Search Results (40)

Background: Reliable and non-invasive methods for assessing welfare in poultry are essential for improving evidence-based welfare monitoring and advancing management practices in commercial production systems. The iris-to-pupil (IP) ratio, previously validated by our group in primates and cattle, reflects autonomic nervous system balance and may serve as a physiological indicator of stress in laying hens. This study evaluated the utility of the IP ratio under field conditions across diverse commercial layer housing systems. Materials and Methods: In total, 296 laying hens (Lohmann Brown, n = 269; White Leghorn, n = 27) were studied across four locations in Canada housed under different systems: Guelph (indoor; pen), Spring Island (outdoor and scratch; organic), Ottawa (outdoor, indoor and scratch; free-range), and Toronto (outdoor and hobby; free-range). High-resolution photographs of the eye were taken under ambient lighting. Light intensity was measured using the light meter app. The IP ratio was calculated using NIH ImageJ software (Version 1.54p). Statistical analysis included one-way ANOVA and linear regression using GraphPad Prism (Version 5). Results: Birds housed outdoors had the highest IP ratios, followed by those in scratch systems, while indoor and pen-housed birds had the lowest IP ratios (p < 0.001). Subgroup analyses of birds in Ottawa and Spring Island farms confirmed significantly higher IP ratios in outdoor environments compared to indoor and scratch systems (p < 0.001). The IP ratio correlated weakly with ambient light intensity (r² = 0.25) and age (r² = 0.05), indicating minimal influence of these variables. Although White Leghorn hens showed lower IP ratios than Lohmann Browns, this difference was confounded by housing type; all White Leghorns were housed in pens. Thus, housing system but not breed was the primary driver of IP variation. Conclusions: The IP ratio is a robust, non-invasive physiological marker of welfare assessment in laying hens, sensitive to housing environment but minimally influenced by light or age. Its potential for integration with digital imaging technologies supports its use in scalable welfare assessment protocols. Full article

Background: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is an escalating global health challenge, affecting over 82 million individuals each year. The increasing resistance to commonly used antibiotics such as azithromycin, ciprofloxacin, and cefixime hinders timely and effective treatment, primarily due to the delayed detection of resistant strains. Methods: To overcome these limitations, a hybrid machine learning (ML) and deep learning (DL) framework was developed using a dataset comprising 3786 N. gonorrhoeae isolates. The dataset included clinical metadata and phenotypic resistance profiles. The preprocessing steps involved handling 23% data sparsity, imputing 31 skewed columns, and applying resampling and harmonisation techniques sensitive to data skewness. A predictive pipeline was constructed using both clinical variables and genomic unitigs, and a suite of 33 classifiers was evaluated. Results: The CatBoost model emerged as the top-performing ML algorithm, particularly due to its proficiency in handling categorical data, while a three-layered neural network served as the DL baseline. The ML models outperformed genome-wide association study (GWAS) benchmarks, achieving AUC scores of 0.97 (ciprofloxacin), 0.95 (cefixime), and 0.94 (azithromycin), representing a 4–7% improvement. SHAP analysis identified biologically relevant resistance markers, such as penA mosaic alleles and mtrR promoter mutations, validating the interpretability of the model. Conclusions: The study highlights the potential of ML-driven approaches to enhance the real-time prediction of antimicrobial resistance in N. gonorrhoeae. These methods can significantly contribute to antibiotic stewardship programs, although further validation is required in low-resource settings to confirm their generalisability and robustness across diverse populations. Full article

Background/Objectives: In the context of acute heart failure, proenkephalin A (penKid) has emerged as a prognostic marker for acute kidney injury (AKI), whereas bioactive adrenomedullin (bio-ADM) has been identified as a significant biomarker linked to shock and organ dysfunction. This raises the question of whether they can serve as predictors of postoperative complications in patients receiving left ventricular assist devices (LVADs). Methods: This observational study prospectively enrolled patients who had received LVAD implantation. Routine laboratory values as well as plasma levels of penKid and bio-ADM were assessed at four time intervals, spanning from preinduction of anesthesia to 48 h post surgery. Clinical data, the HeartMate 3-risk-score (HM3RS), HeartMateII-risk-score (HMRS), Michigan-right-heart-failure risk score (MRHFS), Euromacs-RHFS (EURORHFS), and kidney failure risk score (KFR) were calculated. Multivariate logistic regression and receiver operating characteristic (ROC) analysis were performed. We entered the biomarkers with the established risk scores into the models. Results: In 20 patients who had undergone LVAD implantation, preoperative penKid level was a predictor of postoperative AKI (OR: 1.05, 95%-CI: 1.0–1.09; p = 0.049) and 30-day mortality (OR: 1.01, 95%-CI: 1.0–1.02; p = 0.033). Bio-ADM was the only predictor of postoperative right heart failure (RHF) (OR: 1.11, 95%-CI: 1.01–1.23; p = 0.034) and rehospitalization (OR: 1.06, 95%-CI: 1.0–1.13; p = 0.047). In the ROC analysis, bio-ADM, as a predictor of post-LVAD RHF, had an area under the curve (AUC) of 0.88. When bio-ADM was added to the accepted clinical scores for post-LVAD RHF prediction (CRITT-score, MRHFS, and EURORHFS), the AUC reached 0.98. The AUC for preoperative penKid, as a predictor of postoperative AKI, was 0.95, and after adding its predictive value to the KFR score, the AUC reached 0.97. Conclusions: In the present study, the biomarkers penKid and bio-ADM predicted clinically significant patient outcomes after LVAD implantation such as AKI, RHF, and 30-day mortality. Adding biomarkers to well-established risk scores improved the AUC for prediction of postoperative complications. Full article

Through an integrated multi-omics analysis of rumen microbial communities, muscle transcriptomes, metabolic profiles, and liver metabolic profiles, this study systematically compared high- and low-performing lambs to elucidate their divergent effects on meat quality attributes and growth development. A total of 100 male lambs with similar birth weight (3.07 ± 0.06 kg) were selected within 72 h. All test lambs were synchronized weaning at 45 days of age and uniformly fed the same diet (total mixed ration) in the same pen until 180 days of age, with ad libitum access to food and water throughout this period. Subsequently, the eight lambs with the highest (HADG) and lowest (LADG) average daily gains were slaughtered for performance evaluation and multi-omics analysis. This study found that HADG lambs increased body weight, muscle fiber diameter, eye muscle area, improved amino acid (histidine, arginine, valine, isoleucine, essential amino acid/total amino acid, and essential amino acid/nonessential amino acid), and fatty acid (linoleic acid, behenic acid, and arachidonic acid) composition enhanced rumen enzymes (pepsase, lipase, xylanase, amylase, and carboxymethyl cellulose) and promoted efficient fermentation (p < 0.05). Analysis of microbial populations indicated a notable increase in Prevotella levels within the rumen of HADG lambs. Furthermore, the rumen markers Schwartzia and Streptococcus exhibited significant correlations with differential meat quality traits. Analysis of the muscle transcriptome indicated a significant correlation between the turquoise module and host phenotypes, particularly body weight. Additionally, muscle metabolism is primarily concentrated within the black module; however, it exhibits a significant correlation with the host body phenotype in the yellow module (p < 0.05). Moreover, liver metabolites, rumen microbes, host phenotype, and muscle transcripts were significantly correlated (p < 0.05). In conclusion, the interactions among rumen microbes, muscle, and liver in lambs promote rumen fermentation, which in turn regulate muscle transcriptional activity and modify metabolic profiles in both the liver and muscle. Moreover, PCK1, SPP1, FGF7, NR4A1, DUSP5, GADD45B, etc., can be candidate genes for muscle growth and development. This finding provides a theoretical basis for further exploiting the production potential of Hu lambs. Full article

A total of sixty crossbred ([Landrace × Yorkshire] × Duroc) pigs with an initial body weight of 46.34 ± 0.13 kg were randomly assigned to four treatments under thermoneutral (TN, 22 °C) or heat-stress (HS, 31 °C) conditions for 54 d trial (Phase 1: 0–26 d; Phase 2: 27–54 d): a control diet (16% CP in phase 1, 14% CP in phase 2) under TN (PC), a control diet under HS (NC), a low crude protein (LCP) diet (14% CP in phase 1, 12% CP in phase 2) under HS (LCP) and an LCP diet with increased crystalline AA (an increase in 5% in Lys, Met, Thr and Trp based on calculated SID AA) (LCP5) under HS. Experimental treatments consisted of five replicate pens, with three pigs per pen. The results showed that HS reduced (p < 0.05) growth performance and nutrient digestibility compared to TN. However, LCP5 improved (p < 0.05) growth performance and nutrient digestibility compared to other HS groups. Heat stress adversely affected (p < 0.05) intestinal morphology, gut integrity and serum oxidative markers, but these effects were alleviated (p < 0.05) by LCP5 supplementation. Notably, LCP5 improved (p < 0.05) the production of butyric acids among short-chain fatty acid production and decreased (p < 0.05) proteobacteria and Spirochaetota in phylum in feces. These findings highlight the potential of LCP diets supplemented with crystalline AA as an effective nutritional strategy to mitigate the negative effects of HS on pigs, enhancing their performance, gut health and overall welfare in high-temperature environments. Full article

The aim of this study was to investigate the impact of incorporating black soldier fly meal (BSFM) into the diet of brooding laying hens, with a focus on growth performance, serum biochemical markers, nutrient digestibility, intestinal morphology, and immune responses. A total of 480 one-day-old chicks (Hy-Line Brown, commercial flock) were randomly divided into four dietary treatment groups, each consisting of six replicates with 20 birds per pen. One group was fed a basal control diet (control/G0 group), while the remaining three groups were fed 3% (G3 group), 6% (G6 group), and 9% (G9 group) BSFM, respectively. The study lasted for 42 days. At both 21 and 42 days of age, several parameters were measured, including average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), and tibia length. Blood serum samples were also collected to assess biochemical and antioxidant indicators. Results showed that the ADG in the G3 group was significantly higher than the G0 group during the 1–21, 22–24, and 1–42 day periods (p < 0.05). The F/G ratio in the G3 group was significantly lower than that of the G0 group during the 1–21 day period (p < 0.05). However, there were no significant differences in ADFI or tibia length across the groups (p > 0.05). The total protein and globulin levels in the G3 and G6 groups were significantly higher than those in the G0 group (p < 0.05). Additionally, blood urea nitrogen levels in the G3 group were significantly higher than in the G0 group (p < 0.05). Conversely, triglyceride levels were significantly lower in the G3 and G6 groups compared to the G0 group (p < 0.05). Total antioxidant activity was significantly higher in the G6 and G9 groups than in the G0 group (p < 0.05). The treated groups also exhibited higher glutathione peroxidase (GSH-Px) activity and lower malondialdehyde (MDA) levels compared to the G0 group (p < 0.05). However, there were no significant differences in total superoxide dismutase activity across the groups (p > 0.05). In conclusion, this study indicates that BSFM can serve as a high-quality protein raw material in the process of laying hen breeding, highlighting its potential as a viable insect protein source in the poultry feed industry. Full article

Anaplasma marginale and Babesia bigemina are tick-borne pathogens, posing significant threats to the health and productivity of cattle in tropical and subtropical regions worldwide. Currently, detection of Babesia bigemina and Anaplasma marginale in infected animals relies primarily on microscopic examination of Giemsa-stained blood or organ smears, which has limited sensitivity. Molecular methods offer higher sensitivity but are costly and impractical in resource-limited settings. Following the development of a pen-side test for detecting Theileria parva infections in cattle, we have created two additional CRISPR-Cas12a assays targeting Anaplasma marginale and Babesia bigemina. The assays target the major surface protein 5 (MSP5) for A. marginale and rhoptry-associated protein 1a (RAP1a) for B. bigemina. These additional tests involve a 20 min recombinase polymerase amplification (RPA) reaction followed by a 60 min CRISPR-Cas12a detection with a lateral strip readout. Results demonstrate high specificity, with no cross-reactivity against other tick-borne parasites, and a limit of detection down to 10² DNA copies/µL of each target marker. The findings pave the way for sensitive and user-friendly pen-side tests to diagnose A. marginale and B. bigemina infections. Full article

Using alternative ingredients or low-quality grain grades to reduce feeding costs for pig diets can introduce mycotoxins such as deoxynivalenol (DON) into feed, which is known to induce anorexia, inflammation, and oxidative stress. Adding vitamin 25(OH)D₃ or vitamins E and C to the feed could increase piglets’ immune system to alleviate the effects of DON. This study used 54 pigs (7.8 ± 0.14 kg) in 27 pens (2 pigs/pen) with a vitamin 25(OH)D₃ or vitamin E-C supplementation, or their combination, in DON-contaminated (5.1 mg/kg) feed ingredients over 21 days followed by a lipopolysaccharide (LPS) challenge (20 µg/kg BW) 3 h prior to euthanasia for 1 piglet per pen. DON contamination induced anorexia, which reduced piglet growth. DON also induced immunomodulation, oxidative stress, and downregulated vitamin D status. The vitamin E and C supplementation and the combination of vitamins E, C, and 25(OH)D₃ provided protection against DON contamination by not only decreasing blood and liver oxidative stress markers, but also by increasing antioxidant enzymes and tocopherol levels in blood, indicating improved antioxidant defense mechanisms. The combination of vitamins also restored the vitamin D status. After LPS challenge, DON contamination decreased intestinal and liver antioxidant statuses and increased inflammation markers. The addition of vitamins E and C to DON-contaminated feed reduced markers of inflammation and improved the antioxidant status after the LPS immune stimulation. The combination of all these vitamins also reduced the oxidative stress markers and the inflammation in the intestine and mesenteric lymph nodes, suggesting an anti-inflammatory effect. Full article

Laying hens can experience a progressive increase in bone fragility due to the ongoing mobilization of calcium from bones for eggshell formation. Over time, this escalates their susceptibility to bone fracture, which can reduce their mobility and cause pain. The provision of perches as an exercise opportunity could potentially enhance bone strength, but the timing of exposure to perches during the birds’ development may modulate its impact. The objective of this study was to investigate the enduring impacts of perch provision timing on the musculoskeletal health of laying hens. A total of 812 pullets were kept in different housing conditions (seven pens/treatment, 29 birds/pen) with either continuous access to multi-tier perches from 0 to 40 weeks of age (CP), no access to perches (NP), early access to perches during the rearing phase from 0 to 17 weeks of age (EP), or solely during the laying phase from 17 to 40 weeks of age (LP). At weeks 24, 36, and 40 of age (n = 84 birds/week), three birds per pen were monitored for individual activity level, and blood samples were collected from a separate set of three birds per pen to analyze serum levels of tartrate-resistant acid phosphatase 5b (TRACP-5b) and C-terminal telopeptide of type I collagen (CTX-I) as markers of bone demineralization. At 40 weeks of age, three birds per pen (n = 84) were euthanized for computed tomography scans to obtain tibial bone mineral density (BMD) and cross-sectional area (CSA) with further analysis including muscle deposition, tibial breaking strength, and tibial ash percent. During week 24, hens from CP, EP, and LP pens had the highest overall activity compared to hens from NP pens (p < 0.05) with no differences between treatments for overall activity level during weeks 36 or 40 (p > 0.05). During weeks 24, 36, and 40, hens from CP and LP pens showed greater vertical and less horizontal activity compared to hens from EP and NP pens (p < 0.05). TRACP-5b and CTX-I concentrations did not differ between treatments at week 24 of age (p > 0.05). Hens from CP pens had the lowest TRACP-5b and CTX-I concentrations at 36 weeks of age with EP and LP hens showing intermediate responses and NP hens having the highest concentration (p < 0.05). At 40 weeks of age, CP hens had the lowest TRACP-5b and CTX-I concentrations compared to NP hens (p < 0.05). Total bone CSA did not differ between treatments (p > 0.05), but CP had greater total BMD than NP (p < 0.05) with no differences between EP and LP treatments. CP and LP hens had larger biceps brachii, pectoralis major, and leg muscle groups as well as greater tibial breaking strengths than EP and NP treatments (p < 0.05). CP hens had higher tibial ash percentages compared to EP, LP, and NP (p < 0.05). Our results indicate that providing continuous perch access improves the musculoskeletal health and activity of laying hens at 40 weeks of age compared to no access and that late access to perches has a beneficial impact on activity, muscle deposition, and bone strength. Full article

Classical swine fever virus (CSFV) is an OIE-listed disease that requires effective surveillance tools for its detection and control. The aim of this study was to develop and evaluate the diagnostic performance of a novel CSFV Erns IgG AlphaLISA for both serum and oral fluid specimens that would likewise be compatible with the use of CSFV E2 DIVA vaccines. Test performance was evaluated using a panel of well-characterized serum (n = 760) and individual (n = 528) or pen-based (n = 30) oral fluid samples from four groups of animals: (1) negative controls (n = 60 pigs); (2) inoculated with ALD strain wild-type CSFV (n = 30 pigs); (3) vaccinated with LOM strain live CSFV vaccine (n = 30 pigs); and (4) vaccinated with live CSFV marker vaccine on commercial farms (n = 120 pigs). At a cutoff of S/P ≥ 0.7, the aggregate estimated diagnostic sensitivities and specificities of the assay were, respectively, 97.4% (95% CI 95.9%, 98.3%) and 100% for serum and 95.4% (95% CI 92.9%, 97.0%) and 100% for oral fluid. The Erns IgG antibody AlphaLISA combined DIVA capability with solid diagnostic performance, rapid turnaround, ease of use, and compatibility with both serum and oral fluid specimens. Full article

Slippery coatings, such as the slippery liquid-infused porous surface (SLIPS), have gained significant attention for their potential applications in anti-icing and anti-fouling. However, they lack durability when subjected to mechanical impact. In this study, we have developed a robust slippery coating by blending polyurethane acrylate (PUA) with methyltriethoxysilane (MTES) and perfluoropolyether (PFPE) in the solvent of butyl acetate. The resulting mixture is homogeneous and allows for uniform coating on various substrates using a drop coating process followed by drying at 160 °C for 3 h. The cured coating exhibits excellent water repellency (contact angle of ~108° and sliding angle of ~8°), high transparency (average visible transmittance of ~90%), exceptional adherence to the substrate (5B rating according to ASTMD 3359), and remarkable hardness (4H on the pencil hardness scale). Moreover, the coating is quite flexible and can be folded without affecting its wettability. The robustness of the coating is evident in its ability to maintain a sliding angle below 25° even when subjected to abrasion, water jetting, high temperature, and UV irradiation. Due to its excellent nonwetting properties, the coating can be employed in anti-icing, anti-graffiti, and anti-sticking applications. It effectively reduces ice adhesion on aluminum substrates from approximately 217 kPa to 12 kPa. Even after 20 cycles of icing and de-icing, there is only a slight increase in ice adhesion, stabilizing at 40 kPa. The coating can resist graffiti for up to 400 cycles of writing with an oily marker pen and erasing with a tissue. Additionally, the coating allows for easy removal of 3M tape thereon without leaving any residue. Full article

This study explores innovative designs for the cap of a marker pen, aiming to address the issues of cap loss and ink evaporation during marker pen usage. This study applies intrinsic safety, universal design and TRIZ as research methods. TRIZ has great potential to address most of the Sustainable Development Goals (SDGs) relevant to conflict-oriented problem solving for innovations. The principles of simplification, foolproof design, clarity of states, and tolerance from intrinsic safety were applied to prevent cap loss and minimize the risks associated with ink evaporation. The TRIZ methodology’s contradiction matrix was utilized to identify relevant inventive principles by improving parameters and avoiding worsening parameters, providing a reference basis for product structure design. Lastly, the principles of equitable use, simplicity, intuitiveness, and effortless design from universal design were employed to enhance the marker pen’s usability for the general public. This study creates a SERVQUAL questionnaire to compare the prototype of the designed pen cap with commercially available pen caps. It utilizes the two-dimensional quality model (Kano model) and Importance–Performance Analysis (IPA) for practical design analysis. Finally, the prototype structure is visualized using graphic software. The innovative design features of this study include the following. (1) Concealable pen tip: the sliding seal hides the pen tip inside the pen body when the pen core is slid upwards, preventing cap loss and ink drying. (2) Quick retractable function: using a pressing mechanism, the pen tip can be quickly retracted with a one-handed press and slide motion. (3) Replaceable pen core: the pen core can be replaced by disassembling the pen body, removing the old pen core, and inserting a new one, thereby extending the pen’s lifespan. (4) Satisfaction evaluation of the innovative pen cap design: through questionnaire surveys and cross-analysis using the IPA and the Kano model, this study assesses the product’s manufacturing and mass production value to reduce actual product development costs and time. Full article

Beta (β)-lactam antibiotic is an industrially important molecule produced by Penicillium chrysogenum/rubens. Penicillin is a building block for 6-aminopenicillanic acid (6-APA), an important active pharmaceutical intermediate (API) used for semi-synthetic antibiotics biosynthesis. In this investigation, we isolated and identified Penicillium chrysogenum, P. rubens, P. brocae, P. citrinum, Aspergillus fumigatus, A. sydowii, Talaromyces tratensis, Scopulariopsis brevicaulis, P. oxalicum, and P. dipodomyicola using the internal transcribed spacer (ITS) region and the β-tubulin (BenA) gene for precise species identification from Indian origin. Furthermore, the BenA gene distinguished between complex species of P. chrysogenum and P. rubens to a certain extent which partially failed by the ITS region. In addition, these species were distinguished by metabolic markers profiled by liquid chromatography–high resolution mass spectrometry (LC-HRMS). Secalonic acid, Meleagrin, and Roquefortine C were absent in P. rubens. The crude extract evaluated for PenV production by antibacterial activities by well diffusion method against Staphylococcus aureus NCIM-2079. A high-performance liquid chromatography (HPLC) method was developed for simultaneous detection of 6-APA, phenoxymethyl penicillin (PenV), and phenoxyacetic acid (POA). The pivotal objective was the development of an indigenous strain portfolio for PenV production. Here, a library of 80 strains of P. chrysogenum/rubens was screened for PenV production. Results showed 28 strains capable of producing PenV in a range from 10 to 120 mg/L when 80 strains were screened for its production. In addition, fermentation parameters, precursor concentration, incubation period, inoculum size, pH, and temperature were monitored for the improved PenV production using promising P. rubens strain BIONCL P45. In conclusion, P. chrysogenum/rubens strains can be explored for the industrial-scale PenV production. Full article

In this paper, an experiment is carried out to acquire the dynamic mechanical properties of a simulated sandstone tunnel by a dual DIC system. The sandstone tunnel is simulated by large sandstone with a prefabricated hole in the center. The speckle size required by DIC system was evaluated, and the results showed that for large specimens a marker pen could be used to spot speckles and make sure that the diameters of speckle points in an image should be ranged from three to five pixels. The dual DIC system is composed of a low-speed camera and a high-speed camera. The low-speed camera is used to record the speckle patterns of the sandstone in one side during the whole process of compression load, and the high-speed camera is placed in the other side to record speckle patterns for 11.5 seconds before and after failure. It is realized that monitoring whole process of deformation and instantaneous failure in two directions is required. Measurement results are effectively analyzed. The results are shown as follows: At the initial stage of loading the sandstone is in an elastic stage without macroscopic cracks. With the increase in compression load the sandstone has several small stress releases and several obvious macroscopic cracks. In the final stage of loading, the distribution of normal stress and shear stress are almost the same, and cracks are subjected to the coupling effect of normal stress and shear stress. The two ends of the prefabricated hole perpendicular to the applied load direction are prone to cracks parallel to the applied load direction. Full article

Physical pellet quality and AME_N concentration are strongly related to each other in broiler feeding. A study was conducted to evaluate the relationship between dietary AME_N concentration and feed processing on pellet quality, nutrient digestibility, broiler performance, serum markers, and yield of commercial cuts. Six diets were formulated. The first diet had the recommended AME_N concentration, each further diet was calculated with 40 kcal/kg less, from 0 to −200 kcal/kg, resulting in six levels for each feed phase: starter (1–14 d), grower (15–28 d), and finisher (29–35 d). These diets were processed with and without expander conditioning prior to pelleting, using an average corn particle size of 1.6 mm, ground with a roller mill. A total of 1008 one-day-old male Ross 308 broiler chickens were placed in a 6 × 2 (6 energy levels and 2 conditionings) factorial trial with six boxes as replications, with three in each broiler performance trial period. Excreta were collected 2 days before the end of each feed phase for apparent total tract digestibility measurement. On day 36, four broilers from each replication (pen) were weighed and then euthanized for blood collection, following which the gastrointestinal organs were weighed, and the ileal and gizzard contents were collected. On day 37, all remaining broilers were slaughtered after fasting to measure commercial cuts and abdominal fat. The results show that the pellet durability index (PDI) was most affected by energy reducing and expander conditioning prior to pelleting, and it was better when diets had energy reduced by 40 to 200 kcal/kg (p > 0.001), as when expander conditioning was used. Digestibility of nutrients was slightly affected by treatments, as was the broiler performance; however, feed efficiency was improved in broiler-fed diets without AME_N reduction and when an expander was used, with p = 0.050 and p = 0.031, respectively. No effects were observed on the weight of gastrointestinal tract organs and serum markers, except for liver (p = 0.037) and α-amylase (p = 0.047). The lowest liver weight and lowest serum protein, cholesterol, triglyceride, gamma-glutamyl, and lipase concentrations were obtained when diets were formulated without energy reduction (Ross-0). There was no effect on commercial cuts relative to live weight at slaughter. The energy reduction was well reflected in the proportion of abdominal fat, which decreased when AME_N was reduced (p = 0.001). The present study shows it is possible to use diets with up to 200 kcal/kg reduction in AME_N without losses in performance, and the use of expander conditioning prior to pelleting promotes higher pellet quality and broiler feed efficiency. Full article