Use of antioxidants and time of cold storage: effects over viability parameters and enzymatic levels in semen of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) / Uso de antioxidantes e tempo de armazenamento a frio: efeitos sobre parâmetros de viabilidade e níveis enzimáticos no sêmen da truta arco-íris (Oncorhynchus mykiss, Walbaum, 1792)

Abstract The cold storage of milt implies potentials alterations in its quality because the storage generates as main process, free radicals that produce spermatozoa membrane lipids damage with the consequent motility and fertilising capacity disruptions. To decrease the damage generated by free radicals the cells have antioxidant defences (proteins, enzymes, and low molecular weight substances). The objective of the present study evaluated the time storage effect and different antioxidants prepared in spermatic diluents on sperm viability of O. mykiss milt stored at 4°C. The two-way ANOVA denoted that the time storage and antioxidant influence have significant effects separated or combined on viability parameters (sperm motility and viability, proteins concentrations and superoxide dismutase enzymatic activity in seminal plasma). In contrast, only the storage time affected the fertilising capacity and catalase enzymatic activity in seminal plasma. The resulting analysis can conclude that the antioxidant presence improves the viability of cold stored milt, especially the transport conditions and the antioxidants allow the fecundity despite motility decrease.

Resumo O armazenamento a frio de leite implica potenciais alterações em sua qualidade, pois gera como processo principal radicais livres que provocam danos aos lipídios da membrana dos espermatozoides, com as consequentes alterações na motilidade e na capacidade de fertilização. Para diminuir os danos causados pelos radicais livres, as células têm defesas antioxidantes (proteínas, enzimas e substâncias de baixo peso molecular). O presente estudo avaliou o efeito do tempo de armazenamento e diferentes antioxidantes preparados em diluentes espermáticos no armazenamento de viabilidade de O. mykiss milt a 4°C. A ANOVA de duas vias denotou que o armazenamento no tempo e a influência antioxidante têm efeitos significativos separados ou combinados nos parâmetros de viabilidade (motilidade espermática, viabilidade espermática, concentrações de proteínas e atividade enzimática da superóxido dismutase no plasma seminal), enquanto apenas o tempo de armazenamento afetou a capacidade de fertilização e atividade enzimática da catalase no plasma seminal. A análise resultante pode concluir que a presença de antioxidante melhora a viabilidade do leite frio, especialmente as condições de transporte, e os antioxidantes permitem a fecundidade apesar da diminuição da motilidade.

Use of antioxidants and time of cold storage: effects over viability parameters and enzymatic levels in semen of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) / Uso de antioxidantes e tempo de armazenamento a frio: efeitos sobre parâmetros de viabilidade e níveis enzimáticos no sêmen da truta arco-íris (Oncorhynchus mykiss, Walbaum, 1792)

The cold storage of milt implies potentials alterations in its quality because the storage generates as main process, free radicals that produce spermatozoa membrane lipids damage with the consequent motility and fertilising capacity disruptions. To decrease the damage generated by free radicals the cells have antioxidant defences (proteins, enzymes, and low molecular weight substances). The objective of the present study evaluated the time storage effect and different antioxidants prepared in spermatic diluents on sperm viability of O. mykiss milt stored at 4°C. The two-way ANOVA denoted that the time storage and antioxidant influence have significant effects separated or combined on viability parameters (sperm motility and viability, proteins concentrations and superoxide dismutase enzymatic activity in seminal plasma). In contrast, only the storage time affected the fertilising capacity and catalase enzymatic activity in seminal plasma. The resulting analysis can conclude that the antioxidant presence improves the viability of cold stored milt, especially the transport conditions and the antioxidants allow the fecundity despite motility decrease.

O armazenamento a frio de leite implica potenciais alterações em sua qualidade, pois gera como processo principal radicais livres que provocam danos aos lipídios da membrana dos espermatozoides, com as consequentes alterações na motilidade e na capacidade de fertilização. Para diminuir os danos causados pelos radicais livres, as células têm defesas antioxidantes (proteínas, enzimas e substâncias de baixo peso molecular). O presente estudo avaliou o efeito do tempo de armazenamento e diferentes antioxidantes preparados em diluentes espermáticos no armazenamento de viabilidade de O. mykiss milt a 4°C. A ANOVA de duas vias denotou que o armazenamento no tempo e a influência antioxidante têm efeitos significativos separados ou combinados nos parâmetros de viabilidade (motilidade espermática, viabilidade espermática, concentrações de proteínas e atividade enzimática da superóxido dismutase no plasma seminal), enquanto apenas o tempo de armazenamento afetou a capacidade de fertilização e atividade enzimática da catalase no plasma seminal. A análise resultante pode concluir que a presença de antioxidante melhora a viabilidade do leite frio, especialmente as condições de transporte, e os antioxidantes permitem a fecundidade apesar da diminuição da motilidade.

Use of antioxidants and time of cold storage: effects over viability parameters and enzymatic levels in semen of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) / Uso de antioxidantes e tempo de armazenamento a frio: efeitos sobre parâmetros de viabilidade e níveis enzimáticos no sêmen da truta arco-íris (Oncorhynchus mykiss, Walbaum, 1792)

The cold storage of milt implies potentials alterations in its quality because the storage generates as main process, free radicals that produce spermatozoa membrane lipids damage with the consequent motility and fertilising capacity disruptions. To decrease the damage generated by free radicals the cells have antioxidant defences (proteins, enzymes, and low molecular weight substances). The objective of the present study evaluated the time storage effect and different antioxidants prepared in spermatic diluents on sperm viability of O. mykiss milt stored at 4°C. The two-way ANOVA denoted that the time storage and antioxidant influence have significant effects separated or combined on viability parameters (sperm motility and viability, proteins concentrations and superoxide dismutase enzymatic activity in seminal plasma). In contrast, only the storage time affected the fertilising capacity and catalase enzymatic activity in seminal plasma. The resulting analysis can conclude that the antioxidant presence improves the viability of cold stored milt, especially the transport conditions and the antioxidants allow the fecundity despite motility decrease.(AU)

O armazenamento a frio de leite implica potenciais alterações em sua qualidade, pois gera como processo principal radicais livres que provocam danos aos lipídios da membrana dos espermatozoides, com as consequentes alterações na motilidade e na capacidade de fertilização. Para diminuir os danos causados pelos radicais livres, as células têm defesas antioxidantes (proteínas, enzimas e substâncias de baixo peso molecular). O presente estudo avaliou o efeito do tempo de armazenamento e diferentes antioxidantes preparados em diluentes espermáticos no armazenamento de viabilidade de O. mykiss milt a 4°C. A ANOVA de duas vias denotou que o armazenamento no tempo e a influência antioxidante têm efeitos significativos separados ou combinados nos parâmetros de viabilidade (motilidade espermática, viabilidade espermática, concentrações de proteínas e atividade enzimática da superóxido dismutase no plasma seminal), enquanto apenas o tempo de armazenamento afetou a capacidade de fertilização e atividade enzimática da catalase no plasma seminal. A análise resultante pode concluir que a presença de antioxidante melhora a viabilidade do leite frio, especialmente as condições de transporte, e os antioxidantes permitem a fecundidade apesar da diminuição da motilidade.(AU)

Fish products developed from ground rainbow trout and tilapia fillet mixtures: physico-chemical, microbiological and toxicological analyses / Produtos de pescado elaborados a partir de misturas de carne moída de truta-arco-íris (Oncorhynchus mykiss) e tilápia (Oreochromis sp. ): análises físico-químicas, microbiológicas e toxicológicas

Constant fishing industry innovations in response to consumer demands for novel, balanced healthy products exhibiting high nutritional value, as well as easy to prepare and ready to consume, have led to the emergence of new technologies. Among them, the development of products based on ground beef and fish mixtures are noteworthy. In this context, the purpose of this study was to develop products from different ground rainbow trout and tilapia fillet ratios, in the form of meatballs and nuggets, determining their proximate composition and physico-chemical, microbiological and toxicological characteristics. The average dry matter percentage of the developed products was 29.20±2.30%, while mineral content was 1.45±0.55%, lipid pulp content, 3.70±0.30% and crude pulp protein, 16.60±2.04%. Total psychotropic counts remained below 102 CFU/g, for standard counting on aerobic microorganism plates. Histamine and sulfur-based compounds were not detected in any of the prepared samples. The purpose of the work proposal was to develop foods and technologies that can serve as standards, allowing for simple handling products that apply ground meat mixtures from different fish species to maintain adequate nutritional indices after processing.(AU)

A constante inovação da indústria pesqueira, em resposta às demandas dos consumidores por novos produtos saudáveis, com alto valor nutritivo, balanceados, de fácil preparo e prontos para consumo, levou ao surgimento de novas tecnologias, entre elas o desenvolvimento de produtos à base de mistura de carne moída de pescado. Nesse contexto, a proposta deste trabalho é desenvolver produtos a partir de carne moída de pescado de truta-arco-íris e tilápia, confeccionando almôndegas e nuggets em diferentes proporções, com determinação da composição centesimal e de suas características físico-químicas, microbiológicas e toxicológicas. A matéria seca percentual média foi de 29,20±2,30%. Teores de matéria mineral nos produtos estão em 1,45±0,55%. Os teores de lipídeos aferidos na polpa foram de 3,70±0,30%, e os níveis de proteína bruta apresentados na polpa de 16,60±2,04%. A contagem de psicrotróficos totais manteve-se abaixo de 102 CFU/g, para contagem padrão em placas de micro-organismos aeróbicos. Nas amostras, não foram detectados níveis de histamina e de compostos à base de enxofre. A proposta de trabalho objetivou, por fim, desenvolver alimentos e tecnologias que possam servir como padrões, permitindo que produtos de manipulação simples e que utilizem misturas de carne moída de diferentes espécies de pescado mantenham índices nutricionais adequados após o processamento.(AU)

Ploidy influences on metabolic substrate deposition of rainbow trout

Triploid fish are usually sterile. Thus, the energy and nutrients intended for sexual maturation may be available to enhance flesh quality and physical growth. The present study aimed to investigate differences in the metabolic substrates, lipids and proteins, between storage tissues from diploid and triploid female rainbow trout. Monthly, metabolic substrates were quantified in liver, muscle, and ovaries, which were collected during the first reproductive cycle. In general, it was possible to identify a seasonal and similar deposition of metabolites in different tissues of 2n and 3n females, mainly at early stages of gonadal maturation. However, from the stages 5-6, the ovaries showed great differences between ploidies, with higher concentration of lipids and protein in 2n females. This result reflects the incorporation of vitellogenin in oocytes, which is a process that does not occur in 3n females. It was possible to observe seasonal hepato-somatic index changes in 2n females, with higher values observed in the post-ovulatory stage, and the triploid animals showed lower values compared to 2n, with no seasonal difference. Viscero-somatic index can reflect the mobilization of substrates, with higher values found for 2n females in stage 5-6, which is the period of active mobilization of tissue substrates.(AU)

Ploidy influences on metabolic substrate deposition of rainbow trout

Triploid fish are usually sterile. Thus, the energy and nutrients intended for sexual maturation may be available to enhance flesh quality and physical growth. The present study aimed to investigate differences in the metabolic substrates, lipids and proteins, between storage tissues from diploid and triploid female rainbow trout. Monthly, metabolic substrates were quantified in liver, muscle, and ovaries, which were collected during the first reproductive cycle. In general, it was possible to identify a seasonal and similar deposition of metabolites in different tissues of 2n and 3n females, mainly at early stages of gonadal maturation. However, from the stages 5-6, the ovaries showed great differences between ploidies, with higher concentration of lipids and protein in 2n females. This result reflects the incorporation of vitellogenin in oocytes, which is a process that does not occur in 3n females. It was possible to observe seasonal hepato-somatic index changes in 2n females, with higher values observed in the post-ovulatory stage, and the triploid animals showed lower values compared to 2n, with no seasonal difference. Viscero-somatic index can reflect the mobilization of substrates, with higher values found for 2n females in stage 5-6, which is the period of active mobilization of tissue substrates.

Modeling the weight gain of freshwater-reared rainbow trout ( Oncorhynchus mykiss ) during the grow-out phase

We used five nonlinear models to calculate the weight gain of rainbow trout (122.11±15.6 g) during the final grow-out phase of 98 days under three different feed types (two commercials diets, A and B, and one experimental diet, C) in triplicate groups. We fitted the von Bertalanffy growth function with allometric and isometric scaling coefficient, Gompertz, Logistic, and Brody functions to weight (g) at age data of 900 fish, distributed in nine tanks. The equations were fitted to the data based on the least squares method using the Marquardt iterative algorithm. The accuracy of the fitted models was evaluated using a model performance metrics, combining mean squared residuals (MSR), mean absolute error (MAE), and Akaike's Information Criterion corrected for small sample sizes (AICc). All models converged in all cases tested. The evaluation criteria for the Logistic model indicated the best overall fit (0.704) under all different feed types, followed by the Gompertz model (0.148), and the von Bertalanffy-I and von Bertalanffy-A with 0.074 each. The obtained asymptotic values are in agreement with the biological attributes of the species, except for the Brody model, whose values were massively exceeding the biologic traits of rainbow trout in 0.556 of tested cases. Additionally, ∆AICc results identify the Brody model as the only model not substantially supported by the data in any case. All other models are capable of reflecting the effects of various feed types; these results are directly applicable in farm management decisions.(AU)

Parasitos em trutas-arco-íris (Oncorhynchus mykiss) criadas em sistema intensivo na região serrana de Santa Catarina, Brasil / [Parasites in rainbow trout (Oncorhynchus mykiss) raised in an intensive system in the mountain region of Santa Catarina, Brazil]

With the aim to determine the prevalence and mean parasite intensity in Oncorhynchus mykiss, 120 specimens were analyzed between April and September 2018. The cavity analysis was done by visual inspection, scraping of mucus, and extraction of the branchial arches. In the evisceration process, the intestine, the liver, and the kidney were separated, while the musculature was analyzed using the "candling table" method. All the collected material was preserved in 10% buffered formaldehyde and sent to the Laboratory of Parasitology and Parasitic Diseases, of the Center for Agroveterinary Sciences (CAV) of the University of the State of Santa Catarina (UDESC) for making the slides and identifying the parasites. Parasites were detected only in the analysis of the scraping of body mucus. Only specimens of the genus Trichodina were identified, in 34 of the 120 fish analyzed, in two collections, resulting in a prevalence of 28.33%. In total, 144 specimens of Trichodina were observed. The overall mean intensity was of 4.24 parasites in each fish analyzed. Characteristic lesions of infection by protozoa were not identified. This is the first report of the occurrence of Trichodina spp. in O. mykiss bred in an intensive system in Brazil, with low rates of parasitic infection in the mountain region of Santa Catarina.(AU)

Nonlinear regression analysis of length growth in cultured rainbow trout / [Análise não linear do crescimento em comprimento de truta-arco-íris de aquicultura ]

Length growth as a function of time has a non-linear relationship, so nonlinear equations are recommended to represent this kind of curve. We used six nonlinear models to calculate the length gain of rainbow trout (Oncorhynchus mykiss) during the final grow-out phase of 98 days under three different feed types in triplicate groups. We fitted the von Bertalanffy, Gompertz, Logistic, Brody, Power Function, and Exponential equations to individual length-at-age data of 900 fish. Equations were fitted to the data based on the least square method using the Marquardt iterative algorithm. Accuracy of the fitted models was evaluated using a model performance metrics combining mean squared residuals (MSR), mean absolute error (MAE) and Akaike's Information Criterion corrected for small sample sizes (AICc). All models converged in all cases tested. Evaluation criteria for the Logistic model indicated the best overall fit (0.67 of combined metric MSR, MAE and AICc) under all different feeding types, followed by the Exponential model (0.185), and the von Bertalanffy and Brody model (0.074, respectively). Additionally, ∆AICc results identify the Logistic and Gompertz models as being substantially supported by the data in 100% of cases. The logistic model can be suggested for length growth prediction in aquaculture of rainbow trout.(AU)

O crescimento em comprimento em função do tempo tem uma relação não linear; por isso, funções não lineares são recomendáveis para descrever essa relação. Seis modelos não lineares foram usados para calcular o ganho em comprimento de truta-arco-íris (Oncorhynchus mykiss) durante 98 dias, na fase final da engorda, submetidas a três dietas diferentes em grupos triplicados. Foram ajustadas as equações de von Bertalanffy, Gompertz, logístico, Brody, função potencial e exponencial a dados individuais de comprimento-idade de 900 peixes. O ajuste foi feito pelo método dos mínimos quadrados, usando-se o algoritmo iterativo de Marquardt. A precisão do ajuste foi avaliada pelo uso de critérios combinados de ajuste: quadrado médio do resíduo (QMR), erro médio absoluto (EMA) e o critério de informação de Akaike corrigido para tamanhos amostrais pequenos (AICc). Todos os modelos atingiram a convergência para cada caso avaliado. Os critérios de avaliação do modelo logístico indicaram o melhor ajuste geral (0,67 vez dos critérios combinados MSR, MAE e AICc) para cada grupo de peixe avaliado, seguido pelo modelo exponencial (0,185) e os modelos von Bertalanffy e Brody, com 0,074, respectivamente. Similarmente, os resultados de ΔAICc identificaram-se ao modelo logístico e ao de Gompertz, com grande suporte das informações em 100% dos casos. Por fim, o modelo logístico pode ser sugerido na predição do crescimento em comprimento de truta-arco-íris cultivada.(AU)

Weissellosis in rainbow trout in Colombia

Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.(AU)

Weissellosis in rainbow trout in Colombia

Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.

Avaliação da viabilidade de microrganismos probióticos incorporados em ração de truta-arco-íris (Oncorhynchus mykiss) / [Evaluation of the viability of probiotic microorganisms impregnated into rainbow trout (Oncorhynchus mykiss) ration]

A produção aquícola mundial tem demandado estudos que buscam soluções para os problemas produtivos e sanitários apresentados na piscicultura. Nesse contexto, o uso de produtos probióticos demonstra ser uma abordagem promissora. Dessa forma, o presente trabalho teve como objetivo avaliar a viabilidade de um pool de cepas de Lactobacillus incorporados à ração de truta-arco-íris. Para tanto, as respectivas cepas foram previamente cultivadas em caldo MRS e submetidas à criocentrifugação. As células obtidas foram ressuspensas em soro fisiológico acrescentado de 2% de óleo de soja, sendo posteriormente incorporadas à ração por meio de misturador circular. Essa ração foi devidamente armazenada sob refrigeração a 4°C, por 120 dias, sendo retiradas aleatoriamente três amostras, a cada 15 dias, para avaliação da viabilidade das bactérias, por meio da contagem em placas. Os resultados demonstraram que houve uma redução não significativa (P>0,05) na população de células viáveis, correspondente a 2%, após 30 dias de armazenamento. Verificou-se também, após esse período, uma população aproximada equivalente a 3,00 x 108 UFC/g. Dessa forma, demonstrou-se a possibilidade de desenvolvimento de formulações probióticas por meio da incorporação de cepas específicas em rações de trutas, o que poderá contribuir para o desenvolvimento de tecnologias alternativas para produção de peixes.(AU)

Among the exotic species of fish produced in Brazil, the rainbow trout (Oncorhynchus mykiss) has been highlighted during the past few years. The expansion of this sector has been intensifying the need for further studies in order to decrease production and health problems presented in aquaculture, as well as to develop alternative technics to controversial antimicrobial treatments. In this context, the use of probiotics has been shown to be a promising approach to the improvement in trout husbandry. Thus, the present study aimed to contribute to the development of an alternative technology in the rainbow trout husbandry by evaluating the effect of probiotic preparations on the performance of the animals subjected to conventional husbandry conditions or chronic stress. Therefore, in this paper we report the results regarding the evaluation of the viability of a pool of 4 Lactobacillus probiotic strains incorporated into rainbow trout ration using soybean oil as vehicle. The results have demonstrated a high efficacy of cell incorporation into the ration with high viability rate after storage for 120 days at 4°C.(AU)

Método do índice de qualidade (MIQ) aplicado em trutas arco-íris (Oncorhynchus mykiss) inteiras e resfriadas oriundas de pesque pague no Estado do Rio de Janeiro, Brasil / Quality index method (QIM) applied to rainbow trout (Oncorhynchus mykiss) whole and refrigerated from pesque pague in the State of Rio de Janeiro, Brazil

Na região serrana do estado do Rio de Janeiro são comuns a prática da truticultura e o consumo dessa espécie de peixe. A aceitação do pescado está estritamente relacionada às características de frescor do mesmo, que pode sofrer alterações devido a processos físico-químicos, microbiológicos e sensoriais de deterioração. Objetivou-se com esse trabalho avaliar o frescor de trutas arco-íris (Oncorhynchus mykiss) e, com isso, desenvolver um padrão específico através da adaptação do Método do Índice de Qualidade (MIQ) para essa espécie, ao longo de 11 dias de armazenamento sob refrigeração. A análise consistiu na avaliação de características determinantes para o frescor das trutas e o registro dos parâmetros foi realizado por meio de um sistema de pontuação de demérito, tendo em vista que quanto menor a pontuação, mais fresco o peixe. Foi concluído que, aos 11 dias, a truta inteira não apresentava aspectos de repugnância ou rejeição de acordo com os parâmetros preconizados pelo RIISPOA.(AU)

Método do índice de qualidade (MIQ) aplicado em trutas arco-íris (Oncorhynchus mykiss) inteiras e resfriadas oriundas de pesque pague no Estado do Rio de Janeiro, Brasil / Quality index method (QIM) applied to rainbow trout (Oncorhynchus mykiss) whole and refrigerated from pesque pague in the State of Rio de Janeiro, Brazil

Na região serrana do estado do Rio de Janeiro são comuns a prática da truticultura e o consumo dessa espécie de peixe. A aceitação do pescado está estritamente relacionada às características de frescor do mesmo, que pode sofrer alterações devido a processos físico-químicos, microbiológicos e sensoriais de deterioração. Objetivou-se com esse trabalho avaliar o frescor de trutas arco-íris (Oncorhynchus mykiss) e, com isso, desenvolver um padrão específico através da adaptação do Método do Índice de Qualidade (MIQ) para essa espécie, ao longo de 11 dias de armazenamento sob refrigeração. A análise consistiu na avaliação de características determinantes para o frescor das trutas e o registro dos parâmetros foi realizado por meio de um sistema de pontuação de demérito, tendo em vista que quanto menor a pontuação, mais fresco o peixe. Foi concluído que, aos 11 dias, a truta inteira não apresentava aspectos de repugnância ou rejeição de acordo com os parâmetros preconizados pelo RIISPOA.

Parâmetros físico químicos de qualidade em trutas arco-íris (Oncorhynchus mykiss) inteiras e resfriadas: uma discussão fundamentada dos valores oficiais / Quality chemical physical parameters in rainbow trout (Oncorhynchus mykiss) whole and refrigerated: a based discussion of official values

Parâmetros de qualidade de peixes marinhos e dulcícolas tem sido foco de muitas polêmicas, e até alvo de problemas jurídicos em empresas de beneficiamento. Objetivou-se avaliar as alterações físico-químicas de trutas arco-íris por meio de análises de pH, NH3 e BVT, por um período de 10 dias em refrigeração. Foram examinadas 10 trutas inteiras, capturadas em um pesque pague da região serrana do Rio de Janeiro. Após captura, os animais foram eutanasiados e acondicionados em recipiente isotérmico com gelo. Foi avaliado o pH em quatro diferentes porções musculares, analisado também as BVT e NH3. Não foram observadas diferenças significativas dos resultados de pH entre as porções avaliadas, com exceção da ventral. Conclui-se que em 10 dias de armazenamento de trutas inteiras e refrigeradas os parâmetros físico químicos são satisfatórios.(AU)

Parâmetros físico químicos de qualidade em trutas arco-íris (Oncorhynchus mykiss) inteiras e resfriadas: uma discussão fundamentada dos valores oficiais / Quality chemical physical parameters in rainbow trout (Oncorhynchus mykiss) whole and refrigerated: a based discussion of official values

Parâmetros de qualidade de peixes marinhos e dulcícolas tem sido foco de muitas polêmicas, e até alvo de problemas jurídicos em empresas de beneficiamento. Objetivou-se avaliar as alterações físico-químicas de trutas arco-íris por meio de análises de pH, NH3 e BVT, por um período de 10 dias em refrigeração. Foram examinadas 10 trutas inteiras, capturadas em um pesque pague da região serrana do Rio de Janeiro. Após captura, os animais foram eutanasiados e acondicionados em recipiente isotérmico com gelo. Foi avaliado o pH em quatro diferentes porções musculares, analisado também as BVT e NH3. Não foram observadas diferenças significativas dos resultados de pH entre as porções avaliadas, com exceção da ventral. Conclui-se que em 10 dias de armazenamento de trutas inteiras e refrigeradas os parâmetros físico químicos são satisfatórios.

Body composition and sensory quality of wild and farmed brown-trout (Salmo trutta) and of farmed rainbow-trout (Oncorhynchus mykiss) / Composição corporal e qualidade sensorial de truta-fário selvagem e cultivada (Salmo trutta) e de truta-arco-íris cultivada (Oncorhynchus mykiss)

Body composition (total crude protein, lipid, ash, dry matter and moisture) and fatty acid profiles were compared between wild and farmed brown trout and between farmed rainbow trout. Farmed brown trout contained the highest amount of crude protein (18.39%), whereas farmed rainbow trout contained higher levels of crude lipid (2.35%). Thirty six fatty acids were found, including sixteen saturated fatty acids (SFA), nine monounsaturated fatty acids (MUFA) and eleven polyunsaturated fatty acids (PUFA). The most abundant SFA in all fish were palmitic acid and stearic acid. However, the most abundant fatty acids in all trout samples were MUFA and PUFA. MUFA were the most abundant fatty acid in farmed brown trout because of high abundance of oleic acid in this samples (35.46g / 100g fatty acids). PUFA were predominating in the samples of wild brown trout and of rainbow trout 56.16 and 56.29g/100g fatty acids, respectively). Linoleic acid was the most abundant fatty acid reported in the rainbow trout (47.17g/100g fatty acids). Significantly higher amounts of docosahexaenoic acid, α-linolenic acid, arachidonic acid and eicosapentaenoic acid were observed in the wild trout samples. Wild brown trout contained significantly more docosahexaenoic acid, α-linolenic acid, Eicosapentaenoic acidArachidonic acid. Sensory quality evaluation, by a consumers panel, revealed all samples were equally well accepted.(AU)

A composição corporal (teores de proteína, gordura total, cinzas, matéria seca e humidade) e os perfis de ácidos gordos da truta-fário (selvagem e proveniente de aquacultura) e da truta-arco-íris (cultivada) foram comparados. A truta-fário cultivada continha a maior quantidade de proteína bruta (18,39%), enquanto a truta arco-íris possuía teores mais elevados de lípidos (2,35%). Foram detectados 36 ácidos graxos, incluindo 16 ácidos graxos saturados (SFA), nove ácidos graxos monoinsaturados (MUFA) e 11 ácidos graxos poliinsaturados (PUFA). Os SFA mais abundantes foram o ácido palmítico e o ácido esteárico. No entanto, os ácidos graxos mais abundantes em todas as amostras de truta foram os MUFA e os PUFA. A grande abundância de ácido oleico existente nas amostras de truta-fário cultivada (35,46g/100g de ácidos graxos) faz com que os MUFA sejam os ácidos graxos mais abundantes nesta variedade de truta (42,43g/100g de ácidos graxos) Nas amostras de truta-fário selvagem e nas de truta arco-íris predominaram os PUFA (56,16 e 56,29g/100g de ácidos graxos, respetivamente), sendo o ácido linoleico o mais abundante na truta-arco-íris (47,17g/100g de ácidos graxos). Nas amostras truta-fário selvagem foram observadas quantidades significativamente mais elevadas de ácido docosahexaenóico, ácido α-linolênico, ácido acidoaraquidônico e ácido eicosapentaenóico. Todas as amostras foram igualmente bem aceitas por um painel de consumidores.(AU)

Environmental indicators in effluent assessment of rainbow trout (Oncorhynchus mykiss) reared in raceway system through phosphorus and nitrogen / Indicadores ambientais na avaliação de efluentes de truta arco-íris (Oncorhynchus mykiss) criados em sistema de raceway através do fósforo e nitrogênio

The phosphorus and nitrogen discharge via effluent of intensive trout farming system was quantified through the use of environmental indicators. The nutrient loads, the mass balance, the estimated amount of nutrients in feed and the amount of nutrients converted in fish biomass were calculated based on the concentrations of phosphorus (P) and nitrogen (N) in the feed and in the water. Of the offered feed, 24.75 kg were available as P and 99.00 kg as N, of these, 9.32 kg P (38%) and 29.12 kg N (25%) were converted into fish biomass and 15.43 kg P (62%) and 69.88 kg N (75%) were exported via effluent. The loads and the mass balance show the excessive discharge of nutrients via effluent, corroborated by the feed conversion ratio (2.12:1) due to the low efficiency of feed utilization, therefore, it is proposed the use of this zootechnical parameter as environmental indicator. In addition, feed management practices are not adequate, highlighting the low frequency of feeding during the day, excessive amount and low quality of feed offered. These results demonstrate the need for adequate feed management and the need for careful monitoring of effluent.(AU)

A descarga de fósforo e nitrogênio via efluente do sistema intensivo de truticultura foi quantificada através da utilização de indicadores ambientais. As cargas de nutrientes, o balanço de massa, a quantidade estimada de nutrientes na ração e a quantidade de nutrientes convertidos em biomassa de peixes foram calculados com base nas concentrações de fósforo (P) e nitrogênio (N) na ração e na água. Da ração oferecida, 24,75 kg estavam disponíveis como P e 99,00 kg como N, destes, 9,32 kg de P (38%) e 29,12 kg de N (25%) foram convertidos em biomassa de peixe e 15,43 kg P (62%) e 69,88 kg N (75%) foram exportados via efluente. As cargas e o balanço de massa mostram a descarga excessiva de nutrientes via efluente, corroborado pela taxa de conversão alimentar (2,12:1), devido à baixa eficiência na utilização da ração, portanto, propõe-se a utilização deste parâmetro zootécnico como indicador ambiental. Além disso, as práticas de manejo alimentar não são adequadas, destacando a baixa frequência de alimentação durante o dia, quantidade excessiva e baixa qualidade da alimentação ofertada. Esses resultados demonstram a necessidade de manejo alimentar adequado e de monitoramento do efluente.(AU)

Biochemical effects of encapsulated radiovaccine via alginate nanoparticles as useful strategy for booster in immunized rainbow trout against Ichthyophytirius multifiliis

Background: The Ichthyophthirius multifiliis is one of the most important protozoan pathogens of farmed and wild fish populations. The vaccination against I. multifiliis can be considered as an alternative to chemical treatments. There are three routes of vaccination; the injection, immersion and oral administration. Oral immunization would be a good candidate since handling fish is not required, it is a not stressful method and it needs less time and labor. In this study a nanoparticle system for protection of radiovaccine and efficient oral vaccine delivery to the intestinal tract against I. multifiliis was tested in rainbow trout.Materials, Methods & Results: Fifty rainbow trout (40 - 50 g) were infected with I. multifiliis via live trophont, trophont were collected with 200-mesh sieve. After collection, dose of gamma ray (170 Gray) was used for irradiation of parasite. Commercial Ergosan was suspended in sterile 0.15 M (pH 7.2) and sonicated. Remaining powder was irradiated by gamma irradiator. The alginate nanoparticle encapsulated radiovaccine was achieved by the addition of PBS (1 mL) to the alginate nanaoparticle solution (4 mL) plus radiovaccine (37˚C, pH 7.5). Fish were distributed equally into 5 groups (60 fish/aquarium). In this study, elevated levels of WBC was found in fish immunized with non-capsulated and encapsulated radiovaccine at 20 days after challenge (P < 0.05). No significant differences in haematocrit and RBC were found among all of groups (P < 0.05). Also, plasma total protein level was found to decrease in vaccinated fish with non-capsulated radiovaccine at 7 and 20 days after challenge. Significant decrease in glucose level was shown in immunized rainbow trout with encapsulated radiovaccine (P < 0.05). A significant increase in plasma glucose level was shown in rainbow trout challenged with live trophonts at 7 days after challenge (P < 0.05).[...](AU)

Biochemical effects of encapsulated radiovaccine via alginate nanoparticles as useful strategy for booster in immunized rainbow trout against Ichthyophytirius multifiliis

Background: The Ichthyophthirius multifiliis is one of the most important protozoan pathogens of farmed and wild fish populations. The vaccination against I. multifiliis can be considered as an alternative to chemical treatments. There are three routes of vaccination; the injection, immersion and oral administration. Oral immunization would be a good candidate since handling fish is not required, it is a not stressful method and it needs less time and labor. In this study a nanoparticle system for protection of radiovaccine and efficient oral vaccine delivery to the intestinal tract against I. multifiliis was tested in rainbow trout.Materials, Methods & Results: Fifty rainbow trout (40 - 50 g) were infected with I. multifiliis via live trophont, trophont were collected with 200-mesh sieve. After collection, dose of gamma ray (170 Gray) was used for irradiation of parasite. Commercial Ergosan was suspended in sterile 0.15 M (pH 7.2) and sonicated. Remaining powder was irradiated by gamma irradiator. The alginate nanoparticle encapsulated radiovaccine was achieved by the addition of PBS (1 mL) to the alginate nanaoparticle solution (4 mL) plus radiovaccine (37˚C, pH 7.5). Fish were distributed equally into 5 groups (60 fish/aquarium). In this study, elevated levels of WBC was found in fish immunized with non-capsulated and encapsulated radiovaccine at 20 days after challenge (P < 0.05). No significant differences in haematocrit and RBC were found among all of groups (P < 0.05). Also, plasma total protein level was found to decrease in vaccinated fish with non-capsulated radiovaccine at 7 and 20 days after challenge. Significant decrease in glucose level was shown in immunized rainbow trout with encapsulated radiovaccine (P < 0.05). A significant increase in plasma glucose level was shown in rainbow trout challenged with live trophonts at 7 days after challenge (P < 0.05).[...]