Paula Adriane Perez Ribeiro

Efeito do uso de óleo na dieta sobre a lipogênese e o perfil lipídico de tilápias-do-nilo

A total of 35 males of Nile tilapia, averaging initial weight of 205 g, were maintained in five 250 L metabolism boxes to evaluate the lipid metabolism of Nile tilapias (Oreochromis niloticus). The experiment lasted 30 days, from October to November 2006. The treatments were: control diet plus olive oil; control diet plus corn oil; control diet plus soybean oil; control diet plus linseed oil; control diet plus fish oil. The experiment was in a completely randomized design with five treatments and seven replicates. The evaluated parameters were: fatty acid profile of the muscle tissue and hepatic activity of glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME). The data were submitted to variance analysis and the means of the treatments were compared by Scott-Knotts test (5% of significance). The fish fed on a diet rich in polyunsaturated fatty acids presented increased contents of such fat acids in their lipid muscle composition. The hepatic activity of G6PD was superior to that of ME, being higher in the specimen fed rations containing olive, corn and soybean oil, thus, evidencing the highest lipid muscle deposition of these fish.

Efficiency of eugenol as anesthetic for the early life stages of Nile tilapia (Oreochromis niloticus)

In aquaculture, activities with anesthetic compounds are usually used in order to ensure the welfare of farmed fish, allowing handling out of water with decreased trauma by stress. Presently, there is no information about anesthetic action of eugenol in early life stages of Nile tilapia (Oreochromis niloticus). The objective of this study was to evaluate different concentrations of eugenol for larvae and juveniles of Nile tilapia. Sixty animals were used for each group of weight, group I = 0.02 g; group II = 0.08 g; group III = 0.22 g; group IV = 2.62 g; and group V = 11.64 g. The eugenol concentrations tested were 50, 75, 100, 125, 150 and 175 mg L-1. No mortality was reported during the tests with eugenol. Tilapia larvae with 0.02 g and juveniles around 11.64 g can be anesthetized with eugenol concentrations between 150 and 175 mg L-1, since they determine the shortest sedation time (23 and 72 seconds, for the group of lowest and highest weights, respectively).

Performance and stress resistance of Nile tilapias fed different crude protein levels

The objective of this study was to evaluate the effect of different levels of diet crude protein on the performance and stress resistance rate (Re) of Oreochromis niloticus larvae and fingerlings. In the first experiment, 5, 15 and 25 day-old animals were submitted to 1, 5, 7, 10, 15, 20, 30 and 40 minutes of air exposure on a sieve. In the second experiment, tilapia larvae were fed with 32, 40 and 55% crude protein (CP) diets. Animals after 15 and 30 days of feeding (21 and 36 days of life, respectively) were submitted to the air exposure test for 7 and 10 minutes. Re was estimated based on survival 24 hours after the tests. In the first experiment, it was observed that 5-day-old animals were more resistant than animals with 10 and 20 days of feeding (15 and 25 days of life, respectively), when Re starts to decrease for longer than 7 minutes. In the second experiment, the different diets affected survival, performance and Re, and, in general, the worst results observed were the ones for the animals which received the 55% CP diet. The air exposure tests were efficient to evaluate the effect of diet on the resistance rate of Nile tilapia.

Influência do tempo de transporte para juvenis de pacamã (Lophiosilurus alexandri)

The aim of this work was to evaluate different transport times for pacama juvenile (Lophiosilurus alexandri) previously trained to feed formulated diets. Four hundred and eighty-six pacama juveniles (2.52±0.71g) were submitted to 24 hours of fasting before transport. The animals were divided into nine plastic bags, with density of 54 juveniles in 5L of clean water for each bag after that inflated with pure oxygen and then sealed. Fish were transported for three hours and bags were open at 5, 6 and 7.5 hours after closing. For each time three replications were used. Survival was monitored for 96 hours post-transport. The longest time tested showed the lowest values of dissolved oxygen and pH, while the total ammonia was similar in the different treatments. Survival was 100% for different transport times after 96 hours. Some juveniles returned to feed 48 hours and the majority 72 hours after opening the bags, suggesting the efficiency of transport made at different times.

Effect of the ration processing on the apparent digestibility values of nutrients for the piau (Leporinus elongatus)

O experimento foi realizado no Centro Nacional de Pesquisa de Peixes Tropicais de Pirassununga, SP, objetivando-se determinar o efeito do processamento da racao sobre os coeficientes de digestibilidade aparente dos ingredientes para o piau (L. elongatus). Foram utilizados 600 machos de piau, distribuidos em seis tanques de 300 L. Os tratamentos aplicados foram: racao farelada, racao peletizada e racao extrusada, formuladas com 32% de PB e 3400 Kcal ED/Kg. O delineamento experimental foi em blocos casualizados, com tres tratamentos, tres blocos e duas repeticoes por tratamento. As analises estatisticas foram realizadas pelo SAEG, com as medias comparadas pelo teste SNK (5%). Houve diferencas entre os coeficientes de digestibilidade da proteina bruta e energia para as racoes peletizada e extusada (P 0,05).

Parâmetros metabólicos de pacus alimentados com diferentes fontes de óleo

The objective of this work was to evaluate the metabolic parameters of pacu (Piaractus mesopotamicus) fed diets with different oils. The experiment was conducted in the laboratory, on May 2009, during 28 days. Sixty four fish with initial weight of 61 g, kept in 250 L tanks, were used. The treatments were: control diet plus olive oil; control diet plus corn oil; control diet plus fish oil; and control diet plus corn oil and fish oil. A completely randomized design was used, with four replicates and a 4x4 factorial arrangement (four diets and four sampling times: 7, 14, 21, and 28 days). The following were evaluated: cholesterol and lipoprotein blood levels, muscle chemical composition, and activity of glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME). The data were subjected to analysis of variance, comparisons of means using the Tukey test, and to regression analysis. There were no differences in muscle levels of moisture or ash, but changes were observed in lipid and protein deposition, depending on collection time, for all treatments. The diets interfered in the evaluated blood parameters. G6PD activity is higher than that of ME, being higher in animals fed with olive and corn oil, suggesting more lipid deposition in the muscles of these fish. Therefore, the lipid metabolism of pacu is influenced by the lipid composition of the diet.