2003 Poultry Science Association, Inc. Evaluating the Use of Ultraviolet Light as a Method for Improving Hatching Egg Selection W. A. Stanley,* C. L. Hofacre,,1 N. Ferguson, J. A. Smith, and M. Ruano *Aviagen North America, Huntsville, Alabama; Poultry Diagnostic and Research Center, Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602-4875; Fieldale Farms, Baldwin, Georgia; and Perdue Farms, Salisbury, Maryland Primary Audience: Breeder Production Managers, Veterinarians, Hatchery Managers SUMMARY Broiler breeder hatching eggs from a commercial operation were categorized using a portable ultraviolet (UV) light (365 nm long wave). Three separate trials were performed using the same selection techniques in each trial. Eggs within each trial were initially separated into two groups: those with visibly adulterating materials and those without. Eggs without visible adulteration were further classified based upon the presence or absence of adulterating materials when viewed under UV light. Criteria for UV light adulteration included urates, blood, fecal material, and cracks. The three groupings of selected eggs and nonselected controls were set in incubators to determine differences in hatchability. Hatchability in trial 1 was improved with UV clean and UV stained eggs compared to farm dirty and control eggs. Trials 2 and 3 demonstrated an improvement in hatchability with UV clean eggs over all other groups. (Hatchability data were not analyzed statistically.) Total aerobic bacterial counts on the eggshells were determined with egg rinses. In trial 1, the farm dirty eggs had significantly higher bacterial counts than eggs in all other groups; however, no significant differences in aerobic bacterial counts were noted between any of the groups in trials 2 and 3. No differences were observed with regard to moisture loss during incubation among groups. Fourteen-day chick mortality was within normal limits, and no significant differences were noted among groups. Results of these trials suggest that UV light may be beneficial when selecting eggs that have a likelihood of poorer hatchability. Key words: broiler hatching egg, chick quality, cuticle, hatchability, ultraviolet light 2003 J. Appl. Poult. Res. 12:237 241 DESCRIPTION OF PROBLEM The cuticle barrier is the outermost layer of the eggshell and plays an integral role in defense against bacterial contamination of the egg [1]. Additionally, the quality and quantity of the cuticle affect the rate of moisture loss and hatchability [2, 3, 4, 5]. Sparks and Board [5] demonstrated increased water uptake in eggs with the cuticle removed, which could lead to an increase in microbial penetration of the eggshell. Peebles and Brake [4] concluded that the cuticle may impede or enhance water vapor diffusion and is affected by the humidity of the air surrounding the egg. Board and Halls [1] determined that the cuticle prevented water-soluble dyes and carbon black 1 To whom correspondence should be addressed: chofacre@arches.uga.edu.
238 JAPR: Field Report from entering the eggshell. Ball et al. [6] demonstrated that the uric acid portion of feces reduces cuticle staining intensity. The current methods for measuring cuticle characteristics, such as staining, water uptake, and scanning electron microscopy, cause eggs to be unsettable. Ultraviolet (UV) light is a rapid, easy method that has no detrimental effect on the embryo and, therefore, may provide a means to evaluate cuticle quality of large numbers of eggs prior to setting. When evaluating cuticle quality, many factors must be considered; however, they can be grouped into two broad categories: internal factors (those that occur before oviposition) and external factors (those that occur after oviposition). Internal factors include individual bird variability; egg variability; breed differences; diseases such as Newcastle disease, infectious bronchitis, and avian influenza; nutrition; and uric acid deposition [6]. External factors include storage temperature, environmental temperature, storage humidity, washing, sanitizing, rubbing with abrasives (i.e., sandpaper), and age [2, 6]. Disinfectants such as hydrogen peroxide, sodium hypochlorite, formaldehyde, quaternary ammonium compounds, and sulfonamides have also been shown to degrade the cuticle [3, 7]. Under UV illumination, the cuticle emits an orange-red fluorescence, which can be evaluated based on its presence, color, intensity, and distribution of the fluorescence. The objective of this study was to demonstrate whether cuticle quality as determined under UV light affected hatchability, moisture loss during incubation, microbial level on the eggshell surface, and 14-d mortality of the hatched chicks of commercial broiler breeder eggs. FIELD REPORT Hatching eggs from Ross Hubbard HiY (trial 1) and Ross Arbor Acre FSY (trials 2 and 3) breeders at ages of 51, 49, and 54 wk, respectively, were selected at a commercial hatchery and placed into four groups. The initial selection of eggs was performed under white (normal) light conditions, in which eggs were divided into two groups: farm dirty and farm clean. Eggs with any visible adulteration resulting from fecal mate- TABLE 1. Hatchability of clean and dirty eggs when selected under normal (white) and UV A light Total Total chicks Hatchability Trial eggs set hatched (%) Trial 1 UV clean 4,860 4,270 DE UV stained 2,592 2,439 DE Farm dirty 3,888 3,132 80.56 Control 3,240 2,581 79.66 Overall flock 82.53 Trial 2 UV clean 2,430 2,266 93.25 UV stained 2,430 2,190 90.12 Farm dirty NT NT NT Control 4,860 4,328 89.05 Overall flock 86.54 Trial 3 UV clean 2,430 2,289 94.20 UV stained 4,860 4,268 87.82 Farm dirty 2,430 2,177 89.59 Control 4,698 4,206 89.53 Overall flock 89.75 UV = ultraviolet; Clean = no visible adulteration under white or UV light; Stained = no visible adulteration under white light but visible adulteration under UV light; Farm dirty = visible adulterated under white light; Control = randomly collected, unselected eggs from same breeder flocks; NT = not tested; DE = data error. rial, blood, cracks, or urates under white light were placed into the farm dirty category. The remainder of the eggs was classified as farm clean. A total of 3,888 and 2,430 eggs were placed in the farm dirty category in trials 1 and 3, respectively. A farm dirty group was not used in trial 2 (Table 1). Farm clean eggs were then evaluated under UV 2 light (365 nm long wavelength) and subdivided into UV clean and UV stained categories [8]. Eggs placed in the UV clean category had an evenly distributed, orange-red fluorescence over the entire shell surface. The UV stained group did not have an even distribution of orangered fluorescence, as stains from materials such as blood, urites, feces, and water not visible under normal white light became readily apparent under UV illumination. Because eggs remained in the hatchery flats, only the top 50% of the eggshell surface was examined. A total of 4,860, 2,430, and 2,430 eggs 2 When using an ultraviolet light, avoid looking directly at the source and avoid contact with exposed skin for prolonged periods. In addition, UV goggles capable of absorbing UV light from 180 to 400 nm should be worn during use.
STANLEY ET AL.: BROILER HATCHING EGGS AND ULTRAVIOLET LIGHT 239 were placed in the UV clean categories and 2,592, 2,430, and 4,860 eggs were placed in the UV stained categories in trials 1, 2, and 3, respectively. The fourth category consisted of nonselected controls, with 3,240, 4,860, and 4,698 eggs used in trials 1, 2, and 3, respectively. All eggs were incubated in multistage Chick Master setters and hatchers [9]. The locations of the four treatments within a setter were rotated between trials. All eggs within a trial were placed in the same setter. No washing or sanitizing was performed on the eggs before selection and setting. Not all eggs from a particular breeder flock on a given hatch day were utilized in this study. Therefore, the hatchability of the remaining eggs set in other incubators was available for comparison purposes (overall flock, Table 1). The groups are summarized in the following list. Group 1: UV Clean Contained no visible adulteration (blood, urates, feces, or water) when viewed under white light and ultraviolet light and emitted an evenly distributed orange-red fluorescence. Group 2: UV Stained Contained no visible adulteration when viewed under white light but contained visible changes in fluorescence under UV illumination. Group 3: Farm Dirty Contained visible adulteration when viewed under white light. Group 4: Control Nonselected eggs. Microbiological Assay To reduce the possibility of factors other than cuticle quality affecting hatchability, total aerobic plate counts for bacteria on the egg surface were performed on 15 randomly selected eggs from each treatment group in each trial. The technique used for microbiological assay was based on the method described by Gentry and Quarles [10]. Eggs were aseptically placed into individual sterile plastic bags containing 10 ml of PBS. To facilitate recovery of bacteria, the eggshell surface was massaged in the plastic bag for 1 min, allowed to set for 5 min, and then massaged again for 1 min. The PBS solution in which the eggs were rinsed was then serially diluted to 10 3 with 1 ml of each serial dilution being placed on a petrifilm plate [11] to determine total aerobic bacterial counts. The petrifilm plates were then incubated at 31 C for 24 h. During the third trial, the petrifilm plates were held at 4 C for 48 h before bacteria were counted. Moisture Loss From each group, three flats containing 54 eggs each for a total of 162 eggs were randomly selected and weighed on 0 and 18 d of incubation to estimate the percentage moisture loss during incubation. Egg flats were identified to ensure that the same eggs were selected for each weighing. The d 18 weights were divided by d 0 weights and multiplied by 100 to obtain percentage moisture loss. 14-Day Mortality Thirty chicks from each group in each trial were randomly selected to evaluate differences in 14-d mortality. The chicks were reared as hatched (males and females together) in floor pens on softwood shavings with one pen provided for each treatment group. Bell drinkers and hanging feeders provided feed and water ad libitum. Natural ventilation and a combination of natural and incandescent lighting were utilized. Statistical Analysis All except hatchability data were analyzed using analysis of variance [12]. Differences among treatment means were estimated by contrasts. Differences were considered significant at P > 0.05. RESULTS AND DISCUSSION The increases in hatchability noted in the UV clean group in trials 2 (3+%) and 3 (4+%) are suggestive that the hatch of broiler breeder eggs may be improved when selected under UV light (Table 1, data not statistically analyzed). An error was made when counting chicks after hatch in trial 1, and therefore, these data are not included. Hatchery managers strive to maintain a uniform loss of moisture from eggs during incubation to ensure an even hatch. Further, the presence of
240 JAPR: Field Report TABLE 2. Moisture loss during incubation of clean and dirty eggs selected under normal (white) and UV A light Flat 1 Flat 2 Flat 3 Mean Trial 1 UV clean 14.0 13.9 14.4 14.1* UV stained 13.4 13.8 13.5 13.6 Farm dirty 14.3 14.8 13.5 14.2 Control 14.1 13.8 13.7 13.9 Trial 2 UV clean 12.0 11.8 12.5 12.1 UV stained 12.2 12.9 11.8 12.3 Farm dirty NT NT NT Control 11.1 12 12 11.7 Trial 3 UV clean 14.9 14.2 14.7 14.6 UV stained 14.7 14.4 14.8 14.6 Farm dirty 15.5 15.1 14.4 15.0 Control 15.3 15.0 13.8 14.7 A UV = ultraviolet; Flat = 54 eggs/flat (162 total eggs); Clean = no visible adulteration under white or UV light; Stained = no visible adulteration under white light but visible adulteration under UV light; Farm dirty = visible adulteration under white light; Control = randomly collected unselected eggs from same breeder flocks; NT = not tested. *Not significantly different. a healthy cuticle has been reported to play a role in this process [2]. However, results from this study did not demonstrate any significant differences among treatment groups within the three trials for percentage moisture loss (Table 2). It is well documented that a healthy cuticle will increase the probability of a successful hatch by reducing the chances that microbes will enter the egg, especially when the vehicle for bacterial penetration is water [1, 2, 3, 7, 10]. In this study, however, there were no significant differences in microbial counts on the eggshell surfaces among the four treatment groups (data not shown). Therefore, it would appear that use of UV light to measure eggshell cleanliness may not be appropriate for evaluating the level of aerobic bacteria on the shell surface. There were also no significant differences in the 14-d mortalities of chicks hatched from the four treatment groups. The portability and low-cost of the UV light may provide an easy method for hatcherymen to screen cuticle quality of large numbers of eggs without affecting their ability to be set, which is not true with other methods of evaluating cuticle quality. As would be expected, removal of eggs with cuticle defects prior to setting in this study appeared to have a positive effect on the hatchability of the eggs set. Results from this study further suggest that UV light may be used to screen large numbers of eggs to assess egg handling practices such as sanding or washing, as well as breeder flock health issues that may affect egg cuticle quality. More controlled studies are needed, however, to verify these field observations. CONCLUSIONS AND APPLICATIONS 1. UV light can be used to identify and remove eggs that have shell surface defects not visible under white light. 2. UV light does not appear to be a good way to measure the level of microbial contamination on the eggshell surface. 3. UV clean eggs had numerically higher percentages of hatchabilities than control, farm dirty, or UV stained eggs.
STANLEY ET AL.: BROILER HATCHING EGGS AND ULTRAVIOLET LIGHT 241 REFERENCES AND NOTES 1. Board, R. G., and N. A. Halls. 1973. The cuticle: A barrier to liquid and particle penetration of the shell of the hen s egg. Br. Poult. Sci. 14:69 97. 2. Board, R. G. 1966. Review article: The course of microbial infection of the hen s egg. J. Appl. Bacteriol. 29:319 341. 3. Peebles, E. D., J. Brake, and R. P. Gildersleeve. 1987. Effects of eggshell cuticle removal and incubation humidity on embryonic development and hatchability of broilers. Poult. Sci. 66:834 840. 4. Peebles, E. D., and J. Brake. 1986. The role of the cuticle in water vapor conductance by the eggshell of broiler breeders. Poult. Sci. 65:1034 1039. 5. Sparks, N. H. C., and R. G. Board. 1984. Cuticle, shell porosity, and water uptake through hen s eggshells. Br. Poult. Sci. 25:267 276. 6. Ball, R. F., V. Logan, and J. F. Hill. 1975. Factors affecting the cuticle of the egg as measured by intensity of staining. Poult. Sci. 54:1479 1484. 7. Sparks, N. H. C., and A. D. Burgess. 1993. Effect of spray sanitising on hatching egg cuticle efficacy and hatchability. Br. Poult. Sci. 34:655 662. 8. UV light source, Spectroline BIB-150P Series, 150-W unit with 365 nm long-wave UV, Spectronics Corporation, Westbury, NY. 9. Chick Master Incubator Company, Medina, OH. 10. Gentry, R. F., and C. L. Quarles. 1972. The measurement of bacterial contamination on egg shells. Poult. Sci. 51:930 933. 11. 3-M Microbiology Products Medical-Surgical Division, St. Paul, MN. 12. SAS Institute. 2000. JMP Statistics and Graphics Guide. Version 4.0.0. SAS Institute Inc., Cary, NC. Acknowledgment The advice and assistance of John Sims is greatly appreciated.