Bernardo Baldisserotto

Analysis of antidiarrhoeic effect of plants used in popular medicine

People customarily use the extracts of plants known to have antidiarrhoeal effects without any scientific base to explain the action of the extract. For this reason, an investigation was undertaken with a view to determining the efficacy of the effects of the brute aqueous extract (BAE) of the leaves of Psidium guajava (guava), Stachytarpheta cayenensis (bastard vervain), Polygonum punctatum (water smartweed), Eugenia uniflora (Brazil or Surinam cherry) and Aster squamatus (zé-da-silva) on the intestinal transport of water in rats and on the gastrointestinal propulsion in mice. With the exception of the BAE of S. cayenensis, all other BAEs have increased the absorption of water in one or more intestinal portion in relation to the control group. All tested BAE, except that of P. punctatum, reduced the gastrointestinal propulsion in relation to that of the control group. The results indicate that the BAE of the leaves of P. guajava, S. cayenensis, P. punctatum, E. uniflora and A. squamatus have a potential antidiarrhoeic effect to be confirmed by additional investigations in animals infected with enteropathogenic agents.

Anesthesia of silver catfish with eugenol: time of induction, cortisol response and sensory analysis of fillet

O objetivo deste estudo foi identificar o tempo de inducao e recuperacao anestesica de jundias (Rhamdia quelen) expostos ao eugenol, bem como a eficacia desse anestesico na inibicao do estresse e realizar analise sensorial dos files dos peixes expostos a essa substância. Os jundias foram expostos ao ar por um minuto para realizacao da biometria, e o sangue foi coletado zero, uma e quatro horas depois. O eugenol pode ser usado na faixa de 20-50mg L-1 para a inducao da anestesia em jundias, e o tempo de recuperacao da anestesia nao foi afetado pela concentracao do eugenol. O grupo de controle mostrou niveis significativamente mais elevados do cortisol quatro horas apos a biometria que no tempo zero. Os peixes anestesiados com eugenol (50mg L-1) apresentaram niveis significativamente mais baixos do cortisol plasmatico do que peixes do grupo de controle do mesmo tempo. Esses dados indicam que o eugenol inibe o aumento do cortisol no sangue. O teste sensorial demonstrou que o eugenol modifica o sabor dos files e consequentemente e contra-indicado para a anestesia do jundia quando o file for destinado ao consumo humano.

Effect of stocking density on water quality, survival, and growth of larvae of the matrinxã, Brycon cephalus (Characidae), in ponds

Experiments were carried out in nine 64 m2 ponds at CEPTA/IBAMA over a period of 21 days in order to evaluate the effect of stocking density (StD) on survival and growth of larvae of matrinxa, Brycon cephalus. The larvae were randomly divided into treatments of 30, 60 and 120 larvae m2 (three replicates per treatment) and fed three times a day. Samples of larvae were collected at days 0, 7, 14 and 21, and the length, weight, coefficient of variation of length, and specific growth rate were determined for each sample. Survival, production and food conversion were calculated at day 21. Data were analyzed statistically by ANOVA and Tukeys multiple range test for mean separation (P<0.05). The following physicochemical parameters of the water were always at satisfactory levels for fish culture throughout the experiments: temperature, dissolved oxygen, pH, hardness, total alkalinity, ammonia and transparency. Increased StD significantly reduced length and weight from day 7, and increased the coefficient of variation of length on day 21. A correlation between specific growth rate and StD was observed only on day 14, and there was no correlation between StD survival. We conclude that an increase in StD reduces the growth and homogeneity but increases the production of B. cephalus larvae.

Piscicultura continental no Rio Grande do Sul: situação atual, problemas e perspectivas para o futuro

This review deals with freshwater fish culture in Rio Grande do Sul State, southern Brazil, and analyzes production and problems of this activity in the last years. This State contributes with a good percentage of Brazilian freshwater fish culture, but its production has been stagnated in the last years. Production is based essentially on exotics fish species (mainly carps). Fish sales are concentrated in the Easter period, and sanitary inspection is still reduced. Fish farmers are making cooperatives in the central region of Rio Grande do Sul. The publishing of books of native species and the freshwater fisheries stagnation in the last years may stimulate the raise of native species, and some are suggested in this review. The culture of native species to be sold as ornamental fishes is still a future option for fish farmers of this State.

Transport of silver catfish (Rhamdia quelen) fingerlings at different times, load densities, and temperatures

Abstract Silver catfish (Rhamdia quelen) fingerlings (5–10 cm) were caught from a fish culture pond and placed in a tank for stomach emptying for 24 h. Fingerlings were then weighed and placed in plastic bags (5 l) with 1.5 l water and oxygen, which were kept at temperatures of 15, 20, and 25 °C. The load densities tested were 50, 67, 87, and 168 g l−1. When bags were opened after 6, 12, or 24 h, mortality, dissolved oxygen, pH, total ammonia, non-ionized ammonia, total hardness, nitrite, total alkalinity, and carbon dioxide levels were determined. There was fingerling mortality only at the load density of 168 g l−1 after 24 h of transport at 20 and 25 °C, suggesting that mortality increased with temperature and time of transport. The dissolved oxygen levels in the water were reduced throughout 24 h of transport in the load density of 168 g l−1 at 20 and 25 °C, but remained unchanged at the other load densities. The pH decreased significantly at all load densities and temperatures throughout 24 h. Total alkalinity, total ammonia, and carbon dioxide levels increased significantly up to 24 h of transport in all treatments. Non-ionized ammonia and nitrite levels were below 0.02 and 0.06 mg l−1, respectively. Total hardness ranged from 20 to 48 mg l−1 CaCO3. The best temperature for transporting fingerlings of this species in plastic bags is 15 °C, because up to 24 h there was no significant mortality even at the load density of 168 g l−1, dissolved oxygen levels were still high, and total ammonia and carbon dioxide presented the lowest increase. Transport at 25 °C and a load density of 168 g l−1 must not exceed 6 h due to the high levels of ammonia and carbon dioxide and low dissolved oxygen levels in the water.

The anesthetic efficacy of eugenol and the essential oils of Lippia alba and Aloysia triphylla in post-larvae and sub-adults of Litopenaeus vannamei (Crustacea, Penaeidae)

The aim of this study was to evaluate the anesthesia induction and recovery times of sub-adult and post-larvae white shrimp (Litopenaeus vannamei) that were treated with eugenol and the essential oils (EOs) from Lippia alba and Aloysia triphylla. Oxidative stress parameters in the hemolymph of this species were also analyzed. The concentrations of eugenol, A. triphylla EO and L. alba EO recommended for anesthesia were 200, 300 and 750 μL L(-1) for sub-adults and 175, 300 and 500 μL L(-1) for post-larvae, respectively. The concentrations studied during the transport of sub-adults were between 20 and 50 μL L(-1) eugenol, 20-30 μL L(-1)A. triphylla EO and 50 μL L(-1)L. alba EO. For post-larvae, the optimal concentrations for transport were 20 μL L(-1) eugenol and between 20 and 50 μL L(-1)A. triphylla EO. The white shrimp sub-adults that were exposed to A. triphylla EO (20 μL L(-1)) showed increases in their total antioxidant capacities (150%), catalase (70%) and glutathione-S-transferase (615%) activity after 6 h. L. alba EO (50 μL L(-1)) and eugenol (20 μL L(-1)) also increased GST activity (1292 and 1315%) after 6 h, and eugenol (20 μL L(-1)) decreased the total antioxidant capacity (100%). Moreover, concentrations above 30 μL L(-1) for the EOs of A. triphylla and L. alba and 20 μL L(-1) eugenol were effective at inducing anesthesia and improving the antioxidant system against reactive oxygen species (ROS) after 6 h.

Survival and growth of silver catfish larvae exposed to different water pH

The objective of this study was to determine the influence ofwater pH (5.5, 6.0, 7.0, 8.0, and 8.5) on survival and growth ofsilver catfsh (Rhamdia quelen) larvae. Larvae were obtained frominduced spawning in November and maintained under controlledconditions of 25 (1) °C using a water re-use system incontinuously aerated 40 L polyethylene tanks (350 larvae/tank).Larvae were fed until satiation six times a day. At days 0, 7, 14,and 21 and after yolk absorption, 10 larvae from each group wererandomly chosen to evaluate length, weight, and specific growthrate (SGR). Length, weight, survival, and biomass at the end of 21days were significantly higher at pH 8.0 and 8.5. As expected,specific growth rate decreased with time. These results suggest that 8.0–8.5 isthe best pH range for survival and growth of the larvae of thisspecies.

Anesthetic activity of Brazilian native plants in silver catfish (Rhamdia quelen)

There is an increasing demand for inexpensive and safe anesthetics that can reduce fish stress caused by some procedures such as capture and handling. In this context, the present study evaluated the potential of essential oils (EO) of three Brazilian native plants (Hesperozygis ringens, Lippia sidoides and Ocotea acutifolia) as anesthetics for the silver catfish - Rhamdia quelen. Moreover, an analysis was made of the chemical composition of these oils and their influence on stress parameter. EO of H. ringens and O. acutifolia were effective as anesthetics, without behavioral side effects. EO of O. acutifolia (150 µL L-1) promoted an increase in blood glucose level. Regarding to the composition, pulegone accounts for 96.63% of the EO of H. ringens, and caryophyllene oxide amounts to 56.90% of the EO of O. acutifolia. Two chemotypes, thymol and carvacrol (68.40% and 67.89%, respectively) were verified for EO of L. sidoides. Both samples of EO of L. sidoides showed anesthetic activity in silver catfish, but exposure also caused loss of mucus and mortality. Thus, only the EO of H. ringens and O. acutifolia are advised for anesthetic use

Growth and survival of Rhamdia quelen (Siluriformes, Pimelodidae) larvae exposed to different levels of water hardness

Abstract The response to water hardness increase varies from species to species. The purpose of this study was to verify the survival and growth of larvae of silver catfish, Rhamdia quelen , in water with different levels of water hardness. Larvae (2.75 mg and 5.00±0.05 mm) were randomly allotted to experimental units (three replicates per treatment) and kept in 44-l boxes (400 larvae/box). Larvae were exposed to five water hardness values (30, 70, 150, 300, and 600 mg l −1 CaCO 3 ) at pH 8.25. Samples of larvae were collected on days 0, 7, 14, and 21, and the length, weight, and specific growth rate (SGR) were determined for each collection. Survival and biomass were calculated on day 21. Higher larvae growth, survival, and biomass were obtained at 30 and 70 mg l −1 CaCO 3 . Therefore, this is the recommended hardness range for growth and survival of silver catfish larvae.

Transport of jundiá Rhamdia quelen juveniles at different loading densities: water quality and blood parameters

O transporte de peixes e uma pratica comum em piscicultura e considerado como um agente estressor que causa efeitos negativos na saude do peixe. O objetivo deste estudo foi avaliar algumas respostas fisiologicas de estresse no jundia causadas pelo transporte em densidades diferentes. Juvenis de jundia foram transportados em sacos plasticos num simulador de transporte por quatro horas em diferentes densidades (75, 150, 250 e 350 g L-1) e transferidos para 16 caixas plasticas de 80 L por 96 horas apos o transporte. Amostras de agua foram coletadas antes e apos o transporte para determinacoes de oxigenio dissolvido, temperatura, pH e amonia. Alem dos momentos da saida e da chegada, amostras de sangue foram retiradas 24 e 96 horas apos o transporte para monitorar os niveis de cortisol, glicose, amonia, cloreto e hematocrito. A amonia na agua aumentou gradualmente acompanhando o aumento das densidades. A amonia plasmatica estava elevada apos o transporte nos peixes de todos os tratamentos. Comparando com os valores iniciais, aumentos substanciais nos niveis plasmaticos de cortisol e amonia foram registrados principalmente nos peixes submetidos a densidade de transporte mais elevada. Os niveis glicemicos parecem ter sido influenciados pelo aumento nas densidades de transporte. Nao foram registradas diferencas significativas nos demais parâmetros sanguineos. O custo da criacao de peixes, da mesma forma que de outros animais, deve ser minimizado e os produtores dependem de tecnicas que permitam lucros maiores. Portanto, com base nos indicadores fisiologicos e na taxa de sobrevivencia obtidos no presente estudo, especialmente considerando o periodo de recuperacao, sugere-se que a melhor densidade para o transporte do jundia em sacos plasticos por quatro horas seja de aproximadamente 350 g/L.