Background: The gut microbiota plays an important role in the colonisation resistance and invasio... more Background: The gut microbiota plays an important role in the colonisation resistance and invasion of pathogens. Salmonella Typhimurium has the potential to establish a niche by displacing the microbiota in the chicken gut causing continuous faecal shedding that can result in contaminated eggs or egg products. In the current study, we investigated the dynamics of gut microbiota in laying chickens during Salmonella Typhimurium infection. The optimisation of the use of an infeed probiotic supplement for restoration of gut microbial balance and reduction of Salmonella Typhimurium load was also investigated.
Chicken meat can potentially become contaminated with bacteria at the processing plant. In Austra... more Chicken meat can potentially become contaminated with bacteria at the processing plant. In Australia, there is currently a lack of knowledge on the parameters and indications of use of non-chlorine based treatments in the chicken meat processing plants. Chlorine is widely used as a sanitizer in Australian chicken meat processing plants but due to occupational health and safety concerns and consumer perception, there is a need to identify alternative sanitizers. This study aimed to assess the efficacy of four different sanitizers in reducing the microbial load from naturally contaminated chicken meat carcasses collected from the processing plants in South Australia. There was a significant variation in a load of Campylobacter and total viable count (TVC) between samples collected from two different processing plants and within carcass batches collected from the same plant that was tested during the study. All sanitizers generally reduced the load of Campylobacter on chicken meat carcasses. Treatment with acidified sodium chlorite significantly reduced the level of Salmonella enterica serovars at all temperatures tested during this study. These findings are helpful to the industry for selection of the appropriate sanitizers. Findings are also useful for the regulatory authorities in Australia for providing approval for the use of sanitizers.
The major pigment in eggshells of brownegg
laying hens is protoporphyrin IX, but traces of
bilive... more The major pigment in eggshells of brownegg laying hens is protoporphyrin IX, but traces of biliverdin and its zinc chelates are also present. The pigment appears to be synthesized in the shell gland. The protoporphyrin IX synthetic pathway is well defined, but precisely where and how it is synthesized in the shell gland of the brown-egg laying hen is still ambiguous. The pigment is deposited onto all shell layers including the shell membranes, but most of it is concentrated in the outermost layer of the calcareous shell and in the cuticle. Recently, the genes that are involved in pigment synthesis have been identified, but the genetic control of synthesis and deposition of brown pigment in the commercial laying hen is not fully understood. The brown coloration of the shell is an important shell quality parameter and has a positive influence on consumer preference. The extent of pigment deposition is influenced by the housing system, hen age, hen strain, diet, stressors, and certain diseases such as infectious bronchitis. In this article, the physiological and biochemical characteristics of the brown pigment in commercial brown-egg layers are reviewed in relation to its various functions in the poultry industry.
Eggs were collected from HyLine brown flocks aged 33, 50 and 67 wk. Thirty eggs from each flock w... more Eggs were collected from HyLine brown flocks aged 33, 50 and 67 wk. Thirty eggs from each flock were analyzed to determine the reliability of MST cuticle blue stain as an indicator of the presence of cuticle and the effective removal of cuticle by use of an EDTA solution. Another 30 eggs were processed for the quantification of protoporphyrin IX (PP IX) from the eggshell with and without the presence of cuticle. L*a* components of the color space system were significantly different among the age groups. There was a high degree of correlation between the extent of MST cuticle blue staining and the amount of cuticle on the egg shell as recorded by scanning electron microscopy. PP IX pigment was quantified by spectrophotometric analysis of digested eggshell solutions. The average amount of PP IX in the shell without cuticle (8.046 x 10-8 g/g of shell) was higher than the amount present in cuticle (1.669 x 10-8 g/g of shell). The amount of PP IX in the cuticle of 1g of shell in the 33 wk eggs was significantly lower than for eggs from the 50 wk and 67 wk flocks whereas, in the shell without cuticle, it was not significantly different among flock ages. PP IX in cuticle, as a percentage of total PP IX in shell was 13% in 33 wk, 20 % in 50 wk and 18 % in 67 wk eggs.
Eggshells were collected at days 1, 3 and 5 post infection from unvaccinated Isa Brown laying hen... more Eggshells were collected at days 1, 3 and 5 post infection from unvaccinated Isa Brown laying hens challenged with infectious bronchitis virus (IBV) strains N1/88 or T as well as from a control group of unvaccinated hens. Shell reflectivity (%) and shell colour L* were measured on shells with and without cuticle and were further processed for the quantification of protoporphyrin IX (PP IX) from the same shell with and without the presence of cuticle. Shell reflectivity and shell colour L* values for the control eggs were significantly lower (P < 0.0001) compared to those from hens challenged with both strains of IBV and were also significantly lower on day 1 compared to days 3 and 5 p.i. The PP IX was quantified by spectrophotometric analysis of digested eggshell solutions. The mean PP IX in 1g of shell with and without cuticle was significantly higher on day 1 compared with days 3 and 5. The amount of PP IX in the shell decreased with time post infection for the IBV groups. The amount of PP IX in whole eggshell was highest for the control group and lowest for the T strain group, with the N1/88 group intermediate.
The cuticle is the outermost layer, deposited on the palisade layer of the eggshell
during the la... more The cuticle is the outermost layer, deposited on the palisade layer of the eggshell during the last 1.5-2 hr of eggshell formation in utero. It is a non-calcified, thin, water-insoluble layer composed mainly of glycoproteins with some carbohydrate and fat constituents. The cuticle functions as a protective layer which regulates gaseous exchange across the shell, acts as a first line of defence against microbial penetration across the eggshell and is associated with termination of calcite crystal growth during shell formation. The extent of cuticle deposition is influenced by hen age and strain. The physiological and microbiological characteristics of the hen eggshell cuticle are reviewed in relation to its protective functions.
Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week inte... more Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week intervals and divided into 4 different groups after candling and scoring for incidence of translucency. A significant effect of production system and flock age was recorded for all the egg quality variables except shell breaking strength (BSN), while interaction between the two was significant for all the egg quality variables except shell deformation. The amount of cuticle on the egg shell was estimated using a Konica Minolta spectrophotometer after MST Cuticle Blue staining of eggs. Statistically significant effects as well as interactions were recorded for production system and age for L*a*b* values. Shell ultra structural features were scored using Scanning Electron Microscope (SEM) following plasma etching of shell pieces. Shell ultra structural variables significantly affected by production system and age were mammillary cap size, cap quality, early fusion, type B bodies and cuffing, while interaction between production system and flock age was recorded for mammillary cap size, late fusion, alignment, type B bodies, cubic cone formation, cuffing and changed membrane. The microbiological studies showed a statistically significant effect of production system and flock age for total bacterial count (TBC) on egg shells and interaction between production system and flock age for TBC and total Enterobacteriaceae count (TEC) on egg shells. A significant effect was also recorded for flock age for TBC and TEC on egg shells and in shell pores in both production systems. All the eggs were negative for Salmonella spp.
The vast majority of eggs in Australia are washed prior to packing to remove dirt and fecal mater... more The vast majority of eggs in Australia are washed prior to packing to remove dirt and fecal material and to reduce the microbial contamination of the egg shell. The egg contents can be an ideal growth medium for microorganisms which can result in human illness if eggs are stored improperly and eaten raw or undercooked, and it is estimated that egg-related salmonellosis is costing Australia $44 million per year. Egg shell characteristics such as shell thickness, amount of cuticle present, and thickness of individual egg shell layers can affect the ease with which bacteria can penetrate the egg shell and washing could partially or completely remove the cuticle layer. The current study was conducted to investigate the effects of egg washing on cuticle cover and effects of egg shell quality and cuticle cover on Salmonella Infantis penetration of the egg shell. A higher incidence of unfavorable ultrastructural variables of the mammillary layer such as late fusion, type B bodies, type A bodies, poor cap quality, alignment, depression, erosion and cubics were recorded in Salmonella penetrated areas of egg shells. The influence of egg washing on the ability of Salmonella Infantis on the egg shell surface to enter the egg internal contents was also investigated using culture-based agar egg penetration and real-time qPCR based experiments. The results from the current study indicate that washing affected cuticle cover. There were no significant differences in Salmonella Infantis penetration of washed or unwashed eggs. Egg shell translucency may have effects on Salmonella Infantis penetration of the egg shell. The qPCR assay was more sensitive for detection of Salmonella Infantis from egg shell wash and internal contents than traditional microbiological methods. The agar egg and whole egg inoculation experiments indicated that Salmonella Infantis penetrated the egg shells. Egg washing not only can be highly effective at removing Salmonella Infantis from the egg shell surface, but also allows subsequent trans-shell and trans-membrane penetration into the egg. Consequently, it is important to prevent recontamination of the egg after washing.
Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week inte... more Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week intervals and divided into 4 different groups after candling and scoring for incidence of translucency. A significant effect of production system and flock age was recorded for all the egg quality variables except shell breaking strength (BSN), while interaction between the two was significant for all the egg quality variables except shell deformation. The amount of cuticle on the egg shell was estimated using a Konica Minolta spectrophotometer after MST Cuticle Blue staining of eggs. Statistically significant effects as well as interactions were recorded for production system and age for L*a*b* values. Shell ultra structural features were scored using Scanning Electron Microscope (SEM) following plasma etching of shell pieces. Shell ultra structural variables significantly affected by production system and age were mammillary cap size, cap quality, early fusion, type B bodies and cuffing, while interaction between production system and flock age was recorded for mammillary cap size, late fusion, alignment, type B bodies, cubic cone formation, cuffing and changed membrane. The microbiological studies showed a statistically significant effect of production system and flock age for total bacterial count (TBC) on egg shells and interaction between production system and flock age for TBC and total Enterobacteriaceae count (TEC) on egg shells. A significant effect was also recorded for flock age for TBC and TEC on egg shells and in shell pores in both production systems. All the eggs were negative for Salmonella spp.
Protoporphyrin has been identified as the main eggshell pigment in brown-shelled eggs. However, t... more Protoporphyrin has been identified as the main eggshell pigment in brown-shelled eggs. However, there has been some uncertainty concerning the distribution of the pigment within the shell (and cuticle) in brown-shelled eggs. Most previous studies have suggested that the bulk of the shell pigment is deposited in the cuticle of the shell. The present study measured the levels of protoporphyrin in intact eggshells and in shells from which the cuticle had been removed, using eggs from flocks at 3 different ages. This enabled the calculation of the relative amount of protoporphyrin in the calcareous eggshell and the cuticle layer of the eggshell. The majority of the protoporphyrin pigment was located in the calcareous part of the eggshell (80-87%) with a minority contained within the cuticle (13-20%). These findings suggest that studies focused on maintenance of shell color in brown-shelled eggs need to consider the stage of egg formation at which the reduction in pigment deposition is occurring.
Food borne Salmonellosis in human is mainly caused by the consumption of contaminated eggs and ot... more Food borne Salmonellosis in human is mainly caused by the consumption of contaminated eggs and other poultry products. Trans-shell route is considered the underlying phenomena leading to the production of Salmonella Infantis contaminated eggs. Salmonella Infantis comes in the top 10 human pathogenic Salmonella serovars, been isolated from human and poultry from diverse group of countries in patients linked to contaminated food. Majority of the Salmonella cases are sporadic, outbreaks occur frequently with a direct or indirect link to contaminated food especially poultry. This review has mainly highlighted the factors affecting Salmonella transmission with a special emphasis on hen eggshell quality.
Contagious caprine pleuropneumonia (CCPP) is caused by Mycoplasma capricolum subsp. capripneumoni... more Contagious caprine pleuropneumonia (CCPP) is caused by Mycoplasma capricolum subsp. capripneumoniae (Mccp) which belongs to the Mycoplasma mycoides cluster, a group of five closely related Mycoplasmas, pathogenic to ruminants. The true lesions of CCPP are restricted to the alveolar tissues of infected goats, which distinguish it from other respiratory diseases of small ruminants caused by members of the Mycoplasma mycoides cluster. The typical signs of CCPP are an accumulation of pleural fluid, unilateral hepatisation, adhesions, pleurisy and pleuropneumonia which clearly differentiate it from "MAKePS" syndrome caused by Mycoplasma mycoides subsp. capri (Mmc). The available literature on CCPP shows that so far in Pakistan, the true causative agent (Mccp) of this disease has only been isolated in the Pashin District of Balochistan and that the disease is more frequently confused with other respiratory diseases of goat caused by the Mycoplasma mycoides cluster. The lack of suitable techniques and extensive knowledge in the field is a big limitation for the isolation and characterisation of Mccp from prevailing CCPP-like cases in the goat population of Pakistan. List of abbreviations CBPP = contagious bovine pleuropneumonia, CCPP = contagious caprine pleuropneumonia; CFT = complement fixation test, ELISA = enzyme linked immunosorbent assay, FAO = Food and Agriculture Organization, GIT = growth inhibition test, IFA = indirect fluorescent antibody, IHA = indirect Haemagglutination, Mcc = Mycoplasma capricolum subspecies capricolum, Mccp = Mycoplasma capricolum subsp. capripneumoniae, MLSA = multi locus sequence analysis, Mmc = Mycoplasma mycoides subsp. capri, MmmLC = Mycoplasma mycoides subsp. mycoides large colony, MmmSC = Mycoplasma mycoides subsp. mycoides small colony, OIE = Office International des Epizooties, PCR = polymerase chain reaction Contents
Eggs were collected from commercial caged layer flocks in early, mid, late and very late lay. Egg... more Eggs were collected from commercial caged layer flocks in early, mid, late and very late lay. Eggs were candled and scored for translucency. Cuticle cover was estimated using MST Cuticle Stain and a Konica Minolta hand-held spectrophotometer. Traditional measures of egg quality were determined using specialised equipment. Shell ultrastructural features were scored following plasma ashing of shell samples and viewing under a benchtop scanning electron microscope. Translucency score was significantly higher in late lay than for all other age groups. Shell quality declined with increasing flock age. However, the extent of cuticle cover on the egg shell was not significantly different among flock age groups. The incidence of shell ultrastructural features associated with good quality shells was lower for older flocks and incidence of ultrastructural features associated with poorer quality shells was higher for older flocks. Translucency score had a low correlation with the ultrastructural features of the mammillary layer.
Background: The gut microbiota plays an important role in the colonisation resistance and invasio... more Background: The gut microbiota plays an important role in the colonisation resistance and invasion of pathogens. Salmonella Typhimurium has the potential to establish a niche by displacing the microbiota in the chicken gut causing continuous faecal shedding that can result in contaminated eggs or egg products. In the current study, we investigated the dynamics of gut microbiota in laying chickens during Salmonella Typhimurium infection. The optimisation of the use of an infeed probiotic supplement for restoration of gut microbial balance and reduction of Salmonella Typhimurium load was also investigated.
Chicken meat can potentially become contaminated with bacteria at the processing plant. In Austra... more Chicken meat can potentially become contaminated with bacteria at the processing plant. In Australia, there is currently a lack of knowledge on the parameters and indications of use of non-chlorine based treatments in the chicken meat processing plants. Chlorine is widely used as a sanitizer in Australian chicken meat processing plants but due to occupational health and safety concerns and consumer perception, there is a need to identify alternative sanitizers. This study aimed to assess the efficacy of four different sanitizers in reducing the microbial load from naturally contaminated chicken meat carcasses collected from the processing plants in South Australia. There was a significant variation in a load of Campylobacter and total viable count (TVC) between samples collected from two different processing plants and within carcass batches collected from the same plant that was tested during the study. All sanitizers generally reduced the load of Campylobacter on chicken meat carcasses. Treatment with acidified sodium chlorite significantly reduced the level of Salmonella enterica serovars at all temperatures tested during this study. These findings are helpful to the industry for selection of the appropriate sanitizers. Findings are also useful for the regulatory authorities in Australia for providing approval for the use of sanitizers.
The major pigment in eggshells of brownegg
laying hens is protoporphyrin IX, but traces of
bilive... more The major pigment in eggshells of brownegg laying hens is protoporphyrin IX, but traces of biliverdin and its zinc chelates are also present. The pigment appears to be synthesized in the shell gland. The protoporphyrin IX synthetic pathway is well defined, but precisely where and how it is synthesized in the shell gland of the brown-egg laying hen is still ambiguous. The pigment is deposited onto all shell layers including the shell membranes, but most of it is concentrated in the outermost layer of the calcareous shell and in the cuticle. Recently, the genes that are involved in pigment synthesis have been identified, but the genetic control of synthesis and deposition of brown pigment in the commercial laying hen is not fully understood. The brown coloration of the shell is an important shell quality parameter and has a positive influence on consumer preference. The extent of pigment deposition is influenced by the housing system, hen age, hen strain, diet, stressors, and certain diseases such as infectious bronchitis. In this article, the physiological and biochemical characteristics of the brown pigment in commercial brown-egg layers are reviewed in relation to its various functions in the poultry industry.
Eggs were collected from HyLine brown flocks aged 33, 50 and 67 wk. Thirty eggs from each flock w... more Eggs were collected from HyLine brown flocks aged 33, 50 and 67 wk. Thirty eggs from each flock were analyzed to determine the reliability of MST cuticle blue stain as an indicator of the presence of cuticle and the effective removal of cuticle by use of an EDTA solution. Another 30 eggs were processed for the quantification of protoporphyrin IX (PP IX) from the eggshell with and without the presence of cuticle. L*a* components of the color space system were significantly different among the age groups. There was a high degree of correlation between the extent of MST cuticle blue staining and the amount of cuticle on the egg shell as recorded by scanning electron microscopy. PP IX pigment was quantified by spectrophotometric analysis of digested eggshell solutions. The average amount of PP IX in the shell without cuticle (8.046 x 10-8 g/g of shell) was higher than the amount present in cuticle (1.669 x 10-8 g/g of shell). The amount of PP IX in the cuticle of 1g of shell in the 33 wk eggs was significantly lower than for eggs from the 50 wk and 67 wk flocks whereas, in the shell without cuticle, it was not significantly different among flock ages. PP IX in cuticle, as a percentage of total PP IX in shell was 13% in 33 wk, 20 % in 50 wk and 18 % in 67 wk eggs.
Eggshells were collected at days 1, 3 and 5 post infection from unvaccinated Isa Brown laying hen... more Eggshells were collected at days 1, 3 and 5 post infection from unvaccinated Isa Brown laying hens challenged with infectious bronchitis virus (IBV) strains N1/88 or T as well as from a control group of unvaccinated hens. Shell reflectivity (%) and shell colour L* were measured on shells with and without cuticle and were further processed for the quantification of protoporphyrin IX (PP IX) from the same shell with and without the presence of cuticle. Shell reflectivity and shell colour L* values for the control eggs were significantly lower (P < 0.0001) compared to those from hens challenged with both strains of IBV and were also significantly lower on day 1 compared to days 3 and 5 p.i. The PP IX was quantified by spectrophotometric analysis of digested eggshell solutions. The mean PP IX in 1g of shell with and without cuticle was significantly higher on day 1 compared with days 3 and 5. The amount of PP IX in the shell decreased with time post infection for the IBV groups. The amount of PP IX in whole eggshell was highest for the control group and lowest for the T strain group, with the N1/88 group intermediate.
The cuticle is the outermost layer, deposited on the palisade layer of the eggshell
during the la... more The cuticle is the outermost layer, deposited on the palisade layer of the eggshell during the last 1.5-2 hr of eggshell formation in utero. It is a non-calcified, thin, water-insoluble layer composed mainly of glycoproteins with some carbohydrate and fat constituents. The cuticle functions as a protective layer which regulates gaseous exchange across the shell, acts as a first line of defence against microbial penetration across the eggshell and is associated with termination of calcite crystal growth during shell formation. The extent of cuticle deposition is influenced by hen age and strain. The physiological and microbiological characteristics of the hen eggshell cuticle are reviewed in relation to its protective functions.
Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week inte... more Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week intervals and divided into 4 different groups after candling and scoring for incidence of translucency. A significant effect of production system and flock age was recorded for all the egg quality variables except shell breaking strength (BSN), while interaction between the two was significant for all the egg quality variables except shell deformation. The amount of cuticle on the egg shell was estimated using a Konica Minolta spectrophotometer after MST Cuticle Blue staining of eggs. Statistically significant effects as well as interactions were recorded for production system and age for L*a*b* values. Shell ultra structural features were scored using Scanning Electron Microscope (SEM) following plasma etching of shell pieces. Shell ultra structural variables significantly affected by production system and age were mammillary cap size, cap quality, early fusion, type B bodies and cuffing, while interaction between production system and flock age was recorded for mammillary cap size, late fusion, alignment, type B bodies, cubic cone formation, cuffing and changed membrane. The microbiological studies showed a statistically significant effect of production system and flock age for total bacterial count (TBC) on egg shells and interaction between production system and flock age for TBC and total Enterobacteriaceae count (TEC) on egg shells. A significant effect was also recorded for flock age for TBC and TEC on egg shells and in shell pores in both production systems. All the eggs were negative for Salmonella spp.
The vast majority of eggs in Australia are washed prior to packing to remove dirt and fecal mater... more The vast majority of eggs in Australia are washed prior to packing to remove dirt and fecal material and to reduce the microbial contamination of the egg shell. The egg contents can be an ideal growth medium for microorganisms which can result in human illness if eggs are stored improperly and eaten raw or undercooked, and it is estimated that egg-related salmonellosis is costing Australia $44 million per year. Egg shell characteristics such as shell thickness, amount of cuticle present, and thickness of individual egg shell layers can affect the ease with which bacteria can penetrate the egg shell and washing could partially or completely remove the cuticle layer. The current study was conducted to investigate the effects of egg washing on cuticle cover and effects of egg shell quality and cuticle cover on Salmonella Infantis penetration of the egg shell. A higher incidence of unfavorable ultrastructural variables of the mammillary layer such as late fusion, type B bodies, type A bodies, poor cap quality, alignment, depression, erosion and cubics were recorded in Salmonella penetrated areas of egg shells. The influence of egg washing on the ability of Salmonella Infantis on the egg shell surface to enter the egg internal contents was also investigated using culture-based agar egg penetration and real-time qPCR based experiments. The results from the current study indicate that washing affected cuticle cover. There were no significant differences in Salmonella Infantis penetration of washed or unwashed eggs. Egg shell translucency may have effects on Salmonella Infantis penetration of the egg shell. The qPCR assay was more sensitive for detection of Salmonella Infantis from egg shell wash and internal contents than traditional microbiological methods. The agar egg and whole egg inoculation experiments indicated that Salmonella Infantis penetrated the egg shells. Egg washing not only can be highly effective at removing Salmonella Infantis from the egg shell surface, but also allows subsequent trans-shell and trans-membrane penetration into the egg. Consequently, it is important to prevent recontamination of the egg after washing.
Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week inte... more Eggs (180/flock per collection) were collected from a cage and a free range flock at 10 week intervals and divided into 4 different groups after candling and scoring for incidence of translucency. A significant effect of production system and flock age was recorded for all the egg quality variables except shell breaking strength (BSN), while interaction between the two was significant for all the egg quality variables except shell deformation. The amount of cuticle on the egg shell was estimated using a Konica Minolta spectrophotometer after MST Cuticle Blue staining of eggs. Statistically significant effects as well as interactions were recorded for production system and age for L*a*b* values. Shell ultra structural features were scored using Scanning Electron Microscope (SEM) following plasma etching of shell pieces. Shell ultra structural variables significantly affected by production system and age were mammillary cap size, cap quality, early fusion, type B bodies and cuffing, while interaction between production system and flock age was recorded for mammillary cap size, late fusion, alignment, type B bodies, cubic cone formation, cuffing and changed membrane. The microbiological studies showed a statistically significant effect of production system and flock age for total bacterial count (TBC) on egg shells and interaction between production system and flock age for TBC and total Enterobacteriaceae count (TEC) on egg shells. A significant effect was also recorded for flock age for TBC and TEC on egg shells and in shell pores in both production systems. All the eggs were negative for Salmonella spp.
Protoporphyrin has been identified as the main eggshell pigment in brown-shelled eggs. However, t... more Protoporphyrin has been identified as the main eggshell pigment in brown-shelled eggs. However, there has been some uncertainty concerning the distribution of the pigment within the shell (and cuticle) in brown-shelled eggs. Most previous studies have suggested that the bulk of the shell pigment is deposited in the cuticle of the shell. The present study measured the levels of protoporphyrin in intact eggshells and in shells from which the cuticle had been removed, using eggs from flocks at 3 different ages. This enabled the calculation of the relative amount of protoporphyrin in the calcareous eggshell and the cuticle layer of the eggshell. The majority of the protoporphyrin pigment was located in the calcareous part of the eggshell (80-87%) with a minority contained within the cuticle (13-20%). These findings suggest that studies focused on maintenance of shell color in brown-shelled eggs need to consider the stage of egg formation at which the reduction in pigment deposition is occurring.
Food borne Salmonellosis in human is mainly caused by the consumption of contaminated eggs and ot... more Food borne Salmonellosis in human is mainly caused by the consumption of contaminated eggs and other poultry products. Trans-shell route is considered the underlying phenomena leading to the production of Salmonella Infantis contaminated eggs. Salmonella Infantis comes in the top 10 human pathogenic Salmonella serovars, been isolated from human and poultry from diverse group of countries in patients linked to contaminated food. Majority of the Salmonella cases are sporadic, outbreaks occur frequently with a direct or indirect link to contaminated food especially poultry. This review has mainly highlighted the factors affecting Salmonella transmission with a special emphasis on hen eggshell quality.
Contagious caprine pleuropneumonia (CCPP) is caused by Mycoplasma capricolum subsp. capripneumoni... more Contagious caprine pleuropneumonia (CCPP) is caused by Mycoplasma capricolum subsp. capripneumoniae (Mccp) which belongs to the Mycoplasma mycoides cluster, a group of five closely related Mycoplasmas, pathogenic to ruminants. The true lesions of CCPP are restricted to the alveolar tissues of infected goats, which distinguish it from other respiratory diseases of small ruminants caused by members of the Mycoplasma mycoides cluster. The typical signs of CCPP are an accumulation of pleural fluid, unilateral hepatisation, adhesions, pleurisy and pleuropneumonia which clearly differentiate it from "MAKePS" syndrome caused by Mycoplasma mycoides subsp. capri (Mmc). The available literature on CCPP shows that so far in Pakistan, the true causative agent (Mccp) of this disease has only been isolated in the Pashin District of Balochistan and that the disease is more frequently confused with other respiratory diseases of goat caused by the Mycoplasma mycoides cluster. The lack of suitable techniques and extensive knowledge in the field is a big limitation for the isolation and characterisation of Mccp from prevailing CCPP-like cases in the goat population of Pakistan. List of abbreviations CBPP = contagious bovine pleuropneumonia, CCPP = contagious caprine pleuropneumonia; CFT = complement fixation test, ELISA = enzyme linked immunosorbent assay, FAO = Food and Agriculture Organization, GIT = growth inhibition test, IFA = indirect fluorescent antibody, IHA = indirect Haemagglutination, Mcc = Mycoplasma capricolum subspecies capricolum, Mccp = Mycoplasma capricolum subsp. capripneumoniae, MLSA = multi locus sequence analysis, Mmc = Mycoplasma mycoides subsp. capri, MmmLC = Mycoplasma mycoides subsp. mycoides large colony, MmmSC = Mycoplasma mycoides subsp. mycoides small colony, OIE = Office International des Epizooties, PCR = polymerase chain reaction Contents
Eggs were collected from commercial caged layer flocks in early, mid, late and very late lay. Egg... more Eggs were collected from commercial caged layer flocks in early, mid, late and very late lay. Eggs were candled and scored for translucency. Cuticle cover was estimated using MST Cuticle Stain and a Konica Minolta hand-held spectrophotometer. Traditional measures of egg quality were determined using specialised equipment. Shell ultrastructural features were scored following plasma ashing of shell samples and viewing under a benchtop scanning electron microscope. Translucency score was significantly higher in late lay than for all other age groups. Shell quality declined with increasing flock age. However, the extent of cuticle cover on the egg shell was not significantly different among flock age groups. The incidence of shell ultrastructural features associated with good quality shells was lower for older flocks and incidence of ultrastructural features associated with poorer quality shells was higher for older flocks. Translucency score had a low correlation with the ultrastructural features of the mammillary layer.
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Papers by Samiullah KHAN
laying hens is protoporphyrin IX, but traces of
biliverdin and its zinc chelates are also present. The
pigment appears to be synthesized in the shell gland.
The protoporphyrin IX synthetic pathway is well defined,
but precisely where and how it is synthesized
in the shell gland of the brown-egg laying hen is still
ambiguous. The pigment is deposited onto all shell
layers including the shell membranes, but most of it
is concentrated in the outermost layer of the calcareous
shell and in the cuticle. Recently, the genes that
are involved in pigment synthesis have been identified,
but the genetic control of synthesis and deposition of
brown pigment in the commercial laying hen is not
fully understood. The brown coloration of the shell is
an important shell quality parameter and has a positive
influence on consumer preference. The extent of
pigment deposition is influenced by the housing system,
hen age, hen strain, diet, stressors, and certain
diseases such as infectious bronchitis. In this article,
the physiological and biochemical characteristics of the
brown pigment in commercial brown-egg layers are reviewed
in relation to its various functions in the poultry
industry.
during the last 1.5-2 hr of eggshell formation in utero. It is a non-calcified, thin,
water-insoluble layer composed mainly of glycoproteins with some carbohydrate
and fat constituents. The cuticle functions as a protective layer which regulates
gaseous exchange across the shell, acts as a first line of defence against microbial
penetration across the eggshell and is associated with termination of calcite crystal
growth during shell formation. The extent of cuticle deposition is influenced by hen
age and strain. The physiological and microbiological characteristics of the hen
eggshell cuticle are reviewed in relation to its protective functions.
laying hens is protoporphyrin IX, but traces of
biliverdin and its zinc chelates are also present. The
pigment appears to be synthesized in the shell gland.
The protoporphyrin IX synthetic pathway is well defined,
but precisely where and how it is synthesized
in the shell gland of the brown-egg laying hen is still
ambiguous. The pigment is deposited onto all shell
layers including the shell membranes, but most of it
is concentrated in the outermost layer of the calcareous
shell and in the cuticle. Recently, the genes that
are involved in pigment synthesis have been identified,
but the genetic control of synthesis and deposition of
brown pigment in the commercial laying hen is not
fully understood. The brown coloration of the shell is
an important shell quality parameter and has a positive
influence on consumer preference. The extent of
pigment deposition is influenced by the housing system,
hen age, hen strain, diet, stressors, and certain
diseases such as infectious bronchitis. In this article,
the physiological and biochemical characteristics of the
brown pigment in commercial brown-egg layers are reviewed
in relation to its various functions in the poultry
industry.
during the last 1.5-2 hr of eggshell formation in utero. It is a non-calcified, thin,
water-insoluble layer composed mainly of glycoproteins with some carbohydrate
and fat constituents. The cuticle functions as a protective layer which regulates
gaseous exchange across the shell, acts as a first line of defence against microbial
penetration across the eggshell and is associated with termination of calcite crystal
growth during shell formation. The extent of cuticle deposition is influenced by hen
age and strain. The physiological and microbiological characteristics of the hen
eggshell cuticle are reviewed in relation to its protective functions.