Poultry, Volume 5, Issue 4 (August 2026) – 14 articles

This research examined how dietary bile acids (BAs) influence hepatic fatty acid composition and cecal microbial community of late-laying hens. A total of 1080 Hy-Line Brown hens, aged 76 weeks, were randomly divided into four groups, each receiving a basal diet with 0 (CON), 200 (BA200), 300 (BA300), or 500 (BA500) mg/kg BAs for 35 days. Results showed that hepatic stearic acid (C18:0) concentrations were significantly reduced in all BAs-supplemented groups (p < 0.05). The BA300 group exhibited a significant increase in oleic acid (C18:1n9c), total monounsaturated fatty acids (MUFAs), and n-3 polyunsaturated fatty acids (PUFAs), alongside a decreased n-6/n-3 PUFA ratio (p < 0.05). Furthermore, the Chao1 index increased in all BAs-supplemented groups (p < 0.05), and the Simpson index was higher in BA300 (p < 0.05). LEfSe analysis indicated that the CON group had a higher abundance of opportunistic pathogens, while BA supplementation altered the cecal microbial composition. Notably, the BA300 group exhibited the most favorable microbial profile, characterized by enrichment of beneficial Enterococcus and improved microbial stability. In conclusion, supplementation with 300 mg/kg BAs most effectively improved hepatic fatty acid composition and cecal microbial diversity in late-laying hens, supporting its use as a nutritional strategy in the late laying phase. Full article

The aim of this study was to provide the first characterization of selected components of innate immunity (lysozyme and complement component C3) and adaptive humoral immunity (immunoglobulin Y) in seven Italian autochthonous chicken breeds and two turkey breeds. A total of 70 chickens (10 animals per breed) and 20 turkeys (10 animals per breed), equally distributed by sex, were sampled. The concentrations of immune traits were determined using avian-specific ELISA kits. In chickens, significant breed effects were detected for all traits, whereas sex influenced lysozyme and complement component C3 levels. Males generally showed greater lysozyme and complement component C3 levels than females. Higher lysozyme levels were found in Bionda Piemontese (920.8 ng/mL) and Bianca di Saluzzo (766.5 ng/mL), while the highest complement component C3 values were observed in Bionda Piemontese (315.2 µg/mL) and Bianca di Saluzzo roosters (287.4 µg/mL) and in Siciliana hens (329.1 µg/mL). Immunoglobulin Y showed limited variation among breeds and sexes. In turkeys, only lysozyme levels differed between breeds. Overall, these preliminary results, obtained from a limited number of individuals, reveal measurable differences in immune traits among Italian autochthonous poultry breeds, particularly for innate immune parameters, suggesting that genetic background may contribute to variation in immune responsiveness. These findings provide baseline data to support genetic conservation strategies and sustainable breeding programs for resilient poultry systems. Full article

In this study, we evaluated the effects of a commercial blend of organic acids (formic acid and propionic acid) added to drinking water on the microbiota of broilers experimentally challenged with Salmonella enterica serovar Minnesota. A total of 108 broilers were randomly assigned to three groups, each with 36 birds: the Treatment group (treated with organic acids + challenge), a Positive Control group (challenge only), and a Negative Control group (no challenge). At seven days of age, broilers in the Treatment group received the organic acid blend through their drinking water (0.2 mL/L/drinking water). At nine days of age, broilers from the challenged groups were inoculated via feed with S. Minnesota (Treatment group—mean: 1.45 × 10⁴ CFU/g; Positive Control group—mean: 3.47 × 10⁴ CFU/g). Swab samples were collected for Salmonella enumeration and cecal content for bacterial community profiling using 16S-rDNA gene sequencing. Our results demonstrated that supplementation with organic acids positively modulated the cecal microbiota of broilers under S. Minnesota challenge. Broilers receiving the organic acid blend showed improvements in microbial community composition, including an increased abundance of bacterial genera associated with butyrate production, which are recognized for their beneficial effects on intestinal health. Overall, our findings suggest that the blend of organic acids may serve as a nutritional strategy for supporting intestinal health and microbiota stability in broilers challenged with S. Minnesota. Full article

Chronic cyclic heat stress impairs thermoregulation, growth, tissue integrity, microbial metabolism, and stress-related molecular responses in broiler chickens. N-acetyl-L-cysteine, a cysteine donor involved in glutathione synthesis, has been proposed as a nutritional strategy to support stress adaptation. Therefore, this study evaluated NAC in 324 Ross 308 broilers allocated to thermoneutral conditions (TN, 7 pens), HS (HS, 10 pens), or HS plus 2000 mg/kg NAC (HS + NAC, 10 pens). From day 20 to 35, HS birds were exposed to 34 °C for 7 h/day and 26 °C otherwise, while TN birds were kept at 22 °C. Heat stress increased rectal temperature and respiratory rate (p < 0.001), reduced average daily gain, and increased drinking and gasping behavior (p < 0.05). Heat stress also increased hepatic cord disorganization, cerebral vacuolisation–necrocytosis, hepatic and cerebral HSP70 expression, and caecal propionate, while reducing cerebral apelin expression (p < 0.05). Jejunal villus morphology and microbiota α-diversity were unchanged, although caecal profiles indicated treatment-related shifts and potentially higher Bilophila spp. in heat-stressed birds. NAC did not improve growth, thermoregulation, oxidative status, caecal fermentation, microbial structure, or HSP70 expression. It increased jejunal villus fusion and hepatocellular vacuolation scores and reduced cerebral ghrelin expression (p < 0.05). In conclusion, heat stress impaired growth and induced tissue, microbial, fermentative, and cerebral gene-expression changes, whereas 2000 mg/kg NAC did not provide measurable protection under the chronic cyclic HS in the present study. Full article

Amino acids are the ‘building blocks’ of protein, including both feathers and whole-body protein, and serve numerous functional roles, including energy provision. Amino acid requirements for broiler chickens are expressed as ideal amino acid ratios relative to digestible lysine. However, ideal amino acid profiles in diets for broiler chickens are likely to remain elusive targets. This review considers the factors contributing to this situation. Just one complicating factor is that amino acids may be deposited as protein in either feathers or whole-body protein. However, in the partitioning of amino acids, it appears that preference may be given to feathering, which requires clarification. A second complicating factor is the transition of amino acids across enterocytes of the small intestinal gut mucosa, and small intestinal uptake of amino acids may be rate-limiting for growth performance. Protein-bound amino acids may be absorbed as oligopeptides or monomeric amino acids, and non-bound amino acids do not require digestion prior to their intestinal uptake. The transition of amino acids across the gut mucosa is involved because amino acids may be diverted into anabolic and/or catabolic pathways and are thereby denied entry to the portal circulation. The metabolic fate of amino acids in the gut mucosa may be subject to manipulation by nutritional strategies, but our comprehension of the relevant metabolism within avian enterocytes is inadequate. The post-enteral availability of twenty proteinogenic amino acids is complex with important implications for the efficiency of utilisation. Importantly, acceptably accurate amino acid profiles will be advantageous for sustainable chicken-meat production into the future. Full article

The overall burden and distribution of haemoparasite infections in free-range chickens remain inadequately studied, even though these parasites can pose serious threats to poultry health and productivity throughout Africa. Therefore, this study aimed to assess the prevalence and diversity of haemoparasites using a systematic review and meta-analysis approach. A comprehensive literature search was conducted across four electronic databases for peer-reviewed articles published from 1995 to 2024. Following critical appraisal, twenty-three studies met the inclusion criteria. The pooled overall prevalence of haemoparasite infection was 5% (95% CI: 3–7%). Eastern Africa recorded the highest prevalence at 18% (95% CI: 5–36%), whereas western Africa reported the lowest prevalence at 5% (95% CI: 3–7%). Comparatively, cocks exhibited a higher pooled prevalence of 28% (95% CI: 17–39%) than hens at 12% (95% CI: 2–25%). Among genus infections, Plasmodium showed the highest pooled prevalence at 14% (95% CI: 8–21%), while Leucocytozoon and Haemoproteus had low pooled prevalence (both 4%). Mixed-infections of Plasmodium and Leucocytozoon showed a pooled prevalence of 3% (95% CI:0–14%). A high level of heterogeneity was observed across all genera, except Trypanosoma (I² = 0%). Studies which used nested PCR reported a higher pooled prevalence (9%; 95% CI: 2–19%) compared with microscopy (5%; 95% CI: 3–8%). Univariate meta-regression identified parasite species and sample size as significant sources of heterogeneity in the prevalence estimates (p < 0.05). Overall, these findings provide valuable insights into the prevalence of haemoparasite infections in free-range chickens and underscore the need for improved diagnostic capacity, through improved access and use of sensitive molecular techniques such as nested PCR, and provision of resources for improved surveillance systems across African countries. Full article

Enterococcus spp. are increasingly recognized as important opportunistic pathogens in poultry production and represent a potential One Health concern because of their virulence potential and capacity to acquire antimicrobial resistance determinants. This study characterized Enterococcus isolates recovered from clinical poultry cases in Chile, focusing on species distribution, virulence-associated genes, antimicrobial resistance patterns and genes, biofilm formation, and cytolysin activity. A total of 39 isolates were identified using the VITEK^® 2 Compact system and confirmed by PCR targeting the tuf gene. Seven Enterococcus species were detected, with E. faecalis predominating (61.5%) and E. faecium following (15.4%). The virulence-associated genes asa1, gelE, and cylA were detected in 97.4%, 97.4%, and 48.7% of the isolates, respectively. Phenotypic antimicrobial susceptibility testing showed resistance mainly to tetracycline (61.5%) and erythromycin (17.9%), whereas all isolates were susceptible to vancomycin, ampicillin, chloramphenicol, and linezolid. Molecular analysis identified tetM (71.8%), ermB (66.7%), and tetL (30.8%) as the most predominant resistance genes. A significant association was observed between tetM and phenotypic tetracycline resistance (Fisher’s exact test, p = 0.010). However, no association was found between ermB and erythromycin resistance. Biofilm formation was observed in 66.7% of the isolates, although most were weak biofilm producers. Despite the relatively high prevalence of cylA, β-hemolytic activity was detected in only 5.1% of isolates, indicating an incomplete genotype–phenotype concordance. Overall, poultry-associated Enterococcus spp. circulating in Chile harbored multiple virulence and antimicrobial resistance determinants that may contribute to their persistence and adaptation in poultry production systems. These findings provide the first baseline molecular epidemiological data on clinical poultry-associated Enterococcus spp. isolates in Chile and support the need for continued surveillance and prudent antimicrobial use in veterinary medicine. Full article

The increasing demand for sustainable and cost-effective feed alternatives has stimulated the use of agro-industrial by-products in poultry nutrition. This study evaluated the effects of acid silage from pirarucu (Arapaima gigas) by-products (ASP), derived from fish-processing waste, on growth performance, physiological responses, and meat quality of slow-growing broilers. A total of 240 male Label Rouge broilers were assigned to diets containing 0, 1, 2, or 3% ASP from 8 to 56 days of age. Moderate ASP inclusion levels (1–2%) improved (p ≤ 0.05) growth performance by increasing weight gain and improving feed conversion ratio, particularly during the grower and finisher stages. Hematological analyses demonstrated favorable physiological responses, including increased (p ≤ 0.05) hemoglobin concentration, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin. Plasma biochemical parameters indicated improved (p ≤ 0.05) protein metabolism, with higher total protein, albumin, and globulin concentrations, while glucose, cholesterol, and urea remained unaffected (p > 0.05). Carcass evaluation revealed improved (p ≤ 0.05) breast yield at 2% ASP inclusion, and breast composition showed increased (p ≤ 0.05) protein, lipid, and mineral deposition, accompanied by reduced (p ≤ 0.05) moisture content. However, the highest inclusion level (3%) did not promote additional productive benefits. These findings demonstrate that moderate ASP inclusion (1–2%) can improve productive efficiency and meat nutritional quality while promoting sustainable reuse of aquaculture by-products, supporting circular and environmentally responsible poultry production systems. Full article

This study evaluated the effects of a Bacillus-based direct-fed microbial on broiler performance, excreta properties, and the impact on the survival of house fly larvae. A completely randomized design was used comprising two dietary treatments: (1) basal standard broiler diet (CON) and (2) CON + Amnil^® at 500 PPM (AMN). Each treatment consisted of 48 replicate cage pens, each containing six male chicks, and were raised until 23 d of age. The average body weight (BW), feed consumption (FC), and feed conversion ratio (FCR) were measured weekly. On d21, blood was collected via the brachial vein for the measurement of corticosterone (CORT) concentrations and heterophil/lymphocyte ratio (H/L). Poultry excreta was collected three times on d14, d18, and d23. Excreta properties were evaluated using proximate analysis. For fly assessment, two assays were conducted: (1) oviposition and (2) fly larval development. For oviposition, adult house flies were provided with a choice between excreta from chicks fed with and without Amnil. For fly larval development, 100 fly larvae (<12 h old) were fed either control excreta or excreta from birds fed Amnil. The data were subjected to ANOVA to determine the treatment differences. BW was higher (p = 0.05) in the AMN group on d 14, but no other differences were found at any other time points. Additionally, BW-adjusted feed conversion ratio was improved (p = 0.046) in the AMN group. Excreta from the AMN group had lower (p < 0.05) moisture, pH, Zinc, Neutral Detergent Fiber, and Acid Detergent Fiber on d18 and lower (p < 0.05) pH and Zn on d 23. No statistical differences (p > 0.05) were observed in the CORT and H/L ratios. There were no differences (p > 0.05) between treatments for preference in oviposition. However, flies showed a significant preference for colonizing bird excreta at d23 than at d14 or d18, regardless of Amnil use. For the development experiment, a reduction (p < 0.001) of 32.2% in resulting pupal survival was observed when excreta from birds fed AMN compared to the control. In conclusion, AMN supplementation improved cumulative FCR and modified the properties of excreta, resulting in the disturbance of normal oviposition and reduction in the survival of fly larvae compared to the CON group. Full article

A 21-day experiment evaluated the effect of different insoluble fiber (IF) sources on growth performance, nutrient and energy utilization, and foregut organ development of broiler chicken starters fed mash diets. Four dietary treatments were developed: a control (a commercial broiler chicken starter diet) and three experimental diets prepared by diluting the control diet (60 g/kg [w/w]) with three IF sources (rice hulls [RH], lentil hulls [LH], and wood shavings [WS]). A total of 120, one-day-old broiler chicks (6 birds/cage; 5 cages/treatment) were used in a completely randomized design. Compared with birds fed the control diet, those fed IF-containing diets showed lower WG and FI (p < 0.001). Feed per gain (F/G; p < 0.05; d1-21) was lowest in the control; however, after correcting for IF inclusion, F/G was not affected by dietary treatments (p > 0.05). The effects of IF on foregut development were source-dependent. Feeding RH and WS improved crop development (p < 0.05) compared to the control. Incorporating RH resulted in higher gizzard growth (p < 0.05) compared to the control and LH diets. Birds fed RH and LH had lower (p < 0.05) gizzard pH compared to those fed WS. Despite being considered a nutrient diluent, tested IF did not impair (p > 0.05) the energy utilization or nutrient digestibility. Full article

Skeletal deterioration is a major welfare and production concern in laying hens, as substantial quantities of calcium are mobilized from bone to support eggshell formation during the laying cycle. Nutritional strategies that promote skeletal development during the pullet phase may therefore improve bone integrity later in production. The objective of this study was to evaluate the effects of dietary genistein supplementation on growth performance, bone development, and mineralization in Hy-Line Brown pullets. A total of 600 pullets were randomly assigned to four dietary treatments consisting of a control diet (0 mg/kg genistein; CON) or diets supplemented with 20 (G20), 60 (G60), or 100 mg/kg (G100) genistein from 5 to 17 weeks of age. Growth performance, bone mineral density, muscle deposition, biomechanical strength, bone ash content, and circulating bone formation biomarkers were evaluated. Pullets receiving G60 and G100 supplementation exhibited greater body weight, bone mineral density, cortical bone area, muscle weights, biomechanical strength, bone ash percentage, and circulating concentrations of BALP and P1NP compared with CON and G20 birds. Feed intake did not differ among treatments. These findings indicate that genistein supplementation, particularly at 60 and 100 mg/kg, may enhance skeletal development during the pullet rearing period. Further research is warranted to determine whether these improvements persist throughout the laying cycle and influence production, as well as the potential deposition of genistein-derived compounds in eggs. Full article

This study investigated the association of polymorphisms in four genes with growth traits in two Japanese quail lines: a high-growth-rate selected line (HGR) and a control line (CL). It utilized 21 generations of divergent selection to identify potential selection signatures, comparing allele frequency shifts between the high-growth and unselected base populations. Growth Hormone (GH), Prolactin (PRL), Bone Morphogenetic Protein Receptor Type-1B (BMPR-1B), and Vasoactive Intestinal Peptide Receptor 1 (VIPR-1) genes were genotyped using PCR-RFLP. While the PRL gene was monomorphic, the GH, BMPR-1B, and VIPR-1 loci were polymorphic. Association analysis demonstrated that these variants significantly influenced body weight. In the HGR line, the homozygous genotypes (BB) of GH and BMPR-1B were significantly correlated with increased body weight at various ages. The AA genotype of VIPR-1 correlated with growth, while the BB genotype reduced body weight. An in silico analysis suggested that GH and VIPR-1 variants were functionally disadvantageous. The BMPR-1B variant was tolerated, indicating its potential as a genetic marker. Significant additive effects were estimated for the associated SNPs, thereby highlighting their heritable potential. These findings suggest that GH, BMPR-1B, and VIPR-1 polymorphisms are valuable for marker-assisted selection to improve growth performance within Japanese quail breeding programs. Full article

This study evaluated the effects of dietary supplementation with dried Haematococcus pluvialis biomass on egg quality in laying hens using a multilevel analytical approach. A total of 100 ISA Brown hens were divided into two groups: a control group (CTRL) fed a basal diet and an experimental group (HP) receiving the same diet supplemented with 0.075% H. pluvialis. Supplementation did not significantly affect most physical egg parameters, although yolk index and yolk height were improved in the HP group. A marked increase in yolk pigmentation was observed, with values reaching 15 on the DSM color fan compared to 8.4 in CTRL (p < 0.0001). Significant enhancements in yolk nutritional quality were detected, including increased total carotenoids and the presence of astaxanthin exclusively in the HP group. Mineral composition was also markedly affected, with significant increases in essential elements such as Fe, Mg, Zn, I, and P in both albumen and yolk. The fatty acid profile was favorably modulated, showing a reduction in saturated fatty acids and an increase in monounsaturated fatty acids, along with improved nutritional indices (AI, TI, HH). Instrumental sensory analysis revealed clear discrimination between groups based on color (E-eye), while differences in volatile profiles (E-nose) were less pronounced. However, a reduction in oviposition rate and egg mass was observed in the supplemented group. Overall, the inclusion of H. pluvialis biomass represents an effective strategy for the natural biofortification of eggs, improving their nutritional and functional value. Full article

Poultry meat producers face pressure to ensure both safety and efficiency as food systems expand in scale and complexity. However, existing diagnostic tools often force a trade-off between speed, accuracy, and cost, leaving limited options for real-time, on-site pathogen detection. This study evaluated the performance of a novel point-of-use rapid diagnostic tool combining filtration and lyophilized isothermal amplification for detecting and semi-quantifying Salmonella in chicken carcass rinse samples. Targeted DNA (invA) was amplified at 65 °C for 60 min, and fluorescence was measured over time. Salmonella was successfully detected in all spiked samples (1.0- to 7.5-log10 CFU/mL; n = 57). An association was observed between the isothermal detection speed data and Salmonella load in the sample (r² = 0.90; p < 0.001), particularly at concentrations ≥ 1.5-log10 CFU/mL. Repeatable data were obtained across three operators and samples of multiple origins (Georgia, Illinois, Nebraska; 0.16-log10; 95%CI: 0.11–0.21). Importantly, complete inclusivity for all tested Salmonella serotypes (n = 46/46) and exclusivity against non-target organisms (n = 0/37) was validated in this study. In conclusion, the technological combination of filtration and lyophilized isothermal amplification enabled the point-of-use detection and quantification of Salmonella in chicken carcass samples within 60 min and minimal lab infrastructure. Full article