Eggshell Surface Research Articles

Survey of Enterobacteriaceae contamination of table eggs collected from layer flocks in Australia

In the present study, eggs from commercial caged layer flocks at different stages of lay in Australia were collected. Enterobacteriaceae populations from eggshell surface and eggshell pore were enumerated and these populations characterized using API® Rapid 20E strips. The eggshell surface, eggshell pore and egg internal content samples were also processed for the isolation of Salmonella and these isolates were tested for the presence or absence of several virulence genes (prgH, sopB, spiC, orfL, invA, sifA, sitC, misL). Results indicated that there was no significant difference in total Enterobacteriaceae count on the eggs of the flock from early, mid or late lay flocks. Enterobacteriaceae isolates were of 11 different genera which included: Cedecea, Citrobacter, Enterobacter, Escherichia, Klebsiella, Kluyvera, Leclercia, Pantoea, Salmonella, Serratia and Yersinia. Out of all 153 identified Enterobacteriaceae isolates, the Escherichia genus was reported most frequently (60.78%). Results also indicated that overall there were 4.51% (14/310) Salmonella positive pooled samples. In this study, 14 Salmonella strains were isolated, serotyping confirmed that 12 out of them were Salmonella Infantis and the 2 others were Salmonella enterica subsp. enterica serovar 4,12:d: Polymerase chain reaction results indicated that all Salmonella Infantis isolates harboured invA, misL, orfL, prgH, sifA, sitC, sopB and spiC genes which suggests that Salmonella Infantis strains isolated from eggshell surface may have the capacity to invade and survive in macrophages.

Comparison of Quality Parameters in Hen’s Eggs According to Egg Shell Color

The aim of this study was to evaluate some quality parameters of commercial hen’s eggs according to egg shell color. A total of 5,424 eggs were purchased from 113 supermarkets situated in 14 cities from the east-center of Entre Rios, Argentina; 3,475 were white eggshell and 1,949 eggs were brown eggshell. The values of Egg Weight (EW), Eggshell Weight (ESW), Eggshell Thickness (EST), % eggshell (% ES) and Total Shell Surface Area (TSSA) were greater in brown eggs than in white eggs. There was a significant positive correlation between EW and ESW and EW and TSSA, but EW had negative correlations with % ES. There were no significant differences in yolk (Y) and albumen (Al) pH between brown eggs and white eggs. The range of Yolk Color (YC) was 2-11 for white eggs and 2-14 for brown eggs. However, in general, eggs had similar YC in a package. This is the first report about the quality of commercial hen’s eggs from supermarkets in Argentina. Although eggs can belong to different hen's breeding systems and ages, there are some differences in the quality parameters studied between white and brown eggs.

Chicken Eggshells Remove Pb(II) Ions from Synthetic Wastewater

Disposal of eggshell wastes has become one of the most serious problems for poultry industries. Efficient utilization of eggshell wastes for other application may solve this problem. This study uses eggshell as an additive to precipitate divalent lead cations [Pb(II)] from aqueous solutions in the pH range of 2–5. Owing to high CaCO3 content, eggshell precipitates Pb(II) to form lead carbonates, which will then settle on the surface of eggshell. Scanning electron microscopy and energy dispersive X-ray analysis of the eggshell exposed to Pb(II) solutions indicated the deposition of lead carbonates on the surface of the eggshell. On reducing the particle size of an eggshell from 750 to 100 μm, the Pb(II) removal efficiency of it increased from 30.7 to 99.6% at an initial Pb(II) concentration of 1045 mg/L. It was found through isotherm experiments that eggshell powder (100 μm) was capable of sorbing 577 mg Pb/g compared with 154 mg Pb/g by eggshell particles (750 μm). The biosorption isotherms were well represented by either Langmuir or Toth models. For eggshell powder, the rate of kinetics was fast with 35 min sufficient to achieve Pb(II) biosorption equilibrium.

Huevos De Saurópodos Del Aptiano-Albiano, Formación Cerro Barcino (Patagonia, Argentina): Un Enigma Paleoambiental y Paleobiológico

SAUROPOD EGGS FROM THE APTIAN-ALBIAN CERRO BARCINO FORMATION, CHUBUT (PATAGONIA, ARGENTINA): A PALEOENVIRONMENTAL AND PALEOBIOLOGICAL ENIGMA. Here are described the first eggs and eggshell fragments from the Lower Cretaceous Chubut province. The two eggs and eggshell materials come from the Huaniman locality at the north-central region of Chubut. In this paper, we provide a paleontological description of the materials to infer their paleoenvironmental setting and we offer a morphological comparison with other South American dinosaur eggs. The egg materials were found in fine tuffaceous sandstone from a proximal floodplain deposits associated to sinuous and multi-episodic river channels, belonging to the Cerro Castaño Member (Aptian-Albian; Cerro Barcino Formation). The eggshell morphology is similar to that of megaloolithid eggs (a paraphyletic group in egg parataxonomy) known from Patagonia such as Auca Mahuevo, Neuquen, positively identified as sauropod titanosaurs on the basis of in ovo embryos, and Salitral Moreno, Rio Negro. However, the new specimens from Chubut exhibit structural features of the eggshell not previously reported such as a horizontal network of pore canals clearly visible near and beneath the outer nodular eggshell surface, similar in morphology but differently placed than in the Auca Mahuevo eggs —where it overlays the membrana testacea. This morphological feature and the 1.5 mm thick eggshell may illustrate a novel adaptation to this specific nesting environment. Although only two isolated eggs were found in Huaniman, this discovery suggests the potential for the existence of a more substantial nesting site in the area.

Calcium mobilization from the avian eggshell during embryonic development

The avian eggshell acts as the major source of calcium for embryogenesis in bird. Using scanning electron microscopy, the inner eggshell surface was analysed before and after embryonic development and its accompanying calcium removal. This was done in eggs from two bird species with different growth rates and modes of development, the precocial Japanese quail Coturnix japonica and the altricial starling Sturnus vulgaris. Next, enzyme histochemistry was used to localize carbonic anhydrase in the extra-embryonic chorioallantoic membrane to provide support for the hypothesis that calcium may be released from the eggshell by means of acidification through the action of carbonic anhydrase. However, neither in the precocial quail nor in the altricial starling could any staining for carbonic anhydrase be detected. These results lead us to the conclusion that the role of carbonic anhydrase in embryonic calcium mobilization from the avian eggshell remains unclear.

Effects of Inclusion of Selenium-Enriched Yeast in the Diet of Laying Hens on Performance, Eggshell Quality, and Selenium Tissue Deposition

The aim of this study was to evaluate the bioavailability of ingested selenium (Se) yeast in laying hens and its effects on performance, eggshell quality, and tissue Se distribution. Forty-eight ISA brown laying hens were divided into 3 treatment groups: Group C, fed a basal diet containing 0.11 mg Se/kg of feed; Group SS, fed a basal diet plus 0.4 mg/kg of feed of Se from sodium selenite; and Group SY, fed a basal diet plus 0.4 mg/kg of feed of Se from selenium yeast. Feed intake, egg mass ratio, and production performance were not affected by Se supplementation, regardless of the Se source. Egg weight (+3.61% and +2.95%), eggshell weight (+4.26% and +5.38%), and eggshell surface (+2.43% and +1.96%) were higher (P<0.05) in SS and SY than C, whereas breaking strength was increased in SY (P<0.01). Breast muscle, liver and skin Se levels were higher in SY than in C, while kidney Se content was higher in SS hens. Eggs from SY had higher Se levels than SS. Blood metabolites were not affected in SS or SY groups than C. A higher Se level was detected in eggs and breast muscle of SY hens (P<0.05). Seleniumenriched eggs and edible tissues from organic Se sources in poultry diet could improve antioxidant status in humans and reduce possible Se deficiency-related diseases.

Beç Tavuğu Yumurtalarında İç ve Dış Kalite Özellikleri Arasındaki Fenotipik Korelasyonların Belirlenmesi

Summary In this study, it was aimed to determine the internal and external quality traits of the Guinea fowl eggs as well as the phenotypic correlation among the these traits. Totally 100 Guinea fowl eggs were collected in three sequential days were used for this study. The birds were housed at Poultry Research Unit of the Department of Animal Science, Faculty of Agriculture, University of Akdeniz. Values of egg weight, egg length, egg width, eggshape index, eggshell weight, eggshell ratio, eggshell thickness, eggshell surface area, unit surface area and egg volume were determined as 40.14 g, 49.47 mm, 37.89 mm, 0.76%, 6.48 g, 16%, 0.54 mm, 65.69 cm 2 , 0.11 g/cm 2 , respectively. In addition, values of yolk weight, yolk height, yolk width, yolk index, yolk ratio, albumen height, albumen width, albumen length, albumen weight, albumen index, yolk/albumen ratio and haugh unit were found as 13.58 g, 14.99 mm, 40.64 mm, 37%, 33%, 4.77 mm, 62.97 mm, 80.07 mm, 21.62 g, 6.7%, 68% and 74.97%, respectively. According to the results determined in this study, all most all external quality traits of the egg were changed at the significant levels depending on the change occurred in the egg weight. The results indicated that egg weight influences external egg quality traits of quinea fowl. The positive correlations obtained among the egg quality traits indicated that they can be improved phenotypically through selection.

Eggshell Structure of the Predator Harpactor angulosus (Hemiptera: Reduviidae)

Abstract Structural analyses of eggs from Reduviidae may provide important data to establish relationships among the representatives of this family. This study described the eggshell morphology of Harpactor angulosus (Lepeletier and Serville 1825) (Reduviidae: Harpactorinae). Eggs of H. angulosus were analyzed using a stereoscopic microscope and a scanning electron microscope. Eggs of H. angulosus are oval-shaped and slightly flattened laterally, with an eggshell surface with several pores and a rounded posterior pole. The anterior pole has a poorly pronounced neck region, without formation of the collar and a small chorionic rim and with an incomplete anterior appendage without connection between the veil and opercular projections. Aeropyles have a tube-like aspect, arising in the middle region of the veil and extending until the sealing bar. Eggs of H. angulosus were similar to those of other Harpactorinae, but with differences in length, width, anterior appendage characteristics, and eggshell invaginations.

Comparison of eggshell porosity and estimated gas flux between the brown‐headed cowbird and two common hosts

The brown‐headed cowbird Molothrus ater is a brood‐parasite that lays eggs in nests of a wide range of host species, including the closely‐related red‐winged blackbird Agelaius phoeniceus and the dickcissel Spiza americana. Although cowbird eggs have accelerated development and hatch sooner than similar‐sized host eggs, this development takes place within a thickened eggshell that could impede gas flux to the developing embryo. We tested the hypothesis that the accelerated development of the cowbird embryo relative to hosts is enabled by an increase in eggshell porosity that allows increased fluxes of respiratory gases to and from the developing embryo. We found cowbird eggshell thickness was significantly greater than the eggshells of these two common hosts. Although the number of pores per egg was similar among all three species, the total pore area per egg in cowbirds was significantly greater than that of either host, despite having a smaller eggshell surface area than the red‐winged blackbird. Cowbird egg pore area was 1.9×larger than that of the red‐winged blackbird. Cowbird eggshells had a significantly greater gas flux than those of the red‐winged blackbird and the dickcissel. When conductance was normalized to published values of egg mass, cowbird eggs had a higher mass‐specific conductance than red‐winged blackbird or dickcissel eggs. These results are consistent with the hypothesis that the rapid development of brown‐headed cowbird embryos is facilitated by increased eggshell porosity, and that changes in eggshell porosity represent an adaptation that enables cowbird eggs to hatch earlier than equivalently‐sized host eggs.

Comparative evaluation of air cell and eggshell temperature measurement methodologies used in broiler hatching eggs during late incubation ,

The current study was conducted to compare and contrast the uses of 2 devices (temperature transponder or infrared thermometer) and their locations (inner air cell membrane or outer eggshell surface) in Ross × Ross 708 broiler hatching eggs. The air cells of 14 embryonated and 10 nonembryonated eggs were implanted with temperature transponders on d 13.5 of incubation. Likewise, for these same eggs, eggshell surface temperature was detected with the use of transponders and an infrared thermometer. Temperatures were recorded every 12 h between 14.5 and 18 d of incubation, and graphs and corresponding regression values were used to track the temperatures over these time periods. The temperature readings using all methods in embryonated and nonembryonated eggs were positively correlated. In nonembryonated eggs, temperatures in the air cell and on the eggshell surface using transponders were higher than those on the eggshell surface using an infrared thermometer. Mean air cell temperature readings of embryonated eggs using transponders were higher than those of the eggshell, as determined with the use of transponders or an infrared thermometer. Furthermore, the differences in air cell temperature using transponders and eggshell temperature using an infrared thermometer in embryonated eggs increased with embryonic age. These readings confirmed increased embryo heat production during the incubational period examined. It was further concluded that when compared with actual embryo body temperatures determined in previous studies, the use of transponders in the air cells of broiler hatching eggs detected a higher and closer temperature than eggshell surface temperature. It is suggested that the air cell transponders in embryonated eggs circumvented the confounding effects of the thermal barrier properties of the eggshell and the flow of air across its surface.

Recovery of Salmonella from eggshell wash, eggshell crush, and egg internal contents of unwashed commercial shell eggs in Australia

The experiment was conducted to study the prevalence of Salmonella spp. on the eggshell surface, eggshell membranes or pores, and in egg internal contents from unwashed eggs collected from commercial caged layer farms in Australia. Eggshell rinsate, shell crush, and egg internal contents (yolk and albumen) of eggs were processed for Salmonella spp. Salmonella Infantis and Salmonella subspecies 1, serotype 4,12:d were isolated from the eggshell surface. Salmonella spp. were not isolated from any eggshell crush or egg internal contents. It would appear that the occurrence of Salmonella in the Australian egg industry is low.

Reduction of high pathogenicity avian influenza virus in eggs from chickens once or twice vaccinated with an oil-emulsified inactivated H5 avian influenza vaccine

The negative impact of high pathogenicity avian influenza virus (HPAIV) infection on egg production and deposition of virus in eggs, as well as any protective effect of vaccination, is unknown. Individually housed non-vaccinated, sham-vaccinated and inactivated H5N9 vaccinated Once or Twice adult White leghorn hens were challenged intranasally/intratracheally 3-weeks post-vaccination with H5N2 HPAIV. The non-/sham-vaccinated layers experienced 100% mortality (0% survivability) within 3–4 days post-challenge (DPC), and major changes to reproductive parameters including precipitous drops in egg production (79–0% in <5 days), production of soft and thin-shelled eggs, and deposition of virus in albumin and yolk, and on the egg shell surface of 53% of eggs. By comparison, the three H5-vaccinated groups had 83%, 100% and 100% survivability after challenge; the two H5-vaccinated Once hens that died had low pre-challenge HI titers (GMT=16). H5-vaccinated Once or Twice groups maintained egg production after challenge (63%), but there was a mild and significant reduction in egg production as compared to pre-challenge egg production (79%). H5-vaccinated groups had reduced number of virus contaminated eggs (28%), and in most groups, reduced quantity of virus in contaminated eggs compared to non-/sham-vaccinated groups. No HPAIV-positive eggs were laid on or after 5 DPC. In conclusion, HPAIV infection had major negative impact on egg production and other reproductive parameters. H5-vaccination Once or Twice prevented declines in egg production after HPAIV challenge, reduced number of virus-infected eggs, and typically reduced the titer of virus in internal contents and on eggshell surface.

PREVALENCE OF SOME ANTIBIOTIC RESISTANT STRAINS OF SALMONELLAE IN COMMERCIAL TABLE EGGS IN PORT-SAID CITY.

Multi-drug resistant Salmonellastrains have emerged, presumably due to the extensive use of antimicrobial agents both in human and animals. In veterinary practice, antibiotics are used in livestock production, disease prevention and as growth-promoting feed additives. In the present study, the occurrence of Salmonellain local chicken eggs and their pattern of antibiotic resistance were determined. One hundred and forty chicken egg samples - collected from different locations of Port-Said City - were analyzed and Salmonella spp . detected in 3.6% of the samples. Among all presumptive Salmonellaisolates,theisolates were confirmed as Salmonella Typhimurium(40%),Salmonella agona (20%) and Salmonella derby (40%) on the basis of serotyping and biochemical analysis. These isolates were subjected to susceptibility test against 9 antimicrobial disks. All the isolates were sensitive (100%) to doxycycline hydrochloride, chloramphenicol and trimethoprim-sulphamethoxazole. The highest percentage of resistance (100%) was found to erythromycin. Resistance against, streptomycin (20%), and penicillin G. (40%) was also found. One isolate of theSalmonella Typhimurium serovars (50%) showed resistance for streptomycin, nalidixic acid, oxytetracycline and penicillin G., while the other Salmonella typhimurium isolate (50%) showed high susceptibility for the same 4 antimicrobial drugs. Nearly similar results were shown for the isolated Salmonella derby, were one isolate (50%) showed high susceptibility for neomycin and oxytetracycline, while it was resistant to penicillin G. The otherSalmonella derby isolate (50%) showed intermediate susceptibility for neomycin and oxytetracycline, while it was highly sensitive for penicillin G. Salmonellaisolated from egg shell surfaces had more antimicrobial resistance than that of the egg contents. The present study suggested that, poultry eggs are potential reservoir of antibiotic resistant Salmonellae. The public health hazard of this microorganism, as well as recommended measures to improve quality status of table eggs were discussed.

Effect of breeder age on eggshell thickness, surface temperature, hatchability and chick weigh

Two experiments were carried out to study the effect of breeder age on incubation parameters (hatchability, eggshell thickness, egg surface temperature and chick weight). In Exp. 1, fertile eggs (30- and 60-wk-old breeders) were incubated at three different temperatures (36.8, 37.8 and 38.8 ºC). Eggshell surface temperature was measured by attaching a thermocouple to the shell and data were collected in a datalogger every ten minutes. This study was conducted according to a 3 x 2 factorial design (three temperatures and two breeder ages). Data revealed that eggshell surface temperature changed according to incubation temperature, with the main increase occurring between 10 and 13 days of incubation, and that the maximum increase in eggshell surface temperature was not higher than +0.6 ºC, irrespective of incubator temperature. The incubator temperature affected total incubation period and hatchability (%) at 38.8 ºC, independent of breeder age. Heavier eggs resulted in heavier chicks, irrespective of incubator temperature. In Exp 2, the eggs (30- and 60-wk-old breeders) were incubated at 37.8 ºC and eggs characteristics (weight, specific gravity, total hatchability and chicks weight) were evaluated according to a randomized experimental design. The data showed that breeder age affected eggshell thickness and chick weight (heavier eggs resulted in heavier chicks), but not specific gravity, eggshell surface temperature or hatchability. The findings of this study revealed that hatchability can be influenced by incubation temperature, but not by the breeder age. Breeder age can affect eggshell thickness, egg weight and eggshell surface temperature, but not specific gravity.

Evaluation of Two Laying Systems (Floor vs. Cage) on Egg Production,Quality, and Safety

A study was conducted to evaluate the effects of two laying systems (floor versus cage) on egg production, egg quality, and microbial safety. One hundred and eighty 42 wk old laying hens were separated into two groups of 90 hens each, and in laying cages anhoused d a floor laying system. Eggs from the hens were collected for 2 weeks, and hen-day egg production, egg quality (whole egg, albumen, yolk, and shell weights), sale ability, and marketability were measured. Total bacteria counts on the egg shell surface were also enumerated at 0, 4, and 8 h after laying. Results indicated that hen-day egg production by hens in the cage system (95%) was significantly (P<.05) higher than production by hens from the floor system (85%), but there was no significant differences in egg weight, albumen, yolk, or shell weights. Hens housed in the cage laying systems produced significantly (P<.05) more marketable eggs (95%) than hens housed in the floor laying system (89%). Significantly (P<.05) more unsaleable eggs were also produced by hens in the floor laying system (11%) than in the cage system (4%). Bacteria counts on egg shells from hens of the cage laying system were significantly (P<.05) lower at 0 and 4 h after laying (4.02 and 5.90 log cfu/ml, respectively) than counts on shells of eggs from the floor laying system (6.58 and 7.25 log cfu/ml, respectively). There was no significant difference in contamination of eggs collected 8 h after laying. Findings indicate hens housed in cages produce more eggs with higher quality and less bacterial contamination than hens house in floors laying systems.

WATER VAPOR CONDUCTANCE OF THE LOWER CRETACEOUS DINOSAURIAN EGGS FROM SANAGASTA, LA RIOJA, ARGENTINA: PALEOBIOLOGICAL AND PALEOECOLOGICAL IMPLICATIONS FOR SOUTH AMERICAN FAVEOLOOLITHID AND MEGALOOLITHID EGGS

The water vapor conductance (GH2O) of the neosauropod eggs from the Lower Cretaceous Sanagasta nesting site in La Rioja Province, Argentina, was examined and compared with other Cretaceous Argentinean oological material. The 2900 mgH2O/day·Torr GH2O of the Sanagasta eggshells confirms an extremely moist nesting environment and supports field observations of dug-out nests in a geothermal setting. The observed thinning of the outer eggshell surface during incubation increases gas conductance and concomitantly decreases eggshell mechanical resistance during the late ontogenetic stages, thus facilitating embryonic development and hatching. The Sanagasta and Entre Rios Province faveoloolithid eggs display the highest and comparable GH2O values and share several morphological and diagenetic characters, indicating comparable nesting strategy in geothermal settings. However, the faveoloolithid Yaminue and La Pampa Province specimens cluster together with lower GH2O values closer to the megaloolithid eggs. The GH2O of the megaloolithid egg Megaloolithus patagonicus was reconsidered and new results are now congruent with other reported megaloolithid GH2O values. Additionally, we hypothesize that Y-shaped pore canals of M. patagonicus, which upper sections reach only the top third or half eggshell thickness and, a wider section in the middle would not compromise the overall egg mechanical resistance like vertical pores connecting directly the outer to the inner eggshell surfaces. Such pore spatial arrangement and geometry would enhance, as the eggshell thins during incubation, a greater GH2O, GO2 and GCO2 and facilitate embryonic development in high moisture nesting contents. Overall, data suggests that neosauropod nesting and brooding behaviors were dependent on elevated moisture nesting environments.

Evolution of avian eggshell structure

Data are presented suggesting that birds have evolved eggs with shells containing different structures (numbers of mammillae per unit of inner eggshell surface area, i.e., mammillary densities) to cope up with different calcium requirements imposed by different growth rates and modes of development. Precocial bird species grow slowly, but have high mammillary density, while altricial bird species grow rapidly, but have low mammillary density. These results suggest an adaptation associated with growth rate and mode of development and show, moreover, that the mammillary layer is indicative of the breeding biology of the bird.

Thermal inactivation of avian influenza virus and Newcastle disease virus in a fat-free egg product.

High-pathogenicity avian influenza (HPAI) virus, low-pathogenicity avian influenza (LPAI) virus, virulent Newcastle disease virus (vNDV) and low-virulent Newcastle disease virus (lNDV) can be present on the eggshell surface, and HPAI viruses and vNDV can be present in the internal contents of chicken eggs laid by infected hens. With the increase in global trade, egg products could present potential biosecurity problems and affect international trade in liquid and dried egg products. Therefore, the generation of survival curves to determine decimal reduction times (D(T)-values) and change in heat resistance of the viruses (z(D)-value) within fat-free egg product could provide valuable information for development of risk reduction strategies. Thermal inactivation studies using A/chicken/Pennsylvania/1370/83 (H5N2) HPAI virus resulted in D(55)-, D(56)-, D(56.7)-, D(57)-, D(58)-, and D(59)-values of 18.6, 8.5, 3.6, 2.5, 0.4, and 0.4 min, respectively. The z(D)-value was 4.4 °C. LPAI virus A/chicken/New York/13142/94 (H7N2) had D(55)-, D(56.7)-, D(57)-, D(58)-, D(59)-, and D(60)-values of 2.9, 1.4, 0.8, 0.7, 0.7, and 0.5 min, respectively, and a z-value of 0.4 °C. vNDV avian paramyxoviruses of serotype 1 (AMPV-1)/chicken/California/212676/2002 had D(55)-, D(56)-, D(56.7)-, D(57)-, D(58)-, and D(59)-values of 12.4, 9.3, 6.2, 5, 3.7, and 1.7 min, respectively. The z(D)-value was 4.7 °C. lNDV AMPV-1/chicken/United States/B1/1948 had D(55)-, D(57)-, D(58)-, D(59)-, D(61)-, and D(63)-values of 5.3, 2.2, 1.1, 0.55, 0.19, and 0.17 min, respectively, and a z(D)-value of 1.0 °C. Use of these data in developing egg pasteurization standards for AI and NDV-infected countries should allow safer trade in liquid egg products.

Characterization of Antibiotic Resistant &lt;i&gt;Salmonella spp&lt;/i&gt; Isolated from Chicken Eggs of Dhaka City

In present study, the occurrence of Salmonella in local chicken eggs and their pattern of antibiotic resistance were determined. 100 egg samples collected from different locations of Dhaka city were analysed and Salmonella spp were found in 8% of the samples. Among all presumptive Salmonella isolates, 8 isolates were confirmed as Salmonella enterica subsp. salamae (4%), Salmonella enterica subsp. indica (1%), Salmonella Paratyphi-A (1%), Salmonella bongori (1%) and Salmonella Choleraesuis (1%) on the basis of serotyping and biochemical analysis. These isolates were subjected to susceptibility test against 10 antibiotic disks. All the isolates were found chloramphenicol sensitive. The highest percentage of resistance (87.5%) was found to amoxicillin and ampicillin. Resistance against erythromycin, cephalexin, doxycycline hydrochloride, ceftazidime, doxycycline and nalidixic acid was also found significant ranging from 25% to 62.5%. Salmonella isolated from egg shell surface were found more antibiotic resistant than that of egg yolk and white. The present study suggests that poultry eggs are potential reservoir of antibiotic resistant Salmonellae.Keywords: Egg; Salmonella; Characterization; Antibiotic resistance.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i1.6109 J. Sci. Res. 3 (1), 191-196 (2011)

Evaluation of a glossmeter for studying the surface appearance of avian eggs

Gloss is a striking characteristic of avian eggshells that may affect both egg recognition and clutch predation. Previously, gloss has proved difficult to quantify objectively. Newly developed handheld glossmeters seem to offer a solution. We evaluated the use of a handheld glossmeter for a range of different eggshell surfaces, shapes and sizes. In all cases, their measurements were strongly affected by egg size and seem currently suitable only for very large eggs; the size of Rhea sp. eggs or larger. A glossmeter may, however, still prove useful to quantify other structures in comparative ornithology, with flat surfaces such as feathers or nest material.