Assessment of the Impact of Humic Acids on Intestinal Microbiota, Gut Integrity, Ileum Morphometry, and Cellular Immunity of Turkey Poults Fed an Aflatoxin B1-Contaminated Diet.

A recent study published data on the growth performance, relative weights of the organs of the gastrointestinal tract, liver histology, serum biochemistry, and hematological parameters for turkey poults fed an experimental diet contaminated with aflatoxin B1 (AFB1) and humic acids (HA) extracted from vermicompost. The negative effects of AFB1 (250 ng AFB1/g of feed) were significantly reduced by HA supplementation (0.25% w/w), suggesting that HA might be utilized to ameliorate the negative impact of AFB1 from contaminated diets. The present study shows the results of the remaining variables, as an extension of a previously published work which aimed to evaluate the impact of HA on the intestinal microbiota, gut integrity, ileum morphometry, and cellular immunity of turkey poults fed an AFB1-contaminated diet. For this objective, five equal groups of 1-day-old female Nicholas-700 turkey poults were randomly assigned to the following treatments: negative control (basal diet), positive control (basal diet + 250 ng AFB1/g), HA (basal diet + 0.25% HA), HA + AFB1 (basal diet + 0.25% HA + 250 ng AFB1/g), and Zeolite (basal diet + 0.25% zeolite + 250 ng AFB1/g). In the experiment, seven replicates of ten poults each were used per treatment (n = 70). In general, HA supplementation with or without the presence of AFB1 showed a significant increase (p < 0.05) in the number of beneficial butyric acid producers, ileum villi height, and ileum total area, and a significant reduction in serum levels of fluorescein isothiocyanate-dextran (FITC-d), a marker of intestinal integrity. In contrast, poults fed with AFB1 showed a significant increase in Proteobacteria and lower numbers of beneficial bacteria, clearly suggesting gut dysbacteriosis. Moreover, poults supplemented with AFB1 displayed the lowest morphometric parameters and the highest intestinal permeability. Furthermore, poults in the negative and positive control treatments had the lowest cutaneous basophil hypersensitivity response. These findings suggest that HA supplementation enhanced intestinal integrity (shape and permeability), cellular immune response, and healthier gut microbiota composition, even in the presence of dietary exposure to AFB1. These results complement those of the previously published study, suggesting that HA may be a viable dietary intervention to improve gut health and immunity in turkey poults during aflatoxicosis.

Early Detection of Histomoniasis in Blood Samples by PCR and Sequencing.

Histomoniasis is a deadly disease of turkeys causing devastating economic losses to the poultry industry. In field outbreaks, a presumptive diagnosis is made based on gross pathology lesions and confirmed by histopathology. An early detection tool with quick turnaround time is needed to prevent the spread of histomoniasis. With this objective, two studies were conducted in turkeys. In Study 1, 40 poults were housed in two pens (20 poults/pen) and challenged at 14 days of age with Histomonas meleagridis by intracloacal route. Blood samples were collected 4 days postchallenge. Fifty-five percent (22/40) of the blood samples tested positive for H. meleagridis based on PCR using primers targeted against the 18S rRNA gene and confirmed by sequencing. In Study 2, 40 poults were housed in two groups and raised in floor pens. Groups 1 and 2 served as negative and challenge controls, respectively. At 14 days of age, the birds in Group 2 were challenged with H. meleagridis by intracloacal route. Blood samples were collected 2 days postchallenge. Five percent (1/20) of the blood samples tested positive for H. meleagridis, based on PCR and confirmed by sequencing. The results from both studies indicate that H. meleagridis DNA can be detected in the blood samples by PCR and confirmed by sequencing as early as 4 days postchallenge. This early detection method could be applied in field outbreaks to detect and confirm histomoniasis as early as possible.

Detección temprana de histomoniasis en muestras de sangre mediante PCR y secuenciación La histomoniasis es una enfermedad mortal de los pavos que causa pérdidas económicas devastadoras a la industria avícola. En los brotes de campo, se realiza un diagnóstico presuntivo basado en lesiones patológicas macroscópicas y se confirma mediante histopatología. Se necesita una herramienta de detección temprana con un tiempo de respuesta rápido para prevenir la propagación de la histomoniasis. Con este objetivo, se realizaron dos estudios en pavos. En el Estudio 1, se alojaron 40 pavipollos en dos corrales (20 pavipollos/corral) y se desafiaron a los 14 días de edad con Histomonas meleagridis por vía intracloacal. Se recolectaron muestras de sangre a los cuatro días después del desafío. El cincuenta y cinco por ciento (22/40) de las muestras de sangre resultaron positivas para H. meleagridis según el método de PCR utilizando iniciadores dirigidos contra el gene 18S rRNA y confirmado mediante secuenciación. En el Estudio 2, se alojaron 40 pavipollos en dos grupos y se criaron en corrales en piso. Los grupos 1 y 2 sirvieron como controles negativos y de desafío, respectivamente. A los 14 días de edad, las aves del Grupo 2 fueron expuestas a H. meleagridis por vía intracloacal. Se recolectaron muestras de sangre dos días después del desafío. El cinco por ciento (1/20) de las muestras de sangre dieron positivo para H. meleagridis, según el método de PCR y confirmado mediante secuenciación. Los resultados de ambos estudios indican que el ADN de H. meleagridis puede detectarse en las muestras de sangre mediante PCR y confirmarse mediante secuenciación tan pronto como cuatro días después de la exposición. Este método de detección temprana podría aplicarse en brotes de campo para detectar y confirmar la histomoniasis lo antes posible.

Detection of lymphoproliferative disease virus in Iowa Wild Turkeys (Meleagris gallopavo): Comparison of two sections of the proviral genome.

An accurate diagnostic test is an essential aspect of successfully monitoring and managing wildlife diseases. Lymphoproliferative Disease Virus (LPDV) is an avian retrovirus that was first identified in domestic turkeys in Europe and was first reported in a Wild Turkey (Meleagris gallopavo) in the United States in 2009. It has since been found to be widely distributed throughout North America. The majority of studies have utilized bone marrow and PCR primers targeting a 413-nucleotide sequence of the gag gene of the provirus to detect infection. While prior studies have evaluated the viability of other tissues for LPDV detection (whole blood, spleen, liver, cloacal swabs) none to date have studied differences in detection rates when utilizing different genomic regions of the provirus. This study examined the effectiveness of another section of the provirus, a 335-nucleotide sequence starting in the U3 region of the LTR (Long Terminal Repeat) and extending into the Matrix of the gag region (henceforth LTR), for detecting LPDV. Bone marrow samples from hunter-harvested Wild Turkeys (n = 925) were tested for LPDV with the gag gene and a subset (n = 417) including both those testing positive and those where LPDV was not detected was re-tested with LTR. The positive percent agreement (PPA) was 97.1% (68 of 70 gag positive samples tested positive with LTR) while the negative percent agreement (NPA) was only 68.0% (236 of 347 gag negative samples tested negative with LTR). Cohen's Kappa (κ = 0.402, Z = 10.26, p<0.0001) and the McNemar test (OR = 55.5, p<0.0001) indicated weak agreement between the two gene regions. We found that in Iowa Wild Turkeys use of the LTR region identified LPDV in many samples in which we failed to detect LPDV using the gag region and that LTR may be more appropriate for LPDV surveillance and monitoring. However, neither region of the provirus resulted in perfect detection and additional work is necessary to determine if LTR is more reliable in other geographic regions where LPDV occurs.

The response of turkeys to dietary balanced protein during two periods of growth.

1. Two experiments were conducted to measure the response of growing turkeys to dietary protein content. In the first, 960 sexed British United Turkey (BUT 6) poults were used to measure the response to balanced protein from 3 to 6 weeks of age. In the second, 1440 sexed BUT and Hybrid Converter poults were raised from 14 to 17 weeks.2. In both experiments, six levels of dietary protein were fed, with feed intake, body and feather weight gain and changes in body composition measured. The levels of protein chosen ranged from 0.53 to 1.2 of the Aviagen requirements for growing turkeys.3. In the first experiment, six poults were sampled from each sex at the start of the experiment for carcass analysis, and four were sampled from each strain and sex in the second. At the end of each experiment, eight poults from each treatment were sampled. Body composition analyses were made on individual defeathered birds.4. Weight gain increased linearly with protein intake in the early period and exponentially in the later period. In both periods, feed intake decreased as protein content reduced.5. In the early period, body lipid content increased from 20.2 to 41.5 g/kg body weight, as dietary protein content decreased, but there was no change in the later period. Efficiency of utilisation of dietary protein declined linearly with an increase in dietary protein content, from 0.87 to 0.46 g/g in the first, and from 0.43 to 0.27 g/g in the later period.6. The inability of the growing turkey to increase feed intake on marginally limiting feeds may have been due to a genetic constraints to store excess energy consumed as body lipid, resulting in the observed decrease in feed intake as dietary protein content is reduced.

Status quo: Levels of Campylobacter spp. and hygiene indicators in German slaughterhouses for broiler and turkey.

Poultry is a common reservoir for Campylobacter and a main source for human campylobacteriosis. With broiler being the predominant poultry for food production, most food safety related research is conducted for this species, for turkey, few studies are available. Although animals are typically colonized at the farm level, the slaughtering process is considered an important factor in re- and cross-contamination. We examined the development of Campylobacter, E. coli and total colony counts (TCC) after several processing steps in three broiler and one turkey slaughterhouses. Whole carcass rinsing and neck skin sampling was applied for broilers resulting in 486 samples in total, while 126 neck skin samples were collected for turkeys. A decrease in the loads of the different bacterial groups along the broiler slaughtering process was observed. Campylobacter mean counts dropped from 4.5 ± 1.7 log10 CFU/ml after killing to 1.6 ± 0.4 log10 CFU/ml after chilling. However, an increase in Campylobacter counts was evident after evisceration before the values again decreased by the final processing step. Although the Campylobacter prevalence in the turkey samples showed a similar development, the bacterial loads were much lower with 1.7 ± 0.3 log10 CFU/g after killing and 1.7 ± 0.4 log10 CFU/g after chilling compared to those of broilers. The loads of E. coli and total colony count of turkey were higher after killing, were reduced by scalding and remained stable until after chilling. This study highlights trends during the slaughtering process in reducing the levels of Campylobacter, E. coli, and total colony counts for broiler and turkey carcasses, from the initial step to after chilling. These results contribute to our understanding of microbial dynamics during meat processing.

Characterization of immune responses and immunopathology in turkeys experimentally infected with clostridial dermatitis-producing strains of Clostridium septicum.

Clostridium septicum is one of the major causative agents of clostridial dermatitis (CD), an emerging disease of turkeys, characterized by sudden deaths and necrotic dermatitis. Despite its economic burden on the poultry industry, the immunopathological changes and pathogen-specific immune responses are poorly characterized. Here, we used three strains of C. septicum, namely Str. A1, Str. B1 and Str. C1, isolated from CD field outbreaks, to experimentally infect turkeys to evaluate local (skin and muscle) and systemic (spleen) pathological and immunological responses. Results showed that while all three strains produced an acute disease, Str. A1 and B1 caused significantly higher mortality when compared to Str. C1. Gross and histopathology evaluation showed that birds infected with Str. A1 and B1 had severe inflammatory, edematous, granulomatous and necrotic lesions in the skin, muscle and spleen, while these lesions produced by Str. C1 were relatively less severe and mostly confined to skin and/or muscle. Immune gene expression in these tissues showed that Str. B1-infected birds had significantly higher expression of interleukin (IL)-1ß, IL-6 and interferon (IFN)γ genes compared to uninfected control, suggesting a robust inflammatory response both locally as well as systemically. The transcription of IL-1ß and IFNγ in the muscle or spleen of Str. A1-infected birds and IL-1ß in the skin of Str. C1-infected group was also significantly higher than control. Additionally, Str. A1 or B1-infected groups also had significantly higher IL-4 transcription in these tissues, while birds infected with all three strains developed C. septicum-specific serum antibodies. Furthermore, splenic cellular immunophenotyping in the infected turkeys showed a marked reduction in CD4+ cells. Collectively, it can be inferred that host responses against C. septicum involve an acute inflammatory response along with antibody production and that the disease severity seem to depend on the strain of C. septicum involved in CD in turkeys.

Monitoring antimicrobial resistance in Campylobacter isolates of chickens and turkeys at the slaughter establishment level across the United States, 2013-2021.

Foodborne infections with antimicrobial-resistant Campylobacter spp. remain an important public health concern. Publicly available data collected by the National Antimicrobial Resistance Monitoring System for Enteric Bacteria related to antimicrobial resistance (AMR) in Campylobacter spp. isolated from broiler chickens and turkeys at the slaughterhouse level across the United States between 2013 and 2021 were analysed. A total of 1,899 chicken-origin (1,031 Campylobacter coli (C. coli) and 868 Campylobacter jejuni (C. jejuni)) and 798 turkey-origin (673 C. coli and 123 C. jejuni) isolates were assessed. Chicken isolates exhibited high resistance to tetracycline (43.65%), moderate resistance to ciprofloxacin (19.5%), and low resistance to clindamycin (4.32%) and azithromycin (3.84%). Turkey isolates exhibited very high resistance to tetracycline (69%) and high resistance to ciprofloxacin (39%). The probability of resistance to all tested antimicrobials, except for tetracycline, significantly decreased during the latter part of the study period. Turkey-origin Campylobacter isolates had higher odds of resistance to all antimicrobials than isolates from chickens. Compared to C. jejuni isolates, C. coli isolates had higher odds of resistance to all antimicrobials, except for ciprofloxacin. The study findings emphasize the need for poultry-type-specific strategies to address differences in AMR among Campylobacter isolates.

Commercial vaccine provides cross-protection by reducing colonization of Salmonella enterica serovars Infantis and Hadar in turkeys.

Human foodborne outbreaks with antibiotic-resistant Salmonella enterica associated with contaminated poultry products have recently involved serogroup C serovars Infantis and Hadar. The current study evaluated a commercially available Salmonella vaccine for cross-protection against Infantis and Hadar serovars in turkeys. The live, attenuated S. Typhimurium (serogroup B) vaccine significantly reduced colonization of intestinal tissues (cecum, cecal tonsils, and cloaca) by serovars Infantis (C1) and Hadar (C2) and significantly limited systemic dissemination to the spleen. S. Infantis, but not S. Hadar, disseminated to bone marrow in non-vaccinated turkeys, but vaccination prevented S. Infantis dissemination to the bone marrow. The S. Infantis challenge strain contained the pESI megaplasmid, and virulence mechanism(s) residing on this plasmid may support dissemination and/or colonization of systemic niches such as myeloid tissue. Collectively, the data indicate that vaccinating turkeys with the serogroup B S. Typhimurium vaccine limited intestinal colonization and systemic dissemination by serogroup C serovars Infantis and Hadar.

Phylogenetically evolutionary analysis provides insights into the genetic diversity and adaptive evolution of porcine deltacoronavirus.

BACKGROUND: Porcine deltacoronavirus (PDCoV) is one of the emerging swine enteric coronaviruses (SECoVs), which has been widely prevalent in the North America and Asia. In addition to causing severe diarrhea in piglets, PDCoV also shows the potential to infect diverse host species, including calves, chickens, turkey poults, and humans. However, the clinical pathogenicity and genetic evolution of PDCoV is still not fully understood. RESULTS: Here, we recorded an outbreak of a novel recombinant PDCoV strain (CHN-HeN06-2022) in a large nursery fattening pig farm. Genomic analysis showed that the CHN-HeN06-2022 strain shared 98.3-98.7% sequence identities with the Chinese and American reference strains. To clarify the evolutionary relationships, phylogenetic analysis was performed using the PDCoV genome sequences available in the GenBank database. Based on genetic distance and geographical distribution, the phylogenetic tree clearly showed that all the PDCoV sequences could be divided into lineage 1 and lineage 2, which were further classified into sublineage 1.1 (Chinese strains), 1.2 (the North American strains), 2.1 (the Southeast Asian strains), and 2.2 (Chinese strains). Corresponding to the evolutionary tree, we found that, compared to lineage 1, lineage 2 strains usually contain a continuous 6-nt deletion in Nsp2 and a 9-nt deletion in Nsp3, respectively. Furthermore, recombination analysis suggested that the CHN-HeN06-2022 occurred segments exchange crossed Nsp2 and Nsp3 region between sublineage 1.1 and sublineage 2.1. Combined with previously reported recombinant strains, the highest recombination frequency occurred in Nsp2, Nsp3, and S gene. Additionally, we identified a total of 14 amino acid sites under positive selection in spike protein, most of which are located in the regions related with the viral attachment, receptor binding, and membrane fusion. CONCLUSIONS: Taken together, our studies provide novel insights into the genetic diversity and adaptive evolution of PDCoV. It would be helpful to the development of vaccine and potential antiviral agent.

Developing a risk management framework to improve public health outcomes by enumerating and serotyping Salmonella in ground turkey.

Salmonella enterica continues to be a leading cause of foodborne morbidity worldwide. A quantitative risk assessment model was developed to evaluate the impact of pathogen enumeration and serotyping strategies on public health after consumption of undercooked contaminated ground turkey in the USA. The risk assessment model predicted more than 20,000 human illnesses annually that would result in ~700 annual reported cases. Removing ground turkey lots contaminated with Salmonella exceeding 10 MPN/g, 1 MPN/g, and 1 MPN/25 g would decrease the mean number of illnesses by 38.2, 73.1, and 95.0%, respectively. A three-class mixed sampling plan was tested to allow the detection of positive lots above threshold levels with 2-6 (c = 1) and 3-8 samples per lot (c = 2) using 25-g and 325-g sample sizes for a 95% probability of rejecting a contaminated lot. Removal of positive lots with the presence of highly virulent serotypes would decrease the number of illnesses by 44.2-87.0%. Based on these model prediction results, risk management strategies should incorporate pathogen enumeration and/or serotyping. This would have a direct impact on illness incidence linking public health outcomes with measurable food safety objectives, at the cost of diverting production lots.

Phenotypic and Genotypic Characterizations of Antimicrobial-Resistant Escherichia coli Isolates from Diverse Retail Meat Samples in North Carolina During 2018-2019.

Surveillance of antimicrobial-resistant pathogens in U.S. retail meats is conducted to identify potential risks of foodborne illness. In this study, we conducted a phenotypic and genotypic analysis of Escherichia coli recovered from a diverse range of retail meat types during 2018-2019 in North Carolina. The investigation was conducted as part of the National Antimicrobial Resistance Monitoring System (NARMS). Retail meat sampling and E. coli isolation were performed in accordance with NARMS retail meat isolation protocols. We used the Sensititre™ broth microdilution system to determine phenotypic resistance to 14 antimicrobial agents and the Illumina next-generation sequencing platform for genotypic resistance profiling. The highest prevalence of E. coli isolates was found in ground turkey (n = 57, 42.9%) and chicken (n = 27, 20.3%), followed by ground beef (n = 25, 18.9%) and pork (n = 24, 18%). The isolates were divided into seven different phylogroups using the Clermont typing tool, with B1 (n = 59, 44.4%) and A (n = 39, 29.3%) being the most dominant, followed by B2 (n = 14, 10.5%), D (n = 7, 5.3%), F (n = 6, 4.5%), E (n = 3, 2.3%), and C (n = 2, 1.5%). Using multilocus sequence typing (MLST), 128 Sequence types (STs) were identified indicating high diversity. Phenotypic and genotypic resistance was observed toward aminoglycosides, sulfonamides, beta-lactams, macrolides, tetracyclines, phenicols, and fluoroquinolones. Ground turkey samples were more resistant to the panel of tested antimicrobials than chicken, beef, or pork (p < 0.05). All isolates were found to be susceptible to meropenem. A high percentage of turkey isolates (n = 16, 28%) were multidrug-resistant (MDR) compared with 18.5% of chicken (n = 5), 8.4% of pork (n = 2), and 8% of beef isolates (n = 2). This study highlights the benefit of surveillance to identify MDR E. coli for epidemiologic tracking and is a comprehensive report of the phenotypic and genotypic characterization of E. coli isolated from retail meats in North Carolina.

A cholesterol switch controls phospholipid scrambling by G protein-coupled receptors.

Class A G protein-coupled receptors (GPCRs), a superfamily of cell membrane signaling receptors, moonlight as constitutively active phospholipid scramblases. The plasma membrane of metazoan cells is replete with GPCRs yet has a strong resting trans-bilayer phospholipid asymmetry, with the signaling lipid phosphatidylserine confined to the cytoplasmic leaflet. To account for the persistence of this lipid asymmetry in the presence of GPCR scramblases, we hypothesized that GPCR-mediated lipid scrambling is regulated by cholesterol, a major constituent of the plasma membrane. We now present a technique whereby synthetic vesicles reconstituted with GPCRs can be supplemented with cholesterol to a level similar to that of the plasma membrane and show that the scramblase activity of two prototypical GPCRs, opsin and the ß1-adrenergic receptor, is impaired upon cholesterol loading. Our data suggest that cholesterol acts as a switch, inhibiting scrambling above a receptor-specific threshold concentration to disable GPCR scramblases at the plasma membrane.

Phenotypic and genotypic characterizations of bacteria isolated from the respiratory microbiota of healthy turkeys with potential for probiotic composition.

Desirable characteristics of Staphylococcus sp., Streptococcus sp., Bacillus sp., Klebsiella sp., Escherichia coli, and Pseudomonas pseudoalcaligenes isolated from the trachea of healthy turkeys were evaluated as probiotic candidates in the search for new alternatives to solve antimicrobial resistance issues in poultry. In current study phenotypic and genotypic capacity to produce bacteriocin-like substances, efficacy to inhibit the growth of avian pathogens, susceptibility to antimicrobials of bacteria isolated from the respiratory microbiota of healthy turkeys, and the presence of virulence-associated genes (VAGs) predictors of Avian Pathogenic Escherichia coli (APEC) were evaluated. Nine E. coli and one Klebsiella sp. strains produced bacteriocin-like substances, and all harbored the cvaA gene. Some strains also showed antagonistic activity against APEC. Multidrug-resistant profile was found in 54% of the strains. Six strains of bacteriocin-like substances producing E. coli also harbored 3-5 VAGs. The study showed that two bacterial genuses (Klebsiella sp. and E. coli) present desirable probiotic characteristics. Our results identified strains with potential for poultry's respiratory probiotic.

Assessing the effect of breed, age, and sex on muscarinic receptor distribution in atria and ventricles of turkeys.

Atrial and ventricular myocardium from young (6-wk-old), young adult (3-6-mo-old), and aged (14-15-mo-old) meat-type (B.U.T. Big 6) and wild-type (Cröllwitzer) turkeys were used to study the influence of age and sex on cholinergic muscarinic receptors using [3H]-N-methyl-scopolamine (3H-NMS) binding studies. In both breeds, saturation experiments indicated the presence of regional-, sex-, and age-related differences in the density of cholinergic muscarinic receptors (Bmax), that is, a decrease or increase. Except for right atria, Bmax was decreased in both male and female B.U.T. Big 6 hearts with increasing age. Similarly, a negative correlation between Bmax and age could be seen in female and male atria of Cröllwitzer turkeys, while positive correlation could be seen in right and left ventricles of male, and only right ventricles of female Cröllwitzer turkeys. The affinity of the receptor (KD) was not affected by age, sex and breed. In all cardiac chamber tissues, the M2-subtype was shown to be predominant followed by the M3-subtype and to a lesser extent the M1-subtype. Aspects of this age-dependent remodeling of the heart differ between sexes, resulting in maladaptive changes in older turkeys with a high degree of frailty. These observations may help explain why males and females are susceptible to different cardiovascular diseases as they age and why frail older adults are most often affected by these diseases.

Chromium propionate in turkeys: effect on performance and animal safety.

Two hundred eighty-eight male Nicholas Large White turkey poults were used to determine the effect of supplementing turkeys with chromium propionate (Cr Prop) from 1 to 84 d of age on performance and animal safety. Treatments consisted of Cr prop supplemented to provide 0, 0.2, or 1.0 mg Cr/kg diet. One mg of supplemental Cr is 5 times (x) the minimal concentration of Cr Prop that enhanced insulin sensitivity in turkeys. Each treatment consisted of 8 floor pens with 12 poults per pen. Turkeys were individually weighed initially, and at the end of the starter 1 (d 21), starter 2 (d 42), grower 1 (d 63), and grower 2 phase (d 84). On d 85, blood was collected from the wing vein in heparinized tubes from 2 turkeys per pen for plasma chemistry measurements. A separate blood sample was collected from the same turkeys in tubes containing K2EDTA for hematology measurements. Turkey performance was not affected by treatment during the starter 1 phase. Gain was greater (P = 0.024) and feed/gain lower (P = 0.030) for turkeys supplemented with Cr compared with controls during the starter 2 phase. Over the entire 84-d study turkeys supplemented with Cr had greater (P = 0.005) ADG and tended (P = 0.074) to gain more efficiently than controls. Gain (P = 0.180) and feed/gain (P = 0.511) of turkeys supplemented with 0.2 mg Cr/kg did not differ from those receiving 1.0 mg Cr/kg over the entire 84-d study. Feed intake was not affected by treatment. Body weights of turkeys supplemented with Cr were heavier (P = 0.005) than controls by d 84. Chromium supplementation did not affect hematological measurements and had minimal effect on plasma chemistry variables. Results of this study indicates that Cr Prop supplementation can improve turkey performance, and is safe when supplemented to turkey diets at 5x the minimal concentration that enhanced insulin sensitivity.

Research Note: Irritating flashing light or poultry-friendly lighting-are flicker frequencies of LED luminaires a potential stress factor in the husbandry of male fattening turkeys?

Conventional fluorescent tubes are increasingly being replaced with innovative light-emitting diodes (LEDs) for lighting poultry houses. However, little is known about whether the flicker frequencies of LED luminaires are potential stressors in poultry husbandry. The term "light flicker" describes the fluctuations in the brightness of an electrically operated light source caused by the design and/or control of the light source. In this context, the critical flicker frequency (CFF) characterizes the frequency at which a sequence of light flashes is perceived as continuous light. It is known that CFF in birds is higher than that in humans and that light flicker can affect behavioral patterns and stress levels in several bird species. As there is a lack of knowledge about the impact of flicker frequency on fattening turkeys, this study aimed to investigate the effects of flicker frequency on the behavior, performance, and stress response in male turkeys. In 3 trials, a total of 1,646 male day-old turkey poults of the strain B.U.T. 6 with intact beaks were reared for 20 wk in 12 barn compartments of 18 m² each. Each barn compartment was illuminated using 2 full-spectrum LED lamps. Flicker frequencies of 165 Hz, 500 Hz, and 16 kHz were set in the luminaires to illuminate the compartments. Analyses of feather corticosterone concentration were performed on fully grown third-generation primaries (P 3) of 5 turkeys from each compartment. No significant differences were found in the development of live weight, feed consumption, or prevalence of injured or killed turkeys by conspecifics reared under the above flicker frequencies. The flicker frequencies also did not significantly influence feather corticosterone concentrations in the primaries of the turkeys. In conclusion, the present results indicate that flicker frequencies of 165 Hz or higher have no detrimental effect on growth performance, injurious pecking, or endocrine stress response in male turkeys and, thus, may be suitable for use as animal-friendly lighting.

Research Note: Chromium propionate for turkeys: effect on tissue chromium concentrations and human food safety.

This study was conducted to determine the effect of supplementing turkey diets with chromium propionate (Cr Prop) on Cr concentrations in tissues consumed by humans. Nicholas White male day-old poults were used in this study. Treatments consisted of 0, 0.20, or 1.0 mg supplemental Cr/kg diet. Each treatment consisted of 8 replicate floor pens with 12 poults housed per pen. Diets were fed ad libitum for 84 d. At the end of the study, 2 turkeys per pen were euthanized and samples of liver, breast muscle, kidney, and skin with adhering fat were collected from a similar location in each bird for Cr analysis. Orthogonal contrasts were used to compare the 2 Cr supplemented treatments to the control (0 added Cr) and 0.20 mg Cr to 1.0 mg Cr/kg diet. When expressed on a DM or wet tissue basis, liver (P = 0.001) and muscle (P = 0.015) Cr concentrations were greater in turkeys supplemented with Cr compared with controls. Chromium concentrations in liver were also greater (P = 0.001) in turkeys supplemented with 1.0 mg Cr/kg than those receiving 0.20 mg Cr/kg. Concentrations of Cr in kidney and skin + fat were not affected by treatment. Considering the adequate intake of Cr established for humans, supplementation of Cr Prop at up to 1.0 mg Cr/kg diet would have minimal effect on total Cr intake by humans.

Lymphoproliferative Disease Virus and Reticuloendotheliosis Virus Detection and Disease in Wild Turkeys (Meleagris gallopavo).

Lymphoproliferative disease virus (LPDV) and reticuloendotheliosis virus (REV) are oncogenic retroviruses that can cause disease in wild and domestic fowl. Lymphoproliferative disease virus infections are common and widespread in Wild Turkeys (Meleagris gallopavo) in the US and east-central Canada, while REV has been detected worldwide in numerous avian host species. We tested tissues (spleen, liver, and/or bone marrow, plus neoplastic tissue, if present) from 172 Wild Turkeys that underwent necropsy from December 2018 through October 2021 for both viruses using PCR. We evaluated demographic, geographic, temporal, and seasonal data by chi-square test of independence and logistic regression for turkeys infected with LPDV and/or REV. At least one of these retroviruses was detected in 80.8% (139/172) of Wild Turkeys from 15 US states, with significantly more turkeys being positive for LPDV (72.1%, 124/172) versus REV (43.6%, 75/172; P<0.001). Both viruses (coinfections) were detected in 34.9% (60/172) of turkeys. Among LPDV-infected turkeys (including coinfections), bone marrow had the highest detection rate (38/58, 65.5%), significantly higher than spleen (30/58, 51.7%) and liver (20/58, 34.5%; P<0.001). In REV-infected turkeys, bone marrow had the highest detection rate (24/58, 41.4%). All three tissues (spleen, liver, bone marrow) concurrently tested positive in most (15/25, 60%) REV-infected turkeys. These results suggest LPDV tissue tropism for bone marrow, whereas REV may have broader tissue tropism. Histopathology consistent with lymphoid proliferation and/or neoplasia characteristic of lymphoproliferative disease was evident in 29/172 (16.9%) turkeys assessed, including two REV-only-infected turkeys. Season was significantly associated with LPDV prevalence (highest in winter); year and season were both significantly associated with REV prevalence (highest in 2020 and winter). These data contribute to optimizing diagnostic strategies that may aid in pathogen monitoring and improve detections to increase our understanding of the potential impacts of these viruses on Wild Turkey populations.

Molecular form identification of anterior pituitary gland-secreted prolactin in chicken.

Endocrine changes during bird reproduction are well documented. Prolactin (PRL) exhibits a strong relationship between incubation and broody behavior. The molecular forms of PRL in the anterior pituitary gland during the reproductive cycle have already been previously identified but not those in the secreted form. To identify the molecular forms of secreted PRL during the reproductive cycle, we thus monitored the physiological status and incubation behavior of 10 Silkie hens by a video recording system over 1-2 years. Nine out of ten mature hens exhibited incubation behavior multiple times during the experiment. Ten hens demonstrated two interesting features. In a typical clutch, hens spent 10-15 min in the nest to lay an egg. Once they spent over 1 h in the nest, the nest occupancy increased incrementally. This shift in the nest occupancy occurred 7-10 days before the incubation onset and was highly repeatable. Based on the behavior of the hens, we cultured the anterior pituitary gland during four stages (premature non-laying, laying, trans, and incubation) with physiological PRL-releasing factor, vasoactive intestinal peptide (VIP). Based on our two-dimensional protein analysis, glycosylated PRL (G-PRL) displayed several isoforms with varying isoelectric points (pI), whereas we could detect one primary signal for non-glycosylated PRL (NG-PRL). However, 3-4 NG-PRL isoforms were detected in the anterior pituitary gland. These results suggested that secreted PRL, especially from the trans and incubation stages, contains various isoforms and it is post-translationally glycosylated and phosphorylated.

Chromium propionate in turkeys: effects on insulin sensitivity.

The objective of this study was to evaluate the effects of dietary chromium (Cr), as Cr propionate (Cr Prop), on measures of insulin sensitivity in turkeys. Plasma glucose and nonesterified fatty acid (NEFA), and liver glycogen concentrations were used as indicators of insulin sensitivity. One-day-old Nicholas Large White female poults (n = 336) were randomly assigned to dietary treatments consisting of 0 (control), 0.2, 0.4, or 0.6 mg supplemental Cr/kg diet. Each treatment consisted of 12 replicate cages with 7 turkeys per cage. Final BW were taken on d 34, and on d 35 two birds from each cage were sampled for plasma glucose and NEFA, and liver glycogen determination at the initiation (fed state) and termination (fasted state) of a 24-h fast. Following a 24-h fast, 2 turkeys per cage were refed (refed state) their treatment diet for 4 h, and then harvested. Feed/gain and ADG did not differ between control and Cr-supplemented turkeys over the 34-d study, but feed intake tended (P = 0.071) to be greater for controls than turkeys receiving 0.4 mg Cr/kg diet. Fed turkeys had greater plasma glucose (P = 0.002) and liver glycogen (P = 0.001) concentrations, and lower (P = 0.001) NEFA concentrations than fasted birds. Turkeys refed after fasting had greater (P = 0.001) plasma glucose and liver glycogen concentrations, and lower (P = 0.001) plasma NEFA levels than fed turkeys. Liver glycogen and plasma NEFA concentrations did not differ among control and Cr-supplemented birds in the fed, fasted, or refed state. Plasma glucose concentrations were not affected by treatment in fed or fasted turkeys. Turkeys supplemented with 0.2 or 0.4 mg Cr/kg and refed after fasting had lower (quadratic, P = 0.038) plasma glucose concentrations than controls. Plasma glucose concentrations in refed birds did not differ among Cr-supplemented turkeys. The lower plasma glucose concentration in Cr-supplemented turkeys following refeeding is consistent with Cr enhancing insulin sensitivity.