Lauric acid content in intramuscular fat is a reliable indicator of black soldier fly larvae meal consumption in Muscovy ducks.

The present research investigated if intramuscular fatty acid (FA) profile could distinguish meat from ducks fed with black soldier fly larvae meal (BSFLM) during fattening. By using stepwise linear discriminant analysis on FA profiles of 96 meat samples, lauric acid (C12:0) was found to be the best predictor, accurately differentiating samples with only two misclassifications. The Fisher classification functions indicated that breast samples with lauric acid content above 0.222 % in intramuscular fat would be classified as BSFLM-fed. The Fisher classification functions were also effective in other poultry species fed BSFLM, with only two misclassified samples out of 42 samples from a dataset compiled from published papers. Misclassifications were linked to an unexpected lauric acid content in the intramuscular fat. In conclusion, given that BSFLM is the only relevant source of lauric acid in the diet, this fatty acid could identify meat from BSFLM-fed ducks and possibly other poultry species, warranting further exploration of other FA as potential identifiers of BSFLM-fed poultry.

Polymer Patterning by Laser-Induced Multipoint Initiation of Frontal Polymerization.

Frontal polymerization (FP) is an approach for thermosetting plastics at a lower energy cost than an autoclave. The potential to generate simultaneous propagation of multiple polymerization fronts has been discussed as an exciting possibility. However, FP initiated at more than two points simultaneously has not been demonstrated. Multipoint initiation could enable both large-scale material fabrication and unique pattern generation. Here, the authors present laser-patterned photothermal heating as a method for simultaneous initiation of FP at multiple locations in a 2-D sample. Carbon black particles are mixed into liquid resin (dicyclopentadiene) to enhance absorption of light from a Ti:sapphire laser (800 nm) focused on a sample. The laser is time-shared by rapid steering among initiation points, generating polymerization using up to seven simultaneous points of initiation. This process results in the formation of both symmetric and asymmetric seam patterns resulting from the collision of fronts. The authors also present and validate a theoretical framework for predicting the seam patterns formed by front collisions. This framework allows the design of novel patterns via an inverse solution for determining the initiation points required to form a desired pattern. Future applications of this approach could enable rapid, energy-efficient manufacturing of novel composite-like patterned materials.

Study of the Direct Costs of Asthma at a Healthcare Service Provider in Bogotá, Colombia.

OBJECTIVES: This study aimed to describe clinical characteristics and direct medical costs associated with disease treatment in Colombia patients with asthma from 1 healthcare provider. METHODS: This was a descriptive study with a retrospective data collection from a healthcare provider's electronic medical records in Colombia. A clinical, demographic, and healthcare resource utilization profile was developed over a 12-month observation period after the identification of eligible patients. To determine the mean cost per patient per year, the total frequencies of resource utilization were added, and the result was multiplied by the unit cost of each of them. RESULTS: A total of 7919 patients were included in the analysis. The mean ± SD cost per patient per year ranged from $189.5 ± $1.900.6 to $240.2 ± $1.903.6 depending on the price guidebook. The total cost had been driven by the medication use (79% of total cost) and by the outpatient visits (20% of total cost). CONCLUSIONS: In the population analyzed, the mean total direct cost per patient per year of asthma was $189.5 and $240.2, depending on the cost source. Direct medical costs were higher in cases classified as severe and in the adult and elderly population. When comparing the sources of resource utilization, it was found that the mean cost per patient obtained from real-life data is lower than the theoretical cost obtained from the bottom-up method with quantification of resources from experts. It is important to consider limitations related to study design and the evolving landscape of asthma treatments.

Delphi Consensus on Clinical Applications of GOLD 2023 Recommendations in COPD Management: How Aligned are Recommendations with Clinical Practice?

INTRODUCTION: The objective of this Delphi study was to understand and assess the level of consensus among respiratory experts on the clinical application of GOLD 2023 recommendations in management of patients with chronic obstructive pulmonary disease (COPD). METHODS: The study comprised two online surveys and a participant meeting with 34 respiratory experts from 16 countries. Responses of 73 questions were recorded using a Likert scale ranging from 0 (disagreement) to 9 (agreement). The consensus threshold was 75%. RESULTS: Survey 1 and survey 2 had 34 and 32 participants, respectively; and 25 attended the participant meeting. Consensus was reached on survey 1: 28/42; survey 2: 18/30 close-ended questions. A consensus was reached on the clinical relevance of most updates in definitions and diagnosis of COPD. Mixed results for the treatment recommendations by GOLD were noted: 74% agreed with the recommendation to initiate treatment with dual bronchodilators for group E patients; 63% agreed for including inhaled corticosteroids (ICS)/long-acting ß2 agonist(LABA)/ Long-acting muscarinic receptor antagonists (LAMA) as a treatment option for GOLD B patients. Also, consensus lacked on removing ICS + LABA as an initial therapeutic option, in countries with challenges in access to other treatment option;. 88% agreed that they use GOLD recommendations in their daily clinical practice. CONCLUSIONS: This Delphi study demonstrated a high level of consensus regarding key concepts of GOLD 2023 report, with most participants favoring recent updates in definitions, diagnosis, management, and prevention of COPD. More evidence on the etiotype based management and treatment options for group B and E are required which could further strengthen clinical application of the GOLD report.

The goal of this Delphi study was to understand and assess the level of alignment among the respiratory experts on the application of key changes and recommendations proposed by the GOLD 2023 report in their routine clinical practice for the management of patients with chronic obstructive pulmonary disease (COPD). There were two online surveys in this study, and experts from 16 countries (primarily focused on developing countries) were invited to participate. Using the Delphi method, expert representatives shared their insights with the aim of optimizing patient care. The alignment was assessed in six well-defined themes: 1) Overall view on GOLD/other recommendations; 2) Assessing patients with COPD; 3) Initial pharmacological treatment in patients with COPD; 4) Vaccination for patients with COPD; 5) Follow-up pharmacological treatment in patients with COPD; and 6) Survival evidence in patients with COPD. Participants expressed a high level of agreement regarding key concepts of the GOLD 2023 report, with most of them agreeing with recent updates in definitions, diagnosis, management, and prevention of COPD. The results also highlighted the need to publish GOLD reports in multiple languages and in a shorter, pocket-sized format to increase awareness and adaptation among healthcare providers.

Lives Versus Livelihoods: The Epidemiological, Social, And Economic Impact Of COVID-19 In Latin America And The Caribbean.

During the COVID-19 pandemic, Latin American and Caribbean countries implemented stringent public health and social measures that disrupted economic and social activities. This study used an integrated model to evaluate the epidemiological, economic, and social trade-offs in Argentina, Brazil, Jamaica, and Mexico throughout 2021. Argentina and Mexico displayed a higher gross domestic product (GDP) loss and lower deaths per million compared with Brazil. The magnitude of the trade-offs differed across countries. Reducing GDP loss at the margin by 1 percent would have increased daily deaths by 0.5 per million in Argentina but only 0.3 per million in Brazil. We observed an increase in poverty rates related to the stringency of public health and social measures but no significant income-loss differences by sex. Our results indicate that the economic impact of COVID-19 was uneven across countries as a result of different pandemic trajectories, public health and social measures, and vaccination uptake, as well as socioeconomic differences and fiscal responses. Policy makers need to be informed about the trade-offs to make strategic decisions to save lives and livelihoods.

Influence of NaCl concentration on the optical scattering properties of water-based aerosols.

We present the characterization of several atmospheric aerosol analogs in a tabletop chamber and an analysis of how the concentration of NaCl present in these aerosols influences their bulk optical properties. Atmospheric aerosols (e.g., fog and haze) degrade optical signal via light-aerosol interactions causing scattering and absorption, which can be described by Mie theory. This attenuation is a function of the size distribution and number concentration of droplets in the light path. These properties are influenced by ambient conditions and the droplet's composition, as described by Köhler theory. It is therefore possible to tune the wavelength-dependent bulk optical properties of an aerosol by controlling droplet composition. We present experimentation wherein we generated multiple microphysically and optically distinct atmospheric aerosol analogs using salt water solutions with varying concentrations of NaCl. The results demonstrate that changing the NaCl concentration has a clear and predictable impact on the microphysical and optical properties of the aerosol.

Structural racism theory, measurement, and methods: A scoping review.

Introduction: Epidemiologic and public health interest in structural racism has grown dramatically, producing both increasingly sophisticated questions, methods, and findings, coupled with concerns of atheoretical and ahistorical approaches that often leave the actual production of health or disease ambiguous. This trajectory raises concerns as investigators adopt the term "structural racism" without engaging with theories and scholars with a long history in this area. This scoping review aims to build upon recent work by identifying current themes about the incorporation of structural racism into (social) epidemiologic research and practice with respect to theory, measurement, and practices and methods for trainees and public health researchers who are not already deeply grounded in this work. Methods: This review uses methodological framework and includes peer-review articles written in English published between January 2000-August 2022. Results: A search of Google Scholar, manual collection, and referenced lists identified a total of 235 articles; 138 met the inclusion criteria after duplicates were removed. Results were extracted by, and organized into, three broad sections: theory, construct measurement, and study practice and methods, with several themes summarized in each section. Discussion: This review concludes with a summary of recommendations derived from our scoping review and a call to action echoing previous literature to resist an uncritical and superficial adoption of "structural racism" without attention to already existing scholarship and recommendations put forth by experts in the field.

Neuropathologic changes associated with stereoelectroencephalography depth electrode placement.

BACKGROUND: The aim of this study was to detail the neuropathologic changes resulting from the surgical placement of stereoelectroencephalography (SEEG) leads in an initial small group of epilepsy cases and to raise awareness of this iatrogenic pathology, especially to those medical providers who specialize in the care of epilepsy patients. METHODS: Five consecutive patients who underwent epilepsy resection surgery following SEEG monitoring at OSF Saint Francis Medical Center were included in our report. Resection specimens were examined grossly and entirely submitted for microscopic evaluation by a neuropathologist. Seizure-related pathologies, as well as histologic changes related to SEEG electrode placement, were documented. RESULTS: The patient cohort included two females and three males, with an age range of 9 to 47 years. Neuropathologic examination revealed one or more seizure-related pathologies in each patient's resection specimen. In addition, all brain resection specimens showed multiple microinfarcts, which appeared to correlate with the placement and size of SEEG electrodes. Patchy leptomeningeal chronic inflammation was also seen in most cases. CONCLUSIONS: SEEG electrode placement is an effective procedure for determining epileptogenic regions and guiding subsequent resection surgeries in medically refractory epilepsy. Multiple microinfarcts and chronic inflammation are commonly seen in brain resection specimens following SEEG electrode insertion, but studies detailing these iatrogenic histopathologic changes are lacking. The clinical significance and long-term implications of multiple small foci of electrode-induced injury that remain in the patient's brain after resection of the epileptogenic focus are unknown and may provide a welcome area for future study.

Decoding EEG rhythms offline and online during motor imagery for standing and sitting based on a brain-computer interface.

Motor imagery (MI)-based brain-computer interface (BCI) systems have shown promising advances for lower limb motor rehabilitation. The purpose of this study was to develop an MI-based BCI for the actions of standing and sitting. Thirty-two healthy subjects participated in the study using 17 active EEG electrodes. We used a combination of the filter bank common spatial pattern (FBCSP) method and the regularized linear discriminant analysis (RLDA) technique for decoding EEG rhythms offline and online during motor imagery for standing and sitting. The offline analysis indicated the classification of motor imagery and idle state provided a mean accuracy of 88.51 ± 1.43% and 85.29 ± 1.83% for the sit-to-stand and stand-to-sit transitions, respectively. The mean accuracies of the sit-to-stand and stand-to-sit online experiments were 94.69 ± 1.29% and 96.56 ± 0.83%, respectively. From these results, we believe that the MI-based BCI may be useful to future brain-controlled standing systems.

Viability and Adhesion of Periodontal Ligament Fibroblasts on a Hydroxyapatite Scaffold Combined with Collagen, Polylactic Acid-Polyglycolic Acid Copolymer and Platelet-Rich Fibrin: A Preclinical Pilot Study.

Background: Conventional periodontal therapy relies on bone regeneration strategies utilizing scaffolds made of diverse materials, among which collagen, to promote cell adhesion and growth. Objective: To evaluate periodontal ligament fibroblast (HPdLF) cell adhesion and viability for periodontal regeneration purposes on hydroxyapatite scaffolds containing collagen (HAp-egg shell) combined with polylactic acid−polyglycolic acid copolymer (PLGA) and Platelet-Rich Fibrin (PRF). Methods: Four variations of the HAp-egg shell were used to seed HPdLF for 24 h and evaluate cell viability through a live/dead assay: (1) (HAp-egg shell/PLGA), (2) (HAp-egg shell/PLGA + collagen), (3) (HAp-egg shell/PLGA + PRF) and (4) (HAp-egg shell/PLGA + PRF + collagen). Cell adhesion and viability were determined using confocal microscopy and quantified using central tendency and dispersion measurements; significant differences were determined using ANOVA (p < 0.05). Results: Group 1 presented low cell viability and adhesion (3.70−10.17%); groups 2 and 3 presented high cell viability and low cell adhesion (group 2, 59.2−11.1%, group 3, 58−4.6%); group 4 presented the highest cell viability (82.8%) and moderate cell adhesion (45%) (p = 0.474). Conclusions: The effect of collagen on the HAp-egg shell/PLGA scaffold combined with PRF favored HPdLF cell adhesion and viability and could clinically have a positive effect on bone defect resolution and the regeneration of periodontal ligament tissue.

Machine learning in the loop for tuberculosis diagnosis support.

The use of machine learning (ML) for diagnosis support has advanced in the field of health. In the present paper, the results of studying ML techniques in a tuberculosis diagnosis loop in a scenario of limited resources are presented. Data are analyzed using a tuberculosis (TB) therapy program at a health institution in a main city of a developing country using five ML models. Logistic regression, classification trees, random forest, support vector machines, and artificial neural networks are trained under physician supervision following physicians' typical daily work. The models are trained on seven main variables collected when patients arrive at the facility. Additionally, the variables applied to train the models are analyzed, and the models' advantages and limitations are discussed in the context of the automated ML techniques. The results show that artificial neural networks obtain the best results in terms of accuracy, sensitivity, and area under the receiver operating curve. These results represent an improvement over smear microscopy, which is commonly used techniques to detect TB for special cases. Findings demonstrate that ML in the TB diagnosis loop can be reinforced with available data to serve as an alternative diagnosis tool based on data processing in places where the health infrastructure is limited.

Terrestrial forcing of marine biodiversification.

The diversification of the three major marine faunas during the Phanerozoic was intimately coupled to the evolution of the biogeochemical cycles of carbon and nutrients via nutrient runoff from land and the diversification of phosphorus-rich phytoplankton. Nutrient input to the oceans has previously been demonstrated to have occurred in response to orogeny and fueling marine diversification. Although volcanism has typically been associated with extinction, the eruption of continental Large Igneous Provinces (LIPs) is also a very significant, but previously overlooked, source of phosphorus involved in the diversification of the marine biosphere. We demonstrate that phosphorus input to the oceans peaked repeatedly following the eruption and weathering of LIPs, stimulating the diversification of nutrient-rich calcareous and siliceous phytoplankton at the base of marine food webs that in turn helped fuel diversification at higher levels. These developments were likely furthered by the evolution of terrestrial floras. Results for the Meso-Cenozoic hold implications for the Paleozoic Era. Early-to-middle Paleozoic diversity was, in contrast to the Meso-Cenozoic, limited by nutrient-poor phytoplankton resulting from less frequent tectonism and poorly-developed terrestrial floras. Nutrient runoff and primary productivity during the Permo-Carboniferous likely increased, based on widespread orogeny, the spread of deeper-rooting forests, the fossil record of phytoplankton, and biogeochemical indices. Our results suggest that marine biodiversity on geologic time scales is unbounded (unlimited), provided sufficient habitat, nutrients, and nutrient-rich phytoplankton are also available in optimal amounts and on optimal timescales.

Associations between college students' personal experience with mental health issues and their mental health literacy: a strengths-based perspective.

BACKGROUND: Mental health literacy (MHL) programs are a promising approach to help prevent mental health issues (MHI) among college students; however, there is an increasing need to understand individual factors that influence the development of students' MHL. AIMS: Following a strengths-based approach, we examined if college students' individual characteristics and MHI experience were associated with students' MHL. METHODS: Using two vastly different college samples (Sample 1, N = 617; Sample 2, N = 306), we used the Mental Health Awareness and Advocacy framework, guided by the health belief model and social-cognitive theory, to investigate associations between students' mental health literacy, demographic factors, and their previous experience with MHI. RESULTS: Results from nested regression analyses suggest that personal experiences with MHI are associated with higher MHL (knowledge, self-efficacy, and behaviors), even after controlling for key individual characteristics. Prior experience with having an MHI and receiving therapy appeared to be most important in explaining MHL behaviors. CONCLUSIONS: Students with personal experience with an MHI may be one of the most valuable resources for increasing MHL and utilization of mental health resources on college campuses. Additional implications and future research directions are offered.

Smart pooling: AI-powered COVID-19 informative group testing.

Massive molecular testing for COVID-19 has been pointed out as fundamental to moderate the spread of the pandemic. Pooling methods can enhance testing efficiency, but they are viable only at low incidences of the disease. We propose Smart Pooling, a machine learning method that uses clinical and sociodemographic data from patients to increase the efficiency of informed Dorfman testing for COVID-19 by arranging samples into all-negative pools. To do this, we ran an automated method to train numerous machine learning models on a retrospective dataset from more than 8000 patients tested for SARS-CoV-2 from April to July 2020 in Bogotá, Colombia. We estimated the efficiency gains of using the predictor to support Dorfman testing by simulating the outcome of tests. We also computed the attainable efficiency gains of non-adaptive pooling schemes mathematically. Moreover, we measured the false-negative error rates in detecting the ORF1ab and N genes of the virus in RT-qPCR dilutions. Finally, we presented the efficiency gains of using our proposed pooling scheme on proof-of-concept pooled tests. We believe Smart Pooling will be efficient for optimizing massive testing of SARS-CoV-2.

Incorporating the effects of objects in an approximate model of light transport in scattering media.

A computationally efficient radiative transport model is presented that predicts a camera measurement and accounts for the light reflected and blocked by an object in a scattering medium. The model is in good agreement with experimental data acquired at the Sandia National Laboratory Fog Chamber Facility (SNLFC). The model is applicable in computational imaging to detect, localize, and image objects hidden in scattering media. Here, a statistical approach was implemented to study object detection limits in fog.

Review of Commercially Available Supraglottic Airway Devices for Prehospital Combat Casualty Care.

BACKGROUND: Airway obstruction is the second leading cause of potentially survivable death on the battlefield. The Committee on Tactical Combat Casualty Care lists airway optimization among the top 5 battlefield research and development priorities; however, studies show that combat medics lack access to the recommended supraglottic airway (SGA) devices. SGA devices are an alternative airway management technique to endotracheal tube intubation. Reports have shown SGA devices are easier to use and take fewer attempts to provide patent airflow to the patient when compared to endotracheal tube intubation. Military settings require a higher degree of skill to perform airway management on patients due to the environment, limited availability of equipment, and potential chaos of the battlefield. Finding the optimal SGA device for the military setting is an unmet need. The International Organization for Standardization describes basic functional requirements for SGA devices, as well as patient configurations and size limitations. Beyond that, no SGA device manufacturer states that their devices are intended for military settings. MATERIALS AND METHODS: We conducted a market review of 25 SGA devices that may meet inclusion into the medics' aid bag. The company's official "Instructions for Use" document, Google Scholar, and FDA reports were reviewed to obtain information for each SGA device. RESULTS: Twenty-five commercially available SGA devices are explored from manufacturer online sources. A commercially available device list is shown later in this paper, which provides the device's features, indications, and contraindications based on the manufacturer's product information documentation. CONCLUSIONS: There are a variety of devices that require further testing to determine whether they should be included in sets, kits, and outfits.

Delving into the Determinants of Default Risk in Savings Groups: Empirical Evidence from Ecuador.

Financial inclusion has been broadly recognized as critical in alleviating poverty and achieving inclusive economic growth. The capability of borrowers to repay their microcredit loans is a critical concern and is the first risk of Microfinance institutions sustainability. Exploring the determinants of credit risk is an issue of substantial importance in microfinance. The purpose of this research was to identify the savings group members' characteristics that have impact on default risk. We have used a multivariate regression model to identify the factors that affect default behaviour among microcredit borrowers from savings groups. We have analysed a sample of more than different 400 Savings Groups and 7251 active users of the "Saving and Learning" program in Ecuador. Empirical results demonstrated that factors such as seniority, accumulated savings and the number of members in the savings groups are determinant variables of default risk. The significant positive sign on variable "Gender" is consistent with the previous authors that indicate that the probability of having problems in loan repayment is higher for males than for females. The generalizability of our findings should, of course, be interpreted with caution, as they may be idiosyncratic of the sample, period or region. To contrast and contextualize these results, we had in-depth discussions with the Savinco managers and their field agent in Ecuador. There are many contributions. For practitioners, relevant factors that can affect savings groups default rates have been identified. For academics, the rich information provided by the Savinco mobile App could be a starting point for further quantitative research.

Il est largement reconnu que l'inclusion financière est essentielle pour réduire la pauvreté et parvenir à une croissance économique inclusive. La capacité des emprunteurs à rembourser leurs prêts de microcrédit est une préoccupation essentielle et constitue le premier risque pour la pérennité des institutions de microfinance. L'étude des déterminants du risque de crédit est une question d'une importance capitale en microfinance. Le but de cette étude est d'identifier les caractéristiques des membres de groupes d'épargne qui ont un impact sur le risque de défaut de paiement. Nous avons utilisé un modèle de régression multivariée pour identifier les facteurs qui affectent le comportement de défaut de paiement parmi les emprunteurs de microcrédit au sein de groupes d'épargne. Nous avons analysé un échantillon de plus de 400 groupes d'épargne différents et 7 251 utilisateurs actifs du programme « Épargne et apprentissage ¼ en Équateur. Les résultats empiriques ont démontré que des facteurs tels que l'ancienneté, l'épargne accumulée et le nombre de membres dans les groupes d'épargne sont des variables déterminantes du risque de défaut de paiement. Sur la variable « Genre ¼, le signe positif significatif est cohérent avec les études précédentes qui indiquent que la probabilité d'avoir des problèmes de remboursement de prêt est plus élevée chez les hommes que chez les femmes. Bien entendu, le caractère généralisable de nos résultats doit être interprété avec prudence, car ces résultats peuvent être uniques à l'échantillon, à la période ou à la région. Pour contraster et contextualiser ces résultats, nous avons eu des discussions approfondies avec les gestionnaires de Savinco et leur agent de terrain en Équateur. Les contributions sont nombreuses. Pour les praticiens, ont été identifiés les facteurs pertinents pouvant affecter le taux de défaut de paiement des groupes d'épargne. Pour les universitaires, les riches informations fournies par l'application mobile Savinco pourraient être un point de départ pour d'autres études quantitatives.

Preliminary Text Analysis from Medical Records for TB Diagnosis Support.

Tuberculosis is an infectious disease that is spread through the air from one person to another and is one of the top ten causes of death in the world according to the World Health Organization. From biomedical engineering, decision support systems based on artificial intelligence have shown advantages for healthcare personnel in tasks such as diagnosis and screening. A specific area of the artificial intelligence is the natural language processing, however, most of these approaches are based on available data. This paper shows the construction of a dataset based on medical records of subjects suspected of tuberculosis. In addition, an initial exploration of the contents of the constructed dataset and how this approach can be followed by a natural language processing to support tuberculosis diagnosis in data demanding scenarios are presented.Clinical Relevance- In some developing countries as Colombia, it is difficult to develop systems based on artificial intelligence due to the availability of data. This proposal holds a strategy to build a dataset to train machine learning models, and to obtain support diagnosis tools, employing natural language from the medical scenario from text written by health professionals in the medical record. In this way, trained models based on this information available can be employed in places where medical infrastructure is precarious.

Improvement in broiler performance by feeding a nutrient-dense diet after a mild feed restriction / Mejora del rendimiento en pollos de engorde mediante una dieta rica en nutrientes tras una ligera restricción alimenticia / Melhoria dos rendimentos de frangos de corte de uma dieta rica em nutrientes após uma restrição ligeira

Abstract Background: The use of early nutrient-restriction programs in broilers can prevent complications such as increased body fat deposition and its consequences. However, feed restriction not always gives the expected results. Objective: To assess the effect of two levels of feed restriction followed by a re-alimentation period with five increasing nutrient levels on growth performance and immune response of broiler chickens. Methods: A total of 330 animals were used. The treatments were: 25 (T25) and 35% (T35) quantitative feed restriction during the starting period, and 0, 2.5, 5, 7.5, 10, and 15% increased energy and protein contents during the growing and finishing periods. Results: For all the T25 treatments, except for T25-0, feed intake (FI) and body weight gain (BWG) were higher, and feed conversion rate (FCR) was lower (p<0.05) compared to the control treatment. In that group, the response of FI and BWG to the increased nutrient density was mostly quadratic (p<0.001), whereas that of FCR was linear (p<0.001). The FI and BWG results were less homogeneous in the T35 treatments, but FCR was lower compared to the control treatment (p<0.05) in all of them. The FCR showed no differences (p>0.05) between treatments during the finishing period. Conclusion: Feeding a nutrient-dense diet after a period of mild feed restriction gives the best results, while increasing nutrient density after a more severe feed restriction does not improve productive results compared to a standard diet. Carcass traits and immune function were not affected by restriction level or nutrient density.

Resumen Antecedentes: El uso de programas de restricción alimenticia temprana en pollos de engorde puede prevenir el incremento de la deposición de grasa corporal y sus consecuencias. Sin embargo, la restricción alimenticia no proporciona siempre los resultados esperados. Objetivo: Investigar los efectos de dos niveles de restricción alimenticia seguida por un período de realimentación con cinco niveles crecientes de nutrientes sobre el rendimiento productivo y la respuesta inmune de pollos de engorde. Métodos: Se utilizaron 330 animales. Los tratamientos fueron: restricción cuantitativa del 25 (T25) y del 35% (T35) durante el periodo de iniciación y aumento de la energía y contenido proteico de la dieta del 0, 2,5, 5, 7,5, 10 y 15% durante los periodos de crecimiento y finalización. Resultados: Para casi todos los T25 el consumo de alimento (FI) y el aumento de peso corporal (BWG) fueron mayores y el índice de conversión (FCR) menor (p<0,05) en comparación con el control. La respuesta del FI y el BWG al aumento de la densidad de nutrientes en este grupo fue mayoritariamente cuadrática (p<0,001), mientras que en el caso del FCR fue lineal (p<0,001). Los resultados del FI y el BWG fueron menos homogéneos en los T35, pero el FCR fue menor que en el control (p<0,05). El FCR no mostró diferencias (p>0,05) entre tratamientos durante el periodo de acabado. Conclusión: La alimentación con una dieta rica en nutrientes después una restricción ligera proporciona los mejores resultados, mientras que el incremento de la densidad de la dieta después de una restricción severa no mejora los resultados productivos en comparación con una dieta estándar. Las características de la canal y la respuesta inmune no se vieron afectadas por el nivel de restricción o la densidad de nutrientes de la dieta.

Resumo Antecedentes: O uso de programas de restrição precoce de nutrientes em frangos de corte tem o potencial de prevenir complicações como o aumento da deposição de gordura corporal e suas consequências. No entanto, a restrição alimentar nem sempre dá os resultados esperados. Objetivo: Investigar os efeitos de dois níveis de restrição alimentar seguidos de um período de re-alimentação com cinco níveis crescentes de nutrientes no rendimento produtivo e na resposta imune de frangos de corte. Métodos: Foram utilizados 330 animais. Os tratamentos foram: restrição quantitativa de 25 (T25) e 35% (T35) durante o período inicial e aumento do conteúdo energético e proteico da dieta de 0, 2,5, 5, 7,5, 10 e 15% durante os períodos de crescimento e finalização. Resultados: Para todos os tratamentos T25, menos para T25-0, consumo de ração (FI) e ganho de peso corporal (BWG) foram maiores e a taxa de conversão (FCR) foi menor (p<0,05) o controle. A resposta do FI e do BWG ao aumento da densidade de nutrientes nesse grupo foi principalmente quadrática (p<0,001), enquanto no caso da FCR foi linear (p<0,001). Os resultados do FI e do BWG foram menos homogêneos nos tratamentos T35, mas o FCR foi menor que no tratamento controle (p<0,05). O FCR não apresentou diferenças (p>0,05) entre os tratamentos durante o período de terminação. Nenhuma tendência clara foi observada no peso relativo dos órgãos linfóides ou na resposta imune devido aos tratamentos testados. Conclusão: A alimentação de uma dieta rica em nutrientes após um período de restrição leve proporcionou os melhores resultados, enquanto o aumento da densidade de nutrientes na dieta após uma restrição severa não melhorou os resultados produtivos em comparação com uma dieta padrão.