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91.
92.
In Channa punctatus maintained under ambient photothermal conditions (10.5L:13.5D; 13 ± 2°C) in the postspawning season, hypothalamic dopamine
(DA) and norepinephrine (NE) content varied diurnally, but serotonin (5-HT) and monoamine oxidase (MAO) did not. Exposure
of the fish to high temperature (25 ± 2°C), with or without altering the photopheriod, increased the NE and DA content, and
NE turnover but decreased DA turnover. Increasing the photoperiod (16L:8D) alone had no significant effect on catecholaminergic
(CA) content or activity. When the fish were exposed to long photoperiod, with or without altering the temperature, a day-night
variation in 5-HT content and activity was induced in the postspawning season. An increase in temperature alone had no significant
effect on 5-HT content or activity. Hypothalamic MAO activity was elevated in fish exposed to high temperature alone, or in
combination with long photoperiod, but was not affected significantly by long photoperiod treatment. These results indicate
that CA activity is influenced largely by ambient high temperature, whereas serotonergic activity is controlled primarily
by photoperiod, with high temperature having an additive effect. MAO activity seems to be influenced by both temperature and
photoperiod in this species. 相似文献
93.
Comparative utility of egg blastomere morphology and lipid biochemistry for prediction of hatching success in Atlantic cod, Gadus morhua L. 总被引:1,自引:0,他引:1
Randy W Penney Pauline L Lush Joy Wade Joseph A Brown Christopher C Parrish & Margaret P M Burton 《Aquaculture Research》2006,37(3):272-283
Six blastomere morphology parameters indicative of cell development abnormalities, egg diameter, dry weight, total lipid, lipid classes and fatty acids were determined for egg batches collected daily from three Atlantic cod (Gadus morhua) broodstock groups over the course of one spawning season. Egg batches were incubated to hatch and each morphological and biochemical parameter was tested as a predictor of hatching success. Five of the six blastomere morphology parameters were significantly positively correlated with each other. Correlation coefficients among several fatty acid parameters were also significant but correlation coefficients among the various lipid classes were mostly not significant. No significant correlations were found between blastomere morphology and lipid class or fatty acid parameters. Egg dry weight was negatively correlated with cell clarity, %docosahexanoic acid (DHA), DHA:eicosapentaenoic acid, and Σ polyunsaturated fatty acids. Fertilization success was not significantly correlated with any of the morphology or biochemistry parameters. Within‐population variability in several morphological and fatty acid parameters was related to elapsed time since onset of first spawning. However, the occurrence of such relationships with elapsed time was highly variable and inconsistent among the three broodstocks, typically being significant for only one or two broodstocks but not all three. Mean hatching success rates were high (>75%) in all three broodstocks but hatching success was not significantly related to any of the morphological or biochemical parameters nor to elapsed time from onset of first spawning. The implications of these results are discussed in terms of the utility of the various morphology and biochemistry parameters as measures of egg quality in marine finfish hatcheries. 相似文献
94.
Gouranga Biswas Joy Krushna Jena Sarat Kumar Singh & Hare Krushna Muduli 《Aquaculture Research》2006,37(5):510-514
Fingerling rearing of Indian major carps, Catla catla, Labeo rohita and Cirrhinus mrigala, were conducted in concrete tanks under a polyculture system at a density of 0.3 million fry ha?1 to evaluate the effect of one, two or three feedings per day on growth, survival and feed utilization. Fry were fed with formulated supplementary diet at 10% of biomass per day during the first 15 days, followed by 8% in the next 15 days and 6% thereafter, for 60 days. Feeding of fish three times daily led to higher growth (103.9±8.5 mm/10.3±2.4 g) than those feeding twice (100.2±4.8 mm/9.9±1.5 g) or once (97.2±9.8 mm/9.4±2.1 g) daily, although the values were not significantly different (P>0.05). Survival rate ranging between 72.3% and 75.1% also did not vary significantly (P>0.05) among the treatments. However, higher feeding frequencies resulted in better feed utilization as evident from decreasing feed conversion ratio values. The present study suggested requirement of a higher feeding frequency for rohu compared with catla and mrigal. 相似文献
95.
R. Kirubagaran B. Senthilkumaran C. C. Sudhakumari K. P. Joy 《Fish physiology and biochemistry》2005,31(2-3):183-188
In the present investigation, significant annual/seasonal variations were noticed in plasma and pituitary gonadotropin (GTH)
which were correlated with gonado-somatic index, plasma estradiol-17β, and nuclear E2 receptor (NE2R) in the pituitary, hypothalamus and telencephalon. The NE2R concentrations and dissociation constant (k
d) values showed significant seasonal variations with high values in the late preparatory phase and low values in the postspawning
phase. The NE2R levels were the highest in the pituitary, followed by the hypothalamus and telencephalon in all the seasons. In the prespawning
phase, ovariectomy (OVX) elicited a strong negative feedback on GTH secretion with a bimodal pattern of release and elevated
the NE2R levels and k
d values, without producing any significant change in the resting phase suggesting that E2 appears to exert differential feedbacks on GTH secretion. 相似文献
96.
97.
Administration of Methallibure, a non-steroidal gonadotropin (GTH) inhibitor 20 g g–1 body weight; i.p., daily for 10 days, to prespawning phase female Heteropneustes fossilis inhibited the brain-pituitary-ovarian axis as indicated by significant reductions in plasma and pituitary levels of GTH-II, and plasma levels of 17-estradiol (E2) and testosterone. Concurrently, the treatment resulted in significant reductions in the hypothalamic content of serotonin, noradrenaline (and adrenaline) that stimulate, and a significant elevation of dopamine that inhibits GTH-II release in this species. Activities of the monoamine degrading enzymes, monoamine oxidase and catechol-O-methyltransferase were significantly increased, while that of the synthesizing enzymes, dopamine--hydroxylase and phenylethanolamine-N-methyltransferase were significantly decreased. These results suggest that the mechanism of inhibition of GTH-II secretion includes, among others, differential actions of the drug on hypothalamic monoamine metabolism. 相似文献
98.
99.
100.
The biological stress of early weaned piglets 总被引:1,自引:0,他引:1