The aim of this study was to examine the effects of heat stress (HS) on the pituitary-adrenal axis and whether the treatments with early-age thermal conditioning (ETC) and vitamin C, alone and in combination, could have a beneficial effect in alleviating these effects. For the experiment, 400 one day-old broilers (both sexes) were used, being divided into four groups. The first group was the control (K), the second group (C) consisted of broilers which received vitamin C from the 22nd to the 42nd day via water in the amount of 2.00 g L-1, in the third group (T), broilers were exposed to ETC for a period of 24 hr at a temperature of 38.00 ± 1.00 ˚C and the fourth group (T + C) was the combination of T and C groups. Immunohistochemically positive adrenocorticotropic hormone (ACTH) cells of broilers in all groups were irregular or stellate and distributed in the periphery and central parts of the pituitary gland, as solitary cells or in clusters. In the T + C group of broilers, a significant increase in the area of ACTH cells (18.91%) and their cores (22.75%), and cortisol level in serum compared to the control group was observed. This reaction of broilers in the T + C group facilitated their adaptation to unfavorable consequences of HS. These results suggest that hypothalamic-pituitary-adrenal axis is stimulated after the exposure to chronic HS, enabling successful adaptation of broilers to adverse conditions.

Poultry meat contaminated with Campylobacter, a major bacterial cause of foodborne gastroenteritis worldwide, is considered the primary source of human campylobacteriosis. Thus, reduction or elimination of Campylobacter in poultry production will have a significant impact on food safety and public health. Despite the significant progress made over the last decades, many puzzles remain about the epidemiology of Campylobacter on poultry farms, hampering the development of an effective control strategy. This longitudinal study was conducted to determine the prevalence and genetic diversity of Campylobacter in a U.S. commercial broiler production farm system. Cecal contents (15 samples/flock) and boot swabs (3 samples/flock) were collected from approximately 6-wk-old birds from 406 conventional broiler flocks reared in 53 houses on 15 farms (located within a relatively close geographic proximity and managed by the same poultry integrator) for up to eight consecutive production cycles and cultured for Campylobacter. Pulsed-field gel electrophoresis was used to investigate the genetic diversity of the Campylobacter jejuni isolates recovered from the cecal contents. The prevalence of Campylobacter at the farm, house, and flock levels were found to be 93% (14/15), 79% (42/53), and 47% (192/406), respectively. Campylobacter prevalence varied remarkably among different farms and flocks, with some farms or houses testing consistently negative while others being positive all the time over the entire study period. Campylobacter isolation rate changed significantly by sample type (higher by cecal contents vs. boot swabs) and season/production cycle (higher in spring vs. other seasons). The majority (88%; 2364/2675) of the isolates were identified as C. jejuni, and almost all the rest (11%; 303/2675) were Campylobacter coli. Genotyping showed limited diversity within a flock and suggested persistence of some C. jejuni clones over multiple production cycles on the same farm. In conclusion, this study indicated that although Campylobacter prevalence was overall high, there were marked differences in the prevalence among the broiler flocks or farms tested. Future studies aimed at identification of potential risk factors associated with differential Campylobacter status are warranted in order to develop effective on-farm interventions.
Estudio longitudinal sobre Campylobacter en parvadas comerciales de pollo de engorde criados convencionalmente en los Estados Unidos: prevalencia y diversidad genética. Los productos cárnicos de origen avícola contaminado con Campylobacter, que es una importante causa bacteriana de gastroenteritis transmitida por alimentos en todo el mundo, se consideran la principal fuente de campilobacteriosis humana. Por lo tanto, la reducción o eliminación de Campylobacter en la producción avícola tendrá un impacto significativo en la seguridad alimentaria y en la salud pública. A pesar de los importantes avances realizados en las últimas décadas, persisten muchos enigmas sobre la epidemiología de Campylobacter en las granjas avícolas, lo que obstaculiza el desarrollo de una estrategia de control eficaz. Este estudio longitudinal se realizó para determinar la prevalencia y la diversidad genética de Campylobacter en un sistema de granja de producción comercial de pollos de engorde en los Estados Unidos. Se recogieron contenidos cecales (15 muestras/parvada) y cubre botas de arrastre (tres muestras/parvada) de aves de aproximadamente seis semanas de edad de 406 parvadas de pollos de engorde convencionales criadas en 53 casetas de 15 granjas (ubicadas dentro de una proximidad geográfica relativamente cercana y manejadas por el mismo integrador avícola) durante ocho ciclos de producción consecutivos y con cultivo para Campylobacter. Se utilizó electroforesis en gel de campo con pulsasiones para investigar la diversidad genética de los aislados de Campylobacter jejuni recuperados del contenido cecal. Se encontró que la prevalencia de Campylobacter a nivel de granja, caseta y parvada era del 93% (14/15), 79% (42/53) y 47% (192/406), respectivamente. La prevalencia de Campylobacter varió notablemente entre diferentes granjas y rebaños, y algunas granjas o casetas dieron resultados consistentemente negativos mientras que otras dieron positivo todo el tiempo durante todo el período del estudio. La tasa de aislamiento de Campylobacter cambió significativamente según el tipo de muestra (mayor con muestras de contenido cecal en comparación con los cubre botas de arrastre) y la estación/ciclo de producción (mayor en primavera frente a otras estaciones). La mayoría (88%; 2364/2675) de los aislados se identificaron como C. jejuni, y casi todo el resto (11%; 303/2675) fueron Campylobacter coli. La genotipificación mostró una diversidad limitada dentro de una parvada y sugirió la persistencia de algunos clones de C. jejuni durante múltiples ciclos de producción en la misma granja. En conclusión, este estudio indicó que, aunque la prevalencia de Campylobacter fue alta en general, hubo marcadas diferencias en la prevalencia entre las parvadas o granjas de pollos de engorde analizadas. Se justifica la conducción de estudios futuros destinados a identificar posibles factores de riesgo asociados con el estado diferencial de Campylobacter para desarrollar intervenciones efectivas en las granjas.

L-tryptophan has been utilized as a feed additive in animal nutrition to improve growth performance, as well as a dietary supplement to alleviate various emotional symptoms in humans. Despite its benefits, concerns regarding its safety arose following the outbreak of eosinophilia-myalgia syndrome (EMS) among individuals who consumed L-tryptophan. The causative material of EMS was determined to be not L-tryptophan itself, but rather L-tryptophan impurities resulting from a specific manufacturing process. To investigate the effect of L-tryptophan and its impurities on humans who consume meat products derived from animals that were fed L-tryptophan and its impurities, an animal study involving broiler chickens was conducted. The animals in test groups were fed diet containing 0.065%-0.073% of L-tryptophan for 27 days. This study aimed to observe the occurrence of toxicological or EMS-related symptoms and analyze the residues of L-tryptophan impurities in meat products. The results indicated that there was no evidence of adverse effects associated with the test substance in the investigated parameters. Furthermore, most of the consumed EMS-causing L-tryptophan impurities did not remain in the meat of broiler chickens. Thus, this study demonstrated the safety of L-tryptophan and some of its impurities as a feed additive.

This study was conducted in order to compare well established used chemical anticoccidial medication (diclazuril) against natural prepared safe alternative products of garlic extract (GE), Moringa oleifera (MO) leaves extract, onion extract (OE), in order to control experimentally infected with Eimeria tenella species in chickens. Performance parameter in form of average body weight (ABW) and feed conversion rate (FCR) were studied together with biochemical parameters (malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT), mortality rate, oocyst count in addition to total white blood cell (WBCs), lymphocytes and heterophils counts. Histopathological examination of intestinal tract in all test groups was studied. Results revealed that the lowest mortality rate was found in group treated with MO leaves extract. All challenged herbal extract treated groups revealed ABW and FCR lower than diclazuril treated infected group. All treated groups were lower in both average lesion score and average oocyst count two weeks post challenge when compared with control positive group indicate positive impact of all studied therapies either chemical or herbal products but with variable degrees as best effect was diclazuril followed by MO group, followed by GE group and finally group treated with OE. Experimental infection of chickens with E. tenella oocysts significantly increased MDA concentration when compared with control negative non-treated group (P < 0.01). However, infected birds fed with OE, GE, MO leaves extracts and diclazuril administration for a week pre-infection had significantly declined MDA concentrations compared with infected non-treated (P < 0.01). Control positive birds showed significant decrease in SOD and CAT activities vs. the healthy birds either at week pre-infection or at two days\' post-infection (P < 0.01). However, SOD activities in birds fed with OE, MO leaves extract and diclazuril for a week pre-infection significantly higher (P < 0.01) than control positive. Histopathological finding revealed that best was group treated with diclazuril followed by group received MO, followed by group received GE and finally group received OE. It could be concluded that herbal extract may be representing a good alternative anticoccidial medications specially that the later may developed resistance for many Eimeria species in continuous use in veterinary field.

UNASSIGNED: Infectious bronchitis virus (IBV) causes severe economic losses worldwide. IBV has a broad tissue distribution with different viral loads in different tissues. Additionally, IBV can induce apoptosis in infected cells.
UNASSIGNED: The present study aimed to evaluate the role of the genetic background of chickens in viral load and the expression level of apoptotic genes in different tissues of two hybrids of commercial broiler chickens (Ross 308 and Cobb 500) challenged with IBV.
UNASSIGNED: Chickens at 21 days of age were nasally challenged with 200 μL of allantoic fluid containing 104 EID50/ml of Iranian variant-2-like IBV (IS/1494). The expression level of apoptotic genes (Fas, FasL, Bax, and Bcl-2) in the tracheal and renal tissues and the amount of viral load in the tracheal, renal, and cloacal swab samples were investigated two, five, and seven days after IBV infection by RT-qPCR assay.
UNASSIGNED: The amount of viral load and apoptotic the expression level of apoptotic genes in the tracheal (two and five days after infection) and renal samples (seven days after infection) were significantly higher in the Ross challenged group than in the Cobb challenged group.Furthermore, no difference was observed in the cloaca viral load on sampling days.
UNASSIGNED: To our knowledge, this is the first report that evaluated the role of the chickens\' genetic background in the amount of viral load and the expression level of apoptotic genes against IBV. Further studies are needed to investigate the pathogenic characteristics of IBV in Ross 308 and Cobb 500 chickens.

This pilot investigation aimed at studying the feasibility of using a low dose (0.2%) of dietary microalgae as a means of improving intestinal morphometry, body weight, and selected meat quality parameters in broilers. A total of 72 one-day-old ROSS 308 male chicks were randomly separated into four groups; three experimental pens in which the birds were fed with biomass from Tysochrysis lutea, Tetraselmis chuii, and Porphyridium cruentum over 30 days and a control group. T. chuii and P. cruentum had a positive effect with regard to body weight. In treated animals, duodenal and ileal sections showed characteristic tall and thin villi, with serrated surfaces and goblet cell differentiation. In both sections, values of the villus-height-to-crypt-depth ratio were increased by microalgae ingestion. The thawing weight loss of fillets was reduced in T. chuii-fed animals. The positive effects exerted by T. chuii and P. cruentum on intestinal architecture were associated with the improved body weight. Arguably, these outcomes exhibit the potential of using these species to enhance growth performance in broiler chickens by promoting gut homeostasis and thus nutrient absorption.

Therapeutic and growth-promoting antibiotics are frequently used in broiler production. Indirect evidence indicates that these practices are linked to the proliferation of antimicrobial resistance (AMR), the spread of antibiotic-resistant bacteria from food animals to humans, and the environment, but there is a lack of comprehensive experimental data supporting this. We investigated the effects of growth promotor (bacitracin) and therapeutic (enrofloxacin) antibiotic administration on AMR in broilers for the duration of a production cycle, using a holistic approach that integrated both culture-dependent and culture-independent methods. We specifically focused on pathogen-harboring families (Enterobacteriaceae, Enterococcaceae, and Staphylococcaceae).
Antibiotic-resistant bacteria and antibiotic resistance genes were ubiquitous in chicken cloaca and litter regardless of antibiotic administration. Environment (cloaca vs. litter) and growth stage were the primary drivers of variation in the microbiomes and resistomes, with increased bacterial diversity and a general decrease in abundance of the pathogen-harboring families with age. Bacitracin-fed groups had higher levels of bacitracin resistance genes and of vancomycin-resistant Enterococcaceae (total Enterococcaceae counts were not higher). Although metagenomic analyses classified 28-76% of the Enterococcaceae as the commensal human pathogens E. faecalis and E. faecium, culture-based analysis suggested that approximately 98% of the vancomycin-resistant Enterococcaceae were avian and not human-associated, suggesting differences in the taxonomic profiles of the resistant and non-resistant strains. Enrofloxacin treatments had varying effects, but generally facilitated increased relative abundance of multidrug-resistant Enterobacteriaceae strains, which were primarily E. coli. Metagenomic approaches revealed a diverse array of Staphylococcus spp., but the opportunistic pathogen S. aureus and methicillin resistance genes were not detected in culture-based or metagenomic analyses. Camphylobacteriaceae were significantly more abundant in the cloacal samples, especially in enrofloxacin-treated chickens, where a metagenome-assembled C. jejuni genome harboring fluoroquinolone and β-lactam resistance genes was identified.
Within a \"farm-to-fork, one health\" perspective, considering the evidence that bacitracin and enrofloxacin used in poultry production can select for resistance, we recommend their use be regulated. Furthermore, we suggest routine surveillance of ESBL E. coli, vancomycin-resistant E. faecalis and E. faecium, and fluoroquinolone-resistant C. jejuni strains considering their pathogenic nature and capacity to disseminate AMR to the environment. Video Abstract.

Silver nanoparticles (AgNPs) have recently emerged as promising growth promoters and immune-lifting agents in the poultry industry. This study investigated the potential impact of AgNP supplementation in the drinking water (DW) of broiler chickens during the fattening period. AgNPs were produced through chemical reduction using starch as a reducing and stabilizing agent. Different concentrations (1-5 ppm) of AgNPs were prepared and added to the DW of five different groups of chickens. Results confirmed efficient and safe application of AgNPs in DW at concentrations up to 2 ppm in term of growth performance (body weight, body weight gain, and feed conversion ratio) and hematological parameters. However, higher concentrations (3-5 ppm) induced dose-dependent mild-to-moderate adverse effects on hematological, biochemical, and oxidative parameters (MDA, TAC, and GSH-px). While growth performance, gene expression of fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA),and insulin-like growth factor (IGF1) in muscle, histopathological and immunohistochemical evaluation of liver, kidney, spleen, bursa, and thymus, and ultrastructural analysis of breast muscle were not significantly affected, even at high concentrations of AgNPs. Therefore, supplementation of AgNPs up to 2 ppm in the DW of broilers is promising.

BACKGROUND: Immunological stress decreases feed intake, suppresses growth and induces economic losses. However, the underlying molecular mechanism remains unclear. Label-free liquid chromatography and mass spectrometry (LC-MS) proteomics techniques were employed to investigate effects of immune stress on the hepatic proteome changes of Arbor Acres broilers (Gallus Gallus domesticus) challenged with Escherichia coli lipopolysaccharide (LPS).
RESULTS: Proteomic analysis indicated that 111 proteins were differentially expressed in the liver of broiler chickens from the immune stress group. Of these, 28 proteins were down-regulated, and 83 proteins were up-regulated in the immune stress group. Enrichment analysis showed that immune stress upregulated the expression of hepatic proteins involved in defense function, amino acid catabolism, ion transport, wound healing, and hormone secretion. Furthermore, immune stress increased valine, leucine and isoleucine degradation pathways.
CONCLUSIONS: The data suggests that growth depression of broiler chickens induced by immune stress is triggered by hepatic proteome alterations, and provides a new insight into the mechanism by which immune challenge impairs poultry production.

Citrinin (CIT) is a polyketide mycotoxin occurring in a variety of food and feedstuff, among which cereal grains are the most important contaminated source. Pigs and poultry are important livestock animals frequently exposed to mycotoxins, including CIT. Concerns are rising related to the toxic, and especially the potential nephrotoxic, properties of CIT. The purpose of this study was to clarify the histopathological effects on kidneys, liver, jejunum and duodenum of pigs, broiler chickens and laying hens receiving CIT contaminated feed. During 3 weeks, pigs (n = 16) were exposed to feed containing 1 mg CIT/kg feed or to control feed (n = 4), while 2 groups of broiler chickens and laying hens (n = 8 per group) received 0.1 mg CIT/kg feed (lower dose group) and 3 or 3.5 mg CIT/kg feed (higher dose group), respectively, or control feed (n = 4). CIT concentrations were quantified in plasma, kidneys, liver, muscle and eggs using a validated ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. Kidneys, liver, duodenum and jejunum were evaluated histologically using light microscopy, while the kidneys were further examined using transmission electron microscopy (TEM). Histopathology did not reveal major abnormalities at the given contamination levels. However, a significant increase of swollen and degenerated mitochondria in renal cortical cells from all test groups were observed (p < 0.05). These observations could be related to oxidative stress, which is the major mechanism of CIT toxicity. Residues of CIT were detected in all collected tissues, except for muscle and egg white from layers in the lowest dose group, and egg white from layers in the highest dose group. CIT concentrations in plasma ranged between 0.1 (laying hens in lower dose group) and 20.8 ng/mL (pigs). In tissues, CIT concentrations ranged from 0.6 (muscle) to 20.3 µg/kg (liver) in pigs, while concentrations in chickens ranged from 0.1 (muscle) to 70.2 µg/kg (liver). Carry-over ratios from feed to edible tissues were between 0.1 and 2% in pigs, and between 0.1 and 6.9% in chickens, suggesting a low contribution of pig and poultry tissue-derived products towards the total dietary CIT intake for humans.