Foodborne unwellness and its deductions on nutrient industry and to the general populace is a concern and this impact could be reduced by set uping effectual, fresh intercession hurdlings to heighten nutrient safety in a “ farm to fork ” attack ( Oliver et al. , 2008 ) . Conventionally, the bulk of the attempts in commanding the pathogens have chiefly focused on post-harvest ; nevertheless, restricting the spread of foodborne pathogens prior to reap ( as they are reservoirs/asymptomatic bearers of several foodborne pathogens ) has progressively gained involvement and focal point among nutrient safety research workers, policy shapers, authorities functionaries ( FSIS/USDA ) , and consumers ( Tuohy et al. , 2005 ; Choct, 2009 ; FSIS/USDA, 2010 ) . Pre-harvest nutrient safety is now being considered more indispensable to protect nutrient supply as foodborne pathogens can come in the nutrient supply during slaughter from the fell, workers or machinery in the processing environment or by direct contact with fecal matters or digesta from the enteric piece of land ( Elder et al. , 2000 ) . In add-on to these factors, carnal farming patterns, managing and processing can besides lend to the incidence of foodborne unwellness ( Beier and Pillai, 2005 and Park et al. , 2008 ) .
2. FOODBORNE PATHOGENS ASSOCIATED WITH POULTRY
The Centers for Disease Control and Prevention ( CDC ) estimated that there are 76 million instances of nutrient borne diseases with 325,000 hospitalizations and 5,000 deceases happening every twelvemonth in the United States ( CDC, 2009 ) . A bulk of these foodborne illness/outbreaks have been linked to contaminated domestic fowl merchandises or contact with nutrient animate beings, waste, and enteral pathogens in domestic fowl ( Doyle and Erickson, 2006 ) . Primary foodborne pathogens chiefly transmitted through natural and processed domestic fowl merchandises are Salmonella and Campylobacter ( Mead, 1999 ; Bryan, 2001 ; Park et al. , 2008 ) . In 2008, the incidences of foodborne diseases associated with Salmonella and Campylobacter were 16.2 and 12.68 % severally ( Vugia et al. , 2009 ) . In add-on to the common bacterial pathogens, zoonotic parasitic infestations such as Trichinella spiralis and Toxoplasma gondii can present wellness hazards to the consumers ( Gebreyes, 2008 ) .
Salmonellosis is the 2nd normally reported foodborne disease associated with ingestion of meat, domestic fowl, eggs, milk and sea nutrients in the United States ( Vugia et al. , 2007 ) . Harmonizing to CDC estimations there are about 1.4 million instances of salmonellosis ensuing in 17,000 hospitalizations and 585 deceases each twelvemonth in the United States ( Mead et al. , 1999 ; Voetsch et al. , 2004 ) . Farm animate beings such as poulet and turkey represent a major reservoir of Salmonella ( Table 1 ) and can besides move as symptomless bearers in the absence of clinical disease ( Oliver et al. , 2008 ) .
Salmonella in poulets can pollute meat and eggs and have become a relentless job associated with the domestic fowl industry in the United States on an one-year footing ( USDA, 2007a ; USDA, 2007b ) . Factors impacting the susceptibleness of domestic fowl to Salmonella colonisation include age, serotype and intial challenge dose degree, emphasis, presence of provender additives, such as disinfectants and anticoccidials, survival through low pH of the tummy, competition with intestine microflora, and presence of compatible colonisation sites ( Bailey, 1988 ) .
Campylobacter jejuni is the major foodborne agents associated with diarrhoea and stomach flu and represents a major concern to the domestic fowl industry ( Altekruse, 1999 ; Newell and Fearnly, 2003 ) . The prevalence of Campylobacter in the U.S. is 32 to 53 % in domestic fowl ( Miller and Mandrell, 2005 ) . Over the old ages, Campylobacter have evolved and adapted to colonise in the bowel in domestic fowl which in bend can present serious public wellness jeopardies ( Heuer et al. , 2001 ; Newell and Davison, 2003 ) .
Harmonizing to the preliminary surveillance informations by FoodNet in 2008, the estimated incidence associated with Salmonella, Campylobacter, and other foodborne pathogens did non alter significantly when compared to the old 3 old ages ( Vugia et al. , 2009 ) . This reinstates the importance and demand for effectual control schemes and intercessions to bring forth wholesome nutrient merchandises.
3. PRE-HARVEST CONTROL STRATEGIES
Developing intercessions that have potential in cut downing pathogens well in the unrecorded animate being can better nutrient security and safety ( Lonergan et al. , 2005 ; Ricke and Jones, 2010 ) . A broad scope of intercession schemes have been developed to cut down the load of foodborne pathogens in domestic fowl, including familial choice of animate beings that are immune to colonisation, engendering interventions to forestall perpendicular transimission of enteral pathogens, sanitation patterns, additives ( provender or H2O ) , and biological interventions that straight or indirectly demobilize the pathogen within the host ( Doyle and Erickson, 2006 ) . However, usage of antibiotics and chemotherapeutics in contraceptive doses for drawn-out periods has led to concerns across the universe sing cross opposition and multiple antibiotic oppositions among foodborne pathogens ( Mathur and Singh, 2005 ) . Furthermore, usage of antibiotics as growing boosters in provender to cut down pathogens impacts the export of meat and domestic fowl merchandises to Eurpoean states ( EC 2001, 2003a ) . This in bend has generated involvement in development of novel, advanced and safe options that would hike natural defence mechanisms which includes, acidification of provender by organic acids, feeding probiotic beings and feeding prebiotic compounds ( Williams et al. , 2001 ; Oliver et al. , 2008 ; Ricke and Jones, 2010 ) . In add-on to nutrient safety issues, high protein monetary values and environmental concerns have caused the domestic fowl industry to see the acceptance of provender addendums such as probiotics that would positively act upon the carnal public presentation including modulating intestine microflora ( Tuohy et al. , 2005 ) .
4. CHICKEN GUT MICROFLORA
Chicken intestine ( besides referred as digestive piece of land or GI piece of land ) begins with the oral cavity and ends at the cloaca with several of import variety meats in between. Based on the microflora kineticss and their colonisation position, the domestic fowl bowel can be divided into three parts: a ) the duodenum and the little bowel, where bacterium Numberss are comparatively low ( less than 108/g ) , B ) the caecum, major site of bacterial colonisation and microbic agitation ( about 108/g ; wet weight ) , degree Celsius ) and the big bowel ( Barnes, 1972 ) .
The GI piece of land and its associated tissues in domestic fowl during hatching clip are comparatively unfertile and developing ( Cressman, 2009 ) . However, as the biddy or poult grows, the GI piece of land provides the needed conditions for bacterial colonisation, including fond regard sites, optimum pH, substrate/nutrients, and waste remotion. At this phase, healthy broilers and poults exhibit important alterations such as more rapid relative weight additions of GI tissues when compared to number organic structure mass and increases villus volume ( 3 to 5 crease ) between 2nd and 14th twenty-four hours and crypt deepness ( 2 to 3 creases by twenty-four hours ) ( Uni et al. , 1998 ) . Similar additions have besides been observed in poults although non to the same extent ( Uni et al. , 1998 ) .
Development of normal GI microflora of domestic fowl has been extensively studied in specific pathogen free ( SPF ) chickens as the consequences would be indifferent due to the absence of competitory microflora. The usage of SPF birds is advantageous compared to utilizing conventionally raised poulets since there is no hazard of extra infective agents such as viruses and parasites that may be present in the latter ( Coloe et al. , 1984 ) . In a survey conducted by Coloe et Al. ( 1984 ) sing the development of normal intestine microflora in SPF poulets, no bacteriums were detected at hatching ( twenty-four hours 1 ) and development of important degrees ( 108 CFU/g ) of facultative anaerobes such as faecal streptococcus and coliforms by twenty-four hours 3 and Proteus sp ( greater than 107 CFU/g ) were accompanied by twenty-four hours 7 in the caecum.
In domestic fowl, major sites of colonisation by intestine microflora in GI piece of land are the harvest, proventriculus, gizzard, little bowel, colon and caecum ( Chichlowski et al. , 2007a ; Gaskins et al. , 2002 ; Heczko et al. , 2000 ; and Rastall, 2004 ) . Normal GI microflora and prevailing species in assorted parts of healthy poulet bowel are presented in Table 2. In the proximal portion of the bowel ( harvest, ventriculus, proventriculus ) there are normally low Numberss of anaerobiotic bacteriums due to the presence of O, low luminal pH, and hydrochloric acid arising from the proventriculus ( Rastall, 2004 ) . In malice of these unfavourable conditions, Lactobacilli can still last in the poulet harvest due to come up receptors on Lactobacilli that have the ability to adhere to the squamous epithelial cells of the harvest to be retained in high Numberss ( 107 to 08 ) ( Fuller, 2001 ) and exhibit stable, relentless and host-specific adhesion effects ( Fuller, 1973 ) . Consequently, predomination of Lactobacilli in the harvest consequences in the production of lactic acid that can cut down Escherichia coli and Salmonella significantly during taint ( Fuller, 1977 ; Durant et al. , 1999 ; 2000 ) .
Microbial colonisation of the domestic fowl GI piece of land starts with microbic contact from eggshell, provender, and other environmental beginnings instantly after hatching ( Cressman, 2009 ) . Normal microflora colonise the GI piece of land get downing with the early post-hatch period, organize a symbiotic relationship with the host and have a important impact on the consumption and use of energy and foods ( Choct et al. , 1996 ; Smits et al. , 1997 ; Apajalahati and Bedford, 2000 ; Torok et al. , 2007 ) . Development of the little enteric microflora is observed in the first two hebdomads of post-hatching until several hebdomads ( Ochi et al. , 1964 ; Smith, 1965 ; Smirnov et al. , 2006 ) . Immediately after hatching there is grounds that bacteriums, peculiarly Streptococci and Enterobacteria, multiply ab initio in the caecum and spread throughout the alimental piece of land within 24 hour ( Smith et al. , 1965 ) . Lactobacilli can go established by the 3rd twenty-four hours, while the streptococcus and enteric bacteria easy diminution in the GI piece of land except in the caecum ( Barnes et al. , 1972 ) . By 2 hebdomads of age, Lactobacilli became the predominant microflora with occasional Streptococci and Enterobacteria in the duodenum, and lower parts of the little bowel ( Barnes et al. , 1972 ) . In the caecum, Bifidobacterium set up as prevailing microflora by 30 yearss ( Ochi et al. , 1964 ) . Recent grounds based on real-time PCR analyses of fecal matters from 3 to 12-day-old broilers besides indicates the presence of methanogens ( Saengkerdsub et al. , 2007b ) . In grownup birds most of the methanogens have been identified as Methanobrevibacter woesei ( Saengkerdsub et al. , 2007a ) . Overall, the composing of the microflora undergoes major alterations during the clip of hatch and the anerobic microflora becomes established which requires important sums of substrates such as saccharides ( Apajalahti et al. , 2002 ) .
The diverse microbic community profile therefore developed over clip can be identified through molecular techniques such as Denatured Gradient Gel Electrophoresis ( DGGE ) % G ( Guanine ) + C ( Cytosine ) profiling and 16S rDNA sequencing ( Apajalahti et al. , 2002 ; Gong et al. , 2002 ; Hanning and Ricke, 2011 ; Holben et al. , 2002 ; Zhu et al. , 2002 ) . Studies conducted based on these methods revealed that: ( 1 ) merely 10 % of the GI bacteriums represent antecedently known bacterial species ( Maidak et al. , 1999 ) , ( 2 ) . Thirty-five % represent antecedently unknown species within a known bacterial genus ; ( 3 ) and the staying 55 % represent bacterium for which even the genus is wholly unknown. Furthermore, a sum of 640 different species and 140 different bacterial genera were found in the lily-livered GI piece of land.
The microbic community profile in the lily-livered GI piece of land is chiefly influenced by the diet ( grain base ) and the age of the bird ( Barnes et al. , 1972 ) . Apajalahati and Bedford ( 2000 ) studied the consequence of grains ( wheat, maize or rye ) on the microbic community profile and concluded that incorporation of rye in the diet increased the copiousness of bacteriums with a 35 to 40 % G + C content significantly when compared to wheat and maize. In the same survey, wheat increased the proportion of bacteriums with G+C between 55 and 59 % and at 69 % . However, this survey did non uncover the bacterial individuality, but concluded that incorporation of diet with maize favored low % G+C micro-organism ( Clostridia and Campylobacter ) , rye stimulated the growing of Lactobacilli and Enterococci, whereas the wheat-based diet favored higher % G+C micro-organism ( Propionibacteria and Bifidobacteria ) . In add-on to diets, processing of grains have besides demonstrated important effects as different processed diets favored different bacteriums in the GI piece of land of poulet regardless of whether they originated from the same natural stuff ( Apajalahti et al. , 2001 ) . Furthermore, anaerobes and Lactobacilli were found to be significantly lower in ventriculuss of broilers fed with sorghum and wheat based diets when compared to broilers raised on barley and maize diets ( Shakouri et al. , 2008 ) . Similar differences were observed in caecum while in the ileum there was no consequence of grains on anaerobic and Lactobacilli populations ( Shakouri et al. , 2008 ) . Supplement of the diets with fats and their beginning has been observed to act upon microbiota construction ( Knarreborg et al. , 2002 ; DAA¤nicke et al. , 1999 ) . Knarreborg et Al. ( 2002 ) studied the consequence of animate being and works derived fats on the microbiota within the ileum of broilers ( 14 to 21 vitamin D ) and reported that the beginning of dietetic fat significantly altered the feasible populations of Clostridium perfringens while Lactobacilli species were non affected. DAA¤nicke et Al. ( 1999 ) demonstrated that broilers fed diets with beef tallow when compared to soybean oil had significantly more Gram positive coccus in the harvest, jejunum, and ileum ( 1.18, 1.05, 1.36, and 2.10 CFU/log10 higher ) at twenty-four hours 16. Enterobacter was well higher in the harvest and duodenum ( 1.05 and 1.30 CFU/log10 higher severally ) in birds fed with soybean oil and the entire figure of anaerobes did non vary well across enteric sections due to the beginning of fat.