The study was carried out with the objective of evaluating the influence of pre-slaughter stress on meat quality of Nile tilapia (O. niloticus) for 10 days of storage in ice. 75 whole fish were used eviscerated, with average weight and length of 825.75 ± 101.59 g and 28.25 ± 0.81 cm, respectively. The treatments consisted of time in which the animals underwent pre-slaughter hypoxia, being 0, 3 and 6 minutes. Rigor mortis and muscle pH were assessed besides the application of the Quality Index Method and analysis of total protein and blood glucose. Rigor mortis did not differ among treatments during the storage period, and after three hours all animals were in rigor stage. The muscle pH values varied widely during the study period, observing higher values on the third day of storage. Sensory analysis showed that after 10 days the tilapia from the different treatments did not differ in the evaluated quality parameters similarly, there was no difference regarding the evaluated blood biochemical parameters Thus, hypoxia of 6 minutes pre-slaughter does not influence the rigor mortis, muscle pH, qualitative perception of the meat quality, total protein and blood glucose of Nile tilapia.Keywords: hypoxia; pH; rigor mortis; quality index method; blood parameters.Practical Application: Study the effects of pre-slaughter stress on the Nile tilapia meat quality.
ResumoO presente estudo objetivou verificar a influência da inclusão de diferentes fontes de hidrolisados cárneos na alimentação do surubim do Iguaçu (Steindachneridion melanodermatum). Para a realização do experimento, foram utilizados 256 juvenis de surubim com peso inicial médio de 23,54±0,83g e comprimento total médio de 13,26±0,22cm. Realizou-se um delineamento em blocos ao acaso com quatro tratamentos e quatro repetições. Foram formuladas 4 dietas isoproteicas e isoenergéticas. Foram incluídas às dietas, hidrolisados de fígado suíno, carcaça de tilápia e sardinha em uma proporção de 60, 40 e 60 g/kg de ração, respectivamente. Na dieta controle não houve acréscimo de hidrolisado. Ao final do experimento, determinaram-se os parâmetros de desempenho zootécnico, hematológicos e composição química da carcaça. Os dados referentes aos parâmetros avaliados foram submetidos à análise de variância de efeitos principais e posteriormente ao teste de Tukey ao nível de 5% de probabilidade através do programa estatístico Statisttics 7.0.Em relação aos parâmetros zootécnicos, as dietas testadas influenciaram significativamente (P<0,05) os valores de peso final, comprimento final e conversão alimentar aparente. Os parâmetros bioquímicos mensurados e a composição de carcaça não diferiram estatisticamente (P>0,05). A inclusão de hidrolisado de fígado suíno e de sardinha em dietas melhora o peso, ganho de peso comprimento e conversão alimentar do surubim do Iuaçu, e não afeta os parâmetros bioquímicos do sangue, bem como sua composição química da carcaça. Dessa forma, a utilização de hidrolisados em rações para peixes pode ser uma alternativa para aumentar o desempenho zootécnico dos animais.Palavras-chave: espécie nativa, nutrição, desempenho zootécnico. AbstractThe present work aimed to verify the influence of different sources of meat hydrolysates in the feed of Iguaçu catfish (Steindachneridion melanodermatum). To perform the experiment, we used 256 catfish juveniles with initial average weight of 23,54±0,83g and total average length of 13,26±0,22cm. We realized a randomized block design with four treatments and four replications. Four diets were formulated being isoproteics and isocalorics. We included hydrolysates of swine liver, tilapia carcass and sardine in proportion of 60, 40 and 60 g/kg of the diet, respectively. In the control diet there was not hydrolysate. At the end of experiment, we determined the performance, hematologic and carcass chemical composition parameters. The data were submitted to main effects variance analysis through statistic program Statisttics 7.0. The diets tested influenced significantly (P<0,05) the values of final weight, final length and feed conversion. The biochemical and carcass chemical composition parameters did not differ statistically (P>0,05). The inclusion of swine liver and sardine hydrolysates in the diets improve the weight, weight gain, length and feed conversion of Iguaçu catfish and does not affect the blood biochemical parameters as well as their carcass chemical composit...
This study evaluated the spatial and temporal limnological characteristics of an aquaculture area in the Itaipu reservoir, Brazil. During a one-year period, water quality parameters were evaluated in seven collection sites using a fish culture system as the reference point. A regression analysis was performed on water transparency versus chlorophyll a and total phosphorus versus chlorophyll a. The trophic state index (TSI) was calculated using data from water transparency, chlorophyll a, and total phosphorus. In addition, a study of the carrying capacity was conducted in situations of high and low flow and rainfall based on 725 m3 s−1 and 298 mm and 34.5 m3 s−1 and 11 mm, respectively. No difference was observed in the parameters of water quality and the TSI in relation to the collection sites; these parameters only varied significantly throughout the seasons. The regression analysis showed that increased total phosphorus in the environment leads to increase in chlorophyll a concentrations and consequently decreased water transparency. Evaluation of the carrying capacity demonstrated that under conditions of high precipitation and flow it is possible to produce 623.7 tons of fish per year, which is above the total cultivated in fish farms at the study site.
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