Hernán Antonio Alzate-Díaz

Red tilapia (Oreochromis sp.) fry are routinely transported between hatcheries and grow out farms, yet the effects of transport duration on epidermal barrier-associated responses and goblet cells remain poorly defined. This study assessed the impact of simulated transport on epidermal morphology, immune-related gene expression and goblet cell density in red tilapia fry. Fish were assigned to four groups (0, 5, 12 and 20 h of transport). Skin samples were analyzed for relative mRNA expression of 10 genes associated with tight junction proteins, mucins, antimicrobial peptides and cytokines using RT-qPCR, and for epidermal goblet cell density by histology. Transport significantly modulated eight genes, forming three co-expression clusters associated with inflammatory, barrier-related, and mucus-related responses, with mainly non-linear time courses. MUC2, DB-4, IL-1β, and TGF-β1b showed transient increases at 5–12 h, whereas MUC5AC and claudin transcripts increased earlier and approached control levels at 20 h. Goblet cell density remained relatively stable up to 12 h but declined after 20 h, coinciding with changes in MUC2 and MUC5AC expression and suggesting altered mucosal responses during prolonged transport. Overall, transport durations ≤ 12 h were associated with relatively stable epidermal responses, whereas 20 h induced pronounced changes in goblet cell density and barrier-associated gene expression. These findings provide information that may assist future optimization of transport practices in tilapia aquaculture. Transport stress in red tilapia fry induces rapid defensive responses, significantly modulating gene expression and mucosal dynamics; this is characterized by increased mucus production, goblet cell density, and early upregulation of mucins (MUC2), followed by later increases in tight junction genes and anti-inflammatory cytokines, alongside a temporary downregulation of antimicrobial peptides.

La medición tradicional de la capacidad de carga turística (CCT) en destinos naturales, mediante metodologías estáticas, limita el seguimiento continuo y la toma de decisiones en tiempo real. Este artículo presenta una Metodología Híbrida Dinámica de Capacidad de Carga Turística (MHDCCT) articulada a una arquitectura de software modular para La Cueva del Esplendor (Jardín, Antioquia). Con un enfoque mixto y un alcance exploratorio-descriptivo con un componente de I+D, el estudio se desarrolló en dos fases: una exploratoria (revisión bibliográfica, visitas de campo, entrevistas y observación) y otra tecnológica (diseño de una arquitectura de software). Los resultados pusieron de manifiesto que ninguna metodología aislada abarca de manera integral las dimensiones física, ambiental, social y de gestión. Por ello, la MHDCCT integra los enfoques de Cifuentes, el Límite de Cambio Aceptable, la Acogida Turística Multicriterio y la Carga Sociocultural. Para hacer frente a la escasa conectividad rural de la zona, la fase tecnológica diseñó una arquitectura de software de cinco capas basada en el IoT y en el protocolo MQTT sobre 4G/LTE, con procesamiento en tres velocidades (rápida, periódica y lenta), almacenamiento local y reenvío de datos. La combinación de la MHDCCT con la telemetría en tiempo real supera la rigidez de las mediciones tradicionales mediante límites dinámicos y alertas automáticas, lo que ofrece un marco metodológico y tecnológico de gestión adaptativa replicable en áreas naturales protegidas sometidas a presión turística.

The growing global interest in aquaculture products has driven efforts to optimize the transport of fingerlings, particularly red tilapia (Oreochromis sp.). This study evaluated, in real time, changes in water quality parameters during the transport of red tilapia fingerlings, using 250 individuals per sealed plastic bag containing 2.5 L of water and 6.5 L of oxygen (99.5%), under three transport durations (5, 12, and 20 hours), with three replicates per treatment (n = 9). Water quality variables, including pH, dissolved oxygen, and temperature, were monitored at the beginning and end of the transport period. Fingerling survival was 100% across all treatments. Data recorded by HOBO data loggers showed a significant increase in dissolved oxygen due to oxygen infusion, with mean values of 7.86 ± 4.15 mg/L at 5 hours, 9.76 ± 3.17 mg/L at 12 hours, and 11.29 ± 3.39 mg/L at 20 hours. pH values decreased slightly but significantly, with means of 5.77 ± 0.17, 6.00 ± 0.19, and 5.95 ± 0.21 at 5, 12, and 20 hours, respectively, indicating progressive water acidification. Scanning electron microscopy (SEM) analysis showed a homogeneous epidermal tissue morphology, with no evidence of structural damage across the different transport durations. Goblet cells measuring 4–5 μm were identified, indicating preservation of epidermal integrity throughout the transport period. Continuous monitoring enabled the identification of environmental changes and their impact on fingerling health and stress responses, providing key information for optimizing transport protocols and highlighting the importance of maintaining suitable water conditions and using data loggers for real-time environmental assessment.

In a context where aquaculture continues to grow, it is essential to understand how culture conditions influence fish stress. The welfare of red tilapia fry (Oreochromis sp.), weighing 0.6 ± 0.3 g and with an initial total length of 3.548 ± 0.285 cm, was evaluated in two culture systems, biofloc and land-based ponds, over a period of 30 days through biomarkers associated with the skin mucosa, such as protein, glucose, lactate, and the hormone cortisol, in addition to their relationships with protein, seeking a comprehensive view of the physiological state and stress of these fish. Mucus samples were thawed and prepared by mechanical homogenization and centrifugation. The results reveal that the biofloc system provides a more conducive environment for welfare, evidenced by higher mucus protein levels of 1.598 ± 0.733 mg/mL, 2.316 ± 1.01 mg/mL, and 1.203 ± 0.640 mg/mL for culture days 10, 20 and 30, respectively, and lower cortisol > 1 ng/mL and lactate contents 1799 ± 1135 µg/mL, 30,271 ± 24,613 µg/mL, and 21,829 ± 23,507 µg/mL for culture days 10, 20 and 30, respectively, compounds largely associated with animal stress. This highlights the direct relationship between culture, environment and fish health and highlights skin mucus as a valuable minimally invasive biomarker. It is also important to note that improved fish welfare supports fish growth and health and promotes more sustainable aquaculture practices, contributing to more efficient and responsible production in the industry.

The objective of this work was to assess the organoleptic and nutritional quality of fillets of cultured pirapitinga (Piaractus brachypomus), fed diets with either partial or total substitution of fishmeal, and to determine the nutritional quality of the biofloc meal. Fish were cultured in 500-L tanks with 84 fish m-3, treated with biofloc technology (BFT), and fed three isoproteic diets (24% crude protein, CP) formulated with the following protein sources: soybean meal (SM); soybean meal + fishmeal (SM+FM); and soybean meal + spirulina (SM+SP). After 84 days of culture, microbiological, nutritional, and sensory analyses were carried out on fillets with skin and without scales. There were not significant differences for dry matter, CP, moisture, and fat content between treatments. The fatty acid profile showed 21.3±1.03% polyunsaturated fatty acids (PUFAs = ω-3 + ω-6), 37.11±1.29% monounsaturated fatty acids (MUFAs), and 41.58±1.34% saturated fatty acids (SFAs). The protein sources soybean meal and spirulina do not affect the fillet quality of pirapitinga nor the nutritional quality of biofloc meal.

Los cultivos con tecnología biofloc (BFT) son sistemas acuícolas cerrados de producción intensiva que permiten generar un control sobre los desechos por medio del reciclaje de nutrientes y a través de la formación de biomasa bacteriana. El objetivo de esta investigación fue evaluar el efecto de la fuente de proteína del alimento sobre el desempeño productivo de cachama blanca Piaractus brachypomus cultivada en sistema BFT. Se evaluaron tres tratamientos con tres repeticiones cada uno, así:T1: torta de soya; T2: torta de soya+harina de pescado y T3: torta de soya+harina de espirulina, para un total de nueve unidades experimentales contenidos en tanques de 500L.Se sembraron 42 peces (54.23±10.7g) por tanque, se cultivaron durante 84 días y se suministró alimento tres veces/día. Para la evaluación del desempeño productivo se registró el consumo de alimento, se acompañó el crecimiento de los peces mediante biometrías quincenales y se determinaron parámetros de calidad del agua. Al final del cultivo los tanques alcanzaron una biomasa promedio final de 15.9±0.8 kg/m3, resultados competitivos comparados con otras producciones intensivas en BFT; la ganancia diaria de peso fue de 1.7±0.1 g/día sin diferencia significativa entre tratamientos. La conversión alimenticia se encontró alrededor de 1.1±0.1 sin diferenciaestadísticasignificativa entre tratamientos (p0.05) aunque dentro de los rangos óptimos para el cultivo de la especie. Se concluyó que la fuente de proteína usada en las dietas experimentales no incidió sobre el resultados productivos de la cachama blanca P. brachypomus cultivada en BFT.