RESUMO
OBJECTIVE: The current study was conducted to evaluate the quality and profile of fatty acid in the breast and thigh, and the performance of broilers fed diets containing seed or oil of chia (Salvia hispanica L.) as a replacement for soybean, in the rearing period from 29 to 42 days of age. METHODS: On the 29th day of age, 120 broilers were distributed in four treatments evaluated in five replicates of six birds. The grain or oil of soybean was respectively replaced on a weightto-weight basis in the formulation by the seed or oil of chia, constituting the experimental diets. The roasted whole soybean and chia seed were included in the feed at 16.4%, whereas the soybean and chia oils were included at 2.5%. RESULTS: The dietary chia oil increased the lipid peroxidation in the thigh meat, and the dietary chia seed increased the cooking loss of the thigh. However, for the other physicochemical parameters evaluated and for the proximate composition of the breast and thigh, in general, the inclusion of chia seed or oil in the diet provided similar or better results than those observed when the diets contained soybean oil or roasted whole soybean. With regard to the fatty acid profile and associated parameters, dietary chia increased the concentrations of α-linolenic, eicosapentaenoic, and docosahexaenoic acids and reduced the Σω-6:Σω-3 ratio and the atherogenicity and thrombogenicity indices of the broiler meat. However, the dietary chia seed worsened the feed conversion ratio. CONCLUSION: Diet containing 2.5% chia oil supplied to broilers during the period from 29 to 42 days of age improves the feed conversion ratio, increases the deposition of the ω-3 fatty acids in the breast and thigh, in addition to reducing the Σω-6:Σω-3 ratio and the atherogenicity and thrombogenicity indices, thereby resulting in meat with higher nutritional quality.
RESUMO
Goblet cells (GCs) and endocrine cells (ECs) play an important role in intestine physiology, and few studies currently exist for Amazonian fishes. This study aimed to quantify the distribution of GCs and ECs producing cholecystokinin-8 and neuropeptide Y, assessed by mucin histochemistry and peptides immunohistochemistry, in the intestine of two Amazonian species with different feeding habits Tambaqui (Colossosoma macropomum) and hybrid catfish (Pseudoplatystoma reticulatum × Leiarius marmoratus), an omnivore and carnivore, respectively. A systematic literature review correlating feeding habit and GC and EC distribution was also included to contribute to the comparative study. The results of this study provided novel information about the gut cells of Tambaqui and hybrid catfish. Both, GCs and ECs can be found sweeping the entire intestine of Tambaqui and hybrid catfish although the cells can be more concentrated in certain segments. The GCs and ECs in Tambaqui were more uniformly distributed in the midgut segments (T1, T2, and T3). Unlike, in hybrid catfish GCs were more concentrated in the hindgut (C4) and ECs mainly in the two midgut segments (C1 and C2) of hybrid catfish. Based on the comparison between Tambaqui, hybrid catfish, and other fishes in the literature review, we suggest that cell distribution can be partially explained by feeding habits, carnivorous vs. omnivorous.
Assuntos
Peixes-Gato/genética , Células Endócrinas/citologia , Água Doce , Hibridização Genética , Intestinos/citologia , Animais , Contagem de Células , Colecistocinina/metabolismo , Mucinas/metabolismo , Neuropeptídeo Y/metabolismo , Fragmentos de Peptídeos/metabolismo , Revisões Sistemáticas como AssuntoRESUMO
Insects are a valuable source of nutrients for fish, but little is known about their nutritional value for Nile tilapia fingerlings. To evaluate the nutritional value and energy apparent digestibility coefficient (ADC) of five insects for Nile Tilapia male fingerlings, 900 fish were distributed in 18 fiberglass conic tanks, in a completely randomized design, with six dietary treatments (control, Nauphoeta cinerea meal (NCM) (Blattodea), Zophobas morio larvae meal (ZMM) (Coleptera), Gromphadorhina portentosa meal (GPM) (Blattodea), Gryllus assimilis meal (GAM) (Orthoptera) and Tenebrio molitor larvae meal (TMM) (Coleptera)) and three replicates (tanks), each containing 50 fish. The control diet had no insect meal included and the other five treatments comprised 80% commercial diet and 20% test ingredient with 0.1% chromic oxide as an inert marker. TMM presented a higher ADC for dry matter, protein, corrected protein and chitin than to other treatments (p < 0.01). GPM presented the highest ADC for lipids (p < 0.01). In general, the TMM presented better ADC of nutrients and energy and all the insect meals evaluated are potential feed for Nile tilapia fingerlings.
RESUMO
Solid-phase microextraction (SPME) and single-drop microextraction (SDME) in headspace mode, were used in the residual determination of the anesthetic 2-phenoxyethanol in fish fillets, to ensure food safety. For the optimization of the methodologies the experimental central composite design (CCD) was used, resulting in accurate evaluations with less amount of analysis. The developed methodologies presented good precision in the evaluated range, o limits of detection (LD) and quantification (LQ) for SDME were 0.2 and 0.62⯵gâ¯mL-1 and for SPME were 0.18 and 0.56⯵gâ¯mL-1, respectively. In the analyzed samples the determined elimination time of post-anesthesia 2-phenoxyethanol was 12â¯h for the SDME and 24â¯h for the SPME, at the anesthesia concentrations evaluated (450-1050⯵gâ¯mL-1). The two techniques presented viability of application for the residual determination of 2-phenoxyethanol in fish, SPME being more sensitive and automated and SDME with lower operation cost.
Assuntos
Etilenoglicóis/análise , Peixes , Contaminação de Alimentos/análise , Microextração em Fase Sólida/métodos , Animais , Alimentos Marinhos/análiseRESUMO
This study evaluated the effect of the consumption of different levels and sources of lipids on metabolic parameters of Wistar rats. Animals were fed with high-fat diet (HFD) containing 20% of lard for 12 weeks to cause metabolic obesity. Subsequently, the animals were divided into six groups and were fed diets with lipid concentrations of 5% or 20% of lard (LD), soybean oil (SO) or fish oil (FO), for 4 weeks. Data were submitted to analysis of variance (two-way) followed by Tukey post hoc test (p < 0.05). The groups that consumed FO showed less weight gain and lower serum levels of triacylglycerol (TAG), total cholesterol and fractions, aspartate aminotransferase (AST) activity, atherogenic index, less amount of fat in the carcass, decreased Lee index and lower total leukocyte counting (p < 0.05). These same parameters were higher in LD treatment (p < 0.05). In the concentration of 20%, carcass fat content, blood glucose levels, as well as alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) decreased in FO groups (p < 0.05). The SO group had intermediate results regarding the other two treatments (FO and LD). We concluded that fish oil intake was able to modulate positively the metabolic changes resulting from HFD.
Assuntos
Dieta Hiperlipídica , Metabolismo Energético/efeitos dos fármacos , Óleos de Peixe/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Obesidade/prevenção & controle , Adiposidade/efeitos dos fármacos , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Biomarcadores/sangue , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/metabolismo , Modelos Animais de Doenças , Óleos de Peixe/metabolismo , Lipídeos/sangue , Masculino , Obesidade/sangue , Obesidade/etiologia , Obesidade/fisiopatologia , Ratos Wistar , Óleo de Soja/administração & dosagem , Óleo de Soja/metabolismo , Fatores de Tempo , Aumento de Peso/efeitos dos fármacos , gama-Glutamiltransferase/sangueRESUMO
An experiment was conducted during 60 days with forty pacu males fed diets supplemented with increasing concentrations of ractopamine (0.00, 11.25, 22.50, 33.75, and 45.00 mg kg−1). Eight fish were evaluated for each experimental diet. Performance and survival rate of the fish were measured. At the end of the experiment, blood was collected to determine the levels of cortisol, triacylglycerol, and protein. Moreover, the liver was collected to determine the activities of glucose-6-phosphate dehydrogenase and malic enzymes. The fillets were collected to determine chemical composition, and histologic cuts were analyzed to verify muscle growth and deposition of adipose tissue between muscle fibers. Increasing concentrations of dietary ractopamine did not change feed intake, fillet yield, fillet content of protein and ash, and frequency of relative distribution of muscle fibers. By increasing the dietary ractopamine concentration, the serum cortisol level was elevated. Ractopamine supplementation (45.00 mg kg−1) increased serum levels of triacylglycerol and protein and reduced the activity of hepatic lipogenic enzymes and the survival rate of the fish, probably in response to the high concentration of circulating cortisol. In addition, the higher level of ractopamine supplementation evaluated in this research impaired the weight gain and feed conversion. However, 11.25 mg kg−1 ractopamine reduced the ether extract level determined in the fillet and the fat deposition between muscle fibers, improving the nutritional quality of meat.(AU)
Assuntos
Animais , Antagonistas Adrenérgicos beta/administração & dosagem , Ingestão de Alimentos/fisiologia , Caraciformes/fisiologia , Aditivos Alimentares/análiseRESUMO
Endocrine cells (ECs) act as a luminal surveillance system responding to either the presence or absence of food in the gut through the secretion of peptide hormones. The aim of this study was to analyze the effects of feeding and fasting on the EC peptide-specific distribution along the intestine of Nile tilapia. We assessed the density of ECs producing gastrin (GAS), cholecystokinin-8 (CCK-8), neuropeptide Y (NPY), and calcitonin gene-related peptide (CGRP) in nine segments of the intestine using immunohistochemistry. Our results show that ECs immunoreactive to CCK-8, GAS, NPY, and CGRP can be found along all the intestinal segments sampled, from the midgut to hindgut, although differences in their distribution along the gut were observed. Regarding nutrient status, we found that the anterior segments of the midgut seem to be the main site responding to luminal changes in Nile tilapia. The NPY+ and CGRP+ EC densities increased in the fasted group, while the amount of CCK-8+ ECs were higher in the fed group. No effects of fasting or feeding were found in the GAS+ EC densities. Changes in ECs density were found only at the anterior segments of the intestine which may be due to the correlation between vagus nerve anatomy, EC location, and peptide turnover. Lastly, ECs may need to be considered an active cell subpopulation that may adapt and respond to different nutrient status as stimuli. Due to the complexity of the enteroendocrine system and its importance in fish nutrition, much remains to be elucidated and it deserves closer attention.
Assuntos
Ração Animal , Ciclídeos/fisiologia , Células Endócrinas/metabolismo , Privação de Alimentos , Intestinos/citologia , Hormônios Peptídicos/metabolismo , Animais , Regulação da Expressão Gênica , Intestinos/inervação , Hormônios Peptídicos/genéticaRESUMO
This study investigated the effect of dietary glycerol on the metabolism of juvenile tilapia (Oreochromis mossambicus) and to determine its metabolic fate. The experimental diets contained 0% (Group CON), 5% (Group G5) and 15% glycerol (Group G15) and were fed for 40 d to apparent satiation, three times a day. For the metabolism trials, six fish from each treatment were randomly chosen and tube-fed with five pellets labelled with 14C-glycerol [14C(U)] in order to evaluate the absorption, catabolism, retention and partition of glycerol in muscle and liver. Group G5 presented the highest 14C-glycerol retention and the lowest catabolism, with no significant differences between Groups CON and G15. In Group CON, the highest percentage of 14C was incorporated in muscle lipids; with no significant differences between Groups G5 and G15. Furthermore, no treatment effects were found for hepatic 14C-lipid and for 14C in hepatic and muscle non-lipid extract. In the non-lipid and non-protein fraction, the highest radioactivity was measured in livers of Group G5, however no significant differences were found for this fraction between Groups CON and G15 in liver and for all treatments in muscle. The results of the present study can have practical implications in diet formulations for tilapia and for other aquaculture species with similar feeding pattern since juvenile tilapia are able to metabolise dietary glycerol into lipids, protein and/or carbohydrates and to use it as energy source.
Assuntos
Carboidratos da Dieta/metabolismo , Glicerol/metabolismo , Fígado/metabolismo , Músculos/metabolismo , Tilápia/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Distribuição AleatóriaRESUMO
We evaluated training adaptation and physical performance parameters in rats orally supplemented with glycerol, glucose, or saline, and submitted to moderate aerobic exercise. Thirty male rats were trained for 6 weeks and administered the supplements during the last 4 weeks of the experiment. Animals were distributed in a completely randomized factorial 2 × 3 design (with or without exercise and 3 substrates). Data were subjected to analysis of variance (ANOVA) and means were compared using the Student-Newmann-Keuls test at 5%. Among the trained animals, none of the substances caused differences in the percentages of protein, fat, or water content in the carcass. Compared with the sedentary animals, the trained animals supplemented with saline and glucose showed a higher protein percentage in the carcass. The relative mass of the heart and adrenal glands was higher in the trained animals. Glycerol improved the protein content in non-trained animals and increased the relative adrenal mass in both groups. Glycerol reduced the variation in levels of lactate and aspartate aminotransferase (AST) during the last exercise session. There was no difference between groups regarding the relative mass of the thymus and gastrocnemius or with the diameter of muscle fibers or the neutrophil-lymphocyte ratio. Supplementation with glycerol was efficient at attenuating variation in AST and lactate levels during exercise.
Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/fisiologia , Suplementos Nutricionais , Glicerol/administração & dosagem , Condicionamento Físico Animal/fisiologia , Administração Oral , Animais , Masculino , Fadiga Muscular/efeitos dos fármacos , Fadiga Muscular/fisiologia , Condicionamento Físico Animal/métodos , Ratos , Ratos WistarRESUMO
The aim of this study was to evaluate the influence of dietary lipid sources on Nile tilapia (Oreochromis niloticus) hematological parameters. 112 juveniles of Nile tilapia with average initial weight of 50 ± 12g were distributed in 16 tanks with total capacity of 100L each in a totally randomized design with four treatments and four repetitions with seven fish each replicate. Treatments were composed of: treatment one - soybean oil; treatment two - fish oil; treatment three - linseed oil; treatment four - olive oil. Experimental diets were semipurified, isonitrogenous (32% crude protein) and isocaloric (3200 kcal gross energy/kg of ration). No difference was found between treatments in hemoglobin rates, number of total erythrocytes and leucocytes differential counting (P>0.05). Fish from treatment one presented higher hematocrit rates compared with treatment two and treatment three (P 0.05). The highest level of mean corpuscular volume was observed in fish from treatment four (P 0.05). Fish from treatment three showed higher levels of mean corpuscular hemoglobin concentration compared with treatment four (P 0.05). Dietary lipid sources can influence the hematological parameters of Nile tilapia (Oreochromis niloticus). It was observed a trend of increased erythropoiesis in Nile tilapia fed diets with high levels of -6 series fatty acid.(AU)
Objetivou-se avaliar a influência das fontes de óleo da dieta sobre os parâmetros hematológicos de tilápias do Nilo (Oreochromis niloticus). Foram utilizados 112 juvenis, com peso médio inicial de 50±12g, distribuídos em 16 caixas com capacidade total de 100L cada, num delineamento inteiramente casualizado com quatro tratamentos e quatro repetições, contendo sete peixes por repetição. Os tratamentos eram constituídos por: tratamento um óleo de soja; tratamento dois óleo de peixe; tratamento três óleo de linhaça; tratamento quatro óleo de oliva. As rações eram semipurificadas, isoproteicas (32% de proteína bruta) e isocalóricas (3200 kcal de energia bruta/kg de ração). Não houve diferença (P>0,05) entre os tratamentos quanto ao número e diferenciação de leucócitos, número de eritrócitos totais e níveis de hemoglobina.(AU)
Assuntos
Animais , Ciclídeos/sangue , Ciclídeos/metabolismo , Ração Animal/análise , Ração Animal , Óleos CombustíveisRESUMO
The aim of this study was to evaluate the influence of dietary lipid sources on Nile tilapia (Oreochromis niloticus) hematological parameters. 112 juveniles of Nile tilapia with average initial weight of 50 ± 12g were distributed in 16 tanks with total capacity of 100L each in a totally randomized design with four treatments and four repetitions with seven fish each replicate. Treatments were composed of: treatment one - soybean oil; treatment two - fish oil; treatment three - linseed oil; treatment four - olive oil. Experimental diets were semipurified, isonitrogenous (32% crude protein) and isocaloric (3200 kcal gross energy/kg of ration). No difference was found between treatments in hemoglobin rates, number of total erythrocytes and leucocytes differential counting (P>0.05). Fish from treatment one presented higher hematocrit rates compared with treatment two and treatment three (P 0.05). The highest level of mean corpuscular volume was observed in fish from treatment four (P 0.05). Fish from treatment three showed higher levels of mean corpuscular hemoglobin concentration compared with treatment four (P 0.05). Dietary lipid sources can influence the hematological parameters of Nile tilapia (Oreochromis niloticus). It was observed a trend of increased erythropoiesis in Nile tilapia fed diets with high levels of -6 series fatty acid.
Objetivou-se avaliar a influência das fontes de óleo da dieta sobre os parâmetros hematológicos de tilápias do Nilo (Oreochromis niloticus). Foram utilizados 112 juvenis, com peso médio inicial de 50±12g, distribuídos em 16 caixas com capacidade total de 100L cada, num delineamento inteiramente casualizado com quatro tratamentos e quatro repetições, contendo sete peixes por repetição. Os tratamentos eram constituídos por: tratamento um óleo de soja; tratamento dois óleo de peixe; tratamento três óleo de linhaça; tratamento quatro óleo de oliva. As rações eram semipurificadas, isoproteicas (32% de proteína bruta) e isocalóricas (3200 kcal de energia bruta/kg de ração). Não houve diferença (P>0,05) entre os tratamentos quanto ao número e diferenciação de leucócitos, número de eritrócitos totais e níveis de hemoglobina.
Assuntos
Animais , Ciclídeos/metabolismo , Ciclídeos/sangue , Ração Animal , Ração Animal/análise , Óleos CombustíveisRESUMO
This study aimed to evaluate the effect of the photoperiod on the fillet composition of Nile tilapia juveniles. We employed a completely randomized design with five treatments (0L:24D, 6L:18D, 12L:12D, 18L:6D, 24L:0D) and four replications. We used 160 Nile tilapia juveniles, distributed in 20 tanks containing 20 liters of water, in a recirculation systems, at controlled temperature of 27 C and density of eight fish per tank. Fish were fed twice a day with commercial extruded feed containing 40% crude protein. Samples of the fillet at the end of 75 days were collected and stored in a freezer at -80 C for subsequent analysis of chemical composition. There was no effect of photoperiod on moisture and ash content of the fillet (P>0.05). The period 18L:6D showed higher amounts of protein in the fillet, as well as lower amounts of fat (P 0.05). Therefore, it can be concluded that the photoperiod can alter Nile tilapia body composition, and the photoperiod 18L:6D contributed to the higher concentration of crude protein and lower fat deposition in Nile tilapia fillets.
Com este estudo objetivou-se avaliar o efeito do fotoperíodo sobre a composição centesimal de filés de juvenis de tilápia do Nilo. Utilizou-se um delineamento inteiramente casualizado com cinco tratamentos (0L:24E; 6L:18E; 12L:12E; 18L:6E; 24L:0E) e quatro repetições. Foram utilizados 160 alevinos de tilápia, distribuídos em 20 aquários (20L) em sistema de recirculação, temperatura controlada em 27 C e densidade de oito peixes por aquário. Os peixes foram alimentados duas vezes ao dia, com ração comercial extrusada contendo 40% de proteína bruta. Ao final de 75 dias, amostras do filé foram coletadas e armazenadas em freezer (-80 C) para posteriores análises da composição bromatológica. Não houve efeito dos diferentes fotoperíodos sobre a umidade e cinzas do filé (P>0,05). Por outro lado, os peixes sob fotoperíodo de 18L:6E apresentaram maior quantidade de proteína e retenção desta no filé, assim como menor quantidade de gordura e retenção de lipídeo (P 0,05). Portanto, pode-se concluir que o fotoperíodo pode alterar a composição corporal de alevinos de tilápia do Nilo, sendo que e o fotoperíodo de 18L:6E contribui para o aumento da concentração de proteína bruta e uma menor deposição de gordura no filé.
Assuntos
Carne , Ciclídeos/crescimento & desenvolvimento , Fotoperíodo , Peixes/crescimento & desenvolvimento , Gorduras , Nutrientes/análiseRESUMO
This study aimed to evaluate the effect of the photoperiod on the fillet composition of Nile tilapia juveniles. We employed a completely randomized design with five treatments (0L:24D, 6L:18D, 12L:12D, 18L:6D, 24L:0D) and four replications. We used 160 Nile tilapia juveniles, distributed in 20 tanks containing 20 liters of water, in a recirculation systems, at controlled temperature of 27 C and density of eight fish per tank. Fish were fed twice a day with commercial extruded feed containing 40% crude protein. Samples of the fillet at the end of 75 days were collected and stored in a freezer at -80 C for subsequent analysis of chemical composition. There was no effect of photoperiod on moisture and ash content of the fillet (P>0.05). The period 18L:6D showed higher amounts of protein in the fillet, as well as lower amounts of fat (P 0.05). Therefore, it can be concluded that the photoperiod can alter Nile tilapia body composition, and the photoperiod 18L:6D contributed to the higher concentration of crude protein and lower fat deposition in Nile tilapia fillets.(AU)
Com este estudo objetivou-se avaliar o efeito do fotoperíodo sobre a composição centesimal de filés de juvenis de tilápia do Nilo. Utilizou-se um delineamento inteiramente casualizado com cinco tratamentos (0L:24E; 6L:18E; 12L:12E; 18L:6E; 24L:0E) e quatro repetições. Foram utilizados 160 alevinos de tilápia, distribuídos em 20 aquários (20L) em sistema de recirculação, temperatura controlada em 27 C e densidade de oito peixes por aquário. Os peixes foram alimentados duas vezes ao dia, com ração comercial extrusada contendo 40% de proteína bruta. Ao final de 75 dias, amostras do filé foram coletadas e armazenadas em freezer (-80 C) para posteriores análises da composição bromatológica. Não houve efeito dos diferentes fotoperíodos sobre a umidade e cinzas do filé (P>0,05). Por outro lado, os peixes sob fotoperíodo de 18L:6E apresentaram maior quantidade de proteína e retenção desta no filé, assim como menor quantidade de gordura e retenção de lipídeo (P 0,05). Portanto, pode-se concluir que o fotoperíodo pode alterar a composição corporal de alevinos de tilápia do Nilo, sendo que e o fotoperíodo de 18L:6E contribui para o aumento da concentração de proteína bruta e uma menor deposição de gordura no filé.(AU)
Assuntos
Fotoperíodo , Ciclídeos/crescimento & desenvolvimento , Peixes/crescimento & desenvolvimento , Carne , Nutrientes/análise , GordurasRESUMO
This study aimed to evaluate the effect of the photoperiod on the fillet composition of Nile tilapia juveniles. We employed a completely randomized design with five treatments (0L:24D, 6L:18D, 12L:12D, 18L:6D, 24L:0D) and four replications. We used 160 Nile tilapia juveniles, distributed in 20 tanks containing 20 liters of water, in a recirculation systems, at controlled temperature of 27 ºC and density of eight fish per tank. Fish were fed twice a day with commercial extruded feed containing 40% crude protein. Samples of the fillet at the end of 75 days were collected and stored in a freezer at -80 ºC for subsequent analysis of chemical composition. There was no effect of photoperiod on moisture and ash content of the fillet (P>0.05). The period 18L:6D showed higher amounts of protein in the fillet, as well as lower amounts of fat (P 0.05). Therefore, it can be concluded that the photoperiod can alter Nile tilapia body composition, and the photoperiod 18L:6D contributed to the higher concentration of crude protein and lower fat deposition in Nile tilapia fillets.
Com este estudo objetivou-se avaliar o efeito do fotoperíodo sobre a composição centesimal de filés de juvenis de tilápia do Nilo. Utilizou-se um delineamento inteiramente casualizado com cinco tratamentos (0L:24E; 6L:18E; 12L:12E; 18L:6E; 24L:0E) e quatro repetições. Foram utilizados 160 alevinos de tilápia, distribuídos em 20 aquários (20L) em sistema de recirculação, temperatura controlada em 27 ºC e densidade de oito peixes por aquário. Os peixes foram alimentados duas vezes ao dia, com ração comercial extrusada contendo 40% de proteína bruta. Ao final de 75 dias, amostras do filé foram coletadas e armazenadas em freezer (-80 ºC) para posteriores análises da composição bromatológica. Não houve efeito dos diferentes fotoperíodos sobre a umidade e cinzas do filé (P>0,05). Por outro lado, os peixes sob fotoperíodo de 18L:6E apresentaram maior quantidade de proteína e retenção desta no filé, assim como menor quantidade de gordura e retenção de lipídeo (P 0,05). Portanto, pode-se concluir que o fotoperíodo pode alterar a composição corporal de alevinos de tilápia do Nilo, sendo que e o fotoperíodo de 18L:6E contribui para o aumento da concentração de proteína bruta e uma menor deposição de gordura no filé.
RESUMO
This study aimed to determine the induction and recovery time in Nile tilapia (Oreochromis niloticus) submitted to the anaesthetic agents 2-phenoxyethanol and menthol. Five concentrations were evaluated of the 2 phenoxyethanol (0.45 mL L-1; 0.60 mL L-1; 0.75 mL L-1; 0.90 mL L-1; 1.05 mL L-1) and menthol (50 mg L-1; 75 mg L-1; 100 mg L-1; 125 mg L-1; 150 mg L-1) in masculinized juvenile tilapia. The experiments were conducted independently in a completely randomized design (CRD), consisting of five treatments for each anaesthetic and 20 repetitions (fish) per treatment. The induction and recovery from anesthesia were divided into three stages, according to the fishes' behavior under the effect of the anesthetic, recording the length of time for each stage. Limnological parameters of water were controlled (pH and dissolved oxygen). Statistical analysis was performed using a generalized linear model with gamma distribution. From this study, it is possible to conclude that, for Nile tilapia juvenile under the same conditions of maintenance, with increasing concentration of 2-phenoxyethanol and menthol there is a reduction in the time of anesthetic induction and recovery. Concentrations of 0.90 mL L-1 of 2-phenoxyethanol and 125 mg L-1 of menthol were suitable for anesthetic induction in tilapia.
Este estudo teve como objetivo determinar o tempo de indução e recuperação em tilápias nilóticas (Oreochromis niloticus) submetidas aos anestésicos 2-fenoxietanol e mentol. Foram avaliadas cinco concentrações anestésicas do 2-fenoxietanol (0,45 mL L-1; 0,60 mL L-1; 0,75 mL L-1; 0,90 mL L-1; 1,05 mL L-1) e mentol (50 mg L-1; 75 mg L-1; 100 mg L-1, 125 mg L-1; 150 mg L-1), em juvenis machos revertidos de tilápia. Os experimentos foram desenvolvidos independentemente, em delineamento inteiramente casualizado (DIC), compostos de cinco tratamentos para cada anestésico e 20 repetições (peixes) por tratamento. A indução e a recuperação da anestesia foram divididas em três estágios de acordo com o comportamento dos peixes sob efeito do anestésico, registrando-se o tempo de permanência em cada estágio. As variáveis limnológicas da água foram controladas (pH e oxigênio dissolvido). Para análise estatística foi utilizado um modelo linear generalizado com distribuição gama. A partir deste estudo pode-se concluir que, para juvenis de tilápia nilótica sob as mesmas condições de manutenção, com o aumento da concentração de 2-fenoxietanol e mentol ocorre uma redução do tempo de indução e recuperação anestésica. As concentrações de 0,90 mL L-1 de 2-fenoxietanol e 125 mg L-1 de mentol foram adequadas para indução anestésica em tilápias para fins de manejo.