Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 mil... more Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 million ounces of silver from the Bodie mining district, eastern California. The veins cut dacitic lava flows, pyroclastic rocks and intrusions. Sinter boulders occur in a graben structure at the top of Bodie Bluff and fragments of sinter and mineralized quartz veins occur in hydrothermal breccias nearby. Explosive venting evidently was part of the evolution of the ore-forming geothermal systems which, at one time, must had reached the paleosurface. Previous reconnaissance studies at Bodie Bluff suggested that the geometry of alteration mineral assemblages and distribution of some of the major and trace elements throughout the system correspond to those predicted by models of hot-spring, volcanic rock hosted precious metal deposits . The current study was undertaken to evaluate these sugestions further.
A study was conducted to evaluate skeletal quality and eggshell parameters of molted hens at the ... more A study was conducted to evaluate skeletal quality and eggshell parameters of molted hens at the end of the second laying cycle. Sixty Single Comb White Leghorn hens were used for this study. There were 2 controls and 4 molting treatments: full-fed control 1 (82 wk old; FF1), full-fed control 2 (122 wk old; FF2), feed withdrawal (FW), 100% alfalfa (A100), 90% alfalfa/10% layer ration (A90), and 70% alfalfa/30% layer ration (A70). At the end of the second laying cycle (approximately 122 wk of age), hens were euthanized by CO 2 . Tibia and femur were collected. There were no differences in bone parameters between FF1 and FF2 (P > 0.05) hens. There were no differences in bone parameters among the different molting dietary treatments (P > 0.05). In the eggshell (
Streptococcus bovis is an indigenous resident in the gastrointestinal tracts of both humans and a... more Streptococcus bovis is an indigenous resident in the gastrointestinal tracts of both humans and animals. S. bovis is one of the major causes of bacterial endocarditis and has been implicated in the incidence of human colon cancer, possibly due to chronic inflammatory response at the site of intestinal colonization. Certain feeding regimens in ruminants can lead to overgrowth of S. bovis in the rumen, resulting in the over-production of lactate and capsular polysaccharide causing acute ruminal acidosis and bloat, respectively. There are multiple strategies in controlling acute lactic acidosis and bloat. The incidence of the two diseases may be controlled by strict dietary management. Gradual introduction of grain-based diets and the feeding of coarsely chopped roughage decrease the incidence of the two disease entities. Ionophores, which have been used to enhance feed conversion and growth rate in cattle, have been shown to inhibit the growth of lactic acid bacteria in the rumen. Other methods of controlling lactic acid bacteria in the ruminal environment (dietary supplementation of long-chain fatty acids, induction of passive and active immune responses to the bacteria, and the use of lytic bacteriophages) have also been investigated. It is anticipated that through continued in-depth ecological analysis of S. bovis the characteristics responsible for human and animal pathogenesis would be sufficiently identified to a point where more effective control strategies for the control of this bacteria can be developed.
The objective of this in vitro study was to evaluate the effects of combining a prebiotic with al... more The objective of this in vitro study was to evaluate the effects of combining a prebiotic with alfalfa on fermentation by laying hen cecal bacteria. Cecal contents from laying hens were diluted to a 1:3,000 concentration with an anaerobic dilution solution and added to serum tubes filled with ground alfalfa or a layer ration with or without fructooligosaccharide (FOS) prebiotic. Samples were processed in an anaerobic hood, pressurized by using a pressure manifold, and incubated at 37°C. Volatile fatty acid (VFA) and lactic acid concentrations were quantified at 6 and 24 h of substrate fermentation. In this study, fermentation of alfalfa resulted in greater
A study was conducted to evaluate effects of different bone preparation methods on bone parameter... more A study was conducted to evaluate effects of different bone preparation methods on bone parameters and the correlations between bone breaking strength and the other bone parameters. Bone breaking strength is dramatically changed depending on bone preparation methods, whereas other bone parameters such as ash content and ash concentration are not significantly influenced by bone preparation methods. Thus, the objective of this study was to evaluate the effects of 3 bone preparations (fresh, dry, and fat-free dry) on bone parameters and the relationship between bone breaking strength and bone parameters. Sixty Single Comb White Leghorn hens were used for this study. Hens were euthanized by CO 2 gas, and the right tibia and femur were collected. The bones were divided into 3 treatment (Key words: bone breaking strength, bone preparation, ash weight, ash concentration)
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2010
The cross-reactivity of egg yolk antibodies specific to antigens of Salmonella Enteritidis and Sa... more The cross-reactivity of egg yolk antibodies specific to antigens of Salmonella Enteritidis and Salmonella Typhimurium to killed bacterial cells of common Salmonella serovars were tested using an indirect Enzyme Linked Immunosorbent Assay (ELISA). Egg yolk antibodies were produced against purified fimbriae, flagella and lipopolysaccharide (LPS) of S. Enteritidis strain ATCC13076 and flagella, LPS and outer membrane proteins (OMP) of S. Typhimurium strain ATCC13311. For immunological specificity of egg yolk antibodies against killed bacterial cells, we found that the titers of the anti-S. Enteritidis egg yolk antibodies were higher than those of the anti-S. Typhimurium antibodies. In the evaluation of cross-reactivity of these egg yolk antibodies to various Salmonella serovars, we observed that the anti-S. Enteritidis antibodies exhibited more specific affinity than those of the anti-S. Typhimurium antibodies. All S. Enteritidis strains reacted specifically with the anti-S. Enteritidis fimbrial and flagellar egg yolk antibody whereas anti-S. Enteritidis LPS and anti-S. Typhimurium LPS, OMP and flagellar antibodies displayed non–specific reactivity to all Salmonella serovars used in this study. This finding suggests that it may be possible to design a anti-fimbrial egg yolk antibody of S. Enteritidis as a diagnostic tool and a cocktail of OMP and LPS antigens of S. Enteritidis and S. Typhimurium could be used for administering broad spectrum passive immunity to protect against the colonization of pathogenic Salmonella strains in food animals.
Aims:  To detect the presence of methanogens in the faeces of broiler chicks during the first 2 w... more Aims:  To detect the presence of methanogens in the faeces of broiler chicks during the first 2 weeks of age.Methods and Results:  Chicken faecal samples from 120 broiler chicks were incubated for methane gas formation and methanogenic archaea were analysed using real-time PCR. The copy number of the order Methanobacteriales 16S rDNA gene in chicken faeces when the broilers were 3–12 days of age, litter and house flies collected in the bird house ranged from 4·19 to 5·51 log10 g−1 wet weight. The number of positive methane culture tubes increased from 25% to 100% as the birds aged.Conclusions:  Methanogens were successfully detected in faecal samples from 3- to 12-day-old broilers, as well as litter and house flies using real-time PCR. The copy number of methanogenic 16S rDNA gene in these samples was also similar to the number observed in litter and house flies.Significance and Impact of the Study:  The same methanogens consistently appeared in chicken faeces a few days after birth. Detection of the methanogenic bacteria in litter and house flies implicated them as potential environmental sources for methanogen colonization in broiler chicks.
Animal feeds can potentially become contaminated with foodborne Salmonella either during harvesti... more Animal feeds can potentially become contaminated with foodborne Salmonella either during harvesting, processing at the feed mill or during storage. Any environment that comes in contact with feed during these stages that also harbors Salmonella can theoretically contaminate the feed. This also holds true for ingredients that are combined with feeds as they are being mixed at the feed mill. Animal feeds are also potential reservoirs for cross contamination from Salmonella containing vectors and environmental sources while being fed to animals. Although several factors may determine the extent of contamination, the potential for infection in animals these have not been well characterized. In addition, certain animal management and feeding programs can lead to animals becoming more susceptible to Salmonella colonization and invasion. Control measures to limit Salmonella contamination of feed include agents that directly reduce or destroy the organism in feed. Antimicrobial compounds and management strategies have also been developed for preventing colonization and eliminating Salmonella colonized in the gastrointestinal tract. The future prospects for minimizing Salmonella contaminated feed will probably involve combining more efficient monitoring and sampling approaches with more rapid and sensitive detection technologies. Futtermittel können schon bei der Ernte der Futterpflanzen sowie während der Futter-Herstellung oder -Lagerung von Salmonellen kontaminiert werden; grundsätzlich kann dies Ă¼berall dort passieren, wo Futtermittel mit der AuĂŸenwelt (mit Salmonellen) in Kontakt kommen. Dies gilt ebenso fĂ¼r Zusatzstoffe, die den Futtermitteln in FuttermĂ¼hlen beigemengt werden. Futtermittel sind auch potenzielle Reservoire fĂ¼r die Kontamination mit Salmonellen während des FĂ¼tterns von Tieren. Obwohl das AusmaĂŸ einer solchen Kontamination mit Salmonellen von etlichen Faktoren bestimmt wird, sind die Umstände, die zur Infektion der Tiere fĂ¼hren können, noch nicht ausreichend charakterisiert worden. AuĂŸerdem können bestimmte Tierhaltungs- und FĂ¼tterungsverfahren eine Infektion von Tieren durch Salmonella sogar begĂ¼nstigen. Um dieses zu verhindern, können Wirkstoffe eingesetzt werden, welche die Salmonella-Populationen im Futter reduzieren oder zerstören. Es wurden ebenso Verfahren mit antimikrobiell wirksamen Stoffen entwickelt, um eine Besiedlung des Gastrointestinaltraktes durch Salmonella zu verhindern bzw. dort bereits vorhandene Samonellen abzutöten. ZukĂ¼nftig muĂŸ ein effektiveres Monitoring- und Probenahme-Verfahren mit schnelleren und empfi ndlicheren Nachweisverfahren kombiniert werden, um eine eventuelle Kontamination von Futtermitteln durch Salmonella zu minimieren.
Food-borne salmonellosis continues to be a major public health concern, and contamination with Sa... more Food-borne salmonellosis continues to be a major public health concern, and contamination with Salmonella spp. in pre-harvest animal production is considered a primary contributor to this problem. Animal feeds can easily become contaminated during primary production, feed mixing and processing as well as during feeding. Consequently, monitoring and surveillance of feeds and feed ingredients for Salmonella spp. contamination may be useful or necessary in the prevention and control of this organism. Cultural and immunological detection methods for salmonellae have been used or suggested as possible approaches for use in animal feeds. Cultural methods remain advantageous owing to their ability to detect viable bacterial cells, while immunological methods have the capability of detecting nonculturable bacterial cells. Advancements and improvements in both methodologies offer opportunities for eventual routine use of these detection technologies in animal feed assays.
The objective of this study was to investigate the effect of combining a prebiotic with poultry f... more The objective of this study was to investigate the effect of combining a prebiotic with poultry feeds on the growth of Salmonella enterica serotype Typhimurium (ST) in an in vitro cecal fermentation system. Cecal contents from three laying hens were pooled and diluted to a 1:3000 concentration in an anaerobic dilution solution. The cecal dilution was added to sterile test tubes filled with alfalfa and layer ration with and without fructooligosaccharide (FOS). Two controls containing cecal dilutions and anaerobic dilution solution were used. The samples were processed in the anaerobic hood and incubated at 37 1C. Samples were inoculated with Salmonella at 0 and 24 h after in vitro cecal fermentation and plated at 0 and 24 h after inoculation with ST. Plates were incubated for 24 h and colony forming units (CFU) enumerated. The samples immediately inoculated with ST without prior cecal fermentation did not significantly lower ST counts 24 h later. However, samples pre-incubated for 24 h with cecal microflora prior to ST inoculation exhibited reduced ST CFU by approximately 2 logarithms, with the most dramatic decreases seen in alfalfa and layer ration combined with FOS. The addition of FOS to feed substrate diets in combination with cecal contents acted in a synergistic manner to decrease ST growth only after ST was introduced to 24 h cecal incubations. r
Animal feed may serve as a carrier for a wide variety of microorganisms. The primary mode of inoc... more Animal feed may serve as a carrier for a wide variety of microorganisms. The primary mode of inoculation of feed materials is the transference of soil by wind, rain, mechanical agitation, or insects to standing crops. Some of the microorganisms are adapted to the desiccated and relatively nutrientpoor conditions in soil and survive in similar niches on growing crops. Gastrointestinal pathogens can also introduced into the food chain by animals defecating in the farm environment or by fertilization of crops with manures. Other microorganisms are introduced during storage. In general, the amount of available water in the feed matrix determines whether a microorganism will grow or survive. Some microorganisms, primarily moulds, are adapted to the low amount of available moisture and grow actively within stored seeds and grains. Others will produce spores or enter survival state until the moisture is high enough for bacterial action. There are numerous ways contaminating microorganisms can affect feed quality negatively including reducing dry matter and nutrients, causing musty or sour odours, causing caking of the feed and producing toxins. Finally, feed can act as a carrier for animal and human pathogens. The type of feed, processing treatments and storage conditions can all be factors that influence the population levels and types of microorganisms present. The incidence and variation in the microflora found in animal feed and feed materials are reviewed.
Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 mil... more Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 million ounces of silver from the Bodie mining district, eastern California. The veins cut dacitic lava flows, pyroclastic rocks and intrusions. Sinter boulders occur in a graben structure at the top of Bodie Bluff and fragments of sinter and mineralized quartz veins occur in hydrothermal breccias nearby. Explosive venting evidently was part of the evolution of the ore-forming geothermal systems which, at one time, must had reached the paleosurface. Previous reconnaissance studies at Bodie Bluff suggested that the geometry of alteration mineral assemblages and distribution of some of the major and trace elements throughout the system correspond to those predicted by models of hot-spring, volcanic rock hosted precious metal deposits . The current study was undertaken to evaluate these sugestions further.
A study was conducted to evaluate skeletal quality and eggshell parameters of molted hens at the ... more A study was conducted to evaluate skeletal quality and eggshell parameters of molted hens at the end of the second laying cycle. Sixty Single Comb White Leghorn hens were used for this study. There were 2 controls and 4 molting treatments: full-fed control 1 (82 wk old; FF1), full-fed control 2 (122 wk old; FF2), feed withdrawal (FW), 100% alfalfa (A100), 90% alfalfa/10% layer ration (A90), and 70% alfalfa/30% layer ration (A70). At the end of the second laying cycle (approximately 122 wk of age), hens were euthanized by CO 2 . Tibia and femur were collected. There were no differences in bone parameters between FF1 and FF2 (P > 0.05) hens. There were no differences in bone parameters among the different molting dietary treatments (P > 0.05). In the eggshell (
Streptococcus bovis is an indigenous resident in the gastrointestinal tracts of both humans and a... more Streptococcus bovis is an indigenous resident in the gastrointestinal tracts of both humans and animals. S. bovis is one of the major causes of bacterial endocarditis and has been implicated in the incidence of human colon cancer, possibly due to chronic inflammatory response at the site of intestinal colonization. Certain feeding regimens in ruminants can lead to overgrowth of S. bovis in the rumen, resulting in the over-production of lactate and capsular polysaccharide causing acute ruminal acidosis and bloat, respectively. There are multiple strategies in controlling acute lactic acidosis and bloat. The incidence of the two diseases may be controlled by strict dietary management. Gradual introduction of grain-based diets and the feeding of coarsely chopped roughage decrease the incidence of the two disease entities. Ionophores, which have been used to enhance feed conversion and growth rate in cattle, have been shown to inhibit the growth of lactic acid bacteria in the rumen. Other methods of controlling lactic acid bacteria in the ruminal environment (dietary supplementation of long-chain fatty acids, induction of passive and active immune responses to the bacteria, and the use of lytic bacteriophages) have also been investigated. It is anticipated that through continued in-depth ecological analysis of S. bovis the characteristics responsible for human and animal pathogenesis would be sufficiently identified to a point where more effective control strategies for the control of this bacteria can be developed.
The objective of this in vitro study was to evaluate the effects of combining a prebiotic with al... more The objective of this in vitro study was to evaluate the effects of combining a prebiotic with alfalfa on fermentation by laying hen cecal bacteria. Cecal contents from laying hens were diluted to a 1:3,000 concentration with an anaerobic dilution solution and added to serum tubes filled with ground alfalfa or a layer ration with or without fructooligosaccharide (FOS) prebiotic. Samples were processed in an anaerobic hood, pressurized by using a pressure manifold, and incubated at 37°C. Volatile fatty acid (VFA) and lactic acid concentrations were quantified at 6 and 24 h of substrate fermentation. In this study, fermentation of alfalfa resulted in greater
A study was conducted to evaluate effects of different bone preparation methods on bone parameter... more A study was conducted to evaluate effects of different bone preparation methods on bone parameters and the correlations between bone breaking strength and the other bone parameters. Bone breaking strength is dramatically changed depending on bone preparation methods, whereas other bone parameters such as ash content and ash concentration are not significantly influenced by bone preparation methods. Thus, the objective of this study was to evaluate the effects of 3 bone preparations (fresh, dry, and fat-free dry) on bone parameters and the relationship between bone breaking strength and bone parameters. Sixty Single Comb White Leghorn hens were used for this study. Hens were euthanized by CO 2 gas, and the right tibia and femur were collected. The bones were divided into 3 treatment (Key words: bone breaking strength, bone preparation, ash weight, ash concentration)
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2010
The cross-reactivity of egg yolk antibodies specific to antigens of Salmonella Enteritidis and Sa... more The cross-reactivity of egg yolk antibodies specific to antigens of Salmonella Enteritidis and Salmonella Typhimurium to killed bacterial cells of common Salmonella serovars were tested using an indirect Enzyme Linked Immunosorbent Assay (ELISA). Egg yolk antibodies were produced against purified fimbriae, flagella and lipopolysaccharide (LPS) of S. Enteritidis strain ATCC13076 and flagella, LPS and outer membrane proteins (OMP) of S. Typhimurium strain ATCC13311. For immunological specificity of egg yolk antibodies against killed bacterial cells, we found that the titers of the anti-S. Enteritidis egg yolk antibodies were higher than those of the anti-S. Typhimurium antibodies. In the evaluation of cross-reactivity of these egg yolk antibodies to various Salmonella serovars, we observed that the anti-S. Enteritidis antibodies exhibited more specific affinity than those of the anti-S. Typhimurium antibodies. All S. Enteritidis strains reacted specifically with the anti-S. Enteritidis fimbrial and flagellar egg yolk antibody whereas anti-S. Enteritidis LPS and anti-S. Typhimurium LPS, OMP and flagellar antibodies displayed non–specific reactivity to all Salmonella serovars used in this study. This finding suggests that it may be possible to design a anti-fimbrial egg yolk antibody of S. Enteritidis as a diagnostic tool and a cocktail of OMP and LPS antigens of S. Enteritidis and S. Typhimurium could be used for administering broad spectrum passive immunity to protect against the colonization of pathogenic Salmonella strains in food animals.
Aims:  To detect the presence of methanogens in the faeces of broiler chicks during the first 2 w... more Aims:  To detect the presence of methanogens in the faeces of broiler chicks during the first 2 weeks of age.Methods and Results:  Chicken faecal samples from 120 broiler chicks were incubated for methane gas formation and methanogenic archaea were analysed using real-time PCR. The copy number of the order Methanobacteriales 16S rDNA gene in chicken faeces when the broilers were 3–12 days of age, litter and house flies collected in the bird house ranged from 4·19 to 5·51 log10 g−1 wet weight. The number of positive methane culture tubes increased from 25% to 100% as the birds aged.Conclusions:  Methanogens were successfully detected in faecal samples from 3- to 12-day-old broilers, as well as litter and house flies using real-time PCR. The copy number of methanogenic 16S rDNA gene in these samples was also similar to the number observed in litter and house flies.Significance and Impact of the Study:  The same methanogens consistently appeared in chicken faeces a few days after birth. Detection of the methanogenic bacteria in litter and house flies implicated them as potential environmental sources for methanogen colonization in broiler chicks.
Animal feeds can potentially become contaminated with foodborne Salmonella either during harvesti... more Animal feeds can potentially become contaminated with foodborne Salmonella either during harvesting, processing at the feed mill or during storage. Any environment that comes in contact with feed during these stages that also harbors Salmonella can theoretically contaminate the feed. This also holds true for ingredients that are combined with feeds as they are being mixed at the feed mill. Animal feeds are also potential reservoirs for cross contamination from Salmonella containing vectors and environmental sources while being fed to animals. Although several factors may determine the extent of contamination, the potential for infection in animals these have not been well characterized. In addition, certain animal management and feeding programs can lead to animals becoming more susceptible to Salmonella colonization and invasion. Control measures to limit Salmonella contamination of feed include agents that directly reduce or destroy the organism in feed. Antimicrobial compounds and management strategies have also been developed for preventing colonization and eliminating Salmonella colonized in the gastrointestinal tract. The future prospects for minimizing Salmonella contaminated feed will probably involve combining more efficient monitoring and sampling approaches with more rapid and sensitive detection technologies. Futtermittel können schon bei der Ernte der Futterpflanzen sowie während der Futter-Herstellung oder -Lagerung von Salmonellen kontaminiert werden; grundsätzlich kann dies Ă¼berall dort passieren, wo Futtermittel mit der AuĂŸenwelt (mit Salmonellen) in Kontakt kommen. Dies gilt ebenso fĂ¼r Zusatzstoffe, die den Futtermitteln in FuttermĂ¼hlen beigemengt werden. Futtermittel sind auch potenzielle Reservoire fĂ¼r die Kontamination mit Salmonellen während des FĂ¼tterns von Tieren. Obwohl das AusmaĂŸ einer solchen Kontamination mit Salmonellen von etlichen Faktoren bestimmt wird, sind die Umstände, die zur Infektion der Tiere fĂ¼hren können, noch nicht ausreichend charakterisiert worden. AuĂŸerdem können bestimmte Tierhaltungs- und FĂ¼tterungsverfahren eine Infektion von Tieren durch Salmonella sogar begĂ¼nstigen. Um dieses zu verhindern, können Wirkstoffe eingesetzt werden, welche die Salmonella-Populationen im Futter reduzieren oder zerstören. Es wurden ebenso Verfahren mit antimikrobiell wirksamen Stoffen entwickelt, um eine Besiedlung des Gastrointestinaltraktes durch Salmonella zu verhindern bzw. dort bereits vorhandene Samonellen abzutöten. ZukĂ¼nftig muĂŸ ein effektiveres Monitoring- und Probenahme-Verfahren mit schnelleren und empfi ndlicheren Nachweisverfahren kombiniert werden, um eine eventuelle Kontamination von Futtermitteln durch Salmonella zu minimieren.
Food-borne salmonellosis continues to be a major public health concern, and contamination with Sa... more Food-borne salmonellosis continues to be a major public health concern, and contamination with Salmonella spp. in pre-harvest animal production is considered a primary contributor to this problem. Animal feeds can easily become contaminated during primary production, feed mixing and processing as well as during feeding. Consequently, monitoring and surveillance of feeds and feed ingredients for Salmonella spp. contamination may be useful or necessary in the prevention and control of this organism. Cultural and immunological detection methods for salmonellae have been used or suggested as possible approaches for use in animal feeds. Cultural methods remain advantageous owing to their ability to detect viable bacterial cells, while immunological methods have the capability of detecting nonculturable bacterial cells. Advancements and improvements in both methodologies offer opportunities for eventual routine use of these detection technologies in animal feed assays.
The objective of this study was to investigate the effect of combining a prebiotic with poultry f... more The objective of this study was to investigate the effect of combining a prebiotic with poultry feeds on the growth of Salmonella enterica serotype Typhimurium (ST) in an in vitro cecal fermentation system. Cecal contents from three laying hens were pooled and diluted to a 1:3000 concentration in an anaerobic dilution solution. The cecal dilution was added to sterile test tubes filled with alfalfa and layer ration with and without fructooligosaccharide (FOS). Two controls containing cecal dilutions and anaerobic dilution solution were used. The samples were processed in the anaerobic hood and incubated at 37 1C. Samples were inoculated with Salmonella at 0 and 24 h after in vitro cecal fermentation and plated at 0 and 24 h after inoculation with ST. Plates were incubated for 24 h and colony forming units (CFU) enumerated. The samples immediately inoculated with ST without prior cecal fermentation did not significantly lower ST counts 24 h later. However, samples pre-incubated for 24 h with cecal microflora prior to ST inoculation exhibited reduced ST CFU by approximately 2 logarithms, with the most dramatic decreases seen in alfalfa and layer ration combined with FOS. The addition of FOS to feed substrate diets in combination with cecal contents acted in a synergistic manner to decrease ST growth only after ST was introduced to 24 h cecal incubations. r
Animal feed may serve as a carrier for a wide variety of microorganisms. The primary mode of inoc... more Animal feed may serve as a carrier for a wide variety of microorganisms. The primary mode of inoculation of feed materials is the transference of soil by wind, rain, mechanical agitation, or insects to standing crops. Some of the microorganisms are adapted to the desiccated and relatively nutrientpoor conditions in soil and survive in similar niches on growing crops. Gastrointestinal pathogens can also introduced into the food chain by animals defecating in the farm environment or by fertilization of crops with manures. Other microorganisms are introduced during storage. In general, the amount of available water in the feed matrix determines whether a microorganism will grow or survive. Some microorganisms, primarily moulds, are adapted to the low amount of available moisture and grow actively within stored seeds and grains. Others will produce spores or enter survival state until the moisture is high enough for bacterial action. There are numerous ways contaminating microorganisms can affect feed quality negatively including reducing dry matter and nutrients, causing musty or sour odours, causing caking of the feed and producing toxins. Finally, feed can act as a carrier for animal and human pathogens. The type of feed, processing treatments and storage conditions can all be factors that influence the population levels and types of microorganisms present. The incidence and variation in the microflora found in animal feed and feed materials are reviewed.
Uploads
Papers by Paul Herrera