Objetivo. Determinar la concentración de glucosa no activadora de la movilidad espermática como componente de futuros diluyentes para la crioconservación de semen de Prochilodus magdalenae. Materiales y métodos. Se analizó semen inactivo de tres machos obtenido por inducción hormonal. Una submuestra de 0.25 μL de semen de cada macho fue depositada sobre una cámara de Makler y evaluada usando diferentes concentraciones de glucosa (0, 1, 2, 3, 4, 5, 6, 7, 8, 9 y 10%) mediante la adición de 75 μL de cada solución sobre el semen (n=3). De cada solución se determinó la osmolaridad, siendo de 0, 62, 124, 186, 250, 310, 360, 410, 472, 536 y 620 mOsm/kg, respectivamente, así como la del plasma seminal (~250–300 mOsm/kg). Mediante el software Sperm Class Analyzer (SCA) se determinó la velocidad curvilínea (VCL) y recta (VSL) (μm/seg), movilidad rápida (%), media (%) y lenta (%) y el porcentaje de espermatozoides inmóviles. El tiempo de activación de la movilidad (segundos) se obtuvo por cronometraje y visualización bajo microscopio de campo claro. Resultados. Concentraciones de 0 a 5% de glucosa produjeron activación de la movilidad espermática, no obstante, a partir de glucosa al 6% no fue detectada activación visual; sin embargo, SCA detectó movilidad total (7.2%), VCL (5.1 μm/seg) y VSL (1.7 μm/seg). A partir de glucosa al 7% el SCA detectó 100% de inmovilidad, no adquirida posteriormente con agua destilada. Conclusiones. La concentración de glucosa tiene efecto determinante en la viabilidad y activación de semen fresco. Una concentración de 6% de glucosa puede ser utilizada como solución no activadora de la movilidad espermática en futuros diluyentes para la crioconservación de semen de esta especie.

The study aimed to evaluate cryo-injury during the cryopreservation in Sorubim cuspicaudus sperm with ethylene glycol (EG) at different rates (6, 8, 10%). Fresh, prefrozen, and post-thawed sperm quality as motility total, velocities, mitochondria damage (Mit-d), membrane damage (Mem-d), and DNA fragmentation (DNA-f), were examined. The Mit-d, Mem-d, and DNA-f were evaluated through flow cytometry. High motility (>95%) and a low percentage of Mem-d (1.0 ± 0.5%), Mit-d (1.4 ± 0.9%), and DNA-f (2.4 ± 0.8%) were recorded for fresh semen. Prefrozen semen increases in Mit-d and DNA-f were observed compared to fresh semen (p < 0.05). In thawed semen, increased Mit-d (2.6 to 3-fold), Mem-d (6 to 1-fold), and DNA-f (3.3 to 6.6-fold) compared to prefrozen was observed. Thawed semen showed Mit-d (34 to 37-fold), Mem-d (24.5 to 26.6-fold) and DNA-f (13 to 18.5-fold) increased high. In conclusion, the present study demonstrated that mitochondria, membrane, and DNA integrity undergo significant damage during both pre-freezing and freezing/thawing with EG inclusion percentages from 6 to 10% that affect its fertilizing capacity, which is reduced to half of that obtained with fresh semen. It is suggested that a cryoprotective solution composed of 6% EG, 6% glucose, and 5% skimmed milk powder is a useful protocol for the cryopreservation of S. cuspicaudus semen.

Hematological and blood biochemical reference information is important to establish physiological status of freshwater stingray populations and improve care and management protocols in artificial environments. Here, we used a commercial freshwater stingray with high mortality rates in the market (Potamotrygon magdalenae), as an example to understand how artificial environments and handling protocols influence physiological status of captive freshwater stingrays. To this purpose, blood from five adult males and six adult females was collected to perform complete blood counts and blood chemistry analyses. All sampled animals showed good body condition with no differences between sexes. Differences between sexes were only found for the differential count of lymphocytes. Red blood results were consistent with previously studied potamotrygonids while white blood results showed higher values of leukocytes, thrombocytes, heterophils and lymphocytes in P. magdalenae compared to other Potamotrygonids. All types of leukocytes described for elasmobranchs were found except neutrophils and basophils. Blood metabolites showed an influence of ex situ diet in total protein, triglycerides and cholesterol. Glucose results were consistent while urea showed lower levels than those recorded for other freshwater stingrays. These results highlight the importance of physical, physiological and health analysis in freshwater stingrays as a part of welfare assessment to improve monitoring protocols and survival rates in public or private aquaria.

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.

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.

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.