Hydrogel capsules as new delivery system for Trichoderma koningiopsis Th003 to control Rhizoctonia solani in rice (Oryza sativa).

The incorporation of biological control agents (BCAs) such as Trichoderma spp. in agricultural systems favors the transition towards sustainable practices of plant nutrition and diseases control. Novel bioproducts for crop management are called to guarantee sustainable antagonism activity of BCAs and increase the acceptance of the farmers. The encapsulation in polymeric matrices play a prominent role for providing an effective carrier/protector and long-lasting bioproduct. This research aimed to study the influence of biopolymer in hydrogel capsules on survival and shelf-life of T. koningiopsis. Thus, two hydrogel capsules prototypes based on alginate (P1) and amidated pectin (P2), containing conidia of T. koningiopsis Th003 were formulated. Capsules were prepared by the ionic gelation method and calcium gluconate as crosslinker. Conidia releasing under different pH values of the medium, survival of conidia in drying capsules, storage stability, and biocontrol activity against rice sheath blight (Rhizoctonia solani) were studied. P2 prototype provided up to 98% survival to Th003 in fluid bed drying, faster conidia releasing at pH 5.8, storage stability greater than 6 months at 18 °C, and up to 67% of disease reduction. However, both biopolymers facilitate the antagonistic activity against R. solani, and therefore can be incorporated in novel hydrogel capsules-based biopreparations. This work incites to develop novel biopesticides-based formulations with potential to improve the delivery process in the target site and the protection of the active ingredient from the environmental factors.

Hydrogel capsules as new approach for increasing drying survival of plant biostimulant gram-negative consortium.

Several plant growth-promoting bacteria (PGPB) are gram-negative, and their cell viability is affected during the bio-inoculant production. Hence, formulation-drying processes provide challenges that limit the adoption of these beneficial microorganisms in sustainable agricultural production. Among delivery system strategies for gram-negative PGPB, the encapsulating cells in biopolymeric materials are emerging as a promising alternative. This research aims to evaluate the effect of additives and crosslinking agents on the survival of the consortium of Herbaspirillum frisingense AP21, Azospirillum brasilense D7, and Rhizobium leguminosarum T88 in hydrogel capsules. Three crosslinkers and diverse potential drying protectors were tested. Calcium gluconate provides notable consortium survival advantages regarding colony-forming units (CFUs) (losses of up to 4 log CFU) compared to calcium lactate and calcium chloride (up to 6 log CFU). Additives such as skimmed milk, whey protein, and Gelita® EC improve the recovery of viable cells after the drying process, demonstrating an increase in cell survival of the three bacteria by up to 4 log CFU. The combination of these substances into a capsule prototype extends the storage stability of bacterial consortium up to 3 months at 18 ± 2 °C. This study expands the knowledge for formulating gram-negative PGPB consortium, regarding the crosslinker and drying protector relationship on encapsulation processes with drying survival and further storage stability performance. KEY POINTS: • Hydrogel immobilization formulation approach for PGPB consortium • Enhancing drying survival of gram-negative PGPB consortium • Increasing storage stability of PGPB consortium at 18 °C.

Trichoderma koningiopsis Survival on Coated Seeds and Effect on Plant Growth Promotion in Rice (Oryza sativa).

Seed coating is an alternative delivery system for beneficial plant microorganisms into the soil. Although seed coats are widely used for the application of agrochemicals, the incorporation of beneficial microorganisms has not been explored deeply and their survival on seeds while in storage is unknown. The study aimed to evaluate the effect of the coating process on microbial survival and on plant growth promotion. Two coating formulations were designed, and assessed by two coating processes: rotating drum and fluidized bed. The rotating drum process resulted in more uniform coatings than in the fluidized bed process. In addition, with this coating technique, lower viability losses over time were observed. The rotatory drum prototype containing a biopolymer and a clay mineral derivate (P90) showed the best behavior at the three temperatures evaluated, with superior viabilities compared to the other prototypes and the lowest loss of viability after 12 months. The formulation of this coating prototype may preserve the viability of Trichoderma koningiopsis Th003 up to 15 months at 8 °C, 9 months at 18 °C, and 3 months at 28 °C, which are very promising shelf-life results. Regarding the effect of seed coating on plant growth, prototypes showed higher yields > 16% than the control, comparable to the conventional use of Tricotec® WG, which may reduce the number of applications and water consumption for dissolution of the inoculant. The results demonstrated that the formulation composition, as well as the coating process may impact the microbial survival on seeds.

High-Throughput Assessments for Storage Stability, In Vitro Release, and Particle Size of Encapsulated Biocontrol Fungi in Hydrogel Beads.

Use of biocontrol fungi (BF) such as Trichoderma spp. minimizes fungicide input and increases both plant nutrition and protection from disease. Thus, the introduction of BF by novel inoculants in crop management is an excellent strategy to promote sustainable antagonism activity. Within these strategies, encapsulation in polymeric matrices such as hydrogel beads will play a prominent role in providing an effective carrier/protector and long-lasting bioproduct. These studies have used biomaterials with tunable physicochemical features, providing differential morphologies, compaction, and disintegration, among other parameters. Aiming at developing bioproducts within polymeric hydrogel beads, viability of encapsulated conidia, storage stability, release of active ingredient, and particle size are essential. However, there are no reports that detail standardized and comprehensive methods to evaluate the characterization of these bioproducts. We describe step-by-step protocols that go from sample preparation to testing the viability and storage stability using vacuum-sealed aluminum foil bags. We also describe a high-throughput in vitro method for quantifying released fungal conidia of BF at different pH values. Finally, the particle size of beads is established by bright-field microscopy. These protocols could be transferable to other biological actives, accessible to researchers in the microbiology and bioengineering communities. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Viability of encapsulated conidia Basic Protocol 2: Study of stability of prototypes under storage Basic Protocol 3: Release profile of encapsulated conidia at different pH conditions Basic Protocol 4: Determination of capsule size.

Seed coating as a delivery system for the endophyte Trichoderma koningiopsis Th003 in rice (Oryza sativa).

Seed coating is a technique to cover seeds with external agents to upgrade their performance, handling, and plant establishment. Plant beneficial microbes (PBMs), such as plant growth-promoting bacteria, mycorrhizal fungi, and other fungi (e.g., Trichoderma spp.), decrease agrochemical inputs, enhance tolerance to biotic-abiotic stresses, and increase essential plant nutrition. The demand for pre-treated seeds as delivery systems for biological agents is advancing. Here, a seed coating formulation containing Trichoderma koningiopsis is presented. The physicochemical and biological characterization of the seed coating prototypes included drying protector screening, the effect of the inoculum concentration on survival, the assessment of microbial release profiles in soil extract, and plant tissue colonization capability under semi-controlled conditions. Gelatine and pectin, two of the tested drying protectors, maintained fungus germination after 60 days at 18 °C with significantly higher values of up to 38% compared with the control. The initial concentration of 106 colony-forming units (CFU) per seed undergoes a positive effect on survival over time. Regarding plant tissue colonization, the fungus establishes endophytically in rice. In conclusion, seed coating is a promising alternative for the formulation of beneficial microbial agents such as Trichoderma sp., maintaining cell survival and further promoting the establishment in rice systems.Key points• Enhancing drying survival of T. koningiopsis formulates• Seed coating formulation approach for T. koningiopsis in rice• Colonization capacity of formulated T. koningiopsis in rice tissue.

Integrated Analysis of Transcriptome and Secretome From Umbilical Cord Mesenchymal Stromal Cells Reveal New Mechanisms for the Modulation of Inflammation and Immune Activation.

Mesenchymal stromal cells (MSC) have been used in over 800 clinical trials with encouraging results in the field of transplant medicine and chronic inflammatory diseases. Today, Umbilical Cord (UC)-derived MSC are the second leading source used for clinical purposes, mainly due to its easy access and superior immune modulatory effects. Although the underlying molecular mechanisms of immune suppressive activities have not been fully understood, research over the last decade strongly suggests that MSC-mediated benefits are closely related to activation of secretome networks. Nevertheless, recent findings also point to cytokine-independent mechanisms as key players of MSC-mediated immune modulation. Here, we set up a robust in vitro immune assay using phytohemagglutinin- or anti-CD3/CD28-treated human peripheral blood mononuclear cells in cell-to-cell interaction or in cell-contact independent format with UC-MSC and conducted integrated transcriptome and secretome analyses to dissect molecular pathways driving UC-MSC-mediated immune modulation. Under inflammatory stimuli, multiparametric analyses of the secretome led us to identify cytokine/chemokine expression patterns associated with the induction of MSC-reprogrammed macrophages and T cell subsets ultimately leading to immune suppression. UC-MSC transcriptome analysis under inflammatory challenge allowed the identification of 47 differentially expressed genes, including chemokines, anti- and pro-inflammatory cytokines and adhesion molecules found also in UC-MSC-immunosupressive secretomes, including the novel candidate soluble IL-2R. This study enabled us to track functionally activated UC-MSC during immune suppression and opened an opportunity to explore new pathways involved in immunity control by UC-MSC. We propose that identified immunomodulatory molecules and pathways could potentially be translated into clinical settings in order to improve UC-MSC-therapy quality and efficacy.

Formulating bacterial endophyte: Pre-conditioning of cells and the encapsulation in amidated pectin beads.

Despite the benefits of bacterial endophytes, recent studies on the mostly Gram-negative bacteria lack of regard for formulation strategies. The encapsulation into biopolymeric materials such as amidated pectins hydrogels is a suitable alternative. Here, this research aimed at supporting the capability of the plant growth-promoting bacteria Kosakonia radicincitans DSM16656T to endophytically colonize plant seedlings. In this approach, the pre-conditioned cells through osmoadaptation and hydroxyectoine accumulation were used. In general, pre-osmoadapted and hydroxyectoine-supplemented bacteria cells formulated in amidated pectin dried beads increased the endophytic activity by 10-fold. Moreover, plant promotion in radish plants enhanced by 18.9% and 20.7% for a dry matter of tuber and leaves. Confocal microscopy studies with GFP-tagged bacteria revealed that bacterial aggregates formed during the activation of beads play an essential role in early colonization stages. This research encourages the integration of fermentation and formulation strategies in a bioprocess engineering approach for exploiting endophytic bacteria.

Anhydrobiotic engineering for the endophyte bacterium Kosakonia radicincitans by osmoadaptation and providing exogenously hydroxyectoine.

This study presents an anhydrobiotic engineering approach aiming at conferring a high degree of desiccation tolerance to the Gram-negative endophyte Kosakonia radicincitans. In particular, pre-conditioning of bacteria under high salinities provides a remarkable positive influence on drying survival. The endophytic bacteria accumulate exogenous hydroxyectoine > 500 µmol g-1 dry weight cells exerted by osmotic stress at 4% NaCl. Microfermentation research demonstrated that hydroxyectoine provides positive effects on reducing the lag phase duration and alleviates the dissolved oxygen consumption under high salinity conditions. Beyond the amassing of hydroxyectoine, this work provides evidence supporting the notion that hydroxyectoine can produce significant changes in the endogenous bacterial metabolome during the exponential growth phase at high-osmolarity. Metabolome changes include alterations on tricarboxylic acid cycle, novo-synthesis of specific intracellular metabolites such as mannitol, myo-inositol and trehalose, and fold changes on amino acids such as L-leucine, L-asparagine, L-serine, L-methionine and L-proline. The significant fold change of L-aspartate suggests a potential acidic proteome at high-osmolarity environments, extending the knowledge of salt-stressed bacterial endophytes. Thus, these findings place the metabolic salt stress response and the hydroxyectoine accumulation by K. radicincitans into a physiological context, paving the way into the interaction between cellular phenotype associated with salt stress tolerance and drying survival capacity of Gram-negative endophytes.

Strategy for the Generation of Engineered Bone Constructs Based on Umbilical Cord Mesenchymal Stromal Cells Expanded with Human Platelet Lysate.

Umbilical cord mesenchymal stromal cells (UC-MSC) are promising candidates for cell therapy due to their potent multilineage differentiation, enhanced self-renewal capacity, and immediate availability for clinical use. Clinical experience has demonstrated satisfactory biosafety profiles and feasibility of UC-MSC application in the allogeneic setting. However, the use of UC-MSC for bone regeneration has not been fully established. A major challenge in the generation of successful therapeutic strategies for bone engineering lies on the combination of highly functional proosteogenic MSC populations and bioactive matrix scaffolds. To address that, in this study we proposed a new approach for the generation of bone-like constructs based on UC-MSC expanded in human platelet lysate (hPL) and evaluated its potential to induce bone structures in vivo. In order to obtain UC-MSC for potential clinical use, we first assessed parameters such as the isolation method, growth supplementation, microbiological monitoring, and cryopreservation and performed full characterization of the cell product including phenotype, growth performance, tree-lineage differentiation, and gene expression. Finally, we evaluated bone-like constructs based on the combination of stimulated UC-MSC and collagen microbeads for in vivo bone formation. UC-MSC were successfully cultured from 100% of processed UC donors, and efficient cell derivation was observed at day 14 ± 3 by the explant method. UC-MSC maintained mesenchymal cell morphology, phenotype, high cell growth performance, and probed multipotent differentiation capacity. No striking variations between donors were recorded. As expected, UC-MSC showed tree-lineage differentiation and gene expression profiles similar to bone marrow- and adipose-derived MSC. Importantly, upon osteogenic and endothelial induction, UC-MSC displayed strong proangiogenic and bone formation features. The combination of hPL-expanded MSC and collagen microbeads led to bone/vessel formation following implantation into an immune competent mouse model. Collectively, we developed a high-performance UC-MSC-based cell manufacturing bioprocess that fulfills the requirements for human application and triggers the potency and effectivity of cell-engineered scaffolds for bone regeneration.

Salt stress and hydroxyectoine enhance phosphate solubilisation and plant colonisation capacity of Kosakonia radicincitans.

Gram-negative bacterial endophytes have attracted research interest caused by their advantageous over epiphytic bacteria in plant nutrition and protection. However, research on these typically Gram-negative endophytes has deficiencies concerning the role of cultivation and pre-formulation strategies on further plant colonisation capabilities. Besides, the influence of cultivation conditions and osmotic stress within bacterial endophytes on their phosphate solubilising ability has not yet been addressed. By pre-conditioning cells with an osmoadaptation and a hydroxyectoine accumulation approach, this research aimed at enhancing the capability of the plant growth promoting bacterium Kosakonia radicincitans strain DSM 16656T to both solubilise phosphate and colonise plant seedlings. The results showed that halotolerant bacterial phenotypes increased the root-colonising capability by approximately 3-fold and presented growth-promoting effects in radish plants. Interestingly, findings also demonstrated that salt stress in the culture media along with the accumulation of hydroxyectoine led to an increase in the in vitro phosphate-solubilising ability by affecting the production of acid phosphatases, from 1.24 to 3.34 U mg-1 for non-salt stressed cells and hydroxyectoine-added cells respectively. Thus, this approach provides a useful knowledge upon which the salt stress and compatible solutes in bacteria endophytes can confer phenotypic adaptations to support the eco-physiological performance concerning phosphate-solubilising abilities and endosphere establishment.

Células estromales mesenquimales de gelatina de wharton inducen re-programación de macrófagos inflamatorios hacia un fenotipo inmunomodulador / Jelly of wharton mesenchymal stromal cells induce reprogramming macrophage inflammatory towards an immunomodulator phenotype

El uso incremental de células estromales mesenquimales (CEM) para regeneración tisular y su potencial para el manejo de enfermedades de origen inflamatorio dadas sus propiedades inmunomodulatorias, está garantizado a corto plazo. Sin embargo existe un vacío relaciona-do con los mecanismos celulares y moleculares implicados en el proceso inmunomodulatorio por parte de las CEM de gelatina de Wharton (GW). Este estudio evalúa el efecto de las CEM-GW sobre la regulación y función del fenotipo del macrófago en ambientes inflamato-rios. Se realizaron ensayos con células mononucleares de sangre periférica (PBMCs) (N=4) o con la células CD3+ (N=3), estimuladas con anti-CD3/CD28/CD2, evaluando la inhibición de la proliferación de los linfocitos en co-cultivos con CEM-GW (N=3).

Estereotipos negativos sobre la vejez en estudiantes universitarios de enfermería / Negative stereotypes about old age in college nursing students

Resumen:

Introducción: la vejez es la etapa de la vida que más mitos y estereotipos tiene asociados. Estas ideas suelen ser erróneas y asociadas a aspectos negativos como personas enfermizas, frágiles, improductivas, intransigentes o dependientes.

Objetivo: identificar y describir los estereotipos que los estudiantes de la disciplina de enfermería tienen hacia los adultos mayores.

Metodología: estudio descriptivo y transversal, con una muestra de 95 alumnos del último periodo de la Licenciatura en Enfermería; los estereotipos se midieron con el cuestionario CENVE con un coeficiente de alfa de Cronbach de 0.76 para esta población.

Resultados: en el análisis por dimensión se encontró mayor frecuencia de estereotipos negativos en la dimensión Salud (65.3%). El análisis de la escala global indica que el 50.5% de los estudiantes tenía estereotipos negativos.

Discusión: el porcentaje encontrado de estudiantes con estereotipos negativos es mayor al reportado en otros estudios.

Conclusiones: la mitad de los estudiantes de la Licenciatura en Enfermería tiene estereotipos negativos sobre la vejez.

Abstract:

Introduction: Old aging is the stage of life that most myths and stereotypes are associate with. These ideas are often erroneous and negative aspects associated with unhealthy fragile, unproductive, and intransigent or dependent people.

Objective: To identify and describe the stereotypes that students in the discipline of nursing have towards the elderly.

Methodology: Descriptive study, with a sample of 95 students in the last period of Nursing Bachelor, stereotypes were measured with the CENVE questionnaire with Cronbach's alpha coefficient of 0.76 for this population.

Results: In the analysis, the most frequent negative stereotypes are in the dimension of Health (65.3%). The analysis of the global indicates that 50.5% of students had negative stereotypes. Discussion: The percentage found of students with negative stereotypes is greater than the reported in other studies.

Conclusions: Half of nursing students have negative stereotypes about old age.

Clinical and Parasitological Features of Patients with American Cutaneous Leishmaniasis that Did Not Respond to Treatment with Meglumine Antimoniate.

BACKGROUND: American cutaneous leishmaniasis (ACL) is a complicated disease producing about 67.000 new cases per year. The severity of the disease depends on the parasite species; however in the vast majority of cases species confirmation is not feasible. WHO suggestion for ACL produced by Leishmania braziliensis, as first line treatment, are pentavalent antimonial derivatives (Glucantime or Sodium Stibogluconate) under systemic administration. According to different authors, pentavalent antimonial derivatives as treatment for ACL show a healing rate of about 75% and reasons for treatment failure are not well known. METHODS: In order to characterise the clinical and parasitological features of patients with ACL that did not respond to Glucantime, a cross-sectional observational study was carried out in a cohort of 43 patients recruited in three of the Colombian Army National reference centers for complicated ACL. Clinical and paraclinical examination, and epidemiological and geographic information were recorded for each patient. Parasitological, histopathological and PCR infection confirmation were performed. Glucantime IC50 and in vitro infectivity for the isolated parasites were estimated. RESULTS: Predominant infecting Leishmania species corresponds to L. braziliensis (95.4%) and 35% of the parasites isolated showed a significant decrease in in vitro Glucanatime susceptibility associated with previous administration of the medicament. Lesion size and in vitro infectivity of the parasite are negatively correlated with decline in Glucantime susceptibility (Spearman: r = (-)0,548 and r = (-)0,726; respectively). CONCLUSION: A negative correlation between lesion size and parasite resistance is documented. L. braziliensis was found as the main parasite species associated to lesion of patients that underwent treatment failure or relapse. The indication of a second round of treatment in therapeutic failure of ACL, produced by L. braziliensis, with pentavalent antimonial derivatives is discussable.

Improving Leishmania species identification in different types of samples from cutaneous lesions.

The discrimination of Leishmania species from patient samples has epidemiological and clinical relevance. In this study, different gene target PCR-restriction fragment length polymorphism (RFLP) protocols were evaluated for their robustness as Leishmania species discriminators in 61 patients with cutaneous leishmaniasis. We modified the hsp70-PCR-RFLP protocol and found it to be the most reliable protocol for species identification.

Antibióticos sistémicos para retinocoroiditis por toxoplasmosis. Revisión sistemática de la literatura / Systemic antibiotics for toxoplasmic retinochoroiditis. Systematic literature review / Antibióticos sistémicos para retinocoroiditis por toxoplasmoses. Revisão sistemática da literatura

Objetivo: el objetivo principal de esta revisión sistemática es evaluar eficacia y seguridad de los antibióticos sistémicos en la retinocoroiditis activa por toxoplasmosis. Metodología: se realizó una búsqueda en la que se incluyeron ensayos clínicos controlados aleatorizados o cuasi aleatorizados. Se excluyeron estudios en pacientes inmunocomprometidos. Se incluyeron estudios de pacientes tratados para retinocoroiditis aguda o con cicatrices retinocoroideas inactivas y con historia de dos o más episodios recurrentes de enfermedad activa. Se incluyeron regímenes de antibióticos conocidos (trimetoprim/sulfametoxazol, pirimetamina/sulfadiazina, pirimetamina/ azitromicina) y ampliamente utilizados contra el Toxoplasma gondii. Resultados: los resultados primarios para esta revisión fueron agudeza visual y aparición de recurrencias, definidas como un nuevo foco de inflamación retinocoroidea adyacente a una cicatriz previa. Los resultados secundarios fueron efectos adversos, reducción del tamaño de la lesión retinocoroidea y duración, severidad y frecuencia de los signos y síntomas por la inflamación intraocular. Conclusiones: todavía existe una falta de evidencia que soporte el antibiótico y dosis óptima ideal para el manejo de retinocoroiditis por toxoplasmosis, así como tratamiento profiláctico ideal para las recurrencias.

Objective: The main objective of this systematic review is to evaluate safety and efficacy of systemic antibiotics in active toxoplasmic retinochoroiditis.Methods: An important search was conducted which included randomized or quasi-randomized controlled clinical trials. Studies carried out in immunocompromised patients were excluded. Studies of patients treated for acute retinochoroiditis or patients with inactive retinochoroidal scars and a history of two or more recurrent episodes of active disease were included. Well-known antibiotic regimens (trimethoprim/sulfamethoxazole, pyrimethamine/sulfadiazine, pyrimethamine/azithromycin), which have been widely used against Toxoplasma gondii, were included.Results: The primary outcomes for this review were visual acuity and recurrences, defined as a new focus of inflammation next to a preexisting scar. Secondary outcomes were adverse effects, reduction of retinochoroidal lesion size and duration, severity and frequency of signs and symptoms due to intraocular inflammation.Conclusions: There is still a lack of evidence to support the antibiotic and optimal dosage for the treatment of toxoplasmic retinochoroiditis, as well as the best prophylactic treatment for recurrences.

Objetivo: o objetivo principal desta revisão sistemática é avaliar eficácia e segurança dos antibióticos sistémicos na retinocoroidite ativa por toxoplasmoses.Metodologia: realizou-se uma busca importante em onde se incluíram ensaios clínicos controlados aleatorizados ou quase aleatorizados. Excluíram-se estudos em pacientes imuno-comprometidos. Incluíram-se estudos de pacientes tratados para retinocoroidite aguda ou com cicatrizes retinocoroidites inativas e com história de duas ou mais episódios recorrentes de doença ativa. Incluíram-se regimes de antibióticos conhecidos (trimetoprim/sulfametoxazol, pirimetamina/sulfadiazina, pirimetamina/azitromicina) e amplamente utilizados contra o Toxoplasma gondii. Resultados: os resultados primários para esta revisão foram agudeza visual e aparição de recorrências, definidas como um novo foco de inflamação retinocoroidite adjacente a uma cicatriz prévia. Os resultados secundários foram efeitos adversos, redução do tamanho da lesão retinocoroidite e duração, severidade e frequência dos signos e sintomas devido à inflamação intraocular. Conclusões: ainda existe uma falta de evidência que suporte o antibiótico e dose ótima ideal para o manejo de retinocoroidites por toxoplasmoses, bem como tratamento profiláctico ideal para as recorrências.

Efecto de la densidad de siembra en el alevinaje de la dorada (Brycon sinuensis Dahl, 1955) / Effect of stocking density in the rearing of dorada (Brycon sinuensis) fingerlings

Con el objeto de evaluar el efecto de la densidad de siembra en el alevinaje de dorada Brycon sinuensis se sembraron postlarvas (PL) de dos días de nacidas, con 8.0 mm de longitud total (LT) y 6.3 mg de peso (P), a tres densidades diferentes (50, 100 y 150 PL/m2), en nueve estanques en tierra de 50 m2 en el Centro de Investigación Piscícola de la Universidad de Córdoba (CINPIC). Las PL fueron alimentadas dos veces al día con dieta comercial de 34 por ciento de proteína bruta. Se realizaron muestreos los días 0, 6, 12 y 18 para evaluar el crecimiento; con los valores promedio de LT y P se calculó la tasa de crecimiento específico (G). La productividad final se evaluó a través de la biomasa por área (BA) y el número de alevinos por área (AA). Se realizó un monitoreo diario de temperatura, oxígeno disuelto, pH y transparencia del agua de los estanques. La dureza, alcalinidad y amonio total se midieron cada cinco días. Los resultados se expresaron como promedio±desviación estándar. Las características del agua de los estanques se mantuvieron dentro del rango considerado normal para la piscicultura de especies neotropicales. Al final de los 18 días de cultivo los valores de LT y P oscilaron entre 30.3 mm y 357.5 mg (150 PL/m2) y 37.5 mm y 743.9 mg (50 PL/m2), respectivamente. La sobrevivencia osciló entre 59.9 (150 PL/m2) y 85.4 por ciento (100 PL/m2). Los valores de G oscilaron entre 25.1 (150 PL/m2) y 28.9 por ciento/día (50 PL/m2). La BA osciló entre 22.2 (50 PL/m2) y 46.0 g/m2 (100 PL/m2). En ninguna de las anteriores variables se observó diferencia estadística significativa entre las densidades evaluadas (p>0.05). Los valores de AA en el alevinaje donde se sembró a 100 PL/m2 (85.4 Ind/m2) y 150 PL/m2 (89.8 Ind/m2) no presentaron diferencia estadistica significativa (p>0.05); pero fueron entre 2.4 y 2.6 veces el obtenido a 50 PL/m2 (34.9 Ind/m2) (p<0.05). Los resultados del presente estudio permiten sugerir que el alevinaje de la dorada se puede realizar, por...