Effects of ultraviolet irradiation of the microbiology and hatchability of broiler hatching eggs

Abstract

Hatchery sanitation is an important step in an overall pathogen reduction program for integrated broiler operations. An important part of hatchery sanitation starts with the sanitation of hatching eggs. These eggs are the major source of organic material entering the hatchery and may harbor pathogenic organisms. Egg sanitation is also critical to the production of high quality day-old broiler chicks. Since the discontinuation of the use of formaldehyde fumigation to sanitize hatching eggs, a great deal of research has been conducted to find a suitable replacement. The germicidal effects of ultraviolet (UV) light (radiation) of wavelength 254 nm (UV-C) is well documented. It has been shown to be highly effective at reducing bacteria, viruses, yeasts, molds and fungi on a variety of substances and surfaces including eggshells. Therefore, studies were conducted to test the effects of UV irradiation on microbial populations on eggshells and the hatchability of broiler hatching eggs. High intensity UV light (>14 mW/cm²) was utilized to sanitize incubator flats of 42 hatching eggs in an enclosed cabinet. Laboratory trials were first conducted with broiler hatching eggs to access the effects of UV light on the conductance of the treated eggs and to screen for any detrimental effects on embryo viability or hatchability. No significant differences were found for eggshell conductance, embryo mortality, hatch of fertile eggs (HFE) or internal microbial contamination of eggs. Larger field studies were then conducted at commercial broiler breeder facilities to evaluate the effects of UV irradiation in a commercial setting. Hatchability of UV-treated eggs was significantly reduced in field trial 1, but was significantly improved in trial 2. Microbial contamination of dead embryos and meconium samples from day-old chicks were also evaluated. Significant reductions in numbers of contaminated eggs for UV-treated eggs compared to controls were observed in various trials. It is concluded that UV irradiation of hatching eggs may be a feasible alternative to formaldehyde fumigation.