Rhamdia Quelen Quoy Research Articles

Protein to energy ratios and cost, performance, and ammonia excretion in juvenile jundiá (Rhamdia quelen), South American catfish

ABSTRACT: The determination of nutritional requirements, based on diets administered in practice, considers physiological specificities and sustainability are essential to the development of suitable aquaculture technologies for novel fish species. The growth of jundia (Rhamdia quelen Quoy and Gaimard) juveniles (31.54 ± 4.92 g) fed five diets comprising increasing levels of digestible protein (DP: 24, 29, 34, 39, and 44 %) and digestible energy (DE: 12.13, 13.39, 13.81, 14.64, and 15.06 MJ kg−1) with DP:DE ratios: 20, 22, 25, 27, and 29 g MJ−1, respectively, was evaluated. Each diet was fed to three groups of 25 fish for 75 days. Regression analysis showed that the different DP:DE ratios affected both growth and economic performance as well as excretion of total ammonia nitrogen. Fish fed diets with DP:DE ratios between 22 and 27 g MJ−1 achieved a higher daily weight gain, superior apparent net protein utilization, feed conversion rates, and lower feed costs. For the economically viable and environmentally friendly farming of jundia juveniles in the initial grow–out stage (30 to 80 g average weight), the best DP:DE ratio was 25 g MJ−1 DP:DE (34.05 % DP and 13.81 MJ kg−1 DE).

Molecular characterization of the progenetic metacercariae Crocodilicola pseudostoma parasitizing Rhamdia quelen (Siluriformes, Heptapteridae) in Brazil

The trematodes have developed several adaptations and strategies to complete their life cycle in the intermediate host, without even reaching the definitive host. Thus, metacercariae through progeny can produce viable eggs by self-fertilization in the second intermediate host. We analyzed 30 specimens of Rhamdia quelen Quoy & Gaimard 1824 (Siluriformes, Heptapteridae) collected in the Jacaré-Pepira River, Ibitinga. Among the specimens analyzed, only one host was parasitized by the progenetic metacercariae of Crocodilicola pseudostoma Willemoes-Suhm 1870 (Digenea: Proterodiplostomidae) presenting prevalence of 3.3%, mean intensity of 68.0 ± 12.4 and mean abundance of 2.3 ± 0.4. This is the first record of progenesis in the metacercariae of C. pseudostoma in the Jacaré-Pepira River, as well as the first partial sequence of COI gene obtained from this species in Brazil.

Nutrition and Feeding Aspects for Jundiá (Rhamdia quelen) Rhamdia quelen Nutrition and Feeding

AbstractThe jundiá or silver catfish (Rhamdia quelen Quoy & Gaimard, 1824) is species native to the Americas, omnivorous, with a tendency towards carnivorous feeding habits. The species presents commercial potential, and therefore, knowledge on its nutritional requirements, as well as basic feed ingredients, is essential. Its tendency towards carnivorous feeding habits leads to some concerns regarding plant ingredient digestion abilities, although rice, soybean, flax, sorghum, ground corn or oat bran can be used as feed ingredients for this species, since they present good digestibility coefficients. In order to guarantee adequate performance of metabolic, immunological and reproductive functions, jundiá feed can be supplemented with micronutrients that minimize the effects of antinutritional factors present in plant ingredients. Plant ingredients present several economic advantages such as suitable quality, competitive prices and the fact that they are widely available in South Brazil.

Feeding activity and influence of intraspecific competition on zooplankton communities by jundiá (Rhamdia quelen Quoy and Gaimard, 1824) in laboratory.

Experiments were designed to determine if the juvenile forms of jundia (Rhamdia quelen) exhibit selectivity feeding on zooplanktonic organisms and the influence of intraspecific competition on the diet. The fish were maintained in 5000-L containers, and after seven days from birth, they were acclimated in experimental units with different densities and supplied with water containing plankton (natural), where they remained for 24 h in the environment with food. In the first seven days at densities of 5 and 10 fish.L-1, the fish selected the Rotifera more intensely, and at densities of 20 and 40 fish.L-1, the Cladocera were more selected. At 14 days of age, the Cladocera were the most selected for all densities of fish. At 21 days of age, the juvenile forms of jundia maintained a preference for Cladocera, and there was an increase in the capture of Copepoda at a density of 40 fish.L-1. At 28 days of age, the Cladocera were the most captured at densities of 5 to 20 fish.L-1, and the consumption of copepods increased at a density of 40 fish.L-1. The juvenile forms of Rhamdia quelen showed a high feeding preference for Cladocera at all the ages tested (7, 14, 21 and 28 days), but the density of fish per litre influenced the capture of the preferential food. This study showed that the juvenile forms of jundia had a more rapid response to the presence of food at densities of more than 10 fish.L-1, and that at higher densities the fish decreased interactions of territorial defense and formed schools, which allowed the foraging of zooplanktonic organisms, larger in size, more agile and of greater energy gain, such as the Cladocera and copepods.

Resposta fisiológica à infestação experimental com Ichthyophthirius multifiliis (Fouquet, 1876) em alevinos de jundiá (Rhamdia quelen Quoy e Gaimard, 1824) previamente alimentados com diferentes fontes lipídicas

A limiting factor in the early stage of the jundiá (Rhamdia quelen Quoy; Gaimard, 1824) culture is the presence of diseases such as ichthyophthiriasis or "Ich". Dietary polyunsaturated fatty acids (PUFAs) have a potent immunomodulatory activity; and this activity depend of the fish species, quantity/quality of the dietary PUFAS. The aim of this study was evaluate the physiologic response of jundiá, rather fed diets with different sources of fatty acids when challenge to Ich disease. Fingerlings of jundiá (7.6+/-0.8g) were fed during seven weeks with five diets with a different lipid source: fish, linseed and corn oils. Then, the fish were challenged with the Ichthyophthirius multifiliis (Fouquet, 1876). On the 5(th) day, the presence of the disease was detected. Survival rate, blood samples and infection grade were recorded. Diets affect the survival rate of fingerlings, thus fish fed with diet with fish oil showed a higher survival. Hematocrit and infestation grade no recorder differences among treatment. The differential analysis of white blood cells shows difference. The results point out, at first time in jundiá, that dietary lipids caused diversity physiologic response, this may be represent an opportunity for the disease treatment. New studies must be carrying out to deep knowledge found.

Replacement of fish oil with vegetable oils in diets for jundiá (Rhamdia quelen Quoy and Gaimard 1824): effects on performance and whole body fatty acid composition

The jundiá (Rhamdia quelen) is a siluriform with great potential for aquaculture in South America. Fish oil is a raw material in diets for fish. However, the fisheries that provide fish oil have reached their limit of sustainability. Thus, the use of alternative sources for this ingredient is primordial. The aim of this study was to evaluate the performance and body composition of the jundiá fed with different sources of the vegetable oils. Jundiá (1.0±0.2 g) were fed for 31 days with five isonitrogenous (37%) and isoenergetic (19 kJ g−1) diets, in which the following oils were added: 50 g kg−1 corn oil (CO), 50 g kg−1 fish oil (FO), 50 g kg−1 linseed oil (LO), 33.4 g kg−1 fish oil and 16.7 g kg−1 linseed oil (1/3LO), 16.7 g kg−1 fish oil and 33.4 g kg−1 linseed oil (2/3LO). The performance did not show differences between treatments. The final fatty acid profile and n-3/n-6 ratio of the fish were highly influenced by the diet. Fish-fed diets with linseed and/or fish oil showed superior n-3/n-6 ratios to the minimal recommended by the World Health Organization; whereas fish fed diets with corn oil showed an inferior value. Albeit in the present study the commercial size of fish was not attained, these results show a clear tendency. The desaturation/elongation capacity was evidenced, in this species, for the first time. Linseed oil can be utilized as a substitute for fish oil in diets of jundiá without affecting their performance and for producing good-quality fish. However, more studies are necessary to confirm these results for commercial size.

Introduction of jundia Rhamdia quelen (Quoy & Gaimard) and Nile tilapia Oreochromis niloticus (Linnaeus) increases the productivity of carp polyculture in southern Brazil

Fish polyculture is based on the assumption that each species has its own feeding niche and may increase the maximum standing crop of a pond by exploring a wider range of available food and ecological niches. In order to identify the better species ratio and to introduce jundia (JN) (Rhamdia quelen Quoy & Gaimard) and Nile tilapia (NT) (Oreochromis niloticus Linnaeus) in to the carp polyculture practiced in South Brazil, a 162-day experiment was conducted, in 12 250-m2 earthen ponds (1.2 m deep). Treatment I (T-I) contained 35% common carp, Cyprinus carpio (L.) (CC); 35% grass carp, Ctenopharyngodon idella Valenciennes (GC); 15% silver carp, Hypophthalmichthys molitrix Valenciennes (SC); and 15% bighead carp, Aristichthys nobilis Richardson (BC). Treatment II (T-II) consisted of three ponds stocked at the following ratio: 17.5% CC, 35% GC, 15% SC, 15% BC and 17.5% JN. Treatment III (T-III) consisted of three ponds with 35% CC, 35% GC, 7.5% SC, 7.5% BC and 15% NT. Treatment IV (T-IV) consisted of three ponds with 17.5% CC, 35% GC, 7.5% SC, 7.5% BC%, 17.5% JN and 15% NT. No significant correlation was found between the treatments with different species ratio and water quality parameters. The final weight of different species, in different treatments, was statistically different. The major result was the clear positive effect on growth parameters observed by the introduction of JN and/or NT in to the carp polyculture. The yield per hectare was 2083.33±183 kg ha−1 for polyculture with carp species; 2476.67±139.88 kg ha−1 following the introduction of JN only; 2801.67±111.42 kg ha−1 for isolated introduction of NT; and 2506.67±422.31 kg ha−1 for simultaneous introduction of JN and NT. The introduction of JN and/or NT had a positive effect on growth parameters when compared with carp-only polyculture. The reduction in CC ratio also had a positive effect on growth parameters.

Hematological changes in jundiá ( Rhamdia quelen Quoy and Gaimard Pimelodidae) after acute and chronic stress caused by usual aquacultural management, with emphasis on immunosuppressive effects

Blood samples of 1-year-old male jundiá ( Rhamdia quelen, Quoy and Gaimard) were collected to determine the effects of both acute and chronic stress in hematological parameters. The acute stress was induced by draining the water tank and transferring fish to another tank; chronic stress was induced by maintaining the fish in crowded concrete tanks. The cortisol level of male fish, 1 h after transferring from one tank to another, reached 176.78±21.3 ng/ml in contrast to 28.89±5.19 ng/ml found before transferring. Chronic stress, induced by 10 days of crowding in concrete tank, maintained the cortisol levels in approximately 64.48±18.9 ng/ml. The haematological parameters evaluated (RBC, WBC, and haemoglobin) were not significantly affected by acute stressor. However, after 10 days of chronic stimulation, all these values changed, with a significant decrease in lymphocytes, eosinophils, monocytes and special granulocyte cells, as well in RBC and hematocrit. The main result found in this work was the reduction of approximately 80% in the lymphocyte counts. This reduction could lead to a decreased ability to mount an immune response to environmental pathogen and could be an indication that the correct management of brood and culture stocks is important to prevent stress and the deleterious effects of increased cortisol levels to fish health.

Características hematológicas de teleósteos brasileiros: IV. Variáveis do jundiá Rhamdia quelen ( Pimelodidae)

As características hematológicas do jundiá Rhamdia quelen Quoy & Gaimard, 1824 (Osteichthyes: Pimelodidae), oriundo de cativeiro foram estudadas. Determinou-se o valor médio da contagem de eritrócitos, taxa de hemoglobina, hematócrito, volume corpuscular médio (VCM), concentração de hemoglobina corpuscular média (CHCM) e distribuição percentual de células sangüíneas de defesa orgânica. As células sangüíneas de defesa orgânica (leucócitos e trombócitos) foram identificadas e caracterizadas morfologicamente. Trombócitos e linfócitos foram as células sangüíneas de defesa orgânica mais freqüente nas extensões sangüíneas do R. quelen. A análise de regressão mostrou correlação linear negativa entre o percentual de trombócitos e linfócitos. Os resultados deste estudo fornecem valores sangüíneos normais em R. quelen, em cultivo intensivo, que poderão servir de comparação com dados dessa espécie em outras situações de cultivo.