A experimentação animal apresenta uma grande importância para o desenvolvimento da ciência. O uso de camundongos em experimentos ocorre devido à semelhança destes animais com os seres humanos, fácil criação e manutenção e resposta experimental bastante rápida. Esses animais possuem as mesmas enzimas dessaturases e elongases que os humanos, por isso são usados em pesquisas envolvendo incorporação e síntese de ácidos graxos em tecidos. Os ácidos graxos da família ômega-3 e ômega-6 são de suma importância na dieta humana, pois estes não são sintetizados pela síntese de novo e são precursores dos ácidos graxos poli-insaturados de cadeia muito longa, como os ácidos eicosapentaenóico, docosahexaenóico e araquidônico. Estes desempenham funções importantes no organismo, como a síntese de eicosanóides que estão envolvidos diretamente no sistema imune e nas respostas inflamatórias. A razão entre o consumo de ácidos graxos n-6 e n-3 na dieta é um importante fator para determinar a ingestão adequada de ácidos graxos bem como prevenir o aparecimento de doenças. Este artigo tem como objetivo avaliar a incorporação de ácidos graxos em tecidos de animais e discutir a importância dos ácidos da família n-3 e seus metabólitos no sistema imunológico.

This study evaluated the omega-3 (n-3) fatty acids and the proximate composition of muscle tissue of adult Nile tilapias to select the best feeding time length with a diet containing 70 (g kg )1 wt) flaxseed oil (FO). The results showed that dietary complementation with FO for 45 days is suitable for obtaining high levels of protein (164 g kg )1 ), total lipids (94 g kg )1 ), and ash (18 g kg )1 ). Furthermore, there was a significant difference (P < 0.05) in the reduction of n-6 and an increase in the concentration of n-3. With 45 daysÕ time of FO feeding, fish weight was 532 g and it was improved by the incorporation of total n-3 (9.8%), consisting of alpha-linolenic acid (LNA; 6.3%), and n-3 very long-chain polyunsaturated fatty acid (n-3 VLC-PUFA; 3.5%), and including docosahexaenoic acid (DHA; 1.2%). This gave a better n-6/n-3 ratio (1.1) of muscle tissue, a more desirable ratio than the present ratio sometimes as high as 1 : 20 in human diets. The concentrations of n-3 VLC-PUFA were higher than those of native Brazilian freshwater fish. Thus, 45 days is the shortest time period required for the inclusion of FO oil in tilapia feed to raise the nutritional value of adult Nile tilapia. KEY WORDS

*A quem a correspondência deve ser enviada ResumoAs cabeças de tilápias são resíduos do processamento de peixes comumente descartados e não aproveitadas como alimento. Desta forma realizou-se um estudo sobre a composição química e de ácidos graxos na farinha obtida a partir de cabeças de tilápias. Ainda foram realizadas avaliações sensorial (caldo e sopa) e química e de ácidos graxos na sopa elaborada com a farinha. Os objetivos foram avaliar a composição e aceitação dos produtos elaborados com farinha, visando o aproveitamento na alimentação humana, especialmente para a merenda escolar. Os resultados obtidos foram de elevados teores de proteína (38,4%), cinzas (19,4%) e lipídios (35,5%) na farinha. A sopa apresentou elevada aceitação pelas crianças do ensino fundamental e a composição de ácidos graxos do conteúdo lipídico indicou a presença de diversos ácidos ômega-3, especialmente os ácidos alfa-linolênico (LNA), eicosapentaenóico (EPA), docosahexaenócio (DHA) e excelente razão AGPI/AGS. Todos estes parâmetros evidenciam que a inclusão de cabeça de tilápia na forma de farinha é aceitável como alimento e constitui uma fonte nutritiva e benéfica para a saúde humana. Palavras-chave: tilápia; cabeça; farinha; composição química; ácidos graxos. AbstractFish heads are normally discarded during fish processing and are not used as food. This study therefore investigated the chemical and fatty acids composition of fish meal produced from tilapia heads. An evaluation was made of the sensorial, chemical and fatty acids characteristics of broth and soup containing this fish meal. The purpose of the study was to analyze the composition and acceptance of products containing fish meal, aiming at its use in human food, especially in school meals. The results indicated that the fish meal contained contents of protein (38.4%), ashes (19.4%) and lipids (35.5%). The soup containing fish meal was well accepted by elementary schoolchildren. Moreover, the fatty acids composition of the lipid content indicated the presence of several omega-3 acids, especially alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and an excellent PUFA/SFA ratio. All these parameters indicate that fish meal made from discarded tilapia heads is an acceptable, nutritious and healthy source of food for humans. Keywords: tilapia; head; fish meal; chemical composition; fatty acids.Avaliação química e sensorial da farinha de resíduo de tilápias na forma de sopa IntroduçãoAs tilápias (Oreochromis niloticus) são as espécies de peixes mais cultivadas e consumidas no Brasil nos últimos anos 10 . A preferência nacional de consumo da carne de tilápia pelos brasileiros é na forma de filé, e no processo (filetagem) de sua obtenção são gerados resíduos, comumente não aproveitados, e que são descartados, poluindo o meio ambiente.Os resíduos de peixes incluem todas as sobras de processamento tais como: filetagem, salga, enlatamento, defumação, etc. Estes resíduos apresentam valores relativamente baixos e incluem cabeça, fígado, espinhas, ...

The fatty acid compositions of muscle tissue taken from wild strains of pintado (Pseudoplatystoma corruscans) and pacu (Piaractus mesopotamicus) fish, which were taken from the Brazilian Pantanal, were compared to the fatty acid compositions of tissue taken from two corresponding cultivated strains, which were fed commercial diets. The cultivated species possessed lipid contents of 12.2% (pacu) and 8.9% (pintado) while the wild species contained 7.9% (pacu) and 2.5% (pintado) lipids. Despite the high lipid contents of the cultivated pintado and pacu, the n-3 polyunsaturated fatty acid concentrations in muscle tissue were higher in wild pintado (224.9 mg/g flesh) and wild pacu (485.1 mg/g flesh) than in their respective cultivated strains (129.8 and 106.1 mg/g flesh, respectively). The n-6/n-3 ratios of pacu were 1.2 (wild) and 9.8 (cultivated), and those of pintado were 1.0 (wild) and 7.3 (cultivated). The fatty acid composition of pacu and pintado are strongly influenced by habitat and diet.

RESUMOEspinhaços de tilápias (Oreochromis niloticus) são partes do peixe de composição desconhecida. A composição lipídica dos espinhaços não é citada na literatura, bem como a estabilidade da farinha do espinhaço durante o armazenamento. Nesse sentido, realizou se estudo de processamento dos espinhaços envolvendo etapas de cocção, trituração, secagem, peneiramento e armazenamento da farinha. A farinha ficou armazenada sob refrigeração por um período de 90 dias, sendo sua qualidade monitorada por meio da composição em ácidos graxos, índice de acidez e análises microbiológicas. Os resultados da composição centesimal foram de 14,2% (umidade), 40,8% (proteína), 18,3% (resíduo mineral fixo) e 25,3% de lipídios totais. Nos lipídios totais foi identificado um total de 24 ácidos graxos, com predominância dos ácidos graxos (porcentagem média) de 27.4% (ácido palmítico, 16:0), 35,15% (ácido oléico, 18:1n-9) e 11,82% (ácido linoléico, 18:2n-6) e, em menor proporção: 0,88% (ácido alfa-linolênico, 18:3n-3), 0,08% (ácido eicosapentaenóico, 20:5n-3) e 0,59 (ácido docosahexaenóico, 22:6n-3). Durante os 90 dias de armazenamento, foram observadas algumas alterações no índice de acidez e composição de alguns ácidos graxos, no entanto, para 60 dias de armazenamento, não foram observadas alterações na composição de nenhum ácido graxo, do índice de acidez e nas análises microbiológicas.Termos para indexação: Tilápia, farinha, espinhaço, ácidos graxos, armazenamento. ABSTRACTThe composition of the tilapia (Oreochromis niloticus) fishbone is unknown. Lipid composition fishbone is not cited in the literature, and neither is the stability of the flour of the fishbone during storage. We studied the processing of fishbone cooking, grinding, drying, sieving and the storage of the flour. The flour was stored in a refrigerator for a period of 90 days, and its quality was monitored through fatty acid composition, acid index and microbiology control. The results of the proximate composition were of 14.2% (moisture), 40.8% (protein), 18.3% (ash), and 25.3% total lipids. In the total lipids identified 24 fatty acids were identified, with predominance of the fatty acids (medium percentage) of 27.4% (palmitic acid, 16:0), 35.15% (oleic acmid, 18:1n-9) and 11.82% (linoleic acid , 18:2n-6) and, in smaller proportion: 0.88% (alpha-linolenic acid, 18:3n-3), 0.08% (eicosapentaenoic acid, 20:5n-3) and 0.59 (docosahexaenoic acid, 22:6n-3). During the 90 days of storage some alterations were observed in the acid index and composition of some fatty acids, however, for 60 days of storage no alterations were observed in the fatty acids composition, acid index, and microbiology control.

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In this experiment, the heads of Nile tilapia were used as a raw material to produce flour through cooking, grinding, drying and sieving processes. The flour obtained was stored for 90 days in a refrigerator and shelf time was monitored by chemical methods (acid number [AN] and thiobarbituric acid [TBA] test), fatty acid composition and microbiological methods. The proximate composition was: moisture (6.01%), ash (19.38%), proteins (38.41%) and total lipids (35.46%). Thirty‐six fatty acids were found in the lipidic fraction. The predominant ones were 16:0, 18:1n‐9 and 18:2n‐6. The fatty acids of the series n‐3, 18:3n‐3 (alpha‐linolenic acid), 18:2n‐6 (linolenic acid), 20:5n‐3 (eicosapentaenoic acid) and 22:6n‐3 (docosahexaenoic acid) were found in smaller proportion. No changes were detected in the flour stored for 90 days as to polyunsaturated fatty acids and microbiological analysis. The AN remained constant up to 60 days of storage and TBA values increased throughout the 90‐day storage. PRACTICAL APPLICATIONS Waste Nile tilapia heads are not commonly used in human feeding and, therefore, are discarded. In this experiment, Nile tilapia heads were used as a raw material to produce tilapia flour; it was stored in a refrigerator and the shelf time was monitored for 3 months by chemical and microbiological methods. The flour is a caloric food, has high lipid content with omega‐3 fatty acids, minerals, proteins and can be used as human feeding.

This study evaluated the use of fish processing residues in the preparation of flavored meal from Nile tilapia (Oreochromis niloticus) carcass. Carcasses were washed, labeled, weighed, spice‐brined and smoked. After smoking, the carcasses were weighed and ground to a meal. The samples were vacuum packed, labeled and frozen (−18C) until analysis. The prepared meal presented mean moisture, protein, total lipids and ash contents of 17.41, 32.51, 19.72 and 26.22%, respectively. Some fatty acids of great physiological and nutritional importance were found among the 23 fatty acids that were identified, such as alpha‐linolenic acid, eicosapentaenoic acid and docosahexaenoic acid. The produced meal can be used to enrichment and preparation of several products for human consumption. PRACTICAL APPLICATIONS Nile tilapia carcasses are not commonly used in human feeding, and, most often, they are disposed of. This study was carried out considering the impact of improper disposal of this residue on the environment and seeking suitable technological alternatives for a nobler use of this residue with both economic potential and social application. The prepared meal can be used to enrich school food, as it is a cheap and viable option to food fit for children consumption.