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951.
Abstract. Three oilseed meals (mustard, linseed and sesame) of Bangladeshi origin were evaluated as fish meal substitutes in diets of common carp, Cyprinus carpio L. These oilseed meals were included in the diet at various levels (25, 50 and 75% of dietary protein) and the response of fish fed these diets was compared to fish fed a fish meal based control diet (40% protein). On the basis of observed growth rate, food conversion ratio, protein efficiency ratio and apparent net protein utilization, the control diet produced significantly (P< 0.05) the best growth performance. Growth responses were significantly affected by both type and inclusion level of oilseed protein. Of the oilseed proteins tested, the 25% mustard protein and 25% linseed protein diets produced significantly (P< 0.05) better growth performances than higher inclusion levels tested. Apparent protein digestibilities (APDs) for all diets were fairly high, ranging from 77.72 to 89.8O%. In general, APD values decreased with increasing plant protein. Fish fed diets containing higher levels of oilseed protein had significantly (P< 0.05) higher carcass moisture and lower carcass lipid contents. Fish fed 50% mustard protein had histological abnormalities in liver and thyroid tissues. Results are discussed with respect to dietary levels of essential amino acid and anti-nutritional factors. 相似文献
952.
A.O.L. Wong C.K. Murphy J.P. Chang C.M. Neumann A. Lo R.E. Peter 《Fish physiology and biochemistry》1998,19(1):23-34
In this study, the direct actions of serotonin (5HT) on gonadotropin (GTH)-II and growth hormone (GH) release in the goldfish were tested at the pituitary cell level. 5HT (10 nM - 10 µM) stimulated GTH-II but inhibited GH release from perifused goldfish pituitary cells in a dose-dependent manner. The minimal effective dose of 5HT tested to suppress basal GH secretion (10 nM) was 10-fold lower than that to stimulate GTH-II release (100 nM). The GTH-II releasing effect of 5HT was abolished by repeated 5HT treatment (10 µM) whereas the corresponding inhibition on GH release was unaffected. These results suggest that 5HT receptors on goldfish gonadotrophs and somatotrophs exhibit intrinsic differences in terms of sensitivity to stimulation and resistance to desensitization. Salmon GTH-releasing hormone (sGnRH, 100 nM) stimulated GTH-II and GH release from goldfish pituitary cells. The GTH-II releasing action of sGnRH was unaffected by simultaneous treatment of 5HT (1 µM). However, the corresponding GH response to sGnRH (100 nM) was inhibited. In the goldfish, dopamine is known to stimulate GH release through activation of pituitary D1 receptors. In the present study, the GH-releasing action of dopamine (1 µM) and the D1 agonist SKF38393 (1 µM) was significantly reduced by 5HT (1 µM). To examine the receptor specificity of 5HT action, the effects of 5HT1 and 5HT2 analogs on GTH-II and GH release were tested in goldfish pituitary cells. The 5HT1 agonist 8OH DPAT (0.1 and 1µM) and 5HT2 agonist methyl 5HT (0.1 1µM) mimicked the GTH-II releasing effect of 5HT. The 5HT1 agonist 8OH DPAT (0.1 and 1µM) also stimulated GH release but the 5HT2 agonist methyl 5HT (0.1 and 1µM) was inhibitory to basal GH secretion. In addition, 5HT (1µM) -stimulated GTH-II release was abolished by the 5HT1 antagonist methiothepin (10µM) and 5HT2 antagonist mianserin (10µM). Similarly, the inhibitory action of 5HT (1µM) on basal GH release was blocked by the 5HT2 antagonist mianserin (10µM). The 5HT1 antagonist methiothepin (10µM) was not effective in this regard. These results, taken together, indicate that 5HT exerts its regulatory actions on GTH-II and GH release in the goldfish directly at the pituitary cell level, probably through interactions with other regulators including sGnRH and dopamine. The GTH-II releasing action of 5HT is mediated through 5HT2 and possibly 5HT1 receptors. The inhibition of 5HT on basal GH release is mediated through 5HT2 receptors only. Apparently, 5HT1 receptors are not involved in this inhibitory action. In this study, a paradoxical stimulatory component of 5HT on GH release by activating 5HT1 receptors is also implicated. 相似文献
953.
Measurement of cortisol response is an important tool to asses stress in fisheries research. Radioimmunoassay (RIA) is a common
method for the measure of cortisol in fish. Use of enzyme-linked immunosorbent assays (ELISA) to detect cortisol would eliminate
health hazards, costs of handling radioisotopes, and the short stability time associated with RIA. Enzyme-linked immunosorbent
assays have been used for the determination of cortisol in several fish species. However, the ELISA method of cortisol determination
in fish lacks proper validation testing. We conducted validation procedures for multiple commercial cortisol ELISA kits and
compared the results to RIA. The assays were tested for four species: (1) channel catfish Ictalurus punctatus, (2) largemouth bass Micropterus salmoides, (3) red pacu Piaractus brachypomus, and (4) golden shiners Notemigonus crysoleucas. We evaluated the ELISA methods against RIA, and determined that at least one kit is suitable (accuracy: mean recovery of
spiked samples, 102.8%; reproducibility: interassay coefficient of variation < 10.5% for all species; precision: intra-assay
coefficient of variation < 16.8% for all species; linearity: R
2 > 0.96 for all species) for the measurement of cortisol response in fish and comparative determination of stress. All of
the ELISA assay results varied by more than 10% from the cortisol concentrations detected by the RIA. The high variability
of the kit results indicates that commercial ELISA kits could be utilized for qualitative determination of cortisol in fish,
but should be fully validated in each laboratory for each species before being used for research. 相似文献
954.
955.
The growth data of a commercial aquaculture recirculation system were analysed to investigate the growth performance of reared
turbot (Psetta maxima). Three common growth models (von Bertalanffy, Gompertz and Schnute) were fitted to the growth data documented over a time
period of 6 years. To determine the most suitable model, three different criteria were used: (1) the Akaike index criterion,
(2) the sum of squared residuals and (3) the average daily deviation between the estimated final weight and the observed final
weight. The evaluation of the growth models showed that the Schnute model had the lowest Akaike index, the lowest sum of squared
residuals and the lowest daily deviation between estimated and real weight of all tested growth models. The Schnute model
produced sigmoid growth curves. The estimated growth coefficients were the most realistic ones in regard to biological interpretation.
In contrast, the von Bertalanffy growth model and the Gompertz model estimated inaccurate exponential growth curves and are
therefore unable to simulate the growth data as well as the Schnute model. The results indicate that the von Bertalanffy growth
model is not the optimal model to simulate the present growth data and that the growth potential of reared turbot has probably
not yet been fully exploited in the aquaculture system(s) examined (so far). 相似文献
956.
Yersinia ruckeri is the causative agent of enteric redmouth disease (ERM), a common pathogen affecting aquaculture facilities and implicated in large losses of cultured fish. Fisheries scientists continue to gain a greater understanding of the disease and the pathogen by investigating methods of identification and pre- and post-infection treatment. In this study, a real-time PCR probe set for Y. ruckeri was developed to detect daily changes in the bacterial load during pathogen challenges. Two species of fish, Chinook salmon, Oncorhynchus tshawytscha, and steelhead trout, Oncorhynchus mykiss, were exposed to two strains of Y. ruckeri (Hag and SC) during bath challenges. A subset of fish was killed daily for 14 days, and the kidney tissue was biopsied to enumerate copies of pathogen DNA per gram of tissue. While Chinook exposed to either the Hag or SC strains exhibited similar pathogen loads, those exposed to the Hag strain displayed higher mortality (~66%) than fish exposed to the SC strain (~24% mortality). Steelhead exposed to the Hag strain exhibited a greater pathogen load and higher mortality (~42%) than those exposed to the SC strain (<1% mortality). Steelhead challenged with either strain showed lower pathogen loads than Chinook. The study illustrates the efficacy of the probe set to enumerate Y. ruckeri bacterial growth in the kidneys of fish. Also, strains of Y. ruckeri display species-specific growth patterns that result in differential mortality and pathogen load. 相似文献
957.
An aquabirnavirus (ABV) and a formalin-inactivated betanodavirus [redspotted grouper nervous necrosis virus (RGNNV)] were investigated for their potential to prevent RGNNV-induced viral nervous necrosis (VNN) in the sevenband grouper, Epinephelus septemfasciatus (Thunberg). Three groups of fish were injected intramuscularly with ABV, intraperitoneally with inactivated RGNNV (iRGNNV) or with both ABV and iRGNNV. At 3, 7, 14, 21 and 28 days post-injection (p.i.), fish were challenged by intramuscular injection of RGNNV. Control fish, which received neither ABV nor iRGNNV, showed high mortalities in all RGNNV challenges. Fish that received only ABV exhibited relative percent survival (RPS) of >60 against RGNNV challenges at 3, 7, 14 and 21 days p.i., but not at 28 days p.i., while fish that received only iRGNNV showed significantly higher protection against RGNNV challenges only at 21 and 28 days p.i. In contrast, fish that received both ABV and iRGNNV showed 60 or higher RPS against all RGNNV challenges. Fish inoculated with iRGNNV with or without ABV exhibited similar high titres of neutralizing antibodies to RGNNV at 14, 21 and 28 days p.i. These results indicate that combined inoculation with iRGNNV and ABV conferred both rapid non-specific and delayed specific protection against VNN. 相似文献
958.
HEIDI DEWAR ERIC D. PRINCE MICHAEL K. MUSYL RICHARD W. BRILL CHUGEY SEPULVEDA JIANGANG LUO DAVID FOLEY ERIC S. ORBESEN DERKE SNODGRASS R. MICHAEL LAURS JOHN P. HOOLIHAN BARBARA A. BLOCK LIANNE M. MCNAUGHTON 《Fisheries Oceanography》2011,20(3):219-241
Swordfish are highly specialized top‐level predators that have been challenging to study. In this paper, data from 31 pop‐up satellite archival tags attached to swordfish from (i) the eastern Pacific, (ii) central Pacific, and (iii) western North Atlantic‐Caribbean were analyzed. Common across locations was a pronounced diel vertical pattern with daytime hours spent primarily below the thermocline and nighttime hours spent in warmer waters, close to the surface. One exception to this pattern was periodic daytime basking events which were most common in cooler waters off California. Maximum daytime depths were significantly correlated with light penetration as measured by the diffuse attenuation coefficient at 490 nm. Temperature did not appear to influence daytime depths, and swordfish tolerated both extremely low temperatures (4°C) and rapid and dramatic temperature changes (>20°C). Temperature did appear to influence the nighttime depths in the Pacific where fish typically remained in the surface mixed layer. In contrast, in the warm tropical Atlantic this was not the case, and nighttime depths were much deeper. In all areas, nighttime depth increased around the full moon. Given the parallels between the vertical movement patterns of swordfish and those of the deep sound scattering layer we suggest that swordfish vertical distribution patterns, especially during daytime, are influenced largely by resource availability. At night, when swordfish are typically targeted by fisheries, both ambient light and temperature influence movements. Understanding vertical movement patterns of swordfish can help evaluate gear vulnerability, improve population assessments, and potentially reduce fisheries bycatch. 相似文献
959.
Postlarvae or juveniles of Macrobrachium rosenbergii produced in Mauritius are sold at unit price to prawn farmers and are counted individually by hand. This process is time consuming, labour intensive, subject to error and may stress the juveniles; safe rapid electronic counting would be highly advantageous.The design of the hydraulic component of a successful counter prototype, Type A, is described. The counter has 10 parallel channels through which juveniles are carried in a water current. The detection of juveniles passing through these channels can be done photo-electrically. The counter accepts juveniles up to 15 mm in length (eye orbit to tip telson) and has the significant advantage that it can be constructed using only simple hand tools.Survival and growth rate tests, and microscopic examination for damage to appendages of juveniles were done on machine counted and hand counted juveniles. There was no reduction of growth or survival caused by passage through the counter by comparison with the hand counting method, and it is concluded that the counter is not detrimental to juvenile prawns.About 70% of all juveniles tested showed highly variable amounts of damage. The great majority of this damage appears to originate in the hatchery tanks, prior to the experimental treatments. Only in the case of antennules could the use of the counter be shown to increase damage significantly, i.e. from 25% to 38%, but this has no detectable effect on subsequent survival or growth.This appears to be the first counter made specifically for counting macroscopic crustacean juveniles, and via suitable scaling, adaptation to counting other species of crustaceans, fish larvae, etc., should be possible. 相似文献
960.
Hypothalamic dopamine (DA), noradrenaline (NA) and 5-hydroxytryptamine (5-HT) levels exhibited marked day-night variations under ambient photoperiod and temperature (12L12D; 17±1°C) with peak values at mid-light phase. The 16L8D; 22±1°C treatment reversed the diurnal rhythm of 5-HT, but not that of DA and NA. However, there was an overall increase in the levels of the catecholamines on exposure to the long photoperiod and high temperature. The administration of melatonin in the fish held on 16L8D; 22±1°C regime restored the 5-HT rhythm to that of the 12L12D; 17±1°C control group, but with elevated mid-photophase value. However, there was no effect of the indole treatment on the 5-HT rhythm under the 12L12D; 17±1°C regime. Melatonin causes a significant reduction of NA level in both the groups, while DA level did not change in either group. 相似文献