A Comparative Study Evaluating the Quality of Life and Survival Outcomes in Patients Receiving Chemotherapy Versus Oral Tyrosine Kinase Inhibitor in the Third Line and Beyond Setting for Advanced NSCLC.

Introduction: The outcomes in advanced NSCLC have improved owing to the availability of more effective systemic and improved supportive care. This has increased the number of patients who seek treatment in the third line and beyond setting. We conducted this study to compare the quality of life (QoL), toxicity, and outcomes in patients receiving chemotherapy and EGFR tyrosine kinase inhibitors (TKIs) in this setting. Methods: In this phase 3, randomized, open-label study, patients with stage III or IV NSCLC with disease progression on at least two prior lines of chemotherapy, with a life expectancy of at least 3 months, without prior EGFR TKI exposure, and stable brain metastases (if any) were included. Patients were randomized to receive chemotherapy (gemcitabine or docetaxel or paclitaxel or vinorelbine) or an EGFR TKI (erlotinib or gefitinib). The primary end point was the change in QoL at 8 to 10 weeks; the secondary outcomes were safety and overall survival (OS). Patients underwent clinical evaluation at every visit, and toxicity was assessed as per Common Terminology Criteria for Adverse Events version 4.03. A radiological tumor response assessment was done every 8 to 12 weeks from the start of therapy. The QoL was assessed using the EORTC QLQ C30 and LC13 questionnaires. The change in QoL scores was calculated as the difference between scores at baseline and scores at 8 to 10 weeks (Δ) for each QoL domain. The Mann-Whitney U test was used to compare the mean difference (Δ) for each domain. OS and progression-free survival (PFS) were determined using the Kaplan-Meier method and Cox proportional regression analysis. Results: A total of 246 patients were enrolled in the study, with 123 in each arm. There was a male predominance with 69.1% male patients in the chemotherapy arm and 70.7% in the EGFR TKI arm. The median age of patients in the chemotherapy arm was 54 years and 55 years in the chemotherapy and EGFR TKI arms, respectively. There was no significant difference in the change in QoL at baseline and the second visit (Δ) in both arms in all domains of EORTC QLQ C30 except cognitive function (p = 0.0045) and LC13 except alopecia (0.01249). The mean Δ Global Health Status was -28 in the chemotherapy arm and -26.8 in the EGFR TKI arm; this was not statistically significant (p = 0.973). The median follow-up was 88.1 months (95% confidence interval [CI]: 39.04-137.15). On the intention-to-treat analysis, the median PFS was 3.13 months (95% CI: 2.15-4.11) in the chemotherapy arm and 2.26 months (95% CI: 2.1-2.43) in the EGFR TKI arm, with hazard ratio at 1.074 (95% CI: 0.83-1.38) (p = 0.58). There were 120 deaths in each arm. The median OS was 7.63 months (95% CI: 5.96-9.30) in the chemotherapy arm and 7.5 months in the EGFR TKI arm (95% CI: 5.85-9.14); hazard ratio at 1.033 (95% CI: 0.80-1.33) (p = 0.805). The toxicity profile was similar in both arms except for a significantly higher incidence of fatigue (p = 0.043), peripheral neuropathy (0.000), alopecia, hypokalemia (0.037), and pedal edema (0.007) in the chemotherapy arm and dry skin (p = 0.000) and skin rash (p = 0.019) in the EGFR TKI arm. Conclusions: There was no significant difference in most QoL scales (except cognitive function and alopecia), OS, and PFS of patients with advanced NSCLC receiving an EGFR TKI as compared with chemotherapy TKI in the third-line setting. The toxicity profile is consistent with the known toxicities of the agents.

A Cross-Sectional Study Comparing Application of Hanifin and Rajka Criteria in Indian Pediatric Atopic Dermatitis Patients to that of Other Countries.

Background: Hanifin and Rajka criteria are considered to be the gold standard for atopic dermatitis diagnosis. However, the exhaustive nature limits its use in clinical settings. Objective: To determine the frequency of Hanifin and Rajka criteria commonly found in Indian pediatric atopic dermatitis patients and variation from the findings of other studies. Material and Methods: An observational, descriptive study with a sample size of 52 pediatric atopic dermatitis patients. Patients were divided into infantile, childhood, and adolescent. Results: Overall, xerosis, early age of onset, Dennie-Morgan fold, aggravation because of environmental factors, palmar hyper-linearity, ichthyosis vulgaris, keratosis pilaris, pityriasis alba, and orbital darkening were found in more than 50% of patients. Dennie-Morgan fold was more commonly found in Indian pediatric atopic dermatitis patients. Peri-follicular accentuation was less prevalent in Indian patients as compared to other Asian studies. None of the parents reported food intolerance, which was seen in studies from other countries. Limitations: A small sample size and ophthalmological evaluation was not performed in all patients. Conclusion: The frequency of different Hanifin and Rajka minor criteria varies widely among different study populations. Hence, the criteria specifically applicable to the Indian population need to be derived for ease of diagnosis.

Experimental Studies on Zooplankton-Toxic Cyanobacteria Interactions: A Review.

Cyanobacterial blooms have been recognized as a problem in fresh water for about 150 years. Over the past 50 years, experimental studies on the subject have gained importance considering the increasing need to control toxic cyanobacterial blooms. This article presents information on the different lines of research that have been undertaken on zooplankton-cyanobacteria interactions over the past 50 years. These include information on filtering/ingestion rates and phytoplankton preferences of small and large rotifers, cladocerans, and copepods; growth rates of zooplankton on cyanobacterial diets; feeding rates of other freshwater invertebrates on cyanobacteria; role of zooplankton in top-down biomanipulation efforts; effect of cyanotoxins on zooplankton; bioaccumulation of cyanotoxins; and physical and chemical control of cyanobacterial blooms. We also highlight measures that have led to successful lake management and improvement of water quality in selected waterbodies.

Association Between Coffee Consumption and Incident Atrial Fibrillation (from the Multi-Ethnic Study of Atherosclerosis [MESA]).

This study aimed to elucidate a potential dose-dependent relation between coffee intake and atrial fibrillation (AF) incidence in a multi-ethnic setting. Previous studies were comprised mainly of White populations, and an exploration of dose dependency is limited. To address these gaps, we analyzed the Multi-Ethnic Study of Atherosclerosis data, a prospective cohort study. In the primary analysis, we crudely divided patients into 3 groups: nonconsumers, 1 to 3 cups/month, and ≥1 cup/week. For the secondary analysis, we stratified the cohort into 9 groups of gradual increments for coffee consumption. A multivariable cox proportional hazards regression model was adjusted for 6 potential confounders: age, gender, smoking, hypertension, diabetes mellitus, and alcohol. Subjects who drank ≥1 cup of coffee/week had a higher incidence of AF (adjusted hazard ratio 1.40, p = 0.015) than nonconsumers. Furthermore, in the secondary analysis, there was an overall trend, albeit not consistent, of increasing adjusted hazard ratio with progressively increasing doses of coffee in the following groups: 1 to 3 cups/month, 2 to 4 cups/week, 2 to 3 cups/day and ≥6 cups/day. Notably, AF incidence was highest (9.8%) for the group consuming the most coffee, that is, ≥6 cups/day (p = 0.02). Stratification by race/ethnicity suggested the results may be driven by White and Hispanic rather than Black or Chinese-American subgroups. In conclusion, the findings suggest an association between coffee consumption and incident AF in contrast to most previous studies.

Quality of life in patients with locally advanced head and neck squamous cell carcinoma undergoing concurrent chemoradiation with once-a-week versus once-every-3-weeks cisplatin.

INTRODUCTION: This trial was conducted to compare the efficacy of low dose once-a-week cisplatin and once-every-3-weeks cisplatin with radiation in locally advanced head and neck squamous cell carcinoma (LAHNSCC). The current analysis focuses on the quality of life (QoL) of patients in this trial. METHODS: In this phase III randomized trial, patients with nonmetastatic LAHNSCC were randomized to receive cisplatin 30 mg/m2 once-a-week or 100 mg/m2 once every- 3-weeks concurrently with radiotherapy. The primary endpoint was locoregional control. QoL was a key secondary endpoint. QoL was assessed using EORTC QLQ-C30 and QLQ-H&N35. QoL data were assessed at baseline, days 22 and 43 during treatment; and at 6, 12, 24 months. The linear mixed-effects model was used for longitudinal analysis of QoL to determine the impact of treatment (arm) and time on QoL. RESULTS: Three hundred patients were enrolled, data of 150 patients with available baseline QoL were analyzed. There was no significant difference in the global health status/QoL of the two treatment arms (p = 0.8664). There was no significant difference in the longitudinal QoL scores between the two treatment arms in all scales except constipation (p = 0.0096), less sexuality (p = 0.0002,), and financial difficulty (p = 0.0219). There was a worsening of the QoL scores in all scales in both arms during treatment, which improved after treatment completion in most scales. CONCLUSION: The use of once-every-3-weeks cisplatin did not adversely impact QoL as compared to once-a-week cisplatin in combination with radiotherapy in LAHNSCC.

Infections caused by Aeromonas species in hospitalized patients: A case series.

The Aeromonads are ubiquitous Gram-negative bacilli that cause community acquired, and healthcare associated infections. In this retrospective study we analysed clinical and microbiological characteristics of thirty-six culture proven Aeromonas infections. The most common species isolated was A.hydrophila. Clinical presentation included syndromes like skin and soft tissue infections (SSTI), urinary tract infections, and central line associated bloodstream infections (CLABSI). Most of the isolates were sensitive to aminoglycosides [97.2%], followed by 3 rd generation cephalosporins, quinolones and carbapenems. Overall mortality was 13.88% (5 out of 36 patients). A high index of suspicion is required for diagnosis and better outcomes.

Effects of the endocrine disruptor 4-nonylphenol on the demography of rotifers Plationus patulus and Brachionus havanaensis: a multigenerational study.

The emerging contaminant 4-nonylphenol is an active ingredient in many surfactants. Though 4-nonylphenol has been reported in Mexican waterbodies, no stringent law is available to establish its permissible limits. Most ecotoxicological assays using zooplankton species are based on previously unexposed populations, and multigenerational experiments are rare. Plationus patulus and Brachionus havanaensis are widely distributed species in Mexico and have been used in ecotoxicological assessments. In this work, the median lethal concentration of 4-nonylphenol (LC50, 24 h) for both rotifer species was derived. Based on our acute toxicity data (24 h LC50 of 4-nonylphenol for P. patulus and B. havanaensis were 500 and 250 µg L-1, respectively), three sublethal concentrations (µg L-1) (7.81, 15.82 and 31.25 for B. havanaensis and 15.62, 31.25 and 62.5 for P. patulus) were used in the life table demography tests for two successive generations (F0 and F1) of either rotifer species. Regardless of the concentrations used, 4-nonylphenol had an adverse effect on both rotifer species over two successive generations. P. patulus was more sensitive than B. havanaensis in chronic toxicity tests. F1 generation of both rotifer species was far more adversely affected than the F0 in all toxicant treatments.

Changes in Mode of Oxygen Delivery and Physiological Parameters with Physiotherapy in COVID-19 Patients: A Retrospective Study.

Background: Coronavirus disease (COVID-19) is an infectious disease caused by SARS-CoV-2, clinically presenting with common symptoms of fever, dry cough, and breathlessness within 14 days of exposure. Its severity ranges from mild to severe, latter manifesting into severe acute respiratory syndrome. As a part of multidisciplinary team, physiotherapy along with medical management was administered to patients with COVID-19 in an acute care setup. This retrospective study aims to explore various patient characteristics and will aid in identifying the impairments associated with the disease, giving a direction to the physiotherapy community in planning future management strategy to improve quality of life. Patients and methods: The present study is a unicentric study wherein prospective analysis of retrospective data of patients referred for physiotherapy from May 13 to July 31, 2020, was performed. (i) Characteristics of patients, (ii) associated comorbidities, (iii) hospital course since the time of admission to discharge, (iv) mode of oxygen delivery, (v) pre- and post-physiotherapy treatment values of oxygen saturation and heart rate, and (vi) physiotherapy treatment were recorded. The archived data were analyzed using the commercially available SPSS software version 24. Wilcoxon's matched pair test was used to compare pre- and post-treatment oxygen saturation and heart rate, and McNemar's test was used to compare mode of oxygen delivery and pre- and post-physiotherapy treatment. Results: Descriptive analysis of data showed a better outcome in terms of grade of dyspnea and rate of discharge on day 14 of physiotherapy treatment. Hence, a comparative analysis of day 1 and day 14 was performed for mode of oxygen delivery, oxygen saturation, and heart rate. A statistically significant improvement was observed in the heart rate (p = 0.001) and oxygen delivery (p = 0.000). However, no significant difference in the level of oxygen saturation was found (p = 0.6433). Conclusion: Physiotherapy treatment in conjunction with medical treatment can be effectively administered in patients with COVID-19 in acute care setup taking into consideration the health status and the hemodynamic stability of the patients. It emphasizes the role of physiotherapy in the alleviation of symptoms, facilitating early weaning and recovery enabling early discharge from the hospital. How to cite this article: Verma CV, Arora RD, Mistry HM, Kubal SV, Kolwankar NS, Patil PC, et al. Changes in Mode of Oxygen Delivery and Physiological Parameters with Physiotherapy in COVID-19 Patients: A Retrospective Study. Indian J Crit Care Med 2021;25(3):317-321.

Population responses and fatty acid profiles of Brachionus calyciflorus (Rotifera) in relation to different thermal regimes.

Diurnal temperature fluctuations affect ectothermic species more than endothermic taxa. We tested the effect of three fixed temperatures (20, 25 and 30 °C) and a 24 h variable (20-30 °C) on the population growth and fatty acid profiles of the common rotifer Brachionus calyciflorus. Depending on the temperature treatment, the peak population abundances of B. calyciflorus varied from 65 to 80 ind./ml, the lowest being on variable temperature range. The rate of population increase varied from 0.31 to 0.52 per day, highest being at 30 °C. There was a curvilinear relationship between the population density and the egg ratio (number of eggs/female) in all the tested temperature regimes. The egg ratio was higher (>0.6) for treatments involving fixed temperatures, but for variable temperature regime, the egg ratios were lower (<0.5). Temperature also induced changes in the fatty acid content of B. calyciflorus. While the total saturated fatty acids increased, both mono-unsaturated and poly-unsaturated fatty acids decreased with increasing temperature regime. These results have been interpreted in relation to the role of temperature (both intensity and mode of exposure) on the population growth characteristics of rotifers.

A Long-Term Study on the Effect of Cyanobacterial Crude Extracts from Lake Chapultepec (Mexico City) on Selected Zooplankton Species.

Many urban lakes in Mexico City such as Lake Chapultepec are infested with high densities of cyanobacteria, particularly Microcystis. We tested the effect of cyanotoxins from cyanobacterial crude extracts on the demographic variables of zooplankton. The rotifers Brachionus havanaensis and Brachionus calyciflorus, and the cladocerans Ceriodaphnia dubia and Moina macrocopa were used for the assays. Temperature effects on the response of B. calyciflorus and 2 clones of M. macrocopa were tested. We hypothesized that with an increase in cyanotoxin concentration and temperature there would be an increase in the adverse effect on the test species and that the clone of Moina previously exposed to cyanobacteria from Lake Chapultepec would be more resistant to the cyanotoxins. Demography experiments showed that B. havanaensis was more sensitive than C. dubia. The negative effect of the cyanobacterial crude extract on B. calyciflorus was greater at 30 °C than at 20 °C or 25 °C. The strain of M. macrocopa isolated from Lake Chapultepec was more resistant to the cyanotoxins than the strain that had not been previously exposed to the cyanobacteria. The present study indicated that cyanobacteria in Lake Chapultepec are highly toxic and, considering the recreational use of this lake, should be controlled. Environ Toxicol Chem 2020;39:2409-2419. © 2020 SETAC.

Effect of salinity and temperature on the acute and chronic toxicity of arsenic to the marine rotifers Proales similis and Brachionus ibericus.

Several abiotic factors influence the ecological responses of aquatic invertebrates to metal toxicity. We examined the effect of salinity (10, 20, and 30 psu) and temperature (25 and 32 °C) on acute and chronic arsenic (As) toxicity to the euryhaline rotifers, Proales similis and Brachionus ibericus. In general, higher salinities and low temperature resulted in lower arsenic toxicity. The population growth studies indicated that P. similis was more sensitive than B. ibericus to As. Arsenic toxicity intensified the vulnerability of P. similis to B. ibericus competition. Life table parameters decreased with increasing As levels in the medium. Chronic toxicity bioassays were more sensitive than acute toxicity tests for determining the adverse effect of As to rotifers. Our findings provide useful insights on the effect of arsenic on rotifer populations exposed to different temperature and salinity scenarios. Proales similis could be an important complement to brachionid rotifers for marine toxicity bioassays.

Effect of smokeless tobacco use on salivary glutathione levels among chronic periodontitis patients before and after non-surgical periodontal therapy.

INTRODUCTION: Smokeless tobacco (SLT) jeopardizes periodontal health and also produces an imbalance between reactive oxygen species (ROS) and antioxidants (AO) such as glutathione. Glutathione is an important redox regulator in saliva and its maintenance is essential for periodontal health. Periodontitis patients have a reduced total AO capacity in whole saliva, and periodontal therapy restores the redox balance. Hence, the purpose of this study was to investigate the effects of smokeless tobacco use on saliva glutathione levels in patients with chronic periodontitis and to evaluate these effects after non-surgical periodontal therapy. METHODS: The study included 100 subjects in four groups; healthy, gingivitis, and chronic periodontitis (CP) patients with and without SLT use. Saliva samples were collected, and clinical periodontal parameters were recorded at baseline and at one month after non-surgical periodontal therapy. Glutathione levels were analyzed using spectrophotometry at 412 nm. Statistical analysis was carried out using paired t-test, chi-squared, and analysis of variance (ANOVA). RESULTS: Mean glutathione values in saliva were found to be lower in periodontitis patients compared to SLT users at baseline and at 1 month post non-surgical periodontal therapy (p<0.001) In addition, non-surgical therapy leads to a highly significant improvement in the glutathione levels in gingivitis, in the CP with and without ST groups (p<0.001). CONCLUSIONS: Successful non-surgical periodontal therapy leads to considerable progress in the redox balance, thus regulating glutathione levels and reducing the effects of SLT on the periodontium. This emphasises the importance of non-surgical therapy, especially among SLT users.

More than a Great Idea: Findings from the Profiles in Public Health Social Work Study.

Progress in refining the definition and basic concepts of public health social work (PHSW) is central to its revitalization. Advancing PHSW further depends on understanding the roles, domains, and daily activities of current PHSW practitioners in the contemporary workforce. The goal of the Profiles in PHSW Study is to explore how public health social workers conceptualize and locate their work. Using snowball sampling, 48 PHSW subjects with four or more years of professional experience were recruited; 34 (70.8%) participated. Qualitative survey responses were compiled and thematically analyzed; six themes emerged related to the nuances of integrating public health and social work, wide-ranging practice across systems and settings, leadership, visibility and viability, and recommendations for how to move PHSW forward. Findings suggest that intentional profession-wide integration of public health approaches into social work education, research, and practice is needed to strengthen the field's impact and role in advancing population health.

Penile cancer with visceral metastasis and p16/human papillomavirus positivity: An unusual case of long-term survival.

Squamous cell carcinoma (SCC) of the penis is a rare cancer in the industrialized countries, including the United States. Risk factors for these cancers include inflammatory conditions as well as infection with the human papilloma virus (HPV). Treatment modalities are based on TNM staging and may include surgical management or chemoradiation. Patients with local or some regional disease can have a favorable prognosis; however, with extranodal metastasis, survival decreases sharply. Here, we present a case of long-term disease-free survival in a patient with widely metastatic SCC of the penis.

Toxicity of cyanobacterial blooms from the reservoir Valle de Bravo (Mexico): A case study on the rotifer Brachionus calyciflorus.

Proliferating cyanobacterial blooms due eutrophication in reservoirs is a major global problem. The production of cyanotoxins often increases with grazing pressure and temperature while the sensitivity of zooplankton to cyanotoxins is directly related to temperature. Here we evaluate the effect of different concentrations of the crude extract of cyanobacteria from Valle de Bravo reservoir during dry (January) and rainy (September) seasons at 20 and 25 °C on the rotifer Brachionus calyciflorus based on acute and chronic toxicity tests. We filtered 20 or 150 l of lake water, depending on the intensity of the bloom, and estimated the density and diversity of the cyanobacteria. The crude extracts, after 5 cycles of freezing, thawing and sonication at 14 MHz, were filtered and the microcystin concentration quantified based on ELISA. The extracts were used to conduct the acute and chronic toxicity tests, all in quadruplicate. Acute toxicity tests were based on 24 h mortality. Chronic toxicity tests (population growth and life table experiments) were conducted at 5 and 10% of the median lethal concentration. The field samples were dominated by Microcystis sp. (January) or Woronichinia naegeliana (September). The microcystin concentration in lake water was 9.57 µg/l and 0.097 µg/l and the median lethal concentration was 5.34 µg microcystin/L and 0.35 µg microcystin/L in January and September, respectively. Survival and reproduction of B. calyciflorus were lower in the presence of the cyanobacteria crude extract, more so at 20° than at 25 °C. Our results highlight the urgency of regular monitoring based on zooplankton assays for reservoirs in tropical and temperate regions, subject to frequent and dominant cyanobacterial blooms, often as a result of climate change.

Demographic responses of Cladocerans (Cladocera) in relation to different concentrations of humic substances.

Cladocerans are constantly exposed to humic substances in nature, yet the effects of these substances on their survival and reproduction are not well known. Here, the effects of humic substances (20 and 40 mg L-1) (HS) on the life history variables of three common cladocerans, Ceriodaphnia dubia, Moina macrocopa, and Daphnia pulex were evaluated. The results showed that the effect of humic substances on the tested cladocerans is species-specific, affecting either survival, reproduction or both. For M. macrocopa, exposed to HS at a concentration of 40 mg L-1, the average lifespan and the life expectancy at birth were significantly reduced as compared to controls, but for C. dubia and D. pulex these parameters were increased. Gross reproductive rate was unaffected by the HS level for both D. pulex and M. macrocopa, but it was significantly higher for C. dubia. When compared to the corresponding controls, for HS-exposed cladocerans, the rate of population increase was significantly reduced in case of D. pulex while it was stimulated for both C. dubia and M. macrocopa. It appears that humic substances had a slightly stronger influence on survivorship than on reproduction of the tested cladocerans.

Bioaccumulation of microcystins in seston, zooplankton and fish: A case study in Lake Zumpango, Mexico.

Cyanotoxins from toxic blooms in lakes or eutrophic reservoirs are harmful to several organisms including zooplankton, which often act as vectors of these secondary metabolites, because they consume cyanobacteria, bioaccumulate the cyanotoxins and pass them on along the food chain. Microcystins are among the most commonly found cyanotoxins and often cause zooplankton mortality. Although cyanobacterial blooms are common and persistent in Mexican water bodies, information on the bioaccumulation of cyanotoxins is scarce. In this study we present data on the bioaccumulation of cyanotoxins from Planktothrix agardhii, Microcystis sp., Cylindrospermopsis raciborskii and Dolichospermum planctonicum blooms in the seston (suspended particulate matter more than 1.2 µm) by zooplankton and fish (tilapia (Oreochromis niloticus) and mesa silverside (Chirostoma jordani) samples from Lake Zumpango (Mexico City). The cyanotoxins were extracted from the seston, zooplankton and fish tissue by disintegration using mechanical homogenization and 75% methanol. After extraction, microcystins were measured using an ELISA kit (Envirologix). Concentration of microcystins expressed as equivalents, reached a maximum value of 117 µg g-1 on sestonic samples; in zooplankton they were in the range of 0.0070-0.29 µg g-1. The dominant zooplankton taxa included Acanthocyclops americanus copepodites, Daphnia laevis and Bosmina longirostris. Our results indicate twice the permissible limits of microcystins (0.04 µg kg-1 d-1) for consumption of cyanobacterial products in whole fish tissue of Chirostoma jordani. The data have been discussed with emphasis on the importance of regular monitoring of water bodies in Mexico to test the ecotoxicological impacts of cyanobacterial blooms and the risk that consumption of products with microcystins could promote.

Determination of optimal prey for rearing the Tropical Gar Atractosteus tropicus (Lepisosteiformes: Lepisosteidae) / Determinación de presas óptimas para la crianza del pejelagarto Atractosteus tropicus (Lepisosteiformes: Lepisosteidae)

Abstract Larval feeding studies of both ornamental and consumable fish species are important for formulating successful management, and culture strategies for conservation purposes. In the present study, we evaluated prey selectivity for the tropical gar Atractosteus tropicus in the larval stage (first 8 weeks) using the zooplankton Artemia fransiscana, Daphnia pulex and Moina macrocopa as prey following the hypothesis that prey selection of the fish species is related not only to prey species preferences but to the difference in prey densities present in the environment. Functional responses were tested at prey densities of 0.2, 0.5, 1.0, 2.0, 4.0 and 8.0 ind. mL-1 and analyzed using Manly's α. For prey selectivity, we used the three zooplankton species at three different densities. In these two experiments the fish larvae were allowed to feed for 45 min. To quantify feeding behavior (encounters, attacks, captures, ingestions, rejections) we used a density of 1 ind. mL-1 using each prey species based on 10 minutes of direct observation. Our results showed a functional response Type II for A. tropicus preying mostly on A. franciscana and M. macrocopa. The Manly's α index showed that M. macrocopa and A. franciscana are the most preys selected. The values for encounters for the three prey species were relatively constant during the eight weeks. Encounter values for the cladocerans were low in comparison to A. franciscana; however, high success in capture and ingestion was observed for all prey species used. Our results from the functional response experiments supports the hypothesis that A. tropicus is an active predator presenting a functional response of a carnivorous fish and the shift in prey selection suggests that even at low prey availability, A. tropicus is able to manipulate and feed on zooplankton of wide range in size. Also, according to our results, we suggest the use of a mix of A. franciscana and M. macrocopa to feed A. tropicus in culture systems in concentrations ≈ 2 ind. mL-1 during the first 3 weeks of age and then shift to M. macrocopa from the 4 week. Our results, in conjunction with studies on the survivorship of the juveniles would aid in conservation efforts and improve the production of gars in aquaculture. Rev. Biol. Trop. 66(3): 1018-1033. Epub 2018 September 01.

Resumen Estudios sobre alimentación en etapa larvaria en peces ornamentales como de consumo son importantes para formular estrategias exitosas de manejo y cultivo con fines de conservación. En el presente estudio evaluamos la selectividad de presa del pejelagarto Atractosteus tropicus en etapas larvarias (primeras 8 semanas) utilizando el zooplancton Artemia fransiscana, Daphnia pulex y Moina macrocopa como presas, probando la hipótesis de que la selección de presas en peces está relacionada no solamente a la preferencia por la especie de presa sino también a la diferencia en la densidad de presas en el ambiente. También se probó la respuesta funcional con densidades de presa de 0.2, 0.5, 1.0, 2.0, 4.0 y 8.0 ind. mL-1. Para la selección de presa, utilizamos las tres especies de zooplancton en tres densidades diferentes. En ambos experimentos, las larvas de los peces se alimentaron por 45 min. Para cuantificar el comportamiento alimenticio (encuentros, ataques, capturas, ingestiones y rechazos), se usó una densidad de 1 ind. mL-1utilizando cada especie de presa mediante observación directa por 10 minutos. Nuestros resultados muestran que A. tropicus presenta una respuesta funcional Tipo II, depredando principalmente A. franciscana y M. macrocopa. El índice α de Manly mostró que las especies M. macrocopa and A. franciscana fueron las mayormente seleccionadas. Los valores de encuentros para las tres especies de presa fueron relativamente constantes a lo largo de las ocho semanas. Los valores de ataque, captura e ingestión para los cladóceros fueron bajos; sin embargo, se observó gran éxito en la captura e ingestión para todas las especias de presa utilizadas. Nuestros resultados sobre los experimentos de respuesta funcional soportan la hipótesis de que A. tropicus es un depredador activo y presenta una respuesta funcional relacionada con especies de peces carnívoras y que el cambio en la selección de presas sugiere que aún a bajas densidades y disponibilidad de presas, A. tropicus es capaz de manipular y alimentarse de presas de diferentes tamaños. También, sugerimos el uso de una mezcla de A. franciscana y M. macrocopa para alimentar a A. tropicus en sistemas de cultivo en concentraciones ≈ 2 ind. mL-1 durante las primeras tres semanas de edad y después cambiar a M. macrocopa a partir de la cuarta semana. Nuestros resultados, junto con estudios de sobrevivencia de los juveniles pueden ayudar a generar esfuerzos de conservación y mejorar la producción de pejelagarto en acuicultura.