Chia gel is known for its functional properties such as high water and oil retention capacity, emulsifying activity, and as a stabilizer for foams and emulsions. Thus, the objective of this study was to evaluate the effect of the inclusion of chia gel as a substitute for pork fat in formulations of fishburgers made with Nile tilapia. Five formulations, one control and four with increasing levels of substitution of chia gel (12.50, 25.00, 37.50 and 50.00%) were evaluated. The fishburgers were characterized regarding their physicochemical composition, their technological characteristics, and microbiological viability. With the incorporation of the gel, there was a significant reduction in lipid component and the caloric value of the formulations, in addition to an increase in the percentage of dietary fibre. In addition, no negative effects were observed regarding yield and the main texture parameters studied. However, the formulations with the highest percentage replacement of pork fat by chia gel were darker when compared to the control treatment. Chia gel may be considered as a novel substitute for pork fat; however, it is recommended that techniques be employed to produce lighter gels, thus avoiding possible rejection by the consumer.

Objetivou-se por meio deste estudo determinar a necessidade nutricional de lisina digestível em rações para juvenis de tilápia-do-nilo (Oreochromis niloticus). Setecentos e vinte peixes masculinizados (7,30±0,11g) foram alimentados durante 30 dias com oito rações (26,81% de proteína digestível e 3090kcal/kg de energia digestível da ração) contendo teores crescentes de lisina digestível (1,24; 1,36; 1,48; 1,60; 1,72; 1,84; 1,96 e 2,08%). As tilápias foram distribuídas em delineamento inteiramente ao acaso, com oito tratamentos, seis repetições e 15 peixes por unidade experimental. Foram avaliadas variáveis de desempenho (ganho de peso, taxa de crescimento específico, taxa de sobrevivência, consumo de ração, consumo de lisina digestível, conversão alimentar aparente, eficiência proteica para ganho, eficiência de lisina para ganho e eficiência de retenção de nitrogênio) e de composição corporal (teores de umidade, gordura, proteína, matéria mineral corporal e as taxas de deposição diária de proteína e gordura corporais). A elevação do teor de lisina digestível na ração não influenciou (P>0,05) o consumo de ração, a taxa de sobrevivência e os teores de umidade e de matéria mineral corporal, mas melhorou de forma quadrática (P<0,05) os demais parâmetros avaliados, com exceção do consumo de lisina e da eficiência de lisina para ganho, que aumentou e reduziu, respectivamente, de forma linear (P<0,05). Recomenda-se que rações para juvenis de tilápia-do-nilo devam conter 1,84% de lisina digestível para máximo ganho de peso.

The aim of this study was to determine the nutritional need of lysine in diets for juvenile Nile tilapia (Oreochromis niloticus). Seven hundred and twenty masculinized fish (7.30±0.11g) were fed for 30 days with eight diets (26.81% of digestible protein and 3090 kcal/kg digestible energy of feed) containing increasing levels of lysine (1.24, 1.36, 1.48, 1.60, 1.72, 1.84, 1.96 and 2.08%). The tilapia were distributed in a completely randomized design with eight treatments and six replicates of 15 fish per experimental unit. We evaluated the performance variables (weight gain, specific growth rate, survival rate, feed intake, digestible lysine intake, feed conversion, protein efficiency for gain, efficiency of lysine for gain and efficiency of retention nitrogen) and body composition (moisture, fat, protein, ash body and deposition rates of daily protein and fat). The high levels of dietary lysine did not affect (P>0.05) feed intake, the survival rate and the moisture and ash body, but improved (P<0.05) other parameters, except for lysine intake and efficiency of lysine for gain, which increased and decreased, respectively, linearly (P<0.05). It is recommended that diets for juvenile Nile tilapia should contain 1.84% digestible lysine for maximum weight gain.