Hook selectivity of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the Pantanal, the state of Mato Grosso do Sul, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Yield per recruit of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the pantanal of Mato Grosso do Sul, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ecology of the parasitic endohelminth community of Piaractus mesopotamicus (Holmberg, 1887) (Characiformes) from Aquidauana and Miranda Rivers, Pantanal, state of Mato Grosso do Sul, Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diversidade e distribuição espaço-temporal de anuros em região com pronunciada estação seca no sudeste do Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morfoanatomia do sistema subterrâneo de Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson (Asteraceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morfoanatomia e ontogênese das sementes de espécies de Banisteriopsis C.B. Robinson e Diplopterys A. Juss. (Malpighiaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

EFFECT OF ASCORBIC-ACID DEFICIENCY ON THE GROWTH, GILL FILAMENT LESIONS AND BEHAVIOR OF PACU FRY (PIARACTUS-MESOPOTAMICUS HOLMBERG, 1887)

The effect of ascorbic acid deficiency was determined in Piaractus mesopotamicus Holmberg, 1887, fish (pacu) under laboratory conditions. A total of 120 fish with an average body weight of 8.64 +/- 1.62 g and measuring 6.15 +/- 0.33 cm in length at the beginning of the experiment were fed diets containing 0, 50, 100 or 200 mg palmitate-coated ascorbic acid/kg dry ration for a period of 24 weeks with measurements every 4 weeks. The experiment was conducted in 20 fiber-cement aquaria of 81-liter capacity. Each aquarium was supplied with dechlorinated water at a flow rate of 1 l/min. Water temperature was measured daily and pH, dissolved oxygen, alkalinity and water conductivity were determined weekly. A fully randomized experimental design was utilized, with 5 replicates of each treatment and 6 fish per aquarium. Ascorbic acid-supplemented fish presented significantly increased growth when compared to unsupplemented fish. Furthermore, unsupplemented fish presented a higher incidence of hyperplasia, hypertrophy and dysplasia of the bone cartilage of gill filaments. The gill lamellae of unsupplemented fish had twisted cartilage and an inflammatory infiltrate at the ends. Anorexia and increased handling stress were also observed in fish fed the unsupplemented diet. The present study suggests that 50 mg ascorbic acid/kg dry ration is sufficient to improve development of pacu fingerlings but the optimum level under aquarium conditions, determined by regression analysis, is 139 mg ascorbic acid/kg dry ration.

Growth and metabolism of pacu (Piaractus mesopotamicus Holmberg 1887) juveniles fed diets containing different protein, lipid and carbohydrate levels

To verify the potential of lipids and carbohydrates to spare dietary protein and to understand the intermediary metabolism of interaction of these nutrients in pacu juveniles, an experiment was carried out to evaluate pacu physiological and performance parameters. The experimental design was completely randomized with 12 treatments in a 2 x 2 x 3 factorial arrangement, consisting of diets containing two digestible protein levels (200 and 230 g kg(-1) PD), two lipid levels (40 and 80 g kg(-1)) and three carbohydrate levels (410, 460 and 500 g kg(-1)). Fish-fed 230 g kg(-1) digestable protein (DP) showed increased glycaemia, decreased hepatic glycogen, as well as a smaller intake index and better feed conversion ratio. The higher dietary lipid level (80 g kg(-1)) reduced protein intake and serum protein concentration, increased liver and body fat content, but did not affect growth. At a lipid level of 80 g kg(-1), the increase in dietary carbohydrate levels promoted greater weight gain (WG), crude protein intake (CPI) and better feed conversion ratio (FCR). For fish fed diets containing 40 g kg(-1) lipid, the best energy-productive values (EPV) were obtained at 460 g kg(-1) carbohydrate. Increased levels of the main nutrients in the diets reduced the levels of serum triglycerides, while the increase in energy concentration increased the hepatosomatic (HSI) and glycaemia index values. Pacu used lipids as effectively as carbohydrates in the maximization of protein usage, as long as dietary protein was at a level of 230 g kg(-1) DP. The physiological parameters indicated that the best balance between the DP, dietary lipid and carbohydrate levels within the ranged this trial was obtained at 230, 40 and 460 g kg(-1), respectively, without lower growth.

Growth and survival of pacu Piaractus mesopotamicus (Holmberg, 1887) juveniles reared in ponds or at different initial larviculture periods indoors

Five-day-old pacu larvae (Piaractus mesopotamicus) with average length and weight of 5.96 mm and 0.42 mg, respectively, were reared as follows: in a semi-intensive system with larvae stocked directly into fertilized ponds (IL0)-and an initial intensive larviculture system with larvae maintained in a laboratory for 3 (IL3), 6 (IL6) and 9 (IL9) days, before being transferred to fertilized ponds. During the indoor phase, larvae were fed Artemia nauplii. Intensive-culture survivals were high (95.6%, 86.4% and 83.8% for IL3, IL6 and IL9, respectively) and at the end of the 45-day period, the longer the larvae were kept in the intensive system, the better the juvenile survival in the ponds. IL9 and IL6 survival rates were 54.0% and 45.4%, respectively, significantly higher (P < 0.05) than IL0 (11%) and IL3 presented an intermediate rate (25.3%). Due to the low survival rate of IL0, length and weight were higher (P < 0.05) when compared to IL6 and IL9; and the differences between their survival rates affected size distribution of juveniles among treatments. Treatments, which resulted in high survival (IL6 and IL9), presented a great number of small fish. In contrast, IL0 and IL3 produced many large and extra large individuals. In general, the results indicate that pacu juvenile production by initial intensive larviculture (IL6 and IL9) was the most efficient method. Therefore, further studies should be conducted in order to improve larval growth in the laboratory and handling techniques in both the laboratory and ponds. (C) 2003 Elsevier B.V. B.V. All rights reserved.

On the synonymy between Paraponychus corderoi (Baker & Pritchard, 1962) and P. incanus Gonzalez & Flechtmann, 1977 (Acari, Tetranychidae)

In this paper we propose a new synonymy between P. corderoi (Baker & Pritchard, 1962) and P. incanus Gonzalez & Flechtmann, 1977, based on the examination of type-specimens.

Henneguya piaractus n.sp. (Myxozoa: Myxobolidae), a gill parasite of Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes: characidae), in Brazil

Henneguya piaractus n.sp. was found from the gill filaments of Piaractus mesopotamicus (Characidae). Fishes were collected during a year from the reservoir at Centro de Aquicultura da UNESP, Jaboticabal, SP, Brazil. The prevalence of this parasite was 97.3% in the gills of farmed fish. Observations on spore development into the cysts were done. Studies with scanning electon microscopy were performed to observe the spore and cyst structure.

Le progrès technique chez Joan Robinson : un essai de systématisation et de formalisation

This paper deals with Joan Robinson's contributions to the issue of technical progress and her attempts of treating this subject in accordance to the Keynesian theory of employment and income distribution, mainly in the long run. This paper aims to review this aspect of her work and to establish a systematisation and a formalisation of her approach. At the same time the paper exposes the problems she faced - and did not always solve. Looking through her main contributions, the paper concludes that she used different criteria for the classification of innovations and that they depended on the specific situations described by the models in which she used the classification.

Composição corporal e índices biométricos do pacu, Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes, Characidae) submetido a ciclos alternados de restrição alimentar e realimentação

The present paper evaluated, through hepatosomatic/mesenteric fat indexes and body composition, the pacu energy utilization when submitted to alternated food restriction/refeeding cycles during the growout period. Juveniles were distributed in three pounds and submitted to different feeding programs: A (ad libitum daily feeding), B (4-week feeding restriction and 9-week refeeding) and C (6-week feeding restrictions and 7-week refeeding), totaling 13 weeks for each cycle (4 experimental cycles). At the end of the periods, fish were sampled to obtain biometrics and biochemical data. The results showed that, during the first two cycles, C treatment obtained the best compensatory growth. Carcass lipid and water contents were inversely related, with body fat decrease. Fishes under B and C treatment during food restriction utilized liver and mesentery energy stores. These parameters were re-established in the refeeding phase, in all cycles.