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171.
The present study investigated the relationships between egg viability and ovarian fluid composition, egg physiology and egg metabolism in lake trout, Salmo trutta lacustris, to obtain biomarkers for egg quality determination. The ovarian fluid pH, protein levels and activities of aspartate aminotransferase and -d-glucuronidase were significantly correlated with egg viability expressed as the number of eyed stage embryos. Regression models demonstrated that an ovarian fluid pH between 8.44 and 8.57, protein levels below 235.56 mg 100 ml–1ovarian fluid, aspartate aminotransferase activity below 31.65 m min–1 l–1ovarian fluid and -d-glucuronidase activity below 8.62 m min–1 l–1 ovarian fluid characterized egg batches with high viability (80%).The increase in the egg wet weight during water hardening was also significantly correlated with the number of eyed stage embryos, and egg batches with high egg viability (80%) increased in wet weight by 13% during water hardening.From the investigated metabolic parameters the number of eyed stage embryos was significantly correlated with activities of NADP-dependent isocitrate dehydrogenase (egg viability 80% at 2.07 nM min–1 mg–1 protein) and NAD-dependent malate dehydrogenase (egg viability 80% at 47.25 nM min–1 mg–1 protein), with the respiration rate (egg viability 80% at 8.71 nM min–1 mg–1 protein), with the ratio of NADH to NAD levels (egg viability 80% 0.872), with the levels of free, non-esterified fatty acids (egg viability 80% 72.34 g mg–1 protein), and the ratio of non esterified to esterified fatty acids (egg viability 80% at 0.749). Also, subjective and visual control methods were described to distinguish between batches with viable and non viable eggs. 相似文献
172.
Chronically cannulated rainbow trout were exposed in acid water (pH 4.0) for 72h. The gill potential was strongly dependent on water pH, being blood side negative in neutral water, but positive in acid water. Catecholamine levels increased irregularly during acid exposure, and the Bohr and Root effects were not completely erased by the effect of catecholamines during acid exposure. Long term exposure to low water pH, although causing an acidosis in the fish, did not suppress resting oxygen consumption. Prolonged exposure to acid conditions, however, resulted in an increase in ammonia excretion. Changes in plasma sodium and chloride were similar to that reported previously for trout exposed to low calcium, acid water. We conclude that exposure of trout to pH 4 soft water, although impairing oxygen transport, does not limit resting oxygen consumption but does reduce the scope for activity. More extreme acid conditions do impair resting oxygen uptake. 相似文献
173.
W.?P.?WaserEmail author A.?Schmitz S.?F.?Perry A.?Wobschall 《Fish physiology and biochemistry》2005,31(1):73-82
The teleost pseudobranch, a reduced mandibular gill arch, morphologically closely resembles a gill hemibranch. It consists
of several filaments bearing numerous lamellae. The vascular system of the pseudobranch also matches that of a gill, with
afferent and efferent filamental arteries and the lamellar blood space. Despite the pseudobranch’s gill-like appearance, however,
a gas exchange function is excluded in many teleosts by overlying opercular epithelium, effectively eliminating diffusional
exchange with the external medium. The physiological function of the pseudobranch is still unknown, though its conspicuously
close association with the ocular choroid rete mirabile, a structure supporting elevated oxygen partial pressures in the eye, suggests a role related to the process of oxygen secretion
into the eyes of teleosts. In this paper we present new stereological data on the pseudobranch of rainbow trout (average weight:
478 ± 114 g, x ± SD, n = 12). The total Cavalieri volume of the pseudobranch was 46.4 μl (97 μl kg−1), consisting of lamellae 49%, connective tissue 43.8%, large blood vessels 4.5%, filamental cartilage 2.3%, and central venous
sinus 1.3%. Lamellae were comprised of pillar and pseudobranchial cells 81%, blood space 12.3%, and lacunar tissue 6.4%. The
inner surface of the blood space in the lamellae was 12.2 cm2 (25.5 cm2 kg−1), and its volume was 2.81 μl (5.88 μl kg−1). The results demonstrate the pseudobranch’s potential for physiological functions requiring a high surface area or surface-to-volume
ratio, i.e. ion transfer, gas exchange and other regulatory processes. More detailed analysis of the function of the pseudobranch,
however, has to remain subject of future morphological and physiological studies. 相似文献
174.
Growth of cultured mussels (Perna canaliculus Gmelin 1791) at a deep-water chlorophyll maximum layer
Shaun C Ogilvie Steve P Fox Alex H Ross Mark R James David R Schiel 《Aquaculture Research》2004,35(13):1253-1260
We tested the hypothesis that yield of the mussel Perna canaliculus (Gmelin 1791) could be increased by placing culture ropes deep into the water column to take advantage of deep‐water chlorophyll a maxima. The study site, in Pelorus Sound, New Zealand, showed periods of thermal stratification of the water column, causing a high concentration of phytoplankton in deeper water, at the thermocline. Mussels were grown simultaneously at 5 and 17 m, for up to 96 days. Mussel growth and condition index data showed no significant differences between the two depth treatments, indicating that in this system there may not be substantial mussel productivity benefits from lowering mussel farms to the deep‐water chlorophyll maximum layer. 相似文献
175.
Temporal changes in growth, plasma thyroid hormone, cortisol, growth hormone (GH) and non-esterified fatty acid (NEFA) concentrations, hepatic T3 content and hepatic 5-monodeiodinase activity were measured in rainbow trout (Oncorhynchus mykiss) subjected to a sustained fast for up to eight weeks, and during a four-week re-feeding period. The purpose of the study was to examine aspects of the endocrine control of energy partitioning processes characteristic of short-term (acute; fasting) and long-term (chronic; starvation) food-deprivation states in fish, and to explore the role of the thyroid hormones, cortisol and GH in the energy repartitioning that takes place during an acute anabolic (re-feeding) state following chronic food deprivation.Differences in growth rate between fed and fasted groups were evident after two weeks, but significant weight loss by the fasted groups was not evident until between four and six weeks into the fast. Hepatosomatic indices (HSIs) were significantly reduced in the fasted fish within seven days, and as early as two days in one study; recovery of the HSI in fasted fish was evident within three days of re-feeding. Liver protein content (expressed as % wet weight) was consistently depressed in the fasted fish in only one of the three studies. Liver total lipid content (expressed as % wet weight) was depressed in the fasted fish within two days of food deprivation. Because of the rapid and sustained decrease in the HSI of fasted fish, the hepatic total protein and lipid reserves, when considered on a body weight basis, were markedly lowered within the first few days of the fast. Plasma GH concentrations exhibited a bi-modal pattern of change, with a transient fall in levels, followed by a sustained increase in fasted fish. The indicators of interrenal activity were suggestive of a depressed pituitary-interrenal axis in fasted animals; plasma cortisol levels were elevated to levels of fed animals within one day of re-feeding. The indicators of thyroid hormone economy (plasma thyroid hormone levels, liver triiodothyronine content, hepatic 5-monodeiodinase (MD) activity, thyroid epithelial cell height) were similarly indicative of a depressed pituitary-thyroid axis in fasted animals, with recovery to levels of the fed animals within one week. Despite the compensatory changes in accumulation of reserves (as indicated by a compensatory increase in HSI), there were no apparent compensatory changes in any of the endocrine parameters evident during the re-feeding period. 相似文献
176.
Richard W. Smith Maria Jönsson Dominic F. Houlihan Peter Pärt 《Fish physiology and biochemistry》2001,24(2):157-169
Mechanisms of Cu tolerance were investigated in respiratory epithelial cell cultures, from rainbow trout gills, by studying O2 consumption and protein synthesis rates, intracellular Na concentration and TER. The lowest concentration found to reduce O2 consumption was 25 M Cu. This did not affect either protein synthesis rate or intracellular Na concentration and was interpreted in terms of copper tolerance; i.e., how these two energetically demanding processes are maintained despite a reduction in aerobic ATP supply. The relationship between protein synthesis rate and synthesis cost is exponential and the cost of protein synthesis in gill cells was found to be minimal (i.e., this cell occupies a position on the asymptotic section of the protein synthesis rate/synthesis cost model) and unaffected by 25 M Cu. Thus protein synthesis rates could be maintained since any reduction would represent an insignificant energy saving. Intracellular Na concentrations and O2 consumption rates were linearly correlated suggesting reducing intracellular maintenance costs would have a greater significance in terms of overall energetic conservation. Intracellular Na maintenance costs, calculated from O2 consumption rates and intracellular Na concentrations, were found to decline after exposure to 25 M Cu. Since TER was unaffected this implied the reduced costs arose from membrane `channel arrest'. Thus the Na/K ATPase energy demands, associated with maintaining intracellular Na concentration, could be reduced by decoupling metabolic demand and membrane function. Therefore this study may demonstrate how the flexibility of cellular energetics enables gill epithelial cells to tolerate sub-lethal Cu. 相似文献
177.
Jon G. Stanley Herbert Hidu Standish K. Allen 《Aquaculture (Amsterdam, Netherlands)》1984,37(2):147-155
Triploidy in American oysters (Crassostrea virginica) was induced by blocking polar body formation with cytochalasin B. Triploid oysters created by treatment during meiosis I grew faster during the first 3 years of life than did diploid siblings. Triploid oysters created during meiosis II grew at the same rate as their controls. Because heterozygosity was higher in oysters created during meiosis I than in other groups, the increased growth must be due to heterozygosity rather than to triploidy per se. 相似文献
178.
The various components of the nitrogen budget of white steenbras,Lithognathus lithognathus Cuvier (Sparidae), were determined under experimental culture conditions. A simple closed system respirometer was used where experiments were conducted to investigate faecal prodution, nitrogen excretion rates and absorption efficiencies at 16C and 20C. Faecal loss, as a percentage of the ingested nitrogen, amounted to 3.59%. Gross, carbon and nitrogen absorption efficiencies ranged from 8 6 to 9 8 % and were not significantly affected by fish size, ration size or temperature (P < 0.05). Net protein utilization (NPU) and the biological value (BV) ranged from 78 to95%. Ammonia and urea constituted 77.93 and 10.07%, respectively, of the total exogenous nitrogen excretion, the balance being made up of other dissolved organic nitrogen (DON). Endogenous ammonia excretion rates were significantly greater in small fish compared to large fish (P < 0.05). Total non-faecal losses as a percentage of the ingested ration amounted to 21.86%. Fish size and ration size increased nitrogen excretion, but temperature had no effect. Maintenance rations were 7.55 mg g-1 dry weight day-1 (0.76%dry body weight) and 5.99 mgg-1 (0.60% dry body weight) for small and large fish, respectively. The high absorption efficiencies and high nitrogen indicated that white steenbras utilize the commercial trout pellet diet very efficiently. 相似文献
179.
180.
Gonadotropins (GTH) were isolated from pituitary glands of grass carp and their properties investigated. Acetone-dried pituitaries
were extracted with ammonium acetate-ethanol and were then passed through cation exchanger, anion exchanger, and gel filtration
column. Two glycoprotein gonadotropins (DE I and DE II) were isolated of MW 56,000 and 53,000 daltons, respectively, as determined
by gel filtration technique. Isoelectric points of the two GTHs also differed from each other. Sialic acid contents were 3.64%
and 1.47% for DE I and DE II, respectively. Both GTH's stimulated, in a similar manner, testicular androgen and ovarian estradiol
synthesisin vitro. 相似文献