Effect of formalin in early stages of the freshwater neotropical catfish, Lophiosilurus alexandri.

The objective of this study was to evaluate the acute toxicity of formalin and its level of therapeutic safety in early stages of Lophiosilurus alexandri. Experiment 1, larvae 7 days after hatching (DAH) were exposed to 43.2, 86.4, 172.8, 345.6, 691.2, 1404.0 mg/L of formalin. Experiment 2, juveniles with 22 DAH exposed to 54, 108, 216, 432, 648 mg/L. Experiment 3, 45 DAH exposed to 86.4, 172.8, 345.6, 691.2, 1036.8 mg/L. The experiments had a control without addition of formalin and all were carried out in duplicate. The LC50-12 h were: Experiment 1 = 108.86 mg/L; 2: 152.74 mg/L; 3: 244.38 mg/L of formalin. The respective safety levels were: Experiment 1 = 66.22 mg/L (1 h), 10.89 mg/L (12 h); 2 = 49.17 mg/L (2 h), 15.27 mg/L (12 h); 3 = 68.89 mg/L (2 h), 24.44 mg/L (12 h). The results showed that the developmental stage influenced the sensitivity of animals to formalin.

Description of the composition of fatty acids and lipids in the breeders muscle, oocytes and in the embryonic development of Brycon orthotaenia (Günther, 1864).

The objective of this work was to evaluate the fatty acid and lipid composition of oocytes, newly hatched larvae (NHL), first feeding larvae (FFL) and muscle tissue of female Brycon orthotaenia broodstock. Total and polar lipid was significantly (P<0.05) abundant in oocytes and larvae in different stages of development. The lowest content (P<0.05) of total lipids was found in the muscles, whereas total lipid content of oocytes, NHL and FFL did not show any significant difference. Polar lipid content was different (P<0.05) between NHL and FFL. For the neutral the lowest values of C18:2n 6 occurred during the initial feeding period, whilst C20:4n 6 (AA) exhibited the highest percentage in FFL (P<0.05). C22:6n 3 (DHA) was highest (P<0.05) in FFL. The neutral lipid n-9 and n-6 was highest in muscle of females. The n-3HUFA was highest in NHL and in FFL, n-6HUFA was highest in FFL (P<0.05). The ratios of DHA/EPA were higher (P<0.05) in oocytes and FFL. In fatty acids of polar lipids, C20:5n 3 (EPA) did not show differences (P>0.05) between stages. C18:3n 3 was highest (P<0.05) in NHL and FFL. C20:4n 6 (AA) and C22:6n 3 (DHA) showed the highest percentages during the larval stages. The fatty acids n-3 series was significantly higher (P<0.05) in FFL. The n-6HUFA was highest during development larval (P<0.05). The increases DHA reflects the ability of the species to elongate and desaturate to obtain n-3HUFA from 18:3n 3, shows the importance of this fatty acid during early development.

Evaluation of reproductive performance of pink-shrimp Farfantepenaeus paulensis (Pérez-Farfante, 1967) broodstock in tanks with different water dephts / Avaliação do desempenho reprodutivo do camarão-rosa Farfantepenaeus paulensis (Pérez-Farfante, 1967) em tanques com diferentes profundidades de água

The spawning of unfertilized eggs is commonly observed when the shrimp Farfantepenaeus paulensis is maintained in captivity, and this probably occurs due to the lack of mating in maturation tanks. This study evaluated the effect of water depth on the reproductive performance of this species. Four 3.3 m diameter tanks were used: two tanks had 40 cm of water depth, while the other two were maintained with 80 cm of water. After all females had undergone at least one moulting cycle in captivity, the occurrence of fertilized spawns, number of eggs and fertilization rates were assessed during 33 days. Regardless of treatment, 31 fertilized spawns were sampled (67.7% and 32.3% of fertilized spawns in the tanks of 80 and 40 cm, respectively) demonstrating that mating did take place. No significant differences in fertilization rates were detected between treatments, but the total number of fertilized eggs was two fold higher in the tanks with 80 cm than in those with 40 cm of water depth.

O camarão-rosa Farfantepenaeus paulensis costuma produzir desovas não fertilizadas quando mantido em cativeiro, o que provavelmente se deve ao insucesso na cópula nos tanques de maturação. Este estudo avaliou se a profundidade da água nestes tanques influencia o desempenho de reprodutores desta espécie. Foram utilizados quatro tanques, sendo dois mantidos com 40 cm de profundidade de água e outros dois, com 80 cm. Após assegurar que todas as fêmeas haviam sofrido pelo menos uma muda em cativeiro, a ocorrência de desovas fertilizadas, número de ovos e taxa de fertilização foram analisados durante 33 dias. Independentemente do tratamento, 31 desovas fertilizadas foram amostradas (67,7% e 32,3% de desovas fertilizadas nos tanques de maior e menor profundidade, respectivamente), evidenciando a ocorrência de cópulas. Não foram detectadas diferenças significativas da profundidade da água nos tanques sobre a taxa de fertilização dos ovos, embora a quantidade total de ovos fertilizados nos tanques com 80 cm de profundidade de água tenha sido cerca de duas vezes maior do que nos tanques com 40 cm de água.

Evaluation of reproductive performance of pink-shrimp Farfantepenaeus paulensis (Pérez-Farfante, 1967) broodstock in tanks with different water dephts / Avaliação do desempenho reprodutivo do camarão-rosa Farfantepenaeus paulensis (Pérez-Farfante, 1967) em tanques com diferentes profundidades de água

The spawning of unfertilized eggs is commonly observed when the shrimp Farfantepenaeus paulensis is maintained in captivity, and this probably occurs due to the lack of mating in maturation tanks. This study evaluated the effect of water depth on the reproductive performance of this species. Four 3.3 m diameter tanks were used: two tanks had 40 cm of water depth, while the other two were maintained with 80 cm of water. After all females had undergone at least one moulting cycle in captivity, the occurrence of fertilized spawns, number of eggs and fertilization rates were assessed during 33 days. Regardless of treatment, 31 fertilized spawns were sampled (67.7% and 32.3% of fertilized spawns in the tanks of 80 and 40 cm, respectively) demonstrating that mating did take place. No significant differences in fertilization rates were detected between treatments, but the total number of fertilized eggs was two fold higher in the tanks with 80 cm than in those with 40 cm of water depth.

O camarão-rosa Farfantepenaeus paulensis costuma produzir desovas não fertilizadas quando mantido em cativeiro, o que provavelmente se deve ao insucesso na cópula nos tanques de maturação. Este estudo avaliou se a profundidade da água nestes tanques influencia o desempenho de reprodutores desta espécie. Foram utilizados quatro tanques, sendo dois mantidos com 40 cm de profundidade de água e outros dois, com 80 cm. Após assegurar que todas as fêmeas haviam sofrido pelo menos uma muda em cativeiro, a ocorrência de desovas fertilizadas, número de ovos e taxa de fertilização foram analisados durante 33 dias. Independentemente do tratamento, 31 desovas fertilizadas foram amostradas (67,7% e 32,3% de desovas fertilizadas nos tanques de maior e menor profundidade, respectivamente), evidenciando a ocorrência de cópulas. Não foram detectadas diferenças significativas da profundidade da água nos tanques sobre a taxa de fertilização dos ovos, embora a quantidade total de ovos fertilizados nos tanques com 80 cm de profundidade de água tenha sido cerca de duas vezes maior do que nos tanques com 40 cm de água.