Poultry Science

The widespread use of antibiotics in broiler production has contributed to antimicrobial resistance, necessitating the development of sustainable alternatives. Synbiotics, combining probiotics and prebiotics in a synergistic formulation, have emerged as promising candidates to replace antibiotics. This study evaluated the efficacy of dietary synbiotics as alternatives to early-life antibiotic supplementation in broiler chickens, examining their effects on growth performance, gut morphology, and welfare. A total of 80 mixed-sex Cobb 500 broiler chickens were allocated to a 2 x 2 factorial design investigating synbiotic supplementation (Bacillus subtilis and dried fermented Saccharomyces cerevisiae extract) and enrofloxacin treatment (days 0-5) administered via drinking water. During the initial growth period (days 0-7), synbiotic supplementation reduced body weight gain compared to controls. However, synbiotic x antibiotic interactions were observed during days 7-14 and 14-21, where synbiotics without antibiotics produced the highest weight gain in the second week, while controls without either treatment achieved superior performance in the third week. Feed intake was increased by synbiotic supplementation during days 7-14, while antibiotic treatment consistently elevated feed consumption throughout multiple periods and overall trial duration. Feed conversion efficiency was initially impaired by synbiotics (days 0-7) but improved during days 14-21. Antibiotic supplementation resulted in a poorer overall feed conversion ratio. Gut morphological analysis revealed significant synbiotic x antibiotic interactions for duodenal length and empty weights of duodenum and caeca, with synbiotics enhancing these parameters only when combined with antibiotic treatment. Both synbiotic and antibiotic supplementation independently reduced ileal content weight, while antibiotic treatment specifically decreased ileal weight and caecal length. Immune function evaluation through heterophil-to-lymphocyte ratios demonstrated a tendency for interaction, where synbiotics reduced this ratio in the absence of antibiotics but showed no effect when combined with antibiotic treatment. Neither treatment affected spleen or bursa weights, indicating minimal impact on immune organ development. These findings suggest that while dietary synbiotics show promise as alternatives to antibiotics in broiler production, their efficacy varies depending on concurrent antibiotic exposure and growth phase. Synbiotics demonstrated beneficial effects on gut morphology and stress markers, particularly when administered without concurrent antibiotic treatment, supporting their potential as functional alternatives in antimicrobial-free poultry production.

Salmonella infections are a leading cause of bacterial food-borne illness worldwide. Infections are highly associated with the consumption of contaminated food, and in particular, chicken meat. Understanding how management practices and environmental factors influence Salmonella populations in broiler chicken production may aid in reducing the risk of food-borne illness in humans. Utilizing whole genome sequencing with antimicrobial and heavy metal resistance, virulence factor and plasmid identification, we have characterized the genetic diversity of Salmonella enterica isolates (n = 55) obtained from broiler chicken litter. S. enterica isolates were recovered from the litter of broiler chickens over three consecutive flocks in four broiler houses on a single integrated farm in Georgia, USA. The chickens were raised under a newly adopted "No Antibiotics Ever" program and copper sulfate was administered via drinking water. In-silico serovar prediction identified three S. enterica serovars: Enteritidis (n = 12), Kentucky (n = 40) and Senftenberg (n = 3). Antimicrobial susceptibility testing revealed that only one S. Kentucky isolate was resistant to streptomycin, while the remaining isolates were susceptible to all antibiotics tested. Metal resistance operons, including copper and silver, were identified chromosomally and on plasmids in serovar Senftenberg and Kentucky isolates, respectively. Serovar Kentucky isolates harboring metal resistance operons were the only Salmonella isolates recovered from the litter of third flock cohort. These results suggest the addition of copper sulfate to drinking water may have selected for S. Kentucky isolates harboring plasmid-borne copper resistance genes and may explain their persistence in litter from flock to flock. ImportanceSalmonella foodborne illnesses are the leading cause of hospitalizations and deaths, resulting in a high economic burden on the healthcare system. Globally, chicken meat is one of the highest consumed meats and is a predominant source of foodborne illness. The severity of Salmonella infections depends on the presence of antimicrobial resistance genes and virulence factors. While there are many studies which have investigated Salmonella strains isolated from post-harvest chicken samples, there is a gap in our understanding of the prevalence and persistence of Salmonella in pre-harvest and in particular their makeup of antibiotic resistance genes, virulence factors and metal resistance genes. The objective of this study was to determine how on-farm management practices and environmental factors influence Salmonella persistence, as well as the antimicrobial resistance genes and virulence factors they harbor. In this study we demonstrate that broiler chickens raised without antibiotics are less likely to harbor antibiotic resistance, however the practice of adding acidified copper sulfate to drinking water may select for strains carrying metal resistant genes.

BackgroundDuring 2021-2022, high pathogenicity avian influenza (HPAI) caused mass mortality in wild birds across Europe, with Northern Gannets (Morus bassanus) among the most affected. Following the outbreak, unusual alterations in the species characteristic pale iris were observed in some individuals. MethodsOpportunistically captured gannets on Bass Rock (n=52), selected to represent a range of iris pigmentation, were examined. Slit-lamp biomicroscopy, indirect ophthalmoscopy, rebound tonometry and photography were performed. Iris pigmentation was classified as normal, mottled or black. Eleven birds underwent avian influenza virus (AIV) serology. Histopathology was performed on two eyes. ResultsAbnormal iris pigmentation was found in 74% of adult and immature gannets, with 61% affected bilaterally. Additional signs consistent with uveitis were present in 77% of affected birds. Iris pigmentation abnormalities were positively associated with AIV H5 seropositivity (Fishers exact test, P=0.018). Histopathology from affected eyes showed increased melanin deposition and disorganisation, including loss of a distinct anterior layer of melanocytic cells and hypertrophy of melanocytes within the iris stroma. LimitationsField conditions limited uniform lighting and concurrent serology. ConclusionsIris pigmentation changes were associated with prior HPAI exposure and frequently accompanied by signs of uveitis, suggesting iris alterations may indicate past infection and potential chronic sequelae.

Emerging infectious diseases can have catastrophic impacts on wildlife populations, yet identifying individuals that survived exposure, especially when external symptoms are absent, remains challenging. Since 2021, a virulent strain of highly pathogenic avian influenza virus (HPAIV H5N1 clade 2.3.4.4b) has caused unprecedented mortality in wild birds across continents. Northern Gannets (Morus bassanus) are among the species that suffered significant population declines in Europe and North America. At North Americas largest gannet colony (Bonaventure Island) dramatic mortality and reproductive failure occurred in 2022. Following this event, researchers noted a subset of gannets displaying irregular iris pigmentation, raising the possibility that this visible change may indicate a lasting effect of infection. Here, we build on earlier observations linking irregular iris pigmentation to HPAIV exposure in gannets using anti-nucleoprotein (NP) and anti-hemagglutinin (H5) antibodies. This provides the first quantitative test of this relationship using serological data and field-based digital photography. Iris irregularities were strongly associated ({rho} = -0.72) with antibodies to NP, supporting the hypothesis that they can indicate past exposure. The likelihood of NP antibody detection increased with iris pigment irregularity--about 50% likelihood at 40% irregularity, 65% at 50%, 77% at 60%, and over 90% above 77% irregularity. Moderate correlations ({rho} = 0.30) were observed for H5 antibodies. Our findings provide quantitative support for the hypothesis that iris pigmentation irregularities may serve as a visible, non-invasive marker of past HPAIV exposure in gannets. If validated across colonies and years, iris assessment could offer a rapid tool for tracking population health and recovery following HPAIV outbreaks, enhancing conservation monitoring and disease surveillance. Lay SummaryOur research shows clear evidence that irregular iris pigmentation in Northern Gannets is strongly linked to past infection with a deadly bird flu strain. This visible marker could allow scientists to rapidly identify surviving birds and monitor population health after outbreaks, helping conservation efforts across affected colonies. HighlightsO_LIIris pigmentation irregularities reveal past avian influenza exposure. C_LIO_LIExtent of iris pigmentation irregularity correlates with antibody levels. C_LIO_LIExposure likelihood increases with degree of iris pigmentation irregularity. C_LIO_LICould provide a rapid, non-invasive tool for wildlife disease and conservation monitoring. C_LI Graphical abstracts O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/685885v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@12fa683org.highwire.dtl.DTLVardef@15d23b1org.highwire.dtl.DTLVardef@1d2425eorg.highwire.dtl.DTLVardef@10367cd_HPS_FORMAT_FIGEXP M_FIG C_FIG

Effects of sodium butyrate (SB) and rosemary leaves (RL) on growth performance, biochemical profile, immune status, and carcass traits of broiler were evaluated. Fifty-one-day old Hubbard chicks (unsexed) were purchased from Al-Ahram Company for Poultry, Egypt and reared on floor pens in a private farm. The chicks were weighed on arrival and assigned at random into five equal groups, with four replicates each (25 chicks/replicate). Group 1 was fed on a broiler diet without any additions and used as a control. The diets of groups 2 and 3 were supplemented with 500 g/ton SB and 4 kg/ton RL, respectively. In group 4, the diet was enriched with 250g/ton SB plus 2 kg/ton RL. Chicks in group 5 were fed on a diet fortified with 500 g/ton SB plus 4 kg/ton RL. Body weight gain (BWG) and feed efficiency ratio (FER) were determined weekly. Biochemical indexes, immune system function, and carcass traits were determined. The results revealed that supplementing broiler diet with 500g/ton SB plus 4 kg/ton RL increased BWG and FER of birds. This diet decreased serum levels of aspartate aminotransferase, (AST) alanine aminotransferase (ALT), total cholesterol (TC), triglycerides (TG), malondialdehyde (MDA and increased superoxide dismutase (SOD), catalase (CAT), and immunoglobulins. It also boosted immunity as it elevated phagocytic activity, phagocytic index, lysozyme activity, and nitric oxide (NO) concentrations. Antibody titers against Newcastle disease virus were elevated. It can be concluded that supplementing broiler diet with 500g/ton SB plus 4 kg/ton RL improve performance, normalize biochemical profile, and boost immunity.

Aflatoxin is toxic, carcinogenic and ubiquitous in nature, affecting both crops and livestock. Mitigating aflatoxin effect using toxin binders has not been very effective. Information on the use of biological methods in aflatoxin mitigation has not been adequately documented. Consequently, influence of bio-control method of aflatoxin on some reproductive hormones, ovarian weight and histopathological parameters of laying chickens (LC) were investigated. Point-of-lay Bovan Nera (n=700) were harphazardly distributed to four dietary treatments; Aflasafe maize-based diet (AMBD), farm feed (FF), aflatoxin-contaminated diet with toxin binder (ACDTB) and aflatoxin-contaminated diet without toxin binder (ACDWTB). The contaminated diets contained 306.3ppb aflatoxin and the experimental design was completely randomized into four treatments (n= 175) of five replicates (n=35) per treatment for a period of 14 weeks. Blood (5mL) was collected at 14th week for LC to determine the estrogen, luteinising hormone (LH), follicle stimulating hormone (FSH), histopathology of the ovary using standard procedures. Data were analysed using descriptive statistics and ANOVA at a0.05. The ROW (%) ranged from 0.34{+/-}0.2 (ACDTB) to 0.93{+/-}0.3 (AMBD). Estrogen (mg/dL) value was highest in LC fed ACDWTB (2.75{+/-}1.08) and least in FF (2.07{+/-}0.52). The LH (iu/L) value was highest in LC fed AMBD (1.29{+/-}1.68) and least in ACDTB (0.36{+/-}0.32). Histopathology of the ovary showed cysts, observed along the oviduct wall in LC fed ACDTB. AMBD enhanced active laying period in LC with no sign of aflatoxocosis. The use of aflasafe maize grain in poultry diet is recommended.

This study examined the effects of short-term dietary zinc (Zn) and phosphorus (P) variations on the mobilizable bone Zn pool and overall Zn status in adult laying hens. Forty-eight hens (50% Lohmann Brown Classic, 50% Lohmann LSL Classic) were housed in pairs (one hen per breed per pen) across 24 pens. The pens were randomly assigned to one of two dietary P levels (0.37% or 0.84% in DM) using a high-protein corn-soybean diet (11.4 MJ AME/kg, 21.5% CP) during a 14-day acclimatization period. Following acclimatization, pens from both P groups were further randomized into four dietary treatments in a 2 x 2 factorial design, varying in P levels (low vs. high) and Zn supplementation (28 vs. 131 mg/kg) over an 8-day experimental feeding phase. Performance metrics, egg production and quality, and tissue mineral concentrations (plasma, liver, bone, and eggs) were measured. Statistical analyses were performed using linear mixed models in SAS 9.4, incorporating random effects of pen nested within treatment group and fixed effects of dietary P, dietary Zn, breed, and their interactions. Tukey-corrected 95% confidence intervals were used to estimate effect differences, with significance set at P < 0.05. Performance metrics, including egg production and body weight, were unaffected by dietary treatments (P > 0.1), indicating no clinical symptoms of Zn deficiency. However, hens on low-Zn diets exhibited significant reductions in plasma Zn concentration (-0.83 mg/L; P = 0.0008) and liver Zn concentration (-6.78 mg/kg DM; P = 0.01), confirming subclinical Zn deficiency. Low-Zn diets also increased the femoral molar Ca:P ratio by 0.15 (P = 0.01), irrespective of dietary P supply. Interestingly, low-P diets led to a significant reduction in femur Zn content (-0.46 mg; P = 0.0009), regardless of Zn supplementation, following 21 days of reduced P feeding. These findings highlight the higher susceptibility of laying hens to phytate antagonism compared to broilers, as evidenced by measurable subclinical Zn deficiency under short-term Zn deprivation. Additionally, a temporary suspension of mineral P supply appeared to impair the mobilizable bone Zn pool. The underlying functional mechanisms driving these interactions remain unclear and warrant further investigation.

Though protein demand is increasing day by day but the animal protein industry on a global scale is facing the biggest challenge of replacing antibiotic growth promoters (AGP) to raise broiler chickens. Using AGP is a long-standing practice to include in poultry diets for improving the intestinal health and subsequent performance of the broiler chicken. Due to increased restrictions and bans on the usage of antibiotics, the poultry-producing community is in search of a suitable and sustainable alternative to AGPs. The present study was aimed at to evaluate and analyte the potential impacts and consequences associated with the inclusion of black soldier fly larvae meal (BSFLM) in a commercially available meat type chicken when compared to diets that either contained or lacked the presence of antibiotic growth promoters, specifically enramycin at a concentration of 8% and chlortetracycline at a concentration of 15%. Our study also assessed the influence of inclusion of BSFLM on cecal short chain fatty acids (SCFAs), and the gut health. 180 male day-old Vencobb430Y chicks (mean BW 42.52 g) (P > 0.05) were randomly allocated into isonitrogenous and isoenergetic dietary treatments in three equal groups. BSFLM group has exhibited significant higher concentration of short chain fatty acids in cecum like acetate, isobutyrate, butyrate, and total SCFAs compared to both the AGP and CONTROL groups (P<0.05). The villi height of duodenum and jejunum remained significantly higher in BSFLM supplemented birds as compared to the AGP group (P<0.05). From the analysis of frequency plots depicting the severity of intestinal lesions, it was observed that the presence of serosa and mucosa congestion in the anterior sections of the gastrointestinal tract was within the expected range for both the CONTROL and AGP groups, thus indicating that this particular physiological condition can be considered as normal in these experimental groups. In the duodenal part, incorporating BSFL meal showed significantly higher villi height and crypt depth compared with CONTROL and AGP (P<0.05). Inclusion of full-fat BSF has improved overall intestinal health and lower lesion scores compared to the CONTROL and AGP groups. The present investigation explored thepotential of incorporating full-fat black soldier fly larvae (BSFL) meal into the dietary regimens of broilers for sgnificantly bolstering the health and functionality of their gastrointestinal tract, particularly in instances where the inclusion of antimicrobial growth promoters (AGP) is deliberately omitted from said diets.

Due to their ubiquity, management of parasites is a common and important factor for profitable production of poultry. Heterakis gallinarum, the cecal nematode, is the most common nematode parasite of poultry. While typically causing no pathology on its own, H. gallinarum is the vector of Histomonas meleagridis, a protozoan parasite that causes blackhead disease. Histomonas meleagridis is highly pathogenic in turkeys, potentially causing high mortality. In contrast, disease caused by H. meleagridis is much less severe in chickens, where it primarily reduces productivity without manifestations of clinical disease. There are no approved treatments for H. meleagridis, making control reliant on control of the helminth vector through the use of fenbendazole (FBZ) the only drug labeled for treatment of H. gallinarum in the United States We were contacted by an industry veterinarian regarding health-related concerns in a broiler-breeder house due to histomoniasis, despite frequent anthelmintic treatments. Since we had recently diagnosed resistance to FBZ in Ascaridia dissimilis, a closely related nematode of turkeys, we were interested to determine if H. gallinarum had also evolved resistance to FBZ. Heterakis gallinarum eggs were isolated from litter collected from the house and used to infect 108 chickens. Treatment groups included a non-treated control, a label-dose and a 2X-label dose of FBZ, with 36 birds per group divided into two replicate pens of 18 birds each. Birds were placed at 1-day post hatch, and at 3 weeks of age were infected with 150 embryonated eggs via oral gavage. Two weeks post infection, treated birds were administered a minimum of either a label- or 2X label-dose of FBZ in water for 5 days (SafeGuard(R) Aquasol, 1mg/kg BW). To ensure that all birds consumed the full intended dose at a minimum, the dosage was calculated using 1.25 times the average body weight. One-week post treatment, birds were euthanized, ceca removed, and parasites enumerated. Efficacy was calculated by comparing the total numbers of worms recovered from each treatment group to the numbers recovered in the non-treated control group. There were no significant differences in worm numbers recovered from any of the three groups (p-value=0.81). There also was no efficacy benefit to treatment with a 2X dose; H. gallinarum worm counts were reduced by 42.7% and 41.4%, for the label and 2X dosages, respectively. These data provide strong evidence that H. gallinarum has developed resistance to FBZ. Consequently, in houses infected with FBZ-resistant H. gallinarum, H. meleagridis will be able to cycle through the birds in an unrestricted manner. Further investigation is needed to determine the prevalence of resistance in H. gallinarum on chicken farms, but it is clear this has the potential to have a large-scale economic impact on the poultry industry. These data when viewed together with our recent findings of FBZ resistance in A. dissimilis, suggest that drug resistance in ascarid nematodes may be an important emerging problem on poultry operations.

Organic zinc supplementation in hen has been reported to improve fertility. The current study evaluated the effect of organic zinc supplementation in hens on fertility after insemination with cryopreserved semen. White Leghorn rooster semen was cryopreserved using 4% dimethylsulfoxide (DMSO) in 0.5ml French straws. Different semen parameters and fertility were assessed in post-thaw samples. White Leghorn hens were divided into 5 groups with 30 birds in each group. Each group was further divided into six replicates of five birds each. The control group was fed basal diet, other groups were fed with basal diet supplemented with 40, 60, 120 and 160 mg/kg organic zinc (zinc proteinate). After two weeks of feeding insemination was done in hens per vagina using thawed semen (200 million sperm/0.1 ml). Basal group hens were inseminated with fresh or cryopreserved semen and served as control groups. Sperm motility, live sperm, and acrosome intact sperm parameters were significantly (p &lt; 0.05) lower in post-thaw semen samples. Fertility from cryopreserved semen was significantly (p &lt; 0.05) lower and organic zinc supplemented hens had fertility similar to that of cryopreserved semen inseminated into basal diet group hens. In conclusion, organic zinc supplementation in hens does not improve fertility after insemination with 4% DMSO cryopreserved semen.Competing Interest StatementThe authors have declared no competing interest.View Full Text

Two experiments were performed for evaluating calibration curve (CC) and comparing negative and positive controls (CNP) as a major method for estimating of phytase phosphorus equivalence for layer and broiler chickens. In the first and second experiments, 360 Hy-line W-36 layer hens and 525 day-old Ross-308 broiler chickens were used in a complete randomized design, respectively. Evaluated methods were setting the two regression equations for NPP-supplemented and phytase supplemented treatments with two sub-methods, include calibration curve (CC) or exclude the amount of phosphorus content of basal diet (CC-BD) in calculation, and exploring enzyme equivalency by comparing phosphorus deficient diet as an negative and supplemented diet by inorganic phosphorus sources as a positive control group (CNP). Experiment one included nine treatments (200, 300, 400 and 500 FTU/kg phytase was added to a phosphorus deficient basal diet contained 0.12% AvP, the rest four treatments were included basal diet supplemented with 0.20, 0.27, 0.35 and 0.43% AvP). Experiment two included seven treatments (a basal P deficient diet contained 0.27% AvP, and two increasing levels of AvP, 0.32 and 0.37%, and four doses of phytase 200, 300, 400 and 500 FTU/kg added to basal diet). Each treatment in the both experiments replicated five times. Results indicated that methods of estimation had a significant effect on phosphorus equivalence estimation (P<0.0001). Fitted regression equations considering P content of basal diet (CC-BD) estimated rational values than those ignore it (CC) (0.161% vs 0.365% and 0.432% vs 0.564% for 500 FTU/kg phytase for broiler chicken and layer hens, respectively) (P<0.0001). On average, among three methods used, CC method had the highest estimated values both in broiler chickens and layer hens (p<0.0001). Regardless of mathematical method, there were different significant values for different strains (layer, 0.381% and broiler, 0.179%) (P<0.0001), but not for different traits served as response criteria (P>0.05). In conclusion, the phosphorus equivalent value of enzyme varies according to the estimation methods and strain. Hence, using matrix values of enzyme for accurate feed formulation depend on a variety of circumstances and decision making requires comprehensive information.

ABSTRACTThe rapid increase in antibiotic resistance poses a global threat to public health, necessitating the development of effective antimicrobial alternatives. This study compared an indigenous probiotic mix containing Lactobacillus reuteri and two strains of Enterococcus faecium to a commercial probiotic blend ProtexinR on the growth performance, mortality rate, histomorphology, serum immunoglobulins, and intestinal microflora of broiler chickens challenged with two multi drug resistant Salmonella serovars, Typhimurium and Enteritidis. Two hundred and forty day-old broiler chicks were randomly assigned to six treatment groups for 4 weeks: the treatment groups were; birds continuously supplemented with only indigenous probiotic strains (108 CFU/mL) (IPRO-); birds challenged with Salmonella serovars 106 (CFU/mL) (PC+); birds continuously supplemented with indigenous probiotic strains and challenged with Salmonella serovars (IPRO+); birds supplemented with ProtexinR and challenged with Salmonella serovars (CM+); birds supplemented with only ProtexinR (CM-); and birds with no Salmonella challenge or probiotics (negative control; PC-). The results revealed that IPRO- diets significantly improved feed conversion ratio (FCR) and increased body weight (BW) (P [&le;] 0.05). No effect of probiotic treatments was observed on IPRO- and CM- on relative organ weights as compared to the negative control (PC-). The Salmonella- challenged group PC+ had the highest (20%) mortality rate and lowest BW. The IPRO- had significantly lower FCR (1.55) compared to PC- (1.86) and PC+ (1.95). The broilers in the IPRO- group showed significantly increased serum concentrations of IgA and IgG relative to both control groups (P [&le;] 0.05). Morphological analysis of the ileum revealed significant increases (P [&le;] 0.05) in the villus height and villus height/crypt depth in birds fed IPRO- compared with the PC+. Cecal Lactobacillus and Enterococcus counts were the highest (P [&le;] 0.05) and Salmonella counts were the lowest (P [&le;] 0.05) in the IPRO- group compared to the Salmonella infected group PC+. These results indicated that indigenous probiotic strains Lactobacillus reuteri and Enterococcus faecium can be an effective and low-cost alternative compared to commercial probiotics in the Pakistan poultry industry.

Heat stress is known as one of the most prevalent environmental stressors in poultry production, which is associated with oxidative stress. Stinging nettle is a medicinal herb with strong antioxidant properties. The present study was conducted to evaluate the effects of dietary stinging nettle at two different levels (2% and 4%) on growth performance and oxidative stress indices of broilers exposed to chronic heat stress. On day 14, a total of 240 broiler chickens were randomly assigned to 6 treatment groups as follows: 1) NC: negative control; 2) HS: heat-stressed broiler; 3) HS-SN2: heat-stressed broiler fed by 2% dietary stinging nettle; 4) HS-SN4: heat-stressed broilers fed by 4% stinging nettle; 5) SN2: no heat-stressed broilers fed by 2% dietary stinging nettle; 6) SN4: no heat-stressed broilers fed by 4% dietary stinging nettle. Diet supplementation with stinging nettle was performed from days 14 to 35 and a chronic heat stress was induced from days 22 to 29. The growth performance and oxidative indices were evaluated on days 14, 21, 29, and 35. Rectal temperature and panting frequency were assessed on days 22, 25, and 29. As a result, weight gain and food intake decreased in the HS compared to the NC, and these parameters increased in the HS-SN2 and HS-SN4 compared to the HS (P<0.05). The HS, HS-SN2, and HS-SN4 groups had a significantly higher rectal temperature and panting frequency. The HS had the higher circulating MDA and HSP70, and lower T-AOC, SOD, and GSH-Px compared to the treatments. The HS-SN4 had a significantly lower MDA and HSP70, and higher T-AOC, GSH-Px, and SOD compared to the HS and HS-SN2. In conclusion, the addition of 4% stinging nettle powder to the broilers diet improved the oxidative status in heat-stressed birds. Furthermore, this herb could be utilized as a feed additive in poultry diet to improve birds health and defense mechanisms under stressful conditions.

Intensive broiler production practices impair the transmission of commensal microbes from hens to offspring, resulting in a lower abundance of non-spore-forming strict anaerobic bacteria. We evaluated the effects of colonization by a defined community (DC) of bacteria including and excluding Megamonas hypermegale in chicks challenged with Salmonella. Inoculation with DC resulted in higher phylogenetic diversity and the dominance of Bacteroidetes species in the cecal microbiota, with a decrease in the relative abundance of Salmonella and Escherichia/Shigella, as well as a lower Enterobacteriaceae load. Substantial shifts in microbiota composition were coupled with subtle changes in metabolites and host responses, including changes in interferon-{gamma}, macrophage colony-stimulating factor, propionate, valerate, and isovalerate concentrations in the ceca. We identified bacterial species that were able to establish and persist after a single exposure, many of which were members of Bacteroidetes. Although co-culture with M. hypermegale reduced Salmonella counts by 99.3% in vitro, in vivo inoculation of M. hypermegale increased splenic Salmonella counts in inoculated chicks. The use of DC containing bacteria isolates harvested from the cecal contents of mature chickens can recapitulate the changes in volatile fatty acid concentrations observed in birds colonized with complex communities, and the presence of M. hypermegale specifically enhances the production of propionate. Our findings suggest that the use of DC can be explored as a strategy to control disease occurrence in broiler production; however, further research is warranted to properly understand the role of individual species in the broiler cecal community aiding the formulation of appropriate DCs. ImportanceIntensive production practices can reduce beneficial gut bacteria in broiler chickens, potentially leading to higher disease risk. We investigated whether introducing a defined community (DC) of beneficial bacteria, along with M. hypermegale, could improve gut health and resistance to Salmonella in broiler chicks. Our findings show that DC increases microbial diversity and reduces the relative abundance of potential pathogens, like Salmonella and Escherichia/Shigella, which was coupled with subtle changes in the immune responses of the birds and higher concentration of volatile fatty acids in the ceca. This study suggests that using DC can enhance poultry health and reduce disease, providing a potential strategy to improve broiler production. However, further research is needed to understand the roles of individual bacteria and refine these bacterial communities for practical use in farming. This work holds promise for developing natural methods to enhance poultry health and safety.

Inclusion of fishmeal and fish oil in feeds for farmed fish is not sustainable and alternatives need to be evaluated. The aim of this study was to determine the effect of diets including defatted black soldier fly larvae (Hermetia illucens), adult cricket (Gryllodes sigillatus) and superworm (Zophobas morio) on the growth performance, apparent nutrient digestibility, nutrient retention, and fatty acid profiles of juvenile rainbow trout (Oncorhynchus mykiss). Triplicate tanks of fish (100.5 {+/-} 0.6 g; mean {+/-} SD) were fed one of four diets, a control diet with 20% fishmeal, and three experimental diets containing either 15% defatted black soldier fly meal, 15% full-fat adult cricket meal or 15% full-fat superworm meal, where each insect meal partially replaced fishmeal and fish oil. After 84 days of feeding, no significant differences were observed between diets for growth performance indicators or body indices. Fish fed the control and superworm diets had a higher protein content and retention in whole-body carcass compared to the cricket and black soldier fly diet groups. No significant effects between diets were found on whole-body carcass regarding fatty acid classes SFA, MUFA, PUFA n-3 and PUFA n-6, although lauric acid and myristic acid were significantly higher in fish fed black soldier fly diet and linoleic acid was higher in fish fed superworm and cricket diets. Retention of fatty acids was higher for most classes in fish fed the black soldier fly diet, yet whole carcass lipid content did not differ significantly between diets. Additionally, apparent digestibility of phosphorous was significantly improved for all insect diets compared to the control. These results indicate that insect meals can partially replace fishmeal and fish oil in diets for rainbow trout without compromising growth performance and fatty acid composition, while improving phosphorous utilization.

Zoo data collected by keepers while looking after endangered species are increasingly recognised as important scientific resources. As chicks, New Zealands threatened kiwi (Apteryx spp.) are subject to the protective conservation programme Operation Nest Egg (ONE), during which growth, developmental and life history data are recorded. We have conducted comparative analyses on hand rearing records from 306 chicks, from Coromandel, Eastern and Western populations of Brown kiwi (A. mantelli), and rowi (A. rowi) and Haast tokoeka (A. australis "Haast"). We analysed chick responses to an old diet vs. a new kiwi diet, introduced in 2017. Both diets are fixed nutrient ratio mixtures. The old diet was high-protein, low-energy, while the new diet is high-fat, high-energy, with better micronutrient levels. We found Coromandel chicks, who originate from the environmentally variable K[u]aotunu Peninsula, grow the most efficiently overall on either diet, indicating they may be nutritional generalists. Western and Eastern chicks growth efficiency was intermediate, while the South Island species grew the least efficiently on either diet. Rowi chicks developed the fastest overall on either diet, while Haast tokoeka chicks developed the most slowly, especially on the new diet. Rowi chicks therefore had to eat large volumes of either diet over a short time to maintain their rapid development, while Haast chicks were required to eat large volumes, especially of the new diet, over a protracted developmental period. This situation may have led South Island chicks to over-consume one or another diet component, with likely health consequences. Neither diet was obviously superior for chick wellbeing overall, though the new diet better supported chicks that needed hand feeding. This work demonstrates different genetic populations of kiwi differ in their physiological responses to nutrition. As ONE is ongoing, tailored diets for chicks from each genetic group should be developed, and we present methods to achieve this. In our life history trait analyses, we found chick starting size (hatch mass) did not significantly influence growth efficiency across kiwi genetic group, nor did chick sex. We identified that chicks malpositioned as embryos were more likely to require extended periods of hand feeding, and that Eastern males produce more malpositioned embryos than other populations. Our study shows that effective zoo records can be used to improve captive care, to stimulate future research to refine species management practices, and to explore fundamental questions of life history evolution in wild and captive populations.

Probiotics were introduced as a spray directly in the hatcher when chickens started to leave the eggs which potentially could reduce the horizontal transmission and colonization with pathogenic bacteria. The single introduction of probiotics could limit the cost compared to multiple introductions with feed and/or water. A mixture of five probiotic strains belonging to Escherichia coli, Enterococcus faecalis, Lactobacillus agilis and Lactobacillus rhamnosus was tested with two independent flocks of broilers (Ross 308). For each experiment, a comparison was made to an untreated control flock on the same farm. At day 14 of production the probiotic strains were re-isolated from ileum of euthanized chickens. The first week mortality was slightly increased in the probiotic flock (0.42%) compared to the control (0.35%) in experiment 1, however, it was higher in the control flock (1.45%) compared to the probiotic flock (1.12%) in experiment 2. The average weight of chickens that could be slaughtered for consumption was increased by 3.5% in the probiotic flocks compared to the control flocks, resulting in a 1.9% higher total weight of slaughtered chickens in the probiotics treated flocks compared to the control as a mean of the two experiments. The number of condemned animals was within the normal range for the production system and could not directly be related to effects of probiotics. Although one probiotic strain of E. coli was isolated from dead animals, the probiotics did not affect the proportion of chickens which died due to E. coli during the first week compared to the control. Primary audienceplant managers, veterinarians, nutritionists

This study formulated a novel inactivated vaccine containing Newcastle disease virus (Lasota strain), avian influenza virus (BZ strains), APG, adenovirus and ORT. The vaccine was administered to 1-day-old and 7-day-old fast-growing broiler chickens. Experimental results showed that the vaccine reduced the feed conversion ratio and induced high levels of antibodies against Newcastle disease (Lasota strain), avian influenza (BZ strains), and avian rhinotracheitis. Immunization at 1 day of age had a significant impact on the production of antibodies against adenovirus. Challenge tests indicated that the vaccine partially protected the broiler chickens against Avibacterium paragallinarum types A, B, and C in broilers. Post-mortem examination of the injection sites showed good absorption with no significant unabsorbed oil droplets or hyperplasia in both 1-day-old and 7-day-old immunized chickens. This study demonstrated that combined viral and bacterial vaccine enhanced the feed conversion ratio in broiler chickens.

Available research on non-antibiotic alternative growth promoter (NAGPs) mainly focuses on the effect of a single preparation on the substitution effect of antibiotics. However, different NAGP might work together in harmony. Studies related to NAGP combinations are lacking. This study aimed to screen six non-antibiotic alternative growth promoter combinations (NAGPCs) in vitro so as to find a better alternative method to ensure feed efficiency and the broiler health. Pepsin and 42-d broiler ileal fluid were used for the in vitro digestion test, and the optimal addition levels of NAGPs and NAGPCs were selected based on dry matter (DM) and organic matter (OM) digestibility, microbiota of digestive fluid, and antioxidant capacity of digestive fluid. Results showed the optimum addition amount of Mannose oligosaccharide (MOS), fruit oligosaccharide (FOS), mannanase (MAN), Bacillus subtilis (BS), sodium butyrate (SB), guanidinoacetic acid (CA), xylanase (XYL), glucose oxidase (GO), and phytase (PT) were 0.2%, 0.9%, 0.03%, 0.05%, 0.08%, 0.002%, 0.008%, and 0.004%. The six best combinations were 0.2%MOS + 0.03%MAN + 0.15%SB, 0.2%MOS + 0.03%MAN + 0.05%BS, 0.2%MOS + 0.9%FOS + 0.15%SB, 0.2%MOS + 0.9%FOS + 0.05%BS, 0.2%MOS + 0.9%FOS + 0.03%MAN, and 0.2%MOS + 0.05%BS + 0.004%PT. In conclusion, NAGPCs improved the apparent digestibility of ileal DM and OM, intestinal flora and antioxidant capacity. Comparatively, under this condition, using NAGPC has more beneficial effects than using non-antibiotic alternative growth promoter.

To maintain food safety and flock health in broiler chicken production, biosecurity approaches to keep chicken barns free of pathogens are important. Canadian broiler chicken producers must deep clean their barns with chemical disinfectants at least once annually (full disinfection; FD) and may wash with water (water-wash; WW) throughout the year. However, many producers use FD after each flock, assuming a greater efficacy of more stringent cleaning protocols, although little information is known regarding how these two cleaning practices affect pathogen population and gut microbiota. In the current study, a cross-over experiment over four production cycles was conducted in seven commercial chicken barns to compare WW and FD. We evaluated the effects of barn cleaning method on the commercial broiler performance, cecal microbiota composition, pathogen occurrence and abundance, as well as short-chain fatty acid concentrations in the month-old broiler gut. The 30-day body weight and mortality rate were not affected by the barn cleaning methods. The WW resulted in a modest but significant effect on the structure of broiler cecal microbiota (weighted-UniFrac; adonis p = 0.05, and unweighted-UniFrac; adonis p = 0.01), with notable reductions in Campylobacter jejuni occurrence and abundance. In addition, the WW group had increased cecal acetate, butyrate and total short-chain fatty acid concentrations, which were negatively correlated with C. jejuni abundance. Our results support the use of WW over FD to enhance the activity of the gut microbiota and potentially reduce zoonotic transmission of C. jejuni in broiler production without previous disease challenges.