Rafael Lazzari

Alimentação do jundiá com dietas contendo óleos de arroz, canola ou soja

O objetivo deste trabalho foi avaliar a influencia de oleos vegetais no desenvolvimento corporal e composicao do file de jundias. Foram testadas seis dietas (32%PB), sendo avaliados oleos de arroz, canola ou soja com 5 ou 10% de inclusao, durante 90 dias. Os peixes (180, peso inicial=71,0±0,8g) foram distribuidos ao acaso em 18 caixas (280L) de um sistema de recirculacao de agua, com temperatura controlada. Para avaliacao de desempenho, estimaram-se variaveis como peso, comprimentos totais, padrao, altura caudal, sobrevivencia, taxa de crescimento especifico, fator de condicao, consumo diario, conversao alimentar aparente e rendimento de partes comestiveis. Alem disso, foram avaliadas a composicao centesimal e taxas de deposicao de proteina e gordura nos files. Nao houve diferencas entre os oleos e os niveis sobre o crescimento dos peixes; entretanto, os jundias alimentados com 10% de oleo depositaram mais gordura no file. Conclui-se que os oleos de canola, arroz e soja proporcionam bom crescimento e rendimento de partes comestiveis. As dietas contendo oleo de canola, com 5% de inclusao, possibilitam menor deposicao de gordura no file.

Protein sources and digestive enzyme activities in jundiá (Rhamdia quelen)

Digestive enzymes activity influence feed utilization by fish, and its understanding is important to optimize diet formulation. This study reports the digestive enzyme activities of jundia juveniles fed diets with protein sources. Fish were fed six experimental diets for 90 days: MBY (meat and bone meal + sugar cane yeast), SY (soybean meal + sugar cane yeast), S (soybean meal), MBS (meat and bone meal + soybean meal), FY (fish meal + sugar cane yeast) and FS (fish meal + soybean meal), and then sampled every 30 days and assayed in two intestine sections for digestive enzymes - trypsin, chymotrypsin and amylase - activities; gastric protease was assayed in the stomach. Digestive and hepatosomatic index, intestinal quotient, digestive tract length and weight gain were also measured. Trypsin and chymotrypsin activities were higher (p < 0.0001) in fish fed diets containing animal protein sources (MBY, MBS, FY and FS diets). Alkaline proteases were negatively affected by dietary soybean meal in the SY and S diets. Amylase activity had greater variation between diets and intestine sections. Fish fed MBY and MBS diets showed higher gastric protease activity (p < 0.0001). Weight gains were higher in fish fed the MBS and FS diets (p < 0.05). Highest values (p < 0.05) of digestive tract length were observed in fish fed MBS and FY diets, but no correlation with enzymes activities was found. Hepatosomatic index (HSI) was affected by diet composition. Dietary composition influenced digestive enzymes activities of jundia.

Cultivo de jundiás alimentados com dietas com casca de soja ou de algodão

The objective of this work was to evaluate the effect of crude fiber on growth, digestive parameters, and yield and carcass quality of jundia (Rhamdia quelen) juveniles in net cages. The experimental design was completely randomized in a 2x3 factorial scheme (two sources - soy and cotton hull - and three levels of crude fiber: 4, 7 and 10%), with three replicates. Four hundred and fifty fishes (129.11± 7.8 g) were randomly distributed in 18 net cages (1 m3), at densities of 25 fish per cage, in 0.1 ha earth fishpond. The following parameters were evaluated: weight, total length, weight gain, biomass, survival, carcass and fillet yield, chemical composition of fillet, digestive and hepato-somatic indexes, intestinal quotient. No difference was detected in the growth performance. Fish fed with soy hull diets presented more fat and mineral accumulation on fillets. The sources and fiber levels tested do not affect jundias performance.

Survival, growth and metabolic parameters of silver catfish, Rhamdia quelen, juveniles exposed to different waterborne nitrite levels

Altos niveis de nitrito (NO2-) podem ocorrer em sistemas de cultivo com alta densidade de estocagem, mas analises sobre os valores de concentracao letal e o efeito do NO2- em parâmetros metabolicos e no crescimento sao escassos. Neste estudo foi analisada a concentracao letal em 96 h (CL50-96h) para nitrito (NO2-) em juvenis de jundia, Rhamdia quelen, e o efeito de quatro niveis de nitrito (0,06; 0,46; 1,19 e 1,52 mg.L-1) no crescimento e no lactato, glicose, glicogenio e proteina hepatica e muscular. A CL50-96h para NO2- foi 20,46 (intervalo de confianca: 16,10-23,68) mg.L-1. No experimento de crescimento, a exposicao ao NO2- nao afetou o peso, comprimento ou taxa de crescimento especifico, mas devido a mortalidade (66,7% e 100% apos 20 e 40 dias, respectivamente), a biomassa dos juvenis expostos a 1,52 mg.L-1. NO2- foi significativamente mais baixa que a biomassa dos juvenis expostos aos outros tratamentos. Deste modo, o nivel seguro de NO2- para o crescimento do jundia e abaixo de 1,19 mg.L-1 (2% da CL50-96h). A exposicao do jundia ao NO2- por 40 dias diminuiu os niveis de lactato no musculo, mas esses niveis aumentaram nos exemplares mantidos em 1,19 mg.L-1 NO2-. Alem disso, os niveis de glicose no musculo e figado foram significativamente mais baixos nos jundias expostos a concentracao mais elevada de NO2-. Estes resultados indicam que a exposicao cronica ao NO2- provoca uma oxidacao anaerobica do substrato para obtencao de energia.

Alimentação de fêmeas de jundiá com fontes lipídicas e sua relação com o desenvolvimento embrionário e larval

The aim of this study was to evaluate the efficiency of feeding female South America catfish Rhamdia quelen with different lipids sources and their influence in embryo and larval stage. Twelve (12) female catfishes initial weight of 500g, distributed randomly among three (3) net-tanks and fed for ten (10) weeks were used. The female fishes were fed with three (3) different types of experimental diet containing lipid sources: Swine fat (BS), sunflower oil (OG) canola oil (OC). At hatch time, 10 larvae were collected from each net tank. One post larvae sample was collected at 12, 24, 36, 48 hours after hatch to verify measurement. Three samples were captured and raised in reuse water system during fourteen days (30 larvae L-1). The female reproductive performance and the larval development were not affected by the lipid sources tested. The data revealed that swine fat is as good as sunflower and canola oil as lipid sources for reproductive female catfishes and that they can provide excellent embryo and larval development.

Crescimento e alterações no fígado e na carcaça de alevinos de jundiá alimentados com dietas com aflatoxinas

O objetivo deste trabalho foi avaliar o efeito das aflatoxinas sobre o crescimento de alevinos de jundia (Rhamdia quelen), e sua deposicao no figado e na carcaca de peixes alimentados com racao com diferentes teores da micotoxina. Foram utilizados 960 alevinos, em dois experimentos, o primeiro com duracao de 45 dias e o segundo com 35 dias. As instalacoes experimentais foram compostas por um sistema termorregulado de recirculacao de agua. No primeiro experimento, foram avaliados os teores de 41, 90 e 204 ppb de aflatoxinas kg-1 de alimento e no segundo experimento, 350, 757 e 1.177 ppb de aflatoxinas kg-1 de alimento. Foram estimados os seguintes parâmetros: peso medio, comprimento total e padrao, rendimento de carcaca, fator de condicao, ganho diario, sobrevivencia e deposicao de aflatoxinas no figado e na carcaca. Observou-se, no primeiro experimento, diminuicao do peso e comprimento dos peixes alimentados com 204 ppb aflatoxinas kg-1. No segundo experimento, nao ocorreu diferenca significativa nas variaveis analisadas. A partir de 350 ppb kg-1, ocorreram alteracoes no figado e tecidos, sem comprometer o crescimento, durante os 35 dias.

Efeito do gelo clorado sobre parâmetros químicos e microbiológicos da carne de carpa capim (Ctenopharyngodon idella)

The rapid spoilage of fishes causes economical losses in the processing and marketing of these products. In the present study, the efficiency of chlorinated ice to increase grass carp (Ctenopharyngodon idella) shelf life was evaluated. Mesophilic and psychrotrophic bacteria count, total volatile basic nitrogen (TVBN) and pH were evaluated in the flesh of grass carp stored refrigerated (3±1oC) for 20 days, covered with chlorinated (5ppm) or non-chlorinated ice. Chlorine significantly reduced (p<0,05) mesophilic and psychrotrophic bacteria count in the flesh, as well as pH and the initial values of TVBN. TVBN values were low and did not exhibit great changes over the storage time. Results showed that grass carp shelf life could be extended around 3 days by using chlorinated ice. Besides, pH and TVBN values were considered unsuitable to assess grass carp spoilage.

Crescimento de jundiá e carpa húngara criados em sistema de recirculação de água

A study was conducted to evaluate growth, carcass yield and body composition of jundia and common carp raised in mono or duoculture in a recirculated water system, for 60 days, during the growing. Five treatments were tested with three replicates: 100C=100% carp; 100J=100% jundia, 50C50J=50% carp 50% jundia; 75C25J=75% carp 25% jundia and 25C75J=25% carp 75% jundia. Twenty fishes were distributed in each experimental unit. It was evaluated weight (W), total biomass (TB), condition factor (CF), feed conversion rate (FCR), specific growth rate (SGR), carcass yield (YC), digestive-somatic index, hepatossomatic index, intestinal quotient and the proximate composition and body deposition of protein and fat. Considering jundia performance, no statistical difference was observed for W, CF and SGR (P>0.05). Common carp from treatment 25C75J showed the highest values (P<0.05) for these variables. The best FCR and TB values were obtained for 100J and 25C75J treatments. In both species, there were no differences for carcass yield or digestive indexes. Thus, the treatment 25C75J, composed by 25%carp and 75%jundia presented the highest final weight for carp and total biomass.

Desempenho e composição dos filés de jundiás (Rhamdia quelen) submetidos a diferentes dietas na fase de recria

Avaliaram-se o crescimento e a composicao dos files de juvenis de jundia apos 90 dias de alimentacao com dietas contendo diferentes fontes proteicas. Foram utilizados 540 peixes, peso inicial=15,0±0,62g; comprimento inicial=11,98±0,35cm, distribuidos ao acaso em 18 tanques (30 peixes/tanque) com sistema de recirculacao de agua. Foram testadas seis dietas: 1 - farinha de carne e ossos + levedura (CL), 2 - farelo de soja + levedura (SL), 3 - farelo de soja (S), 4 - farinha de carne e ossos + farelo de soja (CS), 5 - farinha de peixe + levedura (PL) e 6 - farinha de peixe + farelo de soja (PS). Avaliaram-se: peso, comprimento total, taxa de crescimento especifico, fator de condicao, sobrevivencia, conversao alimentar aparente, taxa de eficiencia proteica e consumo diario. Tambem foram analisadas as composicoes do file - umidade, proteina, lipidios, cinzas -, as taxas de deposicao de proteina e gordura, alem dos rendimentos de file e carcaca. Maiores pesos, 111,5 e 108,6g, comprimento total, 22,6 e 21,6cm, e taxa de crescimento especifico, 2,1 e 2,2%/dia, foram observados nos peixes alimentados com as dietas CS e PS. Os peixes alimentados com CS e PS tambem apresentaram maior deposicao de proteina, 69,8 e 71,5mg/dia, e lipidios, 77,2 e 78,3mg/dia. A sobrevivencia foi menor na dieta PS, 92,9%. Os maiores rendimentos de carcaca foram observados nos peixes alimentados com PS e PL, 82,9 e 82,7%, e o menor rendimento de file ocorreu na dieta CL, 34,1%.

Uso de eugenol como anestésico em pacu

The different practices used in fish breeding require intense handling, leading to fish stress . The use of anesthetics is important to overcome this problem . This study aimed at evaluating the impact of eugenol on the induction and anesthetic recovery of Piaractus mesopotamicus from different weight classes. An experiment was carried out in a 5x5 factorial scheme, consisting of five weight classes (50 ± 5.61 g, 100 ± 9.36 g, 150 ± 12.29 g, 200 ± 12.73 g and 250 ± 18.77 g) and five eugenol concentrations (40 mg L -1 , 80 mg L -1 , 120 mg L -1 , 160 mg L -1 and 200 mg L -1 ). The anesthesia induction was divided into four stages, according to the behavior of the anesthetized fish, being the duration of each stage recorded, and the desensitization moment and recovery time evaluated. A quadratic effect was observed at the anesthetic induction time, i.e., when the dose increased, the induction time decreased, tending to stabilize for increasing doses. The best results for anesthetic induction were observed at the 175 mg L -1 , 208 mg L -1 , 203 mg L -1 , 240 mg L -1 and 225 mg L -1 concentrations, respectively for the 50 g, 100 g, 150 g, 200 g and 250 g weight classes . No interaction between the shortest induction time and the shortest recovery time was observed. Thus, the doses which provided a lower induction time for the weight classes range between 175 mg L -1 and 240 mg L -1 .