Acuaristas.cl

DiegoDaz escribió:

Chakal escribió:Como un dato que les interesará, he escuchado a varios criadores de goldfish aca que hacen sus cambios de 50-80% diarios o interdiarios. Eso en crias juveniles para lograr crecimiento rapido. El espacio tambien debe ser tomado en cuenta, ademas de alimentacion de 5 veces al dia en cantidades pequeñas. Esos factores juntos logran un crecimiento optimo en goldfish juveniles.

A la rapida, deduzco que con 5 veces de alimento al dia, dejan el agua mas que sucia, y al cambiar 50-80 % se limpia obviamente, pero estariamos frente a un escenario contradictorio, ya que muchos hablan de las famosas y bien ponderas bacterias beneficiosas...

entonces con tanto cambio, simplemente se reduce al minimo el ciclado =/

en resumen: Mi no entender :B

Saludos

Kelthuzar escribió:

DiegoDaz escribió:

Chakal escribió:Como un dato que les interesará, he escuchado a varios criadores de goldfish aca que hacen sus cambios de 50-80% diarios o interdiarios. Eso en crias juveniles para lograr crecimiento rapido. El espacio tambien debe ser tomado en cuenta, ademas de alimentacion de 5 veces al dia en cantidades pequeñas. Esos factores juntos logran un crecimiento optimo en goldfish juveniles.

A la rapida, deduzco que con 5 veces de alimento al dia, dejan el agua mas que sucia, y al cambiar 50-80 % se limpia obviamente, pero estariamos frente a un escenario contradictorio, ya que muchos hablan de las famosas y bien ponderas bacterias beneficiosas...

entonces con tanto cambio, simplemente se reduce al minimo el ciclado =/

en resumen: Mi no entender :B

Saludos

Una cosa diego es un acuario maduro para que VIVAN peces y otra cosa es un acuario de crecimiento de alevines....en el primero necesitas un ambiente óptimo en bacterias benéficas y parámetros adecuados de agua...en uno de crecimiento solo necesitas limpieza del agua y proporcionar condiciones óptimas para que crezcan en un corto tiempo al máximo posible....

Cuando el nitrito entra en el flujo sanguíneo, reacciona con la hemoglobina y forma un compuesto llamado metahemoglobina. Este compuesto reduce la capacidad de la sangre para transportar oxígeno. El nivel de oxígeno disminuye, y los bebés muestran síntomas de una enfermedad llamada metahemoglobinemia, también conocida como “la enfermedad de los bebés azules”.

El síntoma más obvio de la metahemoglobinemia es la aparición de un tono azulado en la piel, particularmente alrededor de los ojos y boca. Si se descubre con rapidez, esta enfermedad puede ser tratada exitosamente con una inyección de azul de metileno, que transforma la metahemoglobina de nuevo a hemoglobina. La enfermedad es extremadamente grave si no se trata: la muerte tiene lugar cuando el 70 por ciento de la hemoglobina del cuerpo ha sido transformada a metahemoglobina.

Se ha demostrado que existe una relación entre las muertes de bebés por metahemoglobinemia y altos niveles de nitrato en agua.

Read more: http://www.lenntech.es/nitritos.htm#ixzz29b3110AL

Resumen
La conducta alimentaria de los peces presenta una alta interdependencia con el medio acuático,
su respuesta está asociada a la condición jerárquica y la producción de feromonas, a la presencia de depredadores, a los movimientos de la corriente originada por los diferentes tipos de habitantes acuáticos, lo que incide en la manera como se hace la búsqueda, la localización y la captura; a las conductas de aprendizaje (consumo-rechazo) y a los hábitos de consumo, entre otros, que tienen efecto sobre la dieta consumida y su eficiencia alimenticia, lo que se necesita como punto de partida para garantizar la supervivencia de la especie. Conocer estos aspectos permite diseñar la dieta ideal para las diferentes especies de acuerdo a su fase de vida, y estos hallazgos podrían aplicarse al desarrollo de alimentos para las especies nativas de Colombia, de los cuales no se conoce su ecobiología ni su etología alimentaria.

El papel de las feromonas
La producción de feromonas puede ser del tipo
incitador que induce a la modificación inmediata del
comportamiento del receptor y del tipo modificador
que provoca modificación del estado fisiológico del
individuo que las capta. Los órganos implicados en la
producción de feromonas sociales originan mediadores
presentes en las secreciones de las células mucosas
superficiales emitidas al medio externo. La percepción
de las hormonas tiene un efecto ambiguo de acuerdo
a la jerarquía social. Si las percibe un animal
subordinado, tiende a la huida, pero si es un pez
dominante quien percibe al subordinado, iniciará el
ataque y su nivel de agresividad variará dependiendo
de si las feromonas provienen de un individuo conocido
o no, agrupado o aislado, dominante o dominado (24).

This is an ovcmicw of thc hormoncs which may be involved in food intake control in fish, and some hypothetical pathways of thcir action arc givcn based on mammalian knowledge. Most of the observed effects of these hormones may result from four types of mechanisms, each hormone acting by one or several as follows: (1) hormones could have a direct effect on central nervous system centres, associated with food intake behaviour or via vagal afferent neurons; (2) an indirect effect may occur via the gut which slows gastrointestinal transit, thus rcsulting in stomach distention which activates vagal afferent neurons; (3) they could have an indirect cffcct, acting dircctly on intermediary metabolism via glucose, free fatty acids or amino acids mohilization or storage; (4) the last possible pathway is an indirect effect by modifying directly or indirectly secretions of other hormones involved in food intake control. Some of thesc hormones (CCK,PYY, glucagon, adrenalin) act as short-term factors which regulate meal ingestion and are generally inhibitory factors. On thc othcr hand, other hormones (GH, TH, and leptin) require more time to modify food intake behaviour, and appcar as stored calorie rcgulators. However, the orientation of hormones to short-terin or to long-term action is not always clear as it has been noted for insulin and glucocorticoids, and may depend on the hormonal and metabolite environment.

To investigate differences in behaviour associated with social rank and environmental conditions, a comparison was made between swimming and feeding activities of dominant and subordinate angelfish, housed in groups of six, with those of angelfish housed singly in identical laboratory aquaria. Subordinate individuals were less active, less ready to feed and consumed less food items than dominants, but their feeding and activity levels were still greater than those displayed by isolated fish used as controls. When fish from each of the above categories were transferred to a novel, identical tank to be tested individually for a 6-day period, little change was observed in previously isolated fish. In contrast, the previous social experience had a marked influence on the behaviour of the other individuals, the effects being related to the social status. The strongest initial response to the new environment was shown by subordinate individuals, with a significant increase in swimming and a significant decrease in feeding compared to the group situation. Subordinates were significantly more active than dominants, who in turn moved more than previously isolated fish. Dominants and subordinates were now similarly reluctant to feed, and their food consumption was less than that of previously isolated fish. With time in the novel environment a significant reduction of swimming activity and a recovery of feeding measures were detected, but levels were still depressed in relation to the group condition, and lower in subordinates than in dominants, indicating the long-lasting effects of the previous social interactions. The results have clear implications for laboratory studies using groups of fish in which social hierarchies may be established prior to individuals being tested singly in a novel environment

En estudios
realizados en salmón del Atlántico (Salmo salar), se
ha encontrado que una pequeña proporción (25%) de
los peces obtiene dos tercios del alimento provisto y
los peces subordinados no prueban el alimento si los
dominantes están cerca aún sin comer, ya que se
intimidan ante su presencia, por lo tanto, para garantizar
buena respuesta al alimento, al crecimiento y al
consumo, la distribución del alimento deberá ser amplia
en toda la superficie y no en un solo sitio (19).

Abstract
Previous results suggest that norepinephrine decreases growth hormone (GH) release in goldfish by means of α-2 adrenoceptor activation. The intracellular mechanisms by which norepinephrine inhibits GH release were examined in the present study using dispersed goldfish pituitary cells. In 2-h static incubation experiments, norepinephrine and the α-2 agonist clonidine decreased basal GH release and the GH responses to stimulation by the dopamine D1 agonist SKF38393 and two native gonadotropin-releasing hormones (GnRH). Norepinephrine also reduced GH responses to the adenylate cyclase activator forskolin, two protein kinase C (PKC) activators (phorbol ester and synthetic diacylglycerol), and two Ca2+ ionophores (ionomycin and A23187). Similarly, norepinephrine applied as a 1-h pulse in cell column perifusion experiments reduced basal GH release and abolished the GH response to a 5-min pulse of arachidonic acid. In goldfish, D1-stimulated GH release is mediated by AC-, arachidonic acid-and Ca2+-dependent pathways, whereas GnRH action is coupled to PKC-and Ca2+-dependent mechanisms. These results suggest that norepinephrine activation of α-2 receptors inhibits ligand-induced GH secretion by actions subsequent to activation of these second messenger cascades. To further characterize norepinephrine mechanisms of action on unstimulated hormone release, the ability of norepinephrine and an α-2 agonist to affect activation of two second messenger cascades under basal conditions was also investigated. Static incubation with clonidine reduced cAMP production in a time-and dose-dependent manner, suggesting that norepinephrine inhibitory action can also be expressed at the level of cAMP production. Resting intracellular free calcium levels in single, identified goldfish somatotropes was unaffected by norepinephrine. However, the inhibitory effects of norepinephrine on basal GH secretion was not observed in the presence of a voltage-sensitive Ca2+ channel agonist. Whether these channels are targets for norepinephrine action on unstimulated GH release requires further investigation.

He seguido investigando y me he topado con varios articulos en ingles que hablan del tema, uno de esos es este:

Yunker, Lee, Wong, Chang (2000) Norepinephrine Regulation of Growth Hormone Release from Goldfish Pituitary Cells. II. Intracellular Sites of Action , Journal of Neuroendocrinology, Vol. 12 (4), pp. 323–333.

Abstract
Previous results suggest that norepinephrine decreases growth hormone (GH) release in goldfish by means of α-2 adrenoceptor activation. The intracellular mechanisms by which norepinephrine inhibits GH release were examined in the present study using dispersed goldfish pituitary cells. In 2-h static incubation experiments, norepinephrine and the α-2 agonist clonidine decreased basal GH release and the GH responses to stimulation by the dopamine D1 agonist SKF38393 and two native gonadotropin-releasing hormones (GnRH). Norepinephrine also reduced GH responses to the adenylate cyclase activator forskolin, two protein kinase C (PKC) activators (phorbol ester and synthetic diacylglycerol), and two Ca2+ ionophores (ionomycin and A23187). Similarly, norepinephrine applied as a 1-h pulse in cell column perifusion experiments reduced basal GH release and abolished the GH response to a 5-min pulse of arachidonic acid. In goldfish, D1-stimulated GH release is mediated by AC-, arachidonic acid-and Ca2+-dependent pathways, whereas GnRH action is coupled to PKC-and Ca2+-dependent mechanisms. These results suggest that norepinephrine activation of α-2 receptors inhibits ligand-induced GH secretion by actions subsequent to activation of these second messenger cascades. To further characterize norepinephrine mechanisms of action on unstimulated hormone release, the ability of norepinephrine and an α-2 agonist to affect activation of two second messenger cascades under basal conditions was also investigated. Static incubation with clonidine reduced cAMP production in a time-and dose-dependent manner, suggesting that norepinephrine inhibitory action can also be expressed at the level of cAMP production. Resting intracellular free calcium levels in single, identified goldfish somatotropes was unaffected by norepinephrine. However, the inhibitory effects of norepinephrine on basal GH secretion was not observed in the presence of a voltage-sensitive Ca2+ channel agonist. Whether these channels are targets for norepinephrine action on unstimulated GH release requires further investigation.

Esta investigación viene a decir que las hormonas liberadas en relación con el estrés en el carassius (norepinefrina y epinefrina) pueden reducir el crecimiento al suprimir la liberación de GH (hormona del crecimiento).

- THE INHIBITORY EFFECTS OF g-AMINOBUTYRIC ACID (GABA) ON GROWTH HORMONE SECRETION IN THE GOLDFISH ARE MODULATED BY SEX STEROIDS(http://jeb.biologists.org/content/203/9/1477.full.pdf)

- Pheromone from ovulatory female goldfish induces gonadotropin surge in males (http://www.ncbi.nlm.nih.gov/pubmed/3557068)

- Hormonally Derived Sex Pheromones in Goldfish (http://www.biolbull.org/content/183/1/173.full.pdf)