Electronarcosis of Nile tilapia (Oreochromis niloticus): Effects on Dynamic Physiological Balance and Meat Quality.

INTRODUCTION: Electronarcosis is the most commonly used stunning method for large animals, but its consequences in tilapia still need to be evaluated. The aim of the study was to evaluate the application of electronarcosis in the pre-slaughter stunning of Nile tilapia (Oreochromis ni-loticus) and verify its effects on dynamic physiological balance and meat quality. METHODS: Nile tilapia specimens, totaling 184, with an average weight of 247.08 37.04 g, were randomly distributed. Each fish was individually placed in a rectangular tank constituted by a voltage regulator and aluminum electrode. The behavior of the fish subjected to different expo-sure times (5, 10, 20, and 30 seconds) and electric currents (1.50, 3.00, 4.50, and 6.00 amperes) with alternating and continuous currents was evaluated. Subsequently, the quality of the chilled fillets was checked after slaughter over a period of 35 days. The longest stun time was achieved using an alternating current of 3.00, 4.50, and 6.00A for 30 seconds. RESULTS: The fillet quality index (FQI) showed a high correlation with the storage time. In the first 15 days of storage, the fish stunned with different alternating currents maintained a higher MQI, meeting the meat quality standard when compared to fish slaughtered by ice stunning. The fish fillets obtained using different electrical currents showed a pH similar to the fish fillets stunned with ice. CONCLUSION: Therefore, electronarcosis can be applied in the slaughter of tilapia using al-ternating current between three and six amps for 30 seconds, with euthanasia time of 37 and 46 seconds, ensuring safety in the slaughter procedures in the industry, the quality of the meat, and the well-being of the animal.

Effects of Choline Supplementation in Diets on Juvenile Pacu (Piaractus mesopotamicus): Productive Performance, Proximate Composition and Serum Lipid Level.

INTRODUCTION: Pacu (Piaractus mesopotamicus) is a Brazilian fish species of high commercial value and has emerged as one of the main species with potential for intensive farming. This study aimed to investigate the impact of choline supplementation on productive performance, visceral fat, hepatosomatic indices, proximate composition, serum biochemical profile, and liver coloration in juvenile pacu (Piaractus mesopotamicus). METHOD: The 60-day experiment was conducted in the experimental hatchery of the Study Group of Aquaculture Management - GEMAq of the State University of West Paraná, Brazil. The completely randomized design consisted of five treatments with four replicates each. A total of 200 fish, with an average initial weight and length of 4.25 g and 5.97 cm, were distributed among 20 experimental hapas, resulting in a stocking density of 10 fish per experimental unit. Fish fed a choline-deficient diet exhibited the lowest values for final weight, weight gain, visceral fat, and hepatosomatic index. Conversely, in terms of proximate composition, fish fed choline-deficient diets had the highest moisture content but the lowest crude fat content. Triglyceride levels in juvenile pacu were significantly higher in groups fed diets containing choline (400 to 1200 mg kg-1 ). We also observed significant differences in the cyan color of the liver (P < 0.05). Notably, we observed significant differences in the cyan coloration of the liver (P < 0.05). Other parameters did not exhibit significant changes in response to varying choline levels in the diets. RESULT: Our study demonstrated that choline supplementation in P. mesopotamicus juveniles at an optimal concentration of 400 mg kg-1 significantly impacted growth, metabolism, productive performance, proximate composition, biochemical parameters, and liver color. CONCLUSION: These findings offer crucial guidance for aquaculture professionals, enabling them to enhance growth and health in P. mesopotamicus farming. Further research on choline's influence on lipid metabolism holds potential for more precise dietary recommendations, ultimately improving the efficiency and sustainability of aquaculture practices for this species.

Effects of Feeding Frequency for Nile Tilapia Fingerlings (Oreochromis niloticus).

This study is aimed at assessing the feeding frequency for tilapia fingerlings. 240 fishes were randomly distributed in 24 containers. The feeding consisted of six frequencies: 4 (F4), 5 (F5), 6 (F6), 7 (F7), 8 (F8), and 9 (F9) times a day. The weight gain was significantly higher in F5 and F6 when compared to F4 (p = 0.0409 and 0.0306, respectively). Feed intake and apparent feed conversion did not differ between treatments (p = 0.129 and p = 0.451). About water quality, the nitrogen levels in the water from the treatments differed between F4 and F5 (p = 0.0478) and F4 and F6 (p = 0.0283) and for P between F4 and F6 (p = 0.0215) and F4 and F9 (p = 0.0432). The x 2 test showed a dependence relationship between feed frequencies and the muscle fibers frequency (p < 22 × 10-17), prevailing fibers between 10-20 micrometers in F4, F5, F6, and F7 and 30-40 in F8 and F9. The area of the hepatocytes differed only between F5 and F9, while the nucleus area did not. Partial net revenue differed in 10% between F5 and F4 (p = 0.0812) and between F6 and F4 (p = 0.0568). In conclusion, fingerlings fed 5 to 6 times a day have better zootechnical and partial recipes.

Sunflower meal with and without phytase supplementation in diets for silver catfish (Rhamdia quelen) juveniles / Harina de girasol con y sin suplementación de fitasa en dietas para juveniles de bagre (barbudo, Col.; Rhamdia quelen) / Farelo de girassol com e sem suplementação de fitase em dietas para juvenis de jundiá ( Rhamdia quelen)

Abstract Background: The cost of feed in fish farming can exceed 70% of the total costs. Thus, the feed industry have sought to formulate balanced diets including low-cost by-products. Objective: To evaluate sunflower meal as a partial substitute (0, 10, and 20%) for soybean meal, with or without phytase supplementation (1,500 FTU/kg) in isoproteic (27% crude protein (CP)) and isoenergetic diets (3,400 kcal/ED/kg of feed) for silver catfish (Rhamdia quelen) juveniles. Methods: A total of 360 fish (weight: 15.77 ± 0.56 g) were randomly distributed in 24 tanks in a completely randomized design following a factorial scheme (3x2) with 4 replicates. The fish were evaluated on the following variables after 90 days: productive performance, hematological variables, histology of intestinal tissue, bromatological composition of carcass, and composition of bone mineral matter. Results: 20% dietary inclusion of sunflower meal improved weight gain and protein efficiency. No difference was observed in the other treatments and no interactions were observed between the other factors. Conclusion: 20% sunflower meal can be included in the feed of silver catfish as a substitute for soybean meal. Phytase inclusion (1,500 FTU/kg) did not improve the nutritional value of the treatments.

Resumen Antecedentes: El costo de la alimentación en piscicultura pueden superar el 70% del costo total. Las industrias de alimentos para peces han intentado formular dietas balanceadas con subproductos de menor valor en el mercado para minimizar costos. Objetivo: Evaluar la harina de girasol como sucedáneo parcial (0, 10 y 20%) de la torta de soya, suplementada o no con fitasa (1.500 FTU/kg) en dietas isoprotéicas (27% de PB) e isoenergéticas 3400 kcal / ED / kg de ración) para bagre (barbudo, Col.; Rhamdia quelen). Métodos: Los peces, 360 juveniles (15,77 ± 0,56 g), se distribuyeron aleatoriamente en 24 unidades experimentales, en un diseño completamente al azar, en esquema factorial (3x2) y 4 repeticiones. A los 90 días se evaluó: desempeño productivo, variables hematológicas, histología de tejido intestinal y composición bromatológica de la carcasa y de la materia mineral de los huesos. Resultados: La inclusion de 20% de harina de girasol mejoró la ganancia de peso de los peces y la tasa de eficiencia proteica de la ración, sin diferencia para las otras evaluaciones ni interacción entre los demás factores evaluados. Conclusión: La harina de girasol se puede utilizar en un 20% de la ración del bagre (barbudo, Col.) como sucedáneo a la harina de soja. La inclusión de fitasa (1.500 FTU/kg) no mejoró el valor nutritivo de estas raciones.

Resumo Antecedentes: Os custos relativos a alimentação na piscicultura pode ultrapassar 70% do custo final, neste sentido, as indústrias de rações têm procurado formular dietas balanceadas com subprodutos de menor valor de mercado para minimizar estes custos. Objetivo: Esse estudo objetivou avaliar o farelo de girassol como sucedâneo parcial (0, 10 e 20%) do farelo de soja, suplementado ou não com a fitase (1.500 FTU/kg), em dietas isoprotéicas (27% de PB) e isoenergéticas (3400 kcal/ED/kg de ração) para o jundiá (Rhamdia quelen). Métodos: Os peixes, 360 juvenis (15,77 ± 0,56 g) foram distribuídos aleatoriamente em 24 unidades experimentais, num delineamento inteiramente casualizado, em esquema fatorial (3x2) e 4 repetições. Após 90 dias foram avaliados: desempenho produtivo, variáveis hematológicas, histologia de tecido intestinal, composição bromatológica da carcaça e de matéria mineral dos ossos. Resultados: O emprego de 20% de farelo de girassol melhorou o ganho de peso dos peixes e a taxa de eficiência protéica da ração, sem diferença nas outras avaliações, ou para a interação entre os demais fatores avaliados. Conclusão: Pode-se concluir que o farelo de girassol pode ser utilizado em 20% da ração do jundiá, como sucedâneo ao farelo de soja e, que a inclusão de fitase (1,500 FTU/kg) não melhorou o valor nutritivo destas rações.

Palatability of Protein Hydrolysates from Industrial Byproducts for Nile Tilapia Juveniles.

This study was performed with the aim of determining the palatability of diets containing poultry and swine protein hydrolysates for Nile tilapia. Five experimental diets were made with a 5% inclusion level of fishmeal (FPE), poultry protein hydrolysate (PHF), liquid swine hydrolysate (PHS), feather protein hydrolysate (PHP), and swine mucosa hydrolysate (PHM). Five juveniles (2.81 ± 0.17 g) were placed in 10 L aquariums and fed five times a day after a raffle of offered diets. In each feeding throughout the day, 30 pellets were offered per fish. The experimental design was completely randomized, with five replicates per day. A three-minute footage period was established for each feeding with a digital camera. The following feeding behaviors were observed: time to capture the first pellet, number of pellet rejections, number of approaches without capturing the pellet, and number of consumed pellets. No observed parameters presented significant differences (p > 0.05). PHF provided a palatability index of 12.27%, while PHM had an index of 9.33%, PHF of 8.77%, and PHP of 7.74%. Both diets PHS and PHM increased the final consumption of pellets in comparison to FPE by more than 10%, despite the absence of a significant effect.

Glúten de trigo em dietas para tilápia do Nilo: digestibilidade e desempenho produtivo de larvas / Wheat gluten in the diet of Nile tilapia: digestibility and larvae growth performance

O objetivo do presente trabalho foi avaliar o potencial de utilização do glúten de trigo em dietas para tilápia-do-nilo (Orechromis niloticus), através de estudos de digestibilidade e desempenho produtivo de larvas. Para o estudo de digestibilidade foi elaborada uma dieta referência e uma dieta teste, contendo glúten de trigo. Utilizou-se o óxido de crômio III como marcador inerte. As fezes coletadas foram destinadas à análise de composição química, assim como as rações e o ingrediente teste. Além disso, foi realizada análise de leitura de óxido de crômio das fezes e das dietas. Os resultados obtidos por meio dessas análises foram utilizados para calcular os coeficientes de digestibilidade. Com base nesses coeficientes foram elaboradas as dietas experimentais dos estudos de dose-resposta para larvas. Foram formuladas cinco dietas experimentais com diferentes níveis de inclusão de glúten de trigo, sendo de 0%; 2,5%; 5,0%, 7,5% e 10%. Ao final do experimento foram avaliados o desempenho produtivo dos animais. Os dados de desempenho foram submetidos à análise de regressão linear a 5% de probabilidade. O glúten de trigo apresenta elevados coeficientes de digestibilidade para matéria seca, proteína bruta e energia bruta, sendo de 94,02; 98,18 e 96,90%, respectivamente. A análise de regressão demonstrou um efeito linear negativo quanto ao comprimento final e sobrevivência das larvas conforme aumentou-se o nível desse alimento. Dessa forma, conclui-se que o glúten de trigo é um ingrediente potencial para ser utilizado em dietas para tilápia-do-nilo, não sendo recomendada sua inclusão na fase larval.

The objective of this study was to evaluate the utilization potential of wheat gluten in diets for Nile tilapia (Oreochromis niloticus) through studies of digestibility and productive performance of larvae. For the digestibility study was elaborated a reference diet and a test diet containing wheat gluten. Chromium oxide-III was used as an inert marker. The collected faeces were destined to analysis of chemists compounds as the feed, and the test ingredient. Besides, reading chromium oxide analysis was performed in the faeces and diets. The results obtained through these analyses were used to calculate the digestibility coefficients. Based on these coefficients, experimental diets were elaborated for the dose-response studies in larvae. For the experiment, five experimental diets were formulated with different inclusion levels of wheat gluten, with 0%; 2,5%; 5,0%, 7,5% and 10%. At the end of the experiment, the productive performance was evaluated. The performance data were submitted to linear regression with 5% of probability. The wheat gluten presents high digestibility coefficients for dry matter, crude protein and gross energy with 94,02; 98.18 and 96.90%, respectively. The regression analyses showed a negative linear effect on the final length and survival of the larvae when the level of this food was increased. Thus, it is concluded that wheat gluten is a potential ingredient to be utilized in diets for Nile tilapia, not being recommended its inclusion in the larvae period.

Desempenho de alevinos de tilápia do Nilo alimentados com dietas contendo diferentes fontes de óleos vegetais

No experimento objetivou-se avaliar o desempenho produtivo e a composição bromatológica de alevinos de tilápias-do-nilo, alimentados com dietas contendo diferentes fontes lipídicas vegetais. Foram utilizadas 320 tilápias com peso e comprimento total médio de 2,55±0,57 g e 5,59±0,43 cm, respectivamente, por um período de 60 dias, em um delineamento em blocos casualizados com oito tratamentos e quatro repetições. Os tratamentos consistiram no fornecimento de dietas enriquecidas com oito diferentes tipos de óleos vegetais: girassol, canola, gergelim, linhaça, amendoim, castanha-do-pará, soja e macadâmia com inclusão de 4% na ração. O arraçoamento foi realizado quatro vezes ao dia, até a saciedade aparente. Os parâmetros zootécnicos avaliados foram ganho de peso, conversão alimentar aparente, consumo de ração e sobrevivência. Não foram observadas diferenças significativas (P>0,05) entre as variáveis de desempenho produtivo. Foram observadas distinções (P

Farinha de vísceras de aves na alimentação de alevinos de lambari / Poultry by-product meal in lambari fingerlings diet

O lambari, Astyanax altiparanae, é uma espécie muito comum em rios nacionais, com grande potencial para a piscicultura nacional. Ele apresenta crescimento rápido e carne de excelente sabor, sendo muito apreciado com petisco e como isca viva para a pesca esportiva. A farinha de vísceras de aves é uma importante fonte protéica de origem animal. O trabalho foi realizado com o objetivo de avaliar a inclusão de farinha de vísceras de aves (FV) em rações para alevinos de lambari. Foram utilizados 125 alevinos, apresentando peso e comprimento inicial médio de 0,080±0,002g e 1,86±0,20cm, respectivamente, distribuídos em 25 aquários. As rações foram formuladas de forma a conter 0, 5, 10, 15 e 20 por cento de FV na dieta. O arraçoamento foi realizado quatro vezes ao dia, na forma farelada e à vontade. O valores médios de peso final (1,47, 1,92, 2,02, 2,11 e 2,15g) e comprimento final (4,40, 4,78, 4,92, 4,92 e 5,08cm) dos alevinos de lambari apresentaram aumento linear (P<0,05) diretamente proporcional aos níveis de inclusão (0, 5, 10, 15 e 20 por cento de FV) nas rações. A sobrevivência (88, 96, 92, 76 e 88 por cento) e a conversão alimentar aparente (4,58, 3,29, 3,25, 3,92 e 3,34) não apresentaram diferença (P<0,05) entre os níveis de FV na dieta. A inclusão de farinha de vísceras de aves em rações à base de ingredientes de origem vegetal melhora o desempenho e o teor protéico da carcaça.

The lambari Astyanax altiparanae, is a very common species in the national rivers, with great potential for the national psyculture. It presents a fast growth and meat of eccellent flavor, being very appreciate like a delicacy and like an alive bait to sportive fishing. The poultry by-product meal is an important proteinic source from animal origin. The research was carried out with the objective to evaluate the poultry by-product meal inclusion (FV) in rations for lambari fingerlings. 125 fingerlings presenting average weight and initial length of 0.080±0.002g and 1.86±0.20cm respectively were used, they were distributed in 25 aquariums. The rations were formulated in form to contain 0, 5, 10 15 and 20 percent of FV in the diet. The ration giving was carried through four times a day, in a braning form and at the will. The avarage values of final weight (1.47, 19.2, 2.02, 2.11 and 2.15) and final length of (4.40, 4.78, 4.92 and 5.08cm) of the lambari fingerlings had presented linear increase (P<0.05) directly proportional to the inclusion levels of (0, 5, 10, 15 and 20 percent of FV) in the rations. The survival (88, 96, 92, 76 and 88 percent) and apparent alimentary conversion (4.58, 3.29, 3.25, 3.92 and 3.34) had not presented difference (P<0.05) among the (FV) levels in the diet. The inclusion of poultry by-product meal in rations based in ingredients of vegetable origin provides the performance and the proteic text of the carcass.

Characterization of NTPDase (NTPDase1; ecto-apyrase; ecto-diphosphohydrolase; CD39; EC 3.6.1.5) activity in human lymphocytes.

Human lymphocytes contain NTPDase (NTPDase-1; ecto-apyrase; ecto-diphosphohydrolase; CD39; EC 3.6.1.5), a cation-dependent enzyme that hydrolyzes ATP and ADP and also other di- and triphosphate nucleosides, acting at an optimum pH of 8.0. A significant inhibition of ATP and ADP hydrolysis (P<0.05) was observed in the presence of 20 mM sodium azide. NTPDase inhibitors, 20 mM sodium fluoride, 0.2 mM trifluoperazine and 0.3 mM suramin, significantly decreased ATP and ADP hydrolysis (P<0.05) and ADP hydrolysis was only inhibited by 0.5 mM orthovanadate (P<0.05). ATP and ADP hydrolysis was not inhibited in the presence of 0.01 mM Ap5A (P1,P5-di(adenosine-5')pentaphosphate), 0.1 mM ouabain, 1 mM levamisole, 2 microg/mL oligomycin, 0.1 mM N-ethylmaleimide (NEM), or 5 mM sodium azide. With respect to kinetic behavior, apparent K(m) values of 77.6+/-10.2 and 106.8+/-21.0 microM, and V(max) values of 68.9+/-8.1 and 99.4+/-8.5 (mean+/-S.E., n=3) nmol Pi/min/mg protein were obtained for ATP and ADP, respectively. A Chevilard plot demonstrated that only one enzymatic site is responsible for the hydrolysis of ATP and ADP. The presence of CD39 was determined by flow cytometry, showing a low density of 2.72+/-0.24% (mean+/-S.E.; n=30) in human peripheral lymphocytes. The study of NTPDase activity in human lymphocytes may be important to determine the immune response status against infectious agents related to ATP and ADP hydrolysis.