Effect of egg storage duration and egg turning during storage on egg quality and hatching of broiler hatching eggs.

In commercial hatcheries, it is common to store eggs before incubation. One practice to improve hatchability consists in egg turning during this storage. This work aims to highlight the effects of turning on the physicochemical aspects of eggs and, consequently, how this turning can influence the hatching of chicks. An experiment was conducted to evaluate the effects of storage duration and egg turning during storage on egg quality, hatchability, and residual analysis. A total of 7 500 hatching eggs were collected from a 55-week-old commercial Cobb500 breeder flock and storage according to the treatments. The experiment was completely randomized in a 3×2 factorial design with three storage periods (4, 8, and 12 days) and egg turning (180° turn of eggs once a day) or no turning during storage, totaling six treatments. Regardless of turning, eggs stored for 4 days weighed more than turned eggs stored for 8 and 12 days, which were similar (P < 0.05). Non-turned eggs experienced an increase in relative shell weight with increased storage duration, and non-turned eggs stored for 4 and 8 days differed from non-turned eggs stored for 12 days (P < 0.05). Albumen pH of turned eggs stored for 4 and 8 days was lower than that of non-turned eggs stored for the same durations (P < 0.05). Albumen pH of turned eggs increased as storage duration increased (P < 0.05). Egg turning increased hatching by 2.02% over that of non-turning (P < 0.05). Eggs stored for 12 days, irrespective of turning, had higher late embryonic mortality (P < 0.05) compared to the other treatments. It was concluded that turning eggs during pre-incubation storage was adequate to improve hatchability of fertile eggs. Storing fertile eggs for 12 days is harmful to egg quality and increases embryo mortality even if eggs were turned.

Effects of a dry hydrogen peroxide disinfection system used in an egg cooler on hatchability and chick quality.

A sanitation method that could continually clean and disinfect the air and surfaces in a hatchery could provide a second layer of microbial reduction on top of routine cleaning and disinfection. A gaseous dry hydrogen peroxide (DHP) system has been used in other facilities for this purpose and could have potential for use in chicken hatcheries. Because the DHP is a true gas and can permeate through the entire hatchery space, contact with eggs during storage and incubation could potentially interfere with normal hatching processes. Therefore, the aim of this study was to evaluate the effects of the DHP system on hatching parameters and chick quality. A total of 3,960 hatching eggs were collected from an ∼40-week-old Ross 308 broiler breeder flock and distributed in 2 treatments: treated and nontreated. For the treated group, the egg cooler was cleaned, and 1 DHP generator was placed inside. Two other DHP generators were placed in the common area outside as well. Both areas were treated for 7 D before placement of eggs, and then eggs were collected and placed inside the cooler over a 4-day period. Eggs were then stored for an additional 3 D after the last collection. Dry hydrogen peroxide levels were recorded each day during storage. For the nontreated group, all DHP machines were removed from the cooler and external room, and the egg cooler was cleaned. Eggs were collected in the same way for the control group as the treated group. After storage, eggs were placed into a single stage Natureform incubator. The eggs exposed to DHP showed higher (P < 0.05) hatchability of fertile eggs and lower (P < 0.05) early embryonic dead than eggs from the nontreated group. No other parameters evaluated were different between groups. Based on this work, the DHP treatment of fertile eggs had no detrimental effect on any performance parameter, with potential positive effects seen on hatch of fertile eggs and early embryonic dead embryos.

An evaluation of alternative methods for sanitizing hatching eggs.

Different sanitization methods were evaluated as alternatives to formaldehyde fumigation for the reduction of eggshell and yolk sac microbiological counts, improvement of eggshell quality, incubation parameters, and day-old chick quality. A total of 10,080 hatching eggs were collected from a 70-wk-old commercial broiler breeder flock and distributed in a completely randomized block design with seven treatments: fumigation with paraformaldehyde (5.03 g/m3/30 min), fumigation with ozone (5-15 ppm/30 min), ultraviolet light-C irradiation (8.09 mW/cm2; 120 s; UV-C), hydrogen peroxide spraying (3%; 0.69 mL/egg), peracetic acid spraying (0.3%; 0.69 mL/egg; PAA), water spraying (0.69 mL/egg; water control), and without disinfection (dry control-DC). Spraying eggs with PAA and UV-C significantly reduced aerobic bacteria plate counts compared to the DC group. In addition, eggs disinfected with PAA had lower Enterobacteriaceae counts than the DC and water control groups. Eggshell quality, incubation parameters, and microbiological counts for yolk sac did not differ (P > 0.05) among treatments. This study demonstrated the potential for the application of PAA and UV-C for eggshell disinfection instead of formaldehyde; however, an electronic microscopic evaluation of the eggshell is necessary to determine if these methods cause any damage to the cuticle.

An ongoing immune response to HIV envelope gp120 in human CD4-transgenic mice contributes to T cell decline upon intravenous administration of gp120.

The mechanisms accounting for T cell depletion in AIDS patients are not yet fully understood, nor are the roles of host factors in HIV pathogenesis. We show here that an ongoing humoral immune response to HIV gp120 can sensitize non-infected cells towards apoptosis. Thus, i.v. injection of 1 microg recombinant(r) gp120 into gp120-immunized human CD4-transgenic mice (huCD4 Tg), which express huCD4 on both T and B cells, results in T and B cell depletion in peripheral blood and lymphoid tissues. On day 6 after a bolus injection of gp120, the numbers of peripheral T cells and B cells in gp120-immunized huCD4 Tg decreased sevenfold and two- to threefold, respectively. Annexin V staining revealed a higher percentage of early apoptotic cells on day 1 of gp120 i.v. injection from gp120-primed huCD4 Tg spleens compared to gp120-primed controls. Boosting the primed huCD4 Tg mice with soluble gp120 and hen egg-white lysozyme led to lower secondary titers to both antigens than found in controls. Furthermore, splenocytes from gp120-pretreated immunized huCD4 Tg had a lower level of stimulation in response to anti-CD3 treatment. These in vivo results are consistent with in vitro data demonstrating that cross-linking CD4 on splenocytes of huCD4 Tg by rgp120SF2 and anti-gp120 not only sensitizes T cells for apoptosis, but also induces apoptosis per se, and suggest that anti-gp120 responsiveness can contribute to T cell depletion in AIDS.