 ± 1.06; 5.61 ± 1.37; 6.93 ± 1.66%) compared with biofilm-coated eggs (3.57 ± 1.26; 4.74 ± 1.8; 6.05 ± 2.21%), respectively. The HU variation in the pectin-coated eggs (86.84-78.02) was smaller than that in the noncoated eggs (83.01-64.36) between the beginning (7 d) and the end (35 d) of the experimental period. Eggs with and without biofilm stored in the refrigerator presented average HU values of 91.26 ± 6.27 and 88.35 ± 6.96, respectively. In contrast, when kept at room temperature, eggs with the coating presented higher HU values (71.27 ± 10.78) than eggs without the coating (59.11 ± 15.97). Coated eggs (0.37 ± 0.16) showed higher YI values than noncoated eggs (0.35 ± 0.16). A pectin-based biofilm effectively maintained egg quality during the 35 d of storage.

SUMMARY Sanitising hatching eggs can reduce the negative effects of microorganisms on bird survival. Formaldehyde gas is commonly used to sanitise hatching eggs. However, handling of and exposure to formaldehyde threaten human and animal health, as this compound can have serious harmful effects. Thus, there is a growing body of research on safe natural compounds, such as essential oils (EOs), as alternatives to formaldehyde. Based on the research carried out to date, EOs may be applicable in the poultry industry since eggs sanitised with EOs were found to have significant reductions in the number of total aerobic mesophilic bacteria (up to 80.77%) and fungi (up to 69.33%) on shells, with hatchability rates significantly improved by up to 12.59%. Notably, to obtain positive results from the application of EOs on eggs, several factors must be considered, such as the time of application and the concentration of the sanitising compound. Further research on the use of EOs as sanitisers for hatching eggs is recommended, as reducing use of synthetic chemicals is essential because of their undesirable effects.