The use efficiency and feed conversion of extruded and pelletized diets were compared. Eight isoproteic diets (220 g kg )1 digestible protein) were assayed for 90 days in a 2 · 2 · 2 multifactorial design with two carbohydrate levels (400 and 500 g kg )1 ), two lipids levels (40 and 80 g kg )1 ) and two diet processing (pelletization and extrusion) with three repetitions. The growth of Piaractus mesopotamicus fed with these diets and the quality control indices of diets were gauged. The density of extruded diets was lower as carbohydrate level was 400 g kg )1 and lipid 40 g kg )1 . The interaction carbohydrate and diet processing presented higher leaching value for low carbohydrate level in extruded diet. Fish fed with extruded diets presented the best feed conversion and protein efficiency ratio. When high levels of carbohydrate and lipid are combined, the weight gain is impaired. The interaction between diet processing diet and lipid levels resulted in the best fish performance when pelletized diets with 40 g kg )1 lipid or extruded diets with 80 g kg )1 lipid were considered. The protein efficiency ratio increased with the increment of carbohydrates in the pelletized diets. The fish show low tolerance to lipids and a preference for carbohydrate when the lipid productive values are taken into account. KEY WORDS

Growth and metabolism were investigated in juvenile tambaqui (Colossoma macropomum) fed with isoenergetic diets in four treatments with protein (P) lipid (L) in g kg−1: P350L49; P301L81; P253L113 and P205L145, respectively. The experiments were carried out in the laboratory facilities. Fish growth, the intermediary metabolites (total sugar, lactate, pyruvate, ammonia, protein, fatty acids, triacylglycerols, amino acids and glycogen), and the enzyme activities of lactate dehydrogenase, malate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were assayed. Fish from treatments P350L49 and P301L81 depicted the best growth. Increase in glycolytic, glycogenolytic and lipolytic activities in liver was observed following dietary lipid increase. In fish fed with high lipid levels, the energetic demand was supplied by enhancement of muscular glycogenesis and lipolysis. The plasma metabolic profile reflected the blood function on metabolites delivery to tissues underlining biochemical adaptations because of changes in the feeding. In conclusion, the increase in dietary lipid plus protein decrease resulted in (i) reduction in fish growth, (ii) augment of liver glycolysis and glycogenolysis (iii) increase in muscular glycogenesis and (iv) predominance of lipolytic metabolism.

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The responses of the digestive physiology of juvenile pacu to different diet processing were studied. Fish were fed with isoproteic diets with 260 g kg À1 of crude protein (CP) containing different levels of carbohydrate (DCh) (400 or 500 g kg À1 ), and two diet processing (pelletization or extrusion) for 90 days. Fish fed with extruded diets showed decrease of the gastrointestinal transit time (GI transfer) and of the amylase activity, but maltase activity did not alter. Protease activity of intestine depicted increase when the DCh was raised. The increase of DCh also caused enhancement of the apparent digestibility coefficient of CP (ADC CP ) in fish fed with extruded diets. Fish fed with pelletized diets showed increase of the amylase activity in pyloric caecum independently of the dietary carbohydrate level. No interaction was observed between dietary carbohydrate level and diet processing. Maltase activities from the stomach and intestine of pacu were not responsive to the carbohydrate level. The extrusion process improved the carbohydrate availability and the digestion efficiency of protein in pacu. Digestive enzymes of pacu were modulated either by nutrients or diet processing.

ResumoEste trabalho teve como finalidade avaliar o eugenol como anestésico para jundiá da Amazônia (Leiarius marmoratus). Foram mensurados o tempo de indução e recuperação à anestesia em diferentes concentrações de eugenol e seus efeitos nas trocas gasosas. Os resultados foram analisados segundo um delineamento inteiramente casualisado (DIC) com oito tratamentos (controle, 10, 20, 40, 80, 120, 150, 200mg ), Sódio (Na), Potássio (K), Cálcio (Ca) e Cloreto (Cl). As concentrações de 40 e 80 mg.L -1 apresentaram tempo de indução a anestesia profunda de 59,5±17,5 seg. e 58,4±18,6 seg. respectivamente. As concentrações acima de 120mg. L-¹ apresentaram mortalidade. Estes peixes submetidos à diferentes concentrações de eugenol não apresentaram alterações na pressão de oxigê 3 nio no sangue (PaO 2 ) e pressão de dióxido de carbono (PaCO 2 ). Os peixes quando submetidos a concentrações acima de 80mg. L -1 apresentaram aumento de bicarbonato. Os valores de glicose plasmática apresentaram elevação significativa em resposta ao banho anestésico com eugenol. As concentrações de sódio, cloreto, potássio e proteína plasmática mantiveram-se constantes indicando que o processo de anestesia não foi duradouro o suficiente para induzir alterações no balanço eletrolítico desta espécie. Foi possível concluir que o eugenol é um anestésico adequado para o jundiá da Amazônia. Palavras-chave: Manejo de peixes, anestesia, hemogasometria AbstractThis work aims to evaluate the use of eugenol as an anesthetic for jundiá da Amazônia (Leiarius marmoratus), measuring the time to anesthesia induction in different concentrações and their effects in gas exchange. The results were analyzed according to a completely randomized design (DIC) with eight treatments (control, 10, 20, 40, 80, 120, 150, 200 mg L -1 of eugenol) and ten repetitions. Time values of anesthetic induction and recovery, according to the level of eugenol underwent polynomial regression (p<0.05). The analysis of variance (ANOVA) and averages were compared by Tukey test. Were determined the time of anesthesia and recovery. The parameters were analyzed blood glucose, pH, partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), concentration of

This study assesses the respiratory dynamics related to stress parameters and resting time before slaughter, in the quality of surubim (Pseudopatystoma spp.) fillets. A completely randomized design was conducted using five treatments: resting time before slaughter of 0, 2, 4, 8 and 24 hours, with 15 fish sampled per treatment. Time 0 corresponded to the treatment without resting time, where the fish were slaughtered immediately after arriving at the processing plant. The resting time did not affect the electrolyte balance, hemoglobin, plasma, hepatic glycogen, myofibrillar fragmentation index (MFI) and water holding capacity (WHC) of surubins. However, with increased resting time, there was a significant decrease in muscle glycogen and an increase in blood pH and blood bicarbonate levels. Additionally, respiratory parameters showed an increase in pO 2 and, consequently, in O 2 saturation and a decrease in pCO 2 .The hematocrit and MCV values of the surubins after 24 hours of resting decreased significantly. In the first hours of resting, the highest values of erythrocytes and CHCM were observed. The lowest level of stress was observed for fish having 24 hours of resting. Fish having longer resting periods (8 and 24 hours) presented fillets with a higher pH (P <0.05) and the rigor mortis establishment time was shorter for the first 2 hours and 24 hours of resting time. There was a linear decrease in fillet lightness and an increase in the intensity of red (CIE a*) color up to 24 hours when resting was increased. In CIE b*, a linear decrease (P <0.05) of the yellow intensity of the fillets was observed as the surubim resting time increased. A resting time of 4 to 8 hours before slaughter is effective in reestablishing homeostasis after transporting surubim, providing fillets with higher quality and a greater length of the pre-rigor mortis period.

ResumoO surubim (Pseudoplatystoma sp.) é uma das espécie de peixe carnívora que exige atenção especial na dieta ofertada. Este trabalho teve o objetivo determinar a exigência de proteína digestível de juvenis de surubim (Pseudoplatystoma sp.) criados em tanque-rede. O ensaio foi constituído por quatro dietas isoenergéticas (2606,69±39,16 kcal. kg-1 de energia digestível) contendo níveis crescentes de proteína digestível (23, 24, 26 e 28 % PD) fornecidas aos juvenis de surubim (157,35± 11,23g) durante cinco meses. Os parâmetros de crescimentos, composição do filé, enzimas metabólicas hepáticas e morfometria do intestino e fígado foram analisados em delineamento inteiramente casualizado com quatro tratamentos e quatro repetições. O aumento de proteína na dieta proporcionou melhor ganho em peso. As enzimas do metabolismo hepático aumentaram nos peixes alimentados com 24%PD. Não foram observadas alterações histopatológicas no fígado dos peixes. A histologia do intestino revelou adaptação ao aumento de proteína na dieta até o nível de 26% PD. Os juvenis de surubim mostraram-se exigentes em proteína digestível, apresentando os melhores resultados de desempenho de produção e de eficiência de utilização dos nutrientes com a dieta contendo 28% de PD. Palavras-chave: Espécie neotropical, fontes protéicas, nutrição de peixes, peixes carnívoros AbstractThe Pseudoplatystoma sp. is species of carnivorous fish that require special attention in the diet offered. This work had the objective to determine the digestible protein requirement of juvenile the Pseudoplatystoma sp. reared in net cages. The test consisted of four isoenergetic diets (2606.69 ± 39.16 kcal kg-1 of digestible energy) containing increasing levels of digestible protein (23, 24, 26 and 28%PD) provided to juveniles of surubim (157.35±11.23g) for five months. The parameters of growth, fillet composition, metabolic liver enzymes and morphometry of the intestine and liver were

O objetivo deste trabalho foi avaliar a histologia e a histoquímica do intestino anterior de tilápia do Nilo alimentadas com dietas contendo farinha de peixe ou silagem de peixe como fonte de proteína de origem animal. A espessura da vilosidade intestinal dos peixes alimentados com silagem fermentada de resíduo de tilápia foi influenciada pelos teores proteicos, independente das proporções de proteína de origem animal das dietas. Observou-se que a variação da intensidade de secreção de glicoproteínas pelas células caliciformes está diretamente ligada com o tipo de dieta fornecida aos animais. O intestino médio de Oreochromis niloticus apresentou diferenças no padrão de secreção de muco glicoproteico neutro, glicoproteínas ácidas e glicoconjugados, dependendo da origem da proteína e da porcentagem utilizada na dieta, demonstrando que esta espécie pode adaptar seu sistema de secreção para a proteção do aparelho digestório durante a absorção de diferentes fontes proteicas.