RESUMO
In the present study, two approaches were followed to evaluate the metabolic responses of tambaqui (Colossoma macropomum), a frugivorous species, to intraperitoneal (IP) administration of glucose (GLU) and fructose (FRU) in fed (FED) and 10-day fasted (FAST) fish. Glucose and fructose tolerance tests were performed to assess the carbohydrate utilization and complementary NMR-metabolomics analyses were done to elucidate the impacts of sugar mobilization on the metabolic profile of plasma, liver and muscle. Blood was sampled from FED groups at 0, 3, 6 and 24 h; and at 0 and 24 h from FAST groups. Significant differences were observed in the hyperglycaemic peak between sugars at 3 h (GLU - 13.7 ± 2.0 mM vs. FRU - 8.7 ± 1.1 mM; saline 6.3 ± 0.6 mM) and on the return to normoglycaemia (GLU - 8.5 ± 2.2 mM vs. FRU - 5.2 ± 0.9 mM; saline 4.9 ± 0.6 mM) 6 h after IP on the FRU fish. The NMR-metabolomics approach allowed to conclude that tambaqui seems to be more responsive to the feeding regime (FED vs. FAST) than to the injected sugar (FRU vs. GLU). From the studied tissues, plasma showed no significant variations between feeding regimes at 24 h after IP, while muscle and liver revealed some variations on the final metabolome profile between FED and FAST groups. The metabolome variations between feeding regimes are indicative of changes on the amino acid utilization. Fish from FAST group seem to utilize amino acids as energy source rather than for protein synthesis and muscle growth. Variations on glucose concentration in muscle can also indicate different utilization of the sugars depending on the feeding regime.
Assuntos
Caraciformes , Frutas , Aminoácidos , Animais , Caraciformes/fisiologia , Frutose , Glucose , Metabolômica , AçúcaresRESUMO
This research aimed to evaluate spray dried alcohol yeast (Saccharomyces cerevisiae) and zinc (zinc oxide) as pronutrient in initial diet for Nile tilapia (Oreochromis niloticus L.). The experimental diets, isoproteic (30.00%DP) and isoenergetic (3200kcal DE/kg diet), were supplemented with three yeast levels (0.50, 1.00 and 2.00%) and three zinc levels (150, 300 and 600mg/kg). An additional diet with no pronutrient was used. The experiment was a factorial 3 x 3 (yeast levels and zinc) plus an additional treatment (control) and four replications in completely randomized block design. Weight gain, apparent feed conversion, specific growth rate, protein efficiency rate, and apparent digestibility coefficients for dry matter, crude protein, total lipid and gross energy of experimental diets were analyzed. The spray dried alcohol yeast and zinc acted as pronutrient for Nile tilapia fingerlings and the levels of 1.00% of yeast and 300mg Zn/kg diet, presented better responses on growth performance and on the apparent digestibility coefficient. There was a positive interaction between yeast levels and zinc on the weight gain, apparent feed conversion and apparent digestibility coefficient of the dry matter, total lipid and gross energy.
Este trabalho teve como objetivo avaliar a levedura desidratada de álcool (Saccharomyces cerevisiae) e o zinco (óxido de zinco) como pró-nutrientes em ração inicial para tilápia do Nilo (Oreochromis niloticus L.). As rações experimentais, isoprotéicas (30,00%PD) e isoenergéticas (3200kcal ED/kg dieta) foram suplementadas com 3 níveis de levedura (0,5%; 1% e 2%) e 3 níveis de óxido de zinco (150, 300 e 600mg/kg). Utilizou-se, ainda, uma ração controle sem esses pró-nutrientes. Adotou-se o delineamento em blocos inteiramente casualizados em esquema fatorial 3 x 3 (níveis de levedura e zinco) com tratamento adicional (controle) e 4 repetições. Avaliou-se o ganho de peso, conversão alimentar aparente, taxa de crescimento específico, taxa de eficiência protéica e os coeficientes de digestibilidade aparente para matéria seca, proteína bruta, lipídio total e energia bruta das rações experimentais. A levedura desidratada de álcool e o zinco atuam como pró-nutrientes para alevinos de tilápia do Nilo, sendo que os níveis de 1% de levedura e 300mg Zn/kg dieta proporcionaram melhores respostas no desempenho produtivo e nos coeficientes de digestibilidade aparente. Houve interação positiva entre os níveis de levedura e zinco para o ganho de peso, conversão alimentar aparente e coeficientes de digestibilidade aparente da matéria seca, lipídio total e energia bruta.
RESUMO
Vegetable feedstuff used in commercial fish diets contains antinutrients, such as phytate, molecule able to complex minerals, amino acids, starch and, which can also acts in a negative way on the digestive enzymatic reactions. Thus, this study aimed to evaluate the effect of phytase enzyme (0; 1,000; 2,000 UF/kg) on the apparent digestibility of five energetic feedstuff (corn, extruded corn, wheat middling, rice meal and sorghum) and five protein feedstuff (soybean meal, extruded soybean meal, sunflower meal, cottonseed meal and gluten meal) using an albumin-gelatin diet and 0.10% of chromic oxide (Cr2O3), as indicator. Apparent digestibility coefficient (ADC) of dry matter, crude protein and gross energy were determinated. One hundred Nile tilapia juveniles, 100.0g average weight, were stocked in 10 cages for feeding and feces collect. Phytase acts in different way on vegetable feedstuffs. The digestible values of dry matter, crude protein and gross energy depend on the biological values of feedstuffs, concentration and nature of phytate and enzyme level supplementation.
Alimentos de origem vegetal utilizados em rações comerciais para peixes contêm fatores antinutricionais tais como o fitato, molécula capaz de complexar com minerais, aminoácidos, amido e que pode, também, atuar de forma negativa nas reações enzimáticas digestivas. Desse modo, esse estudo teve por objetivo avaliar o efeito da enzima fitase (0, 1.000 e 2.000 UF/kg) na digestibilidade aparente de 5 alimentos energéticos (milho, milho extrusado, farelos de trigo, de arroz e de sorgo) e 5 protéicos (soja extrusada, farelos de soja, de girassol, de algodão e glúten de milho) utilizando uma ração à base de albumina e gelatina e 0,10% de óxido de crômio (Cr2O3) como referência. Foram determinados os coeficientes de digestibilidade aparente (CDA) da matéria seca, a proteína bruta e energia bruta. Foram utilizados 100 juvenis de tilápia do Nilo com peso médio de 100,0 g os quais foram alojados em 10 gaiolas para o manejo de alimentação e coleta de fezes. Alimentos de origem vegetal respondem à presença da enzima fitase de forma diferenciada. Os valores digestíveis da matéria seca, da proteína bruta e energia bruta dependem do valor biológico dos alimentos, da concentração e da natureza do fitato e do nível de suplementação de enzima.
RESUMO
The effects of different levels of dietary copper on growth performance and physiological parameters of Nile tilapia (Oreochromis niloticus L.) were analyzed for 120 days. The experimental design was completely randomized, with five treatments (0.0; 4.0; 80.0; 160.0 and 320.0mg cooper/kg diet as cooper sulfate hepahydrate, 24.05% copper) and six replicates. One hundred and eighty fish, with 2.0 ± 0.05g average initial weight, were kept into 30 aquaria (60L) with individual filter and aeration; water temperature was kept at 25.0 ± 1.0oC. An albumin-gelatin diet was formulated to contain 32.0% crude protein and 3,200 kcal of digestible energy/kg. The oxygen concentrations and pH were measured weekly. At the end of the experiment, the weight gain, feed conversion ratio and survival rate were determined. Erythrocytes number, hemoglobin concentration, hematocrit ratio, mean corpuscular volume and mean corpuscular hemoglobin concentration were analyzed as hematological parameters. Liver, bones, carcass and muscle copper concentrations were also determined and the liver morphology and coloration were evaluated. Based on the results, it was concluded that either absence or high levels of dietary copper did not determine alterations in Nile tilapia growth performance and hematology; the liver copper concentration is responsive to dietary copper supplementation; hig
Os efeitos de diferentes níveis de cobre no desempenho produtivo e nos parâmetros fisiológicos da tilápia do Nilo (Oreochromis niloticus L.) foram avaliados por um período de 120 dias. O experimento foi inteiramente casualizado com 5 níveis de suplementação de cobre (0,0; 4,0; 80,0; 160,0 e 320,0mg/kg como sulfato de cobre heptaidratado, 24,05% cobre) e seis repetições por tratamento. Foram utilizados 180 peixes com peso de 2,0 ± 0,05g distribuídos aleatoriamente em 30 aquários de 60L cada, em uma lotação de 6 peixes/aquário. Os aquários foram dotados de sistema de filtragem individual de água e de sistema de aquecimento controlado por termostato (25,0o ± 1,0oC). Confeccionou-se 5 rações purificadas, à base de albumina e gelatina, isoprotéicas (32,0% PB) e isoenergéticas (3200 kcal/kg de energia digestível), diferenciando do controle pela adição de sulfato de cobre. As concentrações de oxigênio dissolvido e de pH foram determinadas semanalmente. Determinou-se o ganho médio de peso, a conversão alimentar aparente e a porcentagem de sobrevivência. Como parâmetros hematológicos, avaliou-se o número de eritrócitos, concentração de hemoglobina, porcentagem de hematócrito e o volume globular médio e a concentração de hemoglobina globular média. Determinou-se a concentração de cobre no fígado, ossos, carcaça e filé e avaliou-se a morfologia e coloração dos fígado