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Typescript (photocopy) Includes bibliographical references (leaves 223-249) Investigates the relationship between feed conversion efficiency and physiological variables among several lines, generations and breeds of hen fed ad libitum or on restricted amounts of feed; and, of the consequences to egg shell quality of restriction of food supplied to laying hens.

Two experiments were conducted to evaluate the combination of hydrogen peroxide (H2O2) and ultraviolet light (UV) as an alternative eggshell sanitization procedure for shell egg processing. In each experiment, two cases of eggs (720 total) were collected at a commercial inline egg production facility. To assure egg uniformity, only eggs between 57 and 62 g were collected from a single hen house. Half of the eggs (360) were commercially processed (washer and sanitizing rinse) following normal procedures outlined by the U.S. Department of Agriculture (USDA) for shell egg processing (control group). The other half of the eggs (360) were washed as normal but without the sanitizing rinse. These eggs were then treated with 3 percent H2O2 and UV light (treated group). The treatment consisted of spraying the eggs with 3 percent H2O2 over the entire shell surface followed immediately by exposure to UV light for 5 s in an enclosed chamber equipped with germicidal lamps (UV-C). This treatment was performed twice. Eggshell aerobic plate counts (APC), eggshell breaking strength and thickness, albumen height and pH, Haugh units, and yolk color were measured after 1, 15, 30, 45, and 60 days of storage. On d 15 and 45, sensory evaluation of scrambled egg samples was conducted to determine if consumers could detect a difference between treatment groups using a triangle test. Results indicate APC for treated eggs were significantly lower than the control eggs for all sampling days in Experiment 1. However, due to low initial APC in the control eggs on d 1 of Experiment 2, no significant differences were observed for APC between control and treated eggs during storage. No consistent differences were found for eggshell and interior quality measures with the exception of albumen pH. Albumen pH was significantly higher in treated eggs than control on d 45 and 60 and d 1, 15, and 45 of Experiment 1 and 2, respectively, with only an average difference of 0.04 pH. In the sensory evaluation, only 33.5 percent of the participants correctly differentiated between the control and treated eggs. Data from this study suggests that H2O2 and UV light can be used as an alternative eggshell sanitizing procedure without impacting eggshell or internal egg quality.

Eggshell of the African Ostrich, Struthio camelus, frequently occurs in African archaeological sites, some of which are beyond the limit of radiocarbon dating. In order to date those sites beyond the range of ¹⁴C dating using amino acid geochemistry, an understanding of the reaction kinetics governing amino acid chemistry must be achieved. The integrity of the eggshell matrix provides an excellent medium to investigate the kinetics of protein hydrolysis, amino acid decomposition, and isoleucine epimerization. Mathematical equations are derived from high temperature simulations of time and well-dated sites at ambient temperatures to determine rate constants for the reactions to a D/L ratio of 1.0. The reactions studied are Free and Total isoleucine epimerization, "classical" and "extended" hydrolysis, and the change in concentrations of free, bound, and total amino acids. Arrhenius plots aided in deriving the equations for each method which are then applied to predict kinetic parameters. Temperatures can be predicted within a 2°C range and time within 15% of its actual value if the appropriate method is used.

Thesis (MTech. degree in Agriculture.)--Tshwane University of Technology, 2011. / A ten week feeding trial was done with layer hens from 18 weeks of age to investigate whether cowpeas can be used as a single protein source for egg production.

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The character and magnitude of predation by Calliopius laeviusculus on the intertidal eggs of capelin (Mallotus villosus) were examined. Average endobenthic densities at Bryant's Cove (NFLD) in 1988 for both amphipods and capelin eggs during capelin egg development (June 17-August 8) were 0.78 amphipods cm$ sp{-2}$ and 62 eggs cm$ sp{-3}$ (750 cm$ sp{-2}$) respectively. At this average capelin egg density, laboratory results suggest that, on a daily basis, only gut capacity and clearance time limit amphipod predation on eggs. In situ, C. laeviusculus biomass closely tracked capelin egg biomass indicating that reproductive cues operating for both capelin and amphipods may be linked. In 1988, ca. 50% of the annual production of C. laeviusculus resulted from predation on capelin eggs. Given the bioenergetic demands of C. laeviusculus and the annual variation in capelin spawning effort, the temporal overlap between capelin eggs and high amphipod biomass could result in predation mortalities ranging from ca. 15-30% of the total capelin egg deposition.