Níveis de proteína bruta para juvenis de pirarucu

The objective of this work was to verify the effect of four protein levels on pirarucu, Arapaima gigas, growth performance. One hundred and twenty pirarucu juveniles, with an average weight of 120.6±3.5 g, were stocked into 12 floating cages with 1 m3 (ten fish per cage), in a complete randomized design with four treatments (32.7%, 39.3%, 43.4% and 48.6% crude protein), in three replicates each. After 45 days, results showed that diet with highest protein level (48.6%) produced a better weight gain, specific growth rate, and differentiated body composition. Feed conversion and protein efficiency ratios did not show any differences among treatments. The dietary protein level required to produce maximum growth is 48.6%

Digestibilidade aparente de dietas práticas com diferentes relações energia:proteína em juvenis de pirarucu

The objective of this work was to determine the apparent digestibility of nutrients and energy of diets for pirarucu (Arapaima gigas) juveniles. Eight experimental diets containing four energy:protein ratios (11, 10.1, 9, 8 kcal digestible energy per gram of crude protein) and two non-protein energy sources (soybean oil and poultry fat) were tested in a 4x2 factorial scheme, in triplicates. Two hundred and forty pirarucu juveniles weighting 96.8±2.3 g were distributed in 24 cylindrical-conical fiberglass tanks, adapted for feces collection (modified Guelph system). Fish were fed twice a day to apparent satiation, with experimental diets containing 0.5% of chromium oxide as inert marker in order to determine the apparent digestibility coefficients. Diets containing an energy:protein ratio of 9 kcal digestible energy per gram of crude protein resulted in significantly lower apparent digestibility coefficient for dry matter, crude protein and non-nitrogenous extract. The highest apparent digestibility coefficients for crude fat was obtained with soybean oil. The dietary energy:protein ratio influences the nutrient and energy apparent digestibility coefficients to pirarucu juveniles

DL5o da bactéria Aeromonas hydrophila para o matrinxã, Brycon amazonicus

In order to determine the lethal dose (96-h LD50) of the bacteria Aeromonas hydrophila to matrinxã, Brycon amazonicus, to be applied in challenge tests, 90 fish (63.23 ± 6.39 g) were divided into five treatments, with different bacterial solutionsT1 - Control (0.9% NaCl saline solution); T2 (4 x 10(11) cells/ mL); T3 (5 x 10(11) cells/ mL); T4 (1.36 x 10(12) cells/ mL) and T5 (3.06 x 10(12) cells/ mL). Fish were previously anesthetized with benzocaine (60 mg L-1), inoculated in the peritoneal cavity with the bacterial suspensions and then distributed into fifteen 80-L test chambers, where the water variables were monitored and fish mortality was observed. The experiment was randomly designed in three replicates and the 96-h LD50 was estimated according to the trimmed Spearman-Karber method. Water quality variables remained within adequate ranges for fish health and performance. Fish mortality rate increased with the bacterial concentrations of A. hydrophila (T1 = 0%; T2 = 16.66%; T3 = 44.44%; T4 = 72.22% and T5 = 100%), and the first mortalities were observed after 57 h, although the signs of the bacterial infection were already observed 24 h after the inoculation. The results indicate that the 96-h LD50 value of A. hydrophila to matrinxã is 6.66 x 10(11) cells/ mL.Para determinar a dose letal (DL50 96-h) da bactéria Aeromonas hydrophila para o matrinxã, Brycon amazonicus, com aplicabilidade para testes de desafio, foram utilizados 90 peixes (63,23 ± 6,39 g), divididos em cinco tratamentos, com diferentes soluções bacterianas: T1 - Controle (solução salina 0,9% NaCl); T2 (4 x 10(11) células/ mL); T3 (5 x 10(11) células/ mL-1); T4 (1,36 x 10(12) células/mL-1) e T5 (3,06 x 10(12) células/ mL-1). Os peixes foram previamente anestesiados com benzocaína (60 mg L-1), inoculados na cavidade peritoneal com as suspensões bacterianas e distribuídos em 15 aquários de vidro de 80 L de capacidade, com aeração constante. O experimento teve duração de 96 h, no qual foram monitoradas a mortalidade e a qualidade da água. O delineamento experimental foi inteiramente casualisado com três réplicas e a DL50 96-h foi estimada de acordo com o método Spearman-Karber. Durante o experimento os parâmetros físico-químicos da água permaneceram dentro das condições consideradas adequadas para o desenvolvimento e saúde dos organismos aquáticos. A mortalidade dos peixes aumentou nas concentrações crescentes de A. hydrophila (T1 = 0%; T2 = 16,66%; T3 = 44,44%; T4 = 72,22% e T5 = 100%), contudo, as primeiras mortalidades ocorreram em 57 h após a inoculação das concentrações bacterianas, sendo observados os primeiros sinais de infecção em 24 h após a inoculação. Os resultados indicam que o valor da DL50 96-h da bactéria A. hydrophila para o matrinxã foi igual a 6,66 x 10(11) células/mL de solução salina