RESUMO A digestibilidade do trigo e seus co-produtos foi avaliada em dietas extrusadas para juvenis de tilápia do Nilo. Foram avaliados os coeficientes de digestibilidade aparente (CDAs) de matéria seca (CDAMS), energia bruta (CDAEB), proteína bruta (CDAPB), aminoácidos essenciais (AAEs) e aminoácidos não essenciais (AANEs) do triguilho, trigo, farelo de trigo, fibra grossa de trigo e gérmen de trigo. Utilizou-se uma dieta de referência e dietas de teste, com 5,0g/kg de óxido crômico (Cr2O3) como indicador externo. O CDAMS, CDAPB e CDAEB foram maiores (P< 0,05) no triguilho, trigo e germen de trigo do que para farelo de trigo e fibra grossa de trigo. Os CDAs de todos os aminoácidos (AAs) foram maiores que 80%, exceto para treonina no farelo de trigo e fibra grossa de trigo, superior a 90% para triguilho e germen de trigo. Os valores de todos os ingredientes investigados foram elevados para CDAPB, e os CDAs de AAEs e AANEs. Uma forte correlação negativa foi detectada para fibra bruta e cinzas com os ADCs de matéria seca, energia bruta e proteína bruta. De maneira geral, os ingredientes provenientes do trigo possuem boa digestibilidade da proteína e aminoácidos, porém o alto conteúdo fibroso reduz os CDAMS e CDAEB, em dietas extrusadas para a tilápia do Nilo.

SUMMARY In the present study, we investigated the digestibility of wheat and its coproducts in extruded diets for juvenile Nile tilapia. Specifically, we evaluated the apparent digestibility coefficients (ADCs) of dry matter (ADCDM), gross energy (ADCGE), crude protein (ADCCP), essential amino acids (EAAs), and non-essential amino acids (NEAAs) in winter wheat, spring wheat, wheat middling, wheat bran, and wheat germ in a diet fed Nile tilapia. A reference diet and test diets were used, with 5.0g/kg chromic oxide (Cr2O3) as the external indicator. The ADCDM, ADCCP, and ADCGE were higher (P< 0.05) in winter wheat, spring wheat, and wheat germ than for wheat middling and wheat bran. The ADCs of all amino acids (AAs) were >80%, except for threonine in wheat middling and wheat bran, exceeding 90% for winter wheat and wheat germ. The values of all investigated ingredients were high for ADCCP, and the ADCs of EAAs and NEAAs. A strong negative correlation was detected for crude fiber and ash with the ADCs of dry matter, gross energy, and crude protein. In general, wheat ingredients have good digestibility of protein and amino acids, but high fiber content reduces CDAMS and CDAEB in extruded diets for Nile tilapia.

Resumo O objetivo deste trabalho foi desenvolver massas de pizza com diferentes níveis de inclusão de farinha de atum (Tunnus spp.). Para a produção da farinha de atum, foram utilizados troncos de atum sem nadadeiras, cozidos por uma hora, prensados, moídos e desidratados por 24 horas a 60 °C. Foram elaboradas massas de pizza sem inclusão (0%) ou com inclusão de 5, 10, 15 e 20% de farinha de atum, sendo estas inclusões calculadas com base na quantidade de farinha de trigo. A farinha de atum e as diferentes massas foram analisadas quanto aos teores de umidade, proteína bruta, lipídeos totais, cinzas e carboidratos, além do valor calórico e do perfil de ácidos graxos. Análises microbiológica e sensorial foram realizadas nas massas de pizza. A crescente inclusão de farinha de atum resultou em aumento do teor de proteína bruta (10,89 a 18,94%), de lipídeos totais (4,63 a 5,89%) e de cinzas (2,54 a 3,54%) nas massas, sem influenciar no teor de umidade e no valor calórico. A inclusão de farinha de atum aumentou linearmente a quantidade de ácidos graxos da série n-3 nas massas, com aumento de 1,56 para 5,93 g/kg, em 20% de inclusão de farinha de atum. A relação entre ácidos graxos poli-insaturados e saturados da farinha de atum e das massas variou entre 1,21 e 1,85. A análise microbiológica demonstrou que as massas foram produzidas em condições adequadas de higiene. Observou-se que a inclusão de 5 a 20% de farinha de atum na massa de pizza não interferiu significativamente (p>0,05) nos parâmetros de aroma, sabor, impressão global e intenção de compra. Concluiu-se que a inclusão de 5 até 20% de farinha de atum é eficaz para melhorar o valor nutritivo e o perfil de ácidos graxos de massa de pizza.

Abstract The aim of this study was to develop pizza dough with different levels of tuna meal (Tunnus spp.). In order to produce tuna meal, tuna torsos without fins were used, cooked for 1 hour, pressed, milled and dehydrated for 24 hours at 60 °C. Pizza dough was produced without (0%) or with the addition of 5, 10, 15 and 20% of tuna meal, calculated based on the quantity of wheat flour. The tuna meal and different pizza pastries were analyzed for moisture content, crude protein, total lipids, ash, carbohydrates, caloric value and fatty acid profiles. Microbiological and sensory analyses were also carried out on the pizza pastries. The increasing addition of tuna meal resulted in gains in the crude protein (10.89 to 18.94%), total lipid (4.63 to 5.89%) and ash (2.54 to 3.54%) contents of the pizza pastries, not influencing the moisture content or caloric value. The inclusion of tuna meal linearly increased the quantity of n-3 series fatty acids in the pizza pastry, from 1.56 to 5.93 g/kg with the addition of 20% tuna meal. The ratio between the polyunsaturated and saturated fatty acids in the tuna meal and pizza pastries varied from 1.21 to 1.85. The microbiological analyses showed that the pizza pastries were produced under proper hygiene conditions. It was also observed that the addition of 5 to 20% of tuna meal to the pizza pastry did not significantly (p>0.05) alter the parameters of aroma, flavor, overall impression and purchase intention. It was therefore concluded that the addition of 5 to 20% tuna meal is effective in improving the nutritional value and fatty acid profile of pizza pastry.

Abstract Tilapia, salmon, tuna and sardine meals were prepared to develop and analyze extruded snacks with residue meal from fish processing. Residue meals were included in five types of corn snacks: control (0% fish meal) and four with 9% tilapia, salmon, tuna and sardine meals. Although moisture, lipids and carbohydrates rates did not differ among the snacks, protein rates increased with the increment of fish meal, reaching 11.85% in the tuna snack. Tuna and sardine snacks had the highest iron levels. The most abundant fatty acids were linoleic, oleic, palmitic, linolenic and stearic acids, with sardine, salmon and tuna snacks presenting the highest values of n-3 series fatty acids. Greater luminosity rate was reported for salmon snack, followed by tilapia, tuna and sardine snacks. The highest sensory acceptance index was verified in tilapia (78.07%) and salmon (72.40%). A 9% addition of residue meals of tilapia, salmon and tuna improved the nutritional value of the snacks.

This trial was conducted to determine the dietary digestible methionine + cystine requirement of Nile tilapia (550 to 700 g) based on the ideal protein concept. Six hundred fish were distributed in a completely randomized design with five treatments and four replicates, with 30 fish per experimental unit. The fish were fed diets containing approximately 262 g of digestible protein/kg, 3,040 kcal of digestible energy/kg and 7.90, 9.40, 10.90, 12.40 or 13.90 g of methionine + cystine/kg. The fish were hand-fed three times a day until apparent satiation for 30 days. No effects of dietary methionine + cystine on feed conversion ratio, daily protein deposition, whole body moisture, fillet moisture, crude protein, ether extract and ash, plasmatic HDL and LDL cholesterol were observed. Dietary methionine resulted in a linear increase in whole body protein and linear reduction in lipid deposition rate, hepatosomatic index, whole body ether extract and ash, plasmatic total cholesterol, plasmatic total lipids and plasmatic triglycerides. According to the Linear Response Plateau, the daily weight gain and fillet yield increased up to a level of 9.00 and 9.90 g methionine + cystine/kg of diet, respectively. The digestible methionine + cystine requirement of Nile tilapia is 9.00 g/kg for weight gain and 9.90 g/kg for fillet yield, corresponding to methionine + cystine:lysine ratios of 0.60 and 0.66, respectively.

O objetivo deste estudo foi a formulação de equações para estimar a energia digestível em alimentos para a tilápia. Foram utilizados valores obtidos na literatura da composição centesimal em proteína bruta, extrato etéreo, matéria mineral e energia bruta (variáveis independentes), bem como a energia digestível (variável dependente) obtidos em ensaios biológicos. Os dados foram submetidos à regressão linear múltipla "stepwise backward". Foi realizada análise de trilha para medir os efeitos diretos e indiretos de cada variável independente sobre a dependente. Para validar o modelo foram utilizados dados de estudos independentes, e os valores obtidos em um ensaio de digestibilidade com juvenis de tilápia do Nilo, testando-se cinco farinhas de carne e ossos (FCO), utilizando o sistema de coleta de fezes de Guelph e óxido de cromo (III) como indicador. A equação obtida não pode estimar os valores de energia digestível (ED) de origem animal e está descrito a seguir: ED (kcalkg-1) = -2364,970+1,287 x EB;R² = 0,775. Os coeficientes de trilha obtidos tem valores de médios a baixo, sendo o maior efeito direto o da energia bruta (0,529), enquanto a proteina bruta apresentou o maior efeito indireto, via energia bruta (0,439).

The objective of this study was to formulate a mathematical model to estimate digestible energy in animal feeds for tilapia. Literature results were used of the proximate composition of crude protein, ether extract, mineral matter and gross energy, as well as digestible energy obtained in biological assays. The data were subjected to stepwise backward multiple linear regression. Path analysis was performed to measure the direct and indirect effects of each independent variable on the dependent one. To validate the model, data from independent studies and values obtained from a digestibility trial with juvenile Nile tilapia testing five meat and bone meals (MBM) were used, using the Guelph feces collecting system and chromium oxide (III) as an indicator. The obtained model is described below and cannot estimate digestible energy (DE) of animal origin: DE (kcal kg-1) = -2364.970+1.287xGE;R² = 0.775. The path coefficients were medium or low, the highest direct effect was from gross energy (0.529), while the highest indirect effect was from crude protein, through gross energy (0.439).

The objective of this study was to formulate mathematical models to estimate digestible protein in some animal feeds for tilapia. Literature results of the proximate composition of crude protein, ether extract, and mineral matter, as well as digestible protein obtained in biological assays, were used. The data were subjected to multiple linear stepwise backward regression. Path analysis was performed to measure the direct and indirect effects of each independent variable on the dependent one. To validate the model, the experience used data from independent studies and values obtained from a digestibility trial with juvenile Nile tilapia testing five meat and bone meals, using the Guelph feces collecting system and chromium oxide (III) as an indicator. The obtained model used to estimate digestible protein values (DP) of animal origin is: DP(g kg-1) = -204.15+1.203xCP;R² = 0.953. The path coefficients showed a high direct positive effect (0.900) of crude protein on the digestible protein content. The mineral matter content has an indirect negative effect on protein digestibility (-0.710), reducing the crude protein content and quality.

This study was conducted to determine the digestible lysine requirements of Nile tilapia fingerlings. Fish (n = 300; average initial weight = 1.44 g) were distributed 15 300-L aquariums, in a completely randomized design with five treatments and three replicates, and fed extruded diets containing 11.3, 13.7, 16.1, 18.4 or 20.8 g/kg of digestible lysine. The arginine:lysine ratio was maintained at 1.3:1. All fish were fed diets containing 281 g/kg of digestible protein and 3,372 kcal digestible energy/kg, hand-fed until apparent satiation. There was no effect of the dietary lysine levels on survival rate, or protein and ash body rates. With increasing levels of lysine in the diet, a quadratic effect on weight gain, feed conversion, protein efficiency ratio, protein deposition rate, deposition rate of fat, body moisture and body lipids was observed, where the best values of the variables were estimated at 15.96, 16.4, 14.35, 15.21, 15.87, 15.21 and 16.29 g/kg of lysine, respectively. The digestible lysine requirement of Nile tilapia fingerlings is 15.21 g/kg (5.41 g/100 g of digestible protein), in diets balanced for the arginine:lysine ratio.