首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The kuruma shrimp, Penaeus (Marsupenaeus) japonicus (Bate, 1888), is a valuable aquaculture species in Queensland, Australia. The shrimp is supplied live to the Japanese market and must survive emersed transport for up to 36 h. In-transit mortality after harvest from high water temperatures (> 30 °C) has been reported by the industry, and a knowledge of the effects of high water temperature may provide important information for producers on grow-out management, timing of production and farm location. Experiments were conducted to determine the effect of high water temperature on survival, moulting and food consumption in P. japonicus. Replicated groups of 15.6 ± 0.2 g shrimp were acclimated and exposed to five temperatures, between 28 and 36 °C, for up to 28 days. Mortality was highest at 36 °C and equally lowest between 28 °C and 32 °C. Intermoult period was not significantly different for temperatures between 28 and 32 °C (19.8–15.5 days) but was significantly greater above 32 °C (27.4 days at 34 °C and > 104 days at 36 °C). There was evidence of moulting synchrony at 28 °C. Mean daily food consumption was highest at 32 °C at 2.34% of body weight, but decreased to 1.56% at 28 °C and 1.33% at 36 °C. Over the range of water temperatures examined, survival, moulting rate and food consumption were highest at 32 °C.  相似文献   

2.
Growth and feeding of white steenbras, Lithognathus lithognathus (Cuvier). under culture conditions was determined to assess its suitability for mariculture. Ration size ranged from 4.50% to 11.52% and from 1.67% 4.00% dry body weight for small (28 ± 2 g) and large (250 ± 23 g) fish, respectively. Condition factor (K) ranged from 1.19 to 1.35 and from 2.00 to 2.19 for small and large fish, respectively. Specific growth rate (SGR) at 16°C was 0.60% day?1 for 28-g fish, 0.29% day?1 for a 74-g fish, and 0.19% day?1 for a 250-g fish. Gross conversion efficiency (GCE) was inefficient at high feeding levels (21.3%) compared with low feeding levels (32.6%). Proximate body composition in terms of moisture, protein. lipid, ash and energy were not significantly affected by feeding regime or temperature (P > 0.05). The experiments indicate that feeding regimes should be maintained at relatively low levels to obtain optimum K, GCE and SGR, and to avoid over-feeding and food wastage. It was concluded that L. lithognathus could be a suitable candidate for mariculture.  相似文献   

3.
Effects of different rearing temperatures (16, 21 and 26°C) on growth, metabolic performance and thermal tolerance of juvenile sea cucumber Apostichopus japonicus (initial body weight 7.72 ± 0.96 g, mean ±SD) were investigated in this study. During the 40‐day experiment, growth, metabolic performance, food intake and energy budget at different reared temperatures were determined. Sea cucumbers rearing at 16°C obtained better growth (final body weight 11.96 ± 0.35 g) than those reared at 21 (10.33 ± 0.41 g) and 26°C (8.31 ± 0.19 g) (P < 0.05), and more energy was allocated for growth at 16°C (162.73 ±11.85 J g?1 d?1) than those at 21(79.61 ± 6.76 J g?1 d?1) and 26°C (27.07 ± 4.30 J g?1 d?1) (P < 0.05). Critical thermal maxima (CTmax) values of juvenile sea cucumbers reared at 16, 21 and 26°C were 33.1, 34.1 and 36.6°C, respectively, and the upregulation of hsps in sea cucumbers reared at 26°C was higher than those acclimated at lower temperatures (16 and 21°C), indicating that temperature acclimation could change the thermal tolerance of the sea cucumber, and CTmax and hsps were sensitive indicators of the sea cucumber's thermal tolerance.  相似文献   

4.
South African juvenile dusky kob Argyrosomus japonicus are more abundant in turbid estuaries than in clear marine‐dominated estuaries. Turbidity can reduce light penetration into the water and create an environment different from that experienced by fish under culture conditions in mechanically filtered clear water. In order to optimize rearing conditions of this species, the effects of light intensity (23–315 lx) and feeding method (restricted ration vs. feeding to apparent satiation) on growth and food conversion ratio (FCR) of juvenile A. japonicus were assessed in a 56‐day growth trial. Fish weight increased from 7.2±1.6 to 41.9±10.2 g fish?1 at a growth rate of 3.25% body weight day?1. Light intensity did not significantly affect growth or FCR. Feeding method did not significantly affect growth rate, but average FCR was significantly better in treatments fed a ration of 3.6% body weight day?1 than in treatments fed to apparent satiation. Therefore, a light intensity range of 23–315 lx can be used to culture dusky kob juveniles. The better FCR in fish fed a restricted ration suggests that a ration of 3.6% body mass day?1 allowed good growth of juvenile dusky kob.  相似文献   

5.
The effects of thermal amplitudes of diel fluctuating temperature on growth and oxygen consumption of the juvenile sea cucumber Apostichopus japonicus (Selenka) were studied at the average temperatures of 15 and 18°C with three diel different fluctuating amplitudes of ±2, ±4 and ±6°C. The optimum thermal amplitudes for growth of the juvenile sea cucumber at the sizes of this experiment, at average temperatures of 15 and 18°C, were estimated to be ±1.38 and ±1.67°C respectively. In the constant temperature regimes, the growth rate at 15°C was higher than that at 18°C. However, the growth rate at 18±2°C was higher than that at 15±2°C. The results from this study suggested that fluctuating temperatures enhanced the optimum temperature for the growth of sea cucumbers compared with that at constant temperatures. Therefore, accurate predictions of the optimum temperature of sea cucumbers in the natural environment, in which water temperatures fluctuate daily and seasonally, should be made from data obtained at fluctuating temperatures.  相似文献   

6.
The effects of four modes of diel temperature-fluctuation with two designated fluctuating temperatures (15 ± 3°C and 18 ± 3°C) on the growth and energy budget of young sea cucumber, Apostichopus japonicus Selenka, were studied to develop a highly efficient temperature-control scheme for aquaculture of the species. Sea cucumbers with a mean wet body weight of 8.0 ± 1.2 g (mean ± SD) were allocated to each treatment randomly with five replicates. After a 38-day trial, specific growth rate (SGR) and food conversion efficiency (FCE) decreased with increasing temperature in constant-temperature treatments. Among the four modes of temperature fluctuation, SGR of sea cucumbers reared under a mode which simulated the natural fluctuation of the temperature (mode C) of seawater was significantly higher than that of sea cucumbers reared at the corresponding constant temperatures. This enhancement of growth rate by use of mode C was attributed to higher FCE and lower energy allocated to respiration and feces. In large-scale culture, a temperature-control mode designed based on mode C could enhance not only growth but also efficiency of food utilization by the young sea cucumber.  相似文献   

7.
To develop a feeding strategy for the Australian freshwater fish silver perch (Bidyanus bidyanus Mitchell), a series of eight experiments was done in 1 m3 cages in an aerated, earthen pond to determine the effects of feeding rate (% body weight) and feeding frequency (no. of feeds day?1) on the growth and feed conversion ratio (FCR) of fingerlings and larger fish under ambient water temperatures over the range 13.8–30.6°C. Fish were fed extruded pellets of a silver perch diet containing 34% digestible protein and 14 MJ kg?1 digestible energy. Commercial silver perch farmers were consulted about feeding practices for large fish (>500 g) and at water temperatures below 12°C, and winter feeding practices for other warmwater species were used to complete the strategy. In the feeding experiments, growth and FCR increased with increasing feeding rates to a level above which only FCR increased. Optimal feeding rates and frequencies were those which resulted in maximal growth, while minimizing effort (feeding frequency) and FCR. The highest feeding frequency required for maximal growth, including that of small fingerlings was twice (2 ×) daily, and the optimal feeding rates varied with water temperature and size of fish. The optimal daily regimes were: small fingerlings (initial mean weight, 2.0 g) 7.5% 2 × at a mean temperature of 23.3°C; fingerlings (14.9–27.7 g) 7.5% 2 × at 27.1°C, 5.0% 2 × at 23.7°C and 2.0% 1 × at 16.8°C; and large silver perch (162.5–510.6 g) 0.5% 1 × daily or 1.0% on alternate days at 15.6°C, 1.0% 1 × at 17.3°C, 3.0% 2 × at 24.1°C and 2.0% 2 × at 27.9°C. It is suggested that regimes of 0.5% 1 × daily for fingerlings (<50 g) and 0.5% 1 × on alternate days for larger fish are used at temperatures of 9–12°C, and 0.5% 3 days week?1 and 0.5% 1 day week?1 for fingerlings and larger fish, respectively, at 6–9°C. Feed inputs should not exceed 150 kg ha?1 day?1 in ponds less than 0.3 ha and 100 kg ha?1 day?1 in larger ponds. Our research has established a feeding strategy for silver perch based on restricted rations.  相似文献   

8.
The individual food intake of each fish in each of four groups of Atlantic halibut, Hippoglossus hippoglossus (L.) (mean weight: 422 g) was monitored by direct observation over a period of 21 days. Gross feed conversion efficiency (= growth·feed intake?1), net feed conversion efficiency and maintenance ration were estimated by regression analysis. Specific growth rates were found to be linearly related to weight-specific consumption at a temperature of 8–9°C: growth = 1.922· feed intake ? 0.242. Maintenance ration was 0.126% of body weight day?1. The gross feed conversion efficiency increased asymptotically with increasing feed intakes and growth rates, and was found to approach 1.9 at high growth rates (0.5 on a dry weight basis). One feeding per day seemed to be sufficient for maximum food intake and growth rate.  相似文献   

9.
Four experiments were conducted to investigate the effects of feeding frequency on growth of juvenile Atlantic halibut, Hippoglossus hippoglossus L. Fish (22–75 g) fed three (3 ×) or five times per day (5 × day?1) under constant light and temperature (13±1°C) consumed significantly more feed than fish fed 1 × day?1 but by the end of the experiment only fish fed 5 × day?1 were heavier and had greater specific growth rates (SGR). Under simulated winter conditions (9L:15D, 5±1°C), halibut (～300 g) fed every other day consumed more feed, had a greater SGR and final weight compared with fish fed every third day. Feed conversion ratios were not different among treatment groups in any of the experiments. These results suggest that growth rates may be improved by feeding juvenile halibut more than 1 × day?1.  相似文献   

10.
The effect of temperature on the food consumption rate and the digestive enzyme activities of Clarias batrachus (80.60 ± 5.34 g) were evaluated. Fish were exposed to six different temperatures of 10, 15, 20, 25, 30 and 35 °C following an acclimation temperature of 25 °C. The rate of temperature change was 2 °C day?1. Highest food consumption was recorded at 25 °C. It gradually reduced with decreasing water temperature. Food consumption rate was significantly (P < 0.05) lower at 10 °C compared with other treatments. Hence, 46.67, 8.20–23.58 and 1.02–6.15% reduced food consumptions were recorded in groups exposed at 10, 15 and 20 °C temperatures, respectively, compared with the 25 °C. The consumption rate was not affected in fish exposed at 30 and 35 °C. Total protease, trypsin and chymotrypsin activities were significantly (P < 0.05) higher in fish exposed at 25 °C compared with others. Lipase activity was significantly (P < 0.05) higher in fish exposed at 30 °C compared with others. Lowest enzyme activities were recorded at 10 °C. Water temperature below 25 °C affected the food consumption and digestive enzyme activities in fish that served as indicators of stress in fish.  相似文献   

11.
The effect of water temperature on growth and food intake of juvenile peled Coregonus peled was tested with specimens of initial age 75 days and 230 days posthatching (dph). The 75‐day group (initial body weight 0.6 ± 0.04 g) were reared for 63 days and 230‐day group (initial body weight 13.75 ± 2.93 g) for 42 days at temperatures of 13, 16, 19, 22 and 25°C under 12:12 L:D photoperiod. The optimal temperature range for the 75 dph fish was found to be 19–22°C. The fish reached final mean weight of 9.7 ± 2.5 g at 19°C and 9.0 ± 2.7 g at 22°C. Final mean weight of 230 dph fish did not differ significantly among temperature groups. Mortality increased at higher temperatures, with the critical temperature of 25°C for both age groups. Maximum food intake (19.0 ± 4.7, 18.8 ± 5.2, 18.6 ± 4.6 g kg?1biomass) was observed in groups reared at temperatures of 19, 22 and 25°C with no significant differences among groups.  相似文献   

12.
Growth and feeding of juvenile triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were investigated at two temperatures of 17 and 21 °C over a 50‐day period. There were no differences in growth between triploid and diploid abalone as measured by shell length and body weight. Both triploid and diploid abalone increased in length but not in weight at 21 °C. Condition indices were similar for triploid abalone maintained at both temperatures; however, those for diploid abalone were significantly higher at 17 °C than at 21 °C. Food intake was significantly greater yet feed conversion efficiency was significantly lower in triploid than in diploid abalone. Both the feeding variables were independent of temperature. On average, diploid abalone were able to convert 1 g of dry food ingested to 0.58 g of body weight, but triploid abalone only 0.44 g.  相似文献   

13.
Individual growth rates, feeding rates (%BWd?1) and food conversions for cuttlefish (S. officinalis) hatchlings and juveniles were determined during this study. A flow‐through system was used. Water temperature reached 30 °C during the hottest part of the day, gradually decreasing to 25 °C during the night; salinity varied between 37 ± 3 ppt and lights were kept on for 14 h day?1. Hatchlings were placed in separate compartments with a water volume of 1.2 L. Juvenile cuttlefish (from 0.5 to 25 g) were placed in bigger baskets, with a water volume of 5.2 L. Water flow was 120 L h?1. The biggest cuttlefish used in these experiments (> 25 g) were gathered in groups of five and placed in circular tanks (water volume of 250–300 L). Thus, results obtained in this case are means and not individual data. During the first 10, 20, 30 and 40 days, mean growth rates (of all individuals sampled by age group) decreased consistently (11.8 ± 4.1, 9.8 ± 1.8, 8.1 ± 2.2 and 7.3 ± 0.7%BW?1 respectively); in similar fashion, mean feeding rates decreased with age group (33.7 ± 13.5, 22.0 ± 7.9, 17.3 ± 3.9 and 16.7%BWd?1 respectively). Mean food conversions varied between 3.6 and 2.5 between the age groups. When grouping results by weight class, similar patterns occur, as growth and feeding rates decrease consistently as cuttlefish grow bigger. Highest mean growth and feeding rates are obtained by hatchlings (< 0.1 g) with 12.4 ± 4.5 and 35.3 ± 15.1%BWd?1, respectively, while the lowest growth and feeding rates were recorded for the largest animals, between 15 and 25 g (3.4 ± 1.1 and 10.8 ± 4.1%BWd?1 respectively). For these weight classes, mean food conversions varied between 2.7 ± 0.9 and 3.8 ± 2.8.  相似文献   

14.
Two groups of Apostichopus japonicus, a thermotolerant strain (group G3: wet weight, 64.22 ± 13.16 g/ind.), which was selected focusing on the performance of thermo‐tolerance through three generations for 10 years, and a control group (group C: wet weight, 62.08 ± 12.01 g/ind.) were collected from July to October in a seawater pond in northern China. Differences in relative faecal mass (RFM), relative intestinal mass (RIM), percentage of individuals with faeces (PIWF) and intestinal metabolites were investigated and compared between the two groups. The temperatures of terminating aestivation of the two groups were assessed according to the values of RFM and RIM. A regression analysis showed that the corresponding group G3 temperatures were 0.56–1.34°C and 0.70–1.49°C higher than those of group C when RFM and RIM were 0.01–0.05 and 0.005–0.025 respectively. The PIWF values in group G3 were 11.5%–21.2% higher than that in group C from 20 July to 22 September. Significant differences at the concentrations of 52 metabolites were detected between the two groups, 36 were higher in group G3 and 16 were higher in group C. The concentrations of threitol, 2‐methylglutaric acid, N‐acetyl‐D‐galactosamine, N‐acetyl‐L‐leucine, lactose, oxoproline, 2,3‐dimethylsuccinic acid and d‐glucoheptose were significantly different between groups G3 and C and were considered metabolic markers distinguishing group G3 from group C. Metabolism of A. japonicus in group G3 was more active than that in group C. These results provide new insight for understanding ingestion and intestinal metabolism in the thermotolerant strain of A. japonicus under high summer temperature.  相似文献   

15.
Two feeding trials were carried out to determine the optimum feeding rates in juvenile olive flounder, Paralichthys olivaceus, at the optimum rearing temperature. Fish averaging 5.0 ± 0.11 g (mean ± SD) in experiment 1 and 20.2 ± 0.54 g (mean ± SD) in experiment 2 were fed a commercial diet at the feeding rates of 0%, 3.0%, 4.0%, 4.25%, 4.5% and 4.75% body weight (BW) day?1 and satiation (5.52% BW day?1) in experiment 1 and 0%, 1.0%, 2.0%, 3.0% and 3.5% BW day?1 and satiation (4.12% BW day?1) in experiment 2 at 20 ± 1 °C. Both feeding trials lasted for 2 weeks. Results from experiment 1 indicated that weight gain (WG) and specific growth rate (SGR) of fish fed to satiation were significantly higher than those of fish fed at other feeding rates while feed efficiency (FE) and protein efficiency ratio (PER) of fish fed at 4.25% BW day?1 were significantly higher than those of fish fed to satiation and fish fed at 3.0% BW day?1 (P < 0.05). In experiment 2 WG, SGR and PER leveled out after the feeding rate of 3.5% BW day?1 whereas FE reached a plateau at 3.0% BW day?1. anova of FE indicated that the optimum feeding rates in 5.0 and 20 g juvenile olive flounder could be 4.25% and 3.0% BW day?1, respectively. Broken line analysis of WG suggested the optimum feeding rates of 5.17% and 3.47% BW day?1 in 5.0 and 20 g fish, respectively. Therefore, these results indicated that the optimum feeding rates could be >4.25 but <5.17% BW day?1 for 5.0 g, and it could be >3.0 but <3.47% BW day?1 for 20 g size of juvenile olive flounder at the optimum rearing temperature.  相似文献   

16.
Sea cucumber, Apostichopus japonicus (Selenca), tolerates salinity fluctuations inhabiting intertide zone. This study deals with growth, food intake, food conversion and the bioenergetic responses of the red variant (wet weight of 2.60 ± 0.11g) and green variant (wet weight of 2.56 ± 0.08 g) A. japonicus to different salinities of 22, 26, 30, 34, and 38 psu at 16.5 ± 0.5°C. The results showed that salinity had a significant effect on specific growth rate (SGR) of both green and red variants A. japonicus (P < 0.05). Both colour variants of sea cucumber had highest SGR at 30 psu, and then decreased when salinity below or above this point. Maximum SGR (the green 1.07 ± 0.08% day?1, the red 1.14 ± 0.09% day?1 respectively) is related with maximum food intake (FI) and highest food conversion efficiency (FCE) (P < 0.05) occurring at 30 psu. Only under 22 psu, the green variant grew faster than the red variant (P < 0.05), and under other four salinity treatments there was no significant difference between SGR of two colour variant holothruians (P > 0.05). Values of adaptable salinity scope for green and red variants sea cucumber survival are 18.5~39 psu and 20.9~38.6 psu respectively. The average energy budget formula of sea cucumber at 30 psu was: 100C = 6G +42F +3U+49R (C, energy ingested; G, energy for growth; F, energy loss as faeces; U, energy used for ammonia excretion; R, energy loss for respiration). The sea cucumber had maximum energy ingested (C) and highest proportion of energy for growth (G) at 30 psu, and then decreased when salinity is above or below this salinity. Both red and green variants of A. japonicus deposited for growth were very low, and the energy loss in faeces and energy for respiration accounted for the majority of assimilation energy. The result clearly showed that the optimum condition for farming green and red variants A. japonicus, both with respect growth and energy allocation, is the salinity scope of 26 ~ 30 psu.  相似文献   

17.
Formulated abalone feeds used by the culture industry are believed to be unsuitable for use at elevated water temperatures (>20 °C). The aim of this study was to develop a feed that could safely be fed to abalone cultured at elevated water temperatures by optimizing dietary protein/energy levels. Abalone (54.90 ± 0.08 mm; 28.99 ± 0.16 g) were cultured at either 18, 22 or 24 °C, and fed diets containing graded levels of protein (18–26%) and energy (11.6–16.2 MJ kg?1). Abalone growth was temperature dependent, declining from 4.33 g month?1 at 18 °C to 0.77 g month?1 at 24 °C. Shell length and weight gain were independent of dietary protein, provided that the digestible energy content of the diet was not lower than 13.5 MJ kg?1. Dietary energy levels below 13.5MJ kg‐1 resulted in significant reductions in shell growth, weight gain and increased mortality from 5% to 27%. Feed consumption of the 22% and 26% protein diets with 11.6 MJ kg?1 was significantly higher (0.53 ± 0.04 and 0.55 ± 0.04% bd. wt. day?1 respectively) compared with abalone fed the 16.2 MJ kg?1 diets at the same protein levels (combined mean of 0.45 ± 0.04% bd. wt. day?1) indicating that consumption was linked to energy requirement. The growth and mortality results suggest that abalone cultured at these temperatures have a dietary digestible energy requirement of at least 13.5 MJ kg?1.  相似文献   

18.
Feed requirements were estimated from specific growth rates in standardized soft tissue dry weight (SGRDW’) and atomic O:N ratios for mussels fed seven rations of microalgae (5–735 μg C h?1 ind?1) at 7 and 14°C respectively. The mean oxygen consumption and ammonia‐N excretion rates were significantly higher at 14°C (0.29 μg O2 and 27.3 μg N ind?1 h1) compared with those at 7°C (0.16 μg O2 and 11.4 μg N ind?1 h?1) (P < 0.05), resulting in O:N ratios between 3 and 45 at 7°C and 7 and 28 at 14°C. Low O:N ratios indicate protein catabolism and an unfavourable condition, whereas high ratios indicate that carbohydrate is the primary energy source. The measured SGRDW’ suggests minimum feed requirements of ~240 and ~570 μg C ind?1 h?1 for weight maintenance at 7 and 14°C, with corresponding O:N ratios of 24 and 16, respectively, indicating a more stressed condition at 14°C. A 0.5% SGRDW’ day?1 was obtained by ~565 (O:N = 29) and ~680 (O:N = 23) μg C ind?1 h?1 at 7 and 14°C respectively. A positive and significantly higher SGRDW’, with the lowest feed ration at 7°C compared with a negative SGRDW’ at 14°C (P < 0.05), indicated that storage time can also possibly be prolonged at low temperatures if the mussels are not fed.  相似文献   

19.
The worldwide demand for sea cucumber is outpacing the sustainable harvest capabilities of fisheries. Sea cucumber ranches and farms are striving to supplement wild harvest, but variable temperature and salinity conditions in pond culture systems make sea cucumber production challenging. In this study, we evaluated how water temperature, salinity and body size affected the energy budget of pond-cultured sea cucumber Apostichopus japonicus Selenka. An orthogonal design was used to identify the most suitable conditions for energy consumption and scope for growth (SFG). After the 42-day experimental period, we found that water temperature, salinity and body size significantly influenced energy consumption, while salinity and body size were the main influencing factors on SFG. Based on these results, we suggest that a water temperature of 16 °C and a salinity of 30 g L?1 are optimal conditions for stocking sea cucumber A. japonicus with a body size of 37.34 ± 4.63 g. As such, the optimum stocking seasons for sea cucumber A. japonicus may be April in the spring and October in the autumn.  相似文献   

20.
We investigated the effects of temperature, age class, and growth on induction of aestivation in the Japanese sandeel (Ammodytes personatus) by means of rearing experiments and field surveys in Ise Bay, central Japan. Acoustic surveys and sampling of shoaling and aestivating sandeels indicated that the sandeels completed aestivation when the water temperature increased to 17–20°C. A rearing experiment showed that the mortality of sandeels reared without sand was greater than it was with sand, under replete feeding conditions. In a non‐aestivation rearing experiment without sand, the condition factor of the sandeels decreased when water temperatures exceeded 20°C, although they were fed to repletion. These results suggest that aestivation is induced by rising seawater temperature and plays an important role in energy conservation. The age‐1 group tended to start aestivation earlier than the age‐0 group in the field. Within the age‐0 group, larger sandeels tended to enter aestivation earlier. These observations indicate that fat reserves are an important cue to start aestivation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号