Abstract This study evaluated the effect of including clove essential oil (EOcl) in Nile tilapia diets on animal performance and antioxidant power, lipid oxidation, gene expression, texture, pH, color and sensory analysis in fillets. Three levels of EOcl in the diets were evaluated (0.70, 1.05 and 1.40 g/kg), provided over three periods before slaughtering the animals (15, 45 and 60 days). The antioxidant power in the diets increased after including EOcl. There was an interaction effect between the level and period of inclusion of EOcl on the antioxidant power and lipid oxidation of fillets stored up to 14 days after slaughter. Lipid oxidation was reduced by 43.3% compared with the control group. EOcl inclusion in the diet, regardless of level and period, improved texture and promote less gene expression of catalase and glutathione synthetase. This demonstrates that the antioxidant in the tilapia diet acts against the oxidative stress process. Considering the results for the interactions and parameters evaluated, including 1.05 g/kg of clove essential oil in the rations for 15 days before slaughter is indicated because it contributes to a higher fillet quality.
ABSTRACT The homeopathy has been practiced for many years, mainly using rodent as a research model. Zebrafish have been used as an animal model in different scientific areas and may represent an important model in studies with this therapy. This paper aimed to evaluate the action of Homeopatila 100® on the growth, the action on the liver and reproduction of zebrafish. The study was carried out with 192 six months old animals. The experimental period was three months, being evaluated the growth, the hepatosomatic and viscerosomatic indexes, the number of hepatocytes per area and the percentage of glycogen in these cells, performing the hepatic histology of males and females. It was evaluated the reproduction of the animals, checking the production and probability of hatching of the eggs. It was found that homeopathy increases the number of hepatocytes and glycogen in females, as well as improved the reproductive indices evaluated.
This study evaluated the incorporation of β-carotene, lutein and lycopene into tilapia (genetically improved farmed tilapia, GIFT) fillets supplemented through 0, 20 and 40 days, and their influence on the fatty acid composition and nutritional quality of raw and grilled fillets. A control diet and a diet containing those carotenoids were elaborated with the same lipid source (soybean oil). For carotenoids analysis, the extraction was performed according to the literature, employing acetone and hexane. The relative intensities of m/z ratios of those carotenoids ions were obtained by ultraperformance liquid chromatography-tandem mass spectrometry with chemical ionization at atmospheric pressure (UPLC-APCI MS/MS), and an increase of carotenoid concentration in the supplemented fillets was observed, especially after the grilling process (180 ºC for 15 min). An increase in the concentration of total carotenoids in grilled fillets (75 and 35% higher than raw fillets, for 20 and 40 days of supplementation, respectively, corresponding to 8.32 and 2.42 µg β-carotene g-1 sample) was also observed. Therefore, the carotenoids promoted the stability of lipid oxidation in grilled samples; fact that can be correlated with antioxidant effect of these compounds, it can be also explained by the breakdown of carotenoids physical barrier and the conditions used in the grilling process. Moreover, acceptable n-6/n-3 indices and recommended polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) values were observed in supplemented fillets. Consequently, lutein, β-carotene and lycopene were considered viable as additive on fish diet, since the supplementation promoted the increase of food quality, even after preparation for consumption.
ABSTRACT. This study aimed to evaluate the digestibility of tilapia by-product protein hydrolysate powder (TBHP) from tilapia filleting by-product, and its inclusion in diets for Nile tilapia larvae. In order to determine the apparent digestibility coefficients, two diets were formulated, the reference diet and the test diet (20% of TBHP) and, to evaluate the inclusion, six diets were formulated, which were with 0.0, 2.0; 4.0; 6.0, and 8.0% of TBHP. The apparent digestibility coefficients of crude protein and gross energy were 89.5 and 98.3%, respectively. At levels above 4.0% of inclusion of TBHP, the weight, final length and weight gain were impaired, however, survival rate was higher (p < 0.05). The TBHP can be used in diets for tilapia due to the high digestibility coefficients for crude protein and gross energy. The inclusion of up to 4.0% of TBHP does not affect the reproductive performance and survival rate of Nile tilapia larvae.
RESUMO. Objetivou-se avaliar a digestibilidade do hidrolisado proteico seco do resíduo da filetagem de tilápias (HPST) e sua inclusão em dietas para larvas de tilápia do Nilo. Para determinar os coeficientes de digestibilidade aparente, duas dietas foram elaboradas, referência e teste (com 20% do HPST) e para avaliação da inclusão, seis dietas foram formuladas com 0,0, 2,0; 4,0; 6,0, e 8,0% de HPST. Os coeficientes de digestibilidade aparente da proteína e energia bruta foram de 89,5 e 98,3%, respectivamente. Nos níveis acima de 4,0% de inclusão de HPST o peso e comprimento final e ganho em peso foram prejudicados, no entanto a sobrevivência foi maior (p < 0,05). O HPST pode ser utilizado em dietas para tilápias em função dos elevados coeficientes de digestibilidade para proteína bruta e energia bruta. A inclusão de até 4,0% de HPST não afeta o desempenho produtivo e a sobrevivência de larvas de tilápias do Nilo.
Abstract 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.
Total phosphorus contents for feeding silver catfish juveniles reared in net cagesPhosphorous is an essential mineral for fishes, because it acts on various metabolic processes. However, high levels may jeopardize the water quality, and its lack could promote deficiency to animals. The aim of this study was to evaluate the productive performance of silver catfish juveniles reared in net cages and fed with diets containing different total phosphorus contents. A total of 600 silver catfish juveniles, with initial weight of 6.88 ± 0.26 g and 9.28 ± 0.99 cm, were randomly distributed in 20 net cages, in a stocking density of 30 fish per cage. A completely randomized design, with four treatments, different total phosphorus contents (0.65%, 0.80%, 0.95%, and 1.10%), and five replicates were used. These contents affected (p < 0,05) the final weight, length, weight gain, specific growth rate, and condition factor. However, the survival rate and feed conversion did not differ (p > 0,05) among treatments. Thus, it is possible to recommend the commercial use of 0.80% total phosphorus in diets for silver catfish juveniles, providing a good productive performance and, above all, reducing the pollution caused by those diets.
O fósforo é um mineral essencial para os peixes, pois atua em vários processos metabólicos. Porém, níveis elevados podem comprometer a qualidade da água, e a sua falta pode provocar deficiência aos animais. O presente estudo objetivou avaliar o desempenho produtivo de juvenis de jundiá criados em tanques-rede, alimentados com rações constituídas por diferentes níveis de fósforo total. Foram utilizados 600 juvenis de jundiá, com massa inicial de 6,88 ± 0,26 g e 9,28 ± 0,99 cm, distribuídos, aleatoriamente, em 20 tanques-rede, na densidade de estocagem de 30 peixes por tanque. Utilizou-se delineamento inteiramente casualizado, com quatro tratamentos, diferentes níveis de fósforo total (0,65%; 0,80%; 0,95%; e 1,10%) e cinco repetições. Estes níveis afetaram (p < 0,05) a massa final, comprimento final, ganho de massa, taxa de crescimento específico e fator de condição. Contudo, a sobrevivência e conversão alimentar não se alteraram, em função dos tratamentos. Pode-se recomendar, comercialmente, a utilização de 0,80% de fósforo total, em rações para juvenis de jundiá, proporcionando bom desempenho produtivo e, principalmente, diminuindo o efeito poluidor das rações.
The objective of this study was to evaluate the influence of two levels of digestible energy (3250 and 3500 kcal kg-1) in conjunction with three levels of crude protein (25, 30 and 35%) on the productive performance of catfish (Rhamdia voulezi) juveniles. Two-hundred and forty catfish juveniles with 95.55±6.70 g average weight and 20.43±1.13 cm total length were randomly assigned into twenty-four 370 L-cages, in a factorial arrangement with six treatments and four reptitions. Feeding was performed four times a day, ad libitum. At end of experimental period, the factorial analysis of variance showed significant influence with respect to the different parameters evaluated. The fish fed with diets of 30% crude protein and 3,250 kcal digestible energy kg-1 of diet presented the best results. Therefore, diets with at least 30% crude protein and 3,250 kcal digestible energy kg-1 are recommend for catfish juveniles.
Objetivou-se com este trabalho avaliar a influência de dois níveis de energia digestível (3.250 e 3.500 kcal kg-1) em combinação a três níveis de proteína bruta (25, 30 e 35%) sobre o desempenho produtivo de juvenis de jundiá (Rhamdia voulezi). Utilizaram-se 240 juvenis de jundiá com peso inicial de 95,55±6,70 g e 20,43±1,13 cm de comprimento total, distribuídos ao acaso em 24 tanques-rede (370 L cada) em delineamento fatorial com seis tratamentos e quatro repetições. O arraçoamento foi realizado quatro vezes ao dia, à vontade. Ao final do período experimental, a análise fatorial de variância evidenciou influência significativa nos parâmetros zootécnicos avaliados. Foram observados melhor ganho de peso e comprimento final médios e menor deposição de gordura visceral nos peixes alimentados com a dieta contendo 30% de proteína bruta e 3.250 kcal de energia digestível kg-1. Portanto, recomendam-se para juvenis de jundiá dietas que contenham no mínimo 30% de proteína bruta e 3.250 kcal de energia digestível kg-1 de ração.