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1.
The effects of salinity and temperature on plasma protein concentration and total haemocytic prophenoloxidase (proPO) were determined. Groups of 10 juvenile yellowleg shrimp, Penaeus californiensis Holmes, were acclimated for 20 days at different salinities (28%o, 32%o, 36%o, 40%o and 44%o at 25 °C) or temperatures (18, 22, 25, 28 and 32 °C at 36%o). While total protein levels were not affected, the quantities of proPO increased as salinity was elevated. Temperature affected both haemolymph parameters, showing a significant decrease in proPO at 32 °C, and an increase of protein at 28 and 32 °C. These results may help to explain the elevated disease susceptibility of shrimp at higher salinities and/or temperatures.  相似文献   

2.
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   

3.
This 28‐day study investigated the effect of three rearing temperatures, 11, 15 and 19°C, on survival and growth of maraena whitefish fry in a recirculating aquaculture system. Three groups of larvae in three repetitions were reared in recirculating system. Each group comprised 200 larvae. Feeding level was fixed at 500–700 Artemia sp. metanauplii per fish per day. Larvae were fed fresh live brine shrimp at 10 ml/tank every 3 hr. Significantly higher body weight (p = 0.00), total length (p = 0.00), larval yield (p = 0.00) and condition factor (p = 0.00) were obtained at 19°C compared to 15 and 11°C, as well as at 15°C compared to 11°C. Significantly higher survival (p = 0.00) was observed in larvae reared at 11 and 15°C compare to 19°C and no significant differences were observed between 11°C compared to 15°C. No significant differences in size heterogeneity among treatments were found (p = 0.46). In larviculture, the optimal assessed temperature for growth of maraena whitefish was 19°C, with highest survival observed at 11°C, at the end of this 28 days trial. The findings in this study apply to the particular study location and may not be applicable more broadly.  相似文献   

4.
A series of experiments were conducted to examine the effects of salinity (1–48 g/L) on the biological performance, as evaluated by growth and survival, of the Pacific white shrimp, Litopenaeus vannamei, and the Atlantic white shrimp, Litopenaeus setiferus, reared at temperatures of 20, 24 or 28 C. Poor growth and survival of L. vannamei was observed after 21–28 d of culture at low salinity (2 and 4 g/L) at 20 C. Raising salinity to 8 and up to 32 g/L significantly increased survival at this temperature, indicating that avoiding low temperatures is critical for survival of this species when reared at low salinity. A major improvement in the growth rate of L. vannamei was observed at 24 C, but it still was sub‐optimal compared to growth observed at 28 C. Irrespective of salinity, high survival rates were observed at both 24 and 28 C, but variable growth rates were recorded. Contrary to L. vannamei, the Atlantic white shrimp, L. setiferus, which was reared for 28 d at 24 C only, had better growth performance at 8 g/L compared to 2, 16 and 32 g/L. Under equal experimental conditions, L. setiferus had considerably lower weight gain and survival than L. vannamei.  相似文献   

5.
Effects of thermal amplitude of diel fluctuating temperature on the growth, food consumption, food conversion efficiency and apparent digestibility coefficient of Chinese shrimp, Fenneropenaeus chinensis (Osbeck), with initial body weight of 0.36 ± 0.04 g were studied at average temperature 25, 28 and 31 °C from May to July, 2000. Among four diel different fluctuation amplitudes of ± 1, ± 2, ± 3 and ± 4°C, the growth rate of shrimp at 25 ± 2, 25 ± 3, 28 ± 2 and 31 ± 1 °C were significantly higher than those at corresponding constant temperatures of 25, 28 and 31 °C, respectively, while growth rate at 31 ± 4 °C was significantly lower than at 31 °C. There is a trend that the optimal thermal amplitude for shrimp growth decreased with the increase of average temperature in the present study. The growth rate of Chinese shrimp was a quadratic function of the thermal amplitude at the same average temperature. Such a growth model may be described byG=β0+β1(TA)+β2⁢(TA)2where G represents the specific growth rate on a 33-day basis, TA is thermal amplitude in degree Celsius, β0 is intercept on G axis, and β1 and β2 are the regression coefficients. The optimal thermal amplitude for the growth of shrimp at sizes of this experiment at average temperature of 25, 28 and 31 °C was estimated to be ± 2.0, ± 2.2 and ± 1.4 °C, respectively. The changes of food conversion efficiency were similar to the growth rate, while the trends of food consumption of shrimp between fluctuating temperature and constant temperature were variable at different average temperatures. There was no significant difference in apparent digestibility coefficient between diel fluctuating temperatures and corresponding constant temperatures. Therefore, more food consumption, high food conversion efficiency and more energy partitioned into growth might account for the enhancement in the growth of shrimp at the diel fluctuating temperatures in the present study.  相似文献   

6.
The purpose of this study was to investigate the growth and physiological status of Litopenaeus vannamei subjected to one constant temperature (25°C) and four cyclical temperature change regimes (25 ± 1°C, 25 ± 2°C, 25 ± 3°C and 25 ± 4°C). The growth rates of shrimp at 25 ± 2°C or 25 ± 3°C were significantly higher than that at a constant temperature of 25°C. On the other hand, the growth rate in 25 ± 4°C regime was significantly lower than those in other regimes. The daily feed intake rate of shrimp at 25 ± 4°C was the lowest, and the food conversion efficiency was also significantly lower than those at 25 ± 2°C and 25 ± 3°C, respectively. The food conversion efficiency at 25 ± 2°C or 25 ± 3°C was significantly higher than those in other regimes. Thus, it can be inferred that the growth enhancement in the test shrimp at the suitable diel fluctuating temperatures was due to high food conversion efficiency. Studies of the physiological parameters showed that at 25 ± 4°C, the hemolymph glucose content of the test shrimp was the lowest, while the activity of PK in hepatopancreas was the highest, which indicated that the test shrimp at 25 ± 4°C was in a stressed condition. The hemolymph glucose content of the test shrimp at 25 ± 3°C was the highest, and the activity of HK in hepatopancreas was the lowest. These results indicated that the test shrimps at 25 ± 3°C were not in a stressed condition. Compared with the constant temperature regime, the expression of HSP70 in any of the four cyclical temperature change regimes was not significantly increased. The reason for this might be that the fluctuation amplitude of ± 4°C did not induce the increased expression of HSP70.  相似文献   

7.
To investigate the possible direct effect of a stepwise reduction in temperature with increasing size on growth, feeding parameters and muscle growth patterns of juvenile Atlantic halibut (Hippoglossus hippoglossus L.), 804 juvenile halibut (mean initial weight individuals: 14.2 g ± 0.2 SEM) were reared at constant 9, 12 and 15°C or shifted (T-step, i.e. 15–12°C after 36 days) for 99 days. Despite indications of lower optimal temperature for growth with increasing size, equal end weights were obtained between the constant 12°C, constant 15°C and T-step groups. Best overall growth was observed for the group kept at constant 12°C. The limited effect of the T-step group may relate to the size at movement (too big), the temperatures investigated (close to optimum) and the time and size interval investigated (too narrow). Differences in growth were reflected more by alterations in feed intake (C T and F%) than by differences in feed conversion efficiencies (FCE). Differences were found with respect to the density of muscle cells, whereas no differences were found between the average muscle cell diameters. The mean diameter of muscle cells tended to increase only slightly with increasing fish weight, while the mean density of muscle cells tended to decrease. Using an optimum temperature of 12°C, an indication of a possible increased rate of hyperplasia in relation to higher growth was seen.  相似文献   

8.
Growth parameters of whiteleg shrimp Litopenaeus vannamei and red seaweed Gracilaria corticata were measured using integrated culturing method under zero‐water exchange system in a 45‐day period. A 2 × 3 factorial design was used with two levels of shrimp stocking densities and three levels of seaweed weight densities. G. corticata was cultured on a net tied to a round polyethylene frame. Culture tanks were filled with 750‐L filtered seawater. A 40‐W compact fluorescent lamp was hung over each tank to provide adequate and sufficient light for seaweed growth. Growth parameters of shrimp and seaweed such as specific growth rate (SGR), weight gained (WG) and average daily growth (ADG) were computed based on the initial and final weight of shrimp and seaweed. The maximum and minimum SGR of L. vannamei (1.97 and 1.69%/day) were observed in treatment S1A3 (25 shrimp/m2 and 400 g seaweed/m2) and S2A1 (50 shrimp/m2 without seaweed) respectively. The best survival rate (94.67 ± 1.33%), WG (129.9 ± 2.9%) and feed conversion ratio (1.67 ± 0.04) were also observed in treatment S1A3. The SGR of G.corticata in the treatment S1A3 (1.97 ± 0.00%/day) was significantly higher, compared to others. Strong positive correlations were obtained between the density of G. corticata and the growth parameters of L. vannamei. The red seaweed G. corticata could boost the growth parameters, survival rate and total production of L. vannamei under zero‐water exchange system.  相似文献   

9.
The present work was carried out with a view of determining the chilling rates for cold anaesthetization and live storage of Penaeus monodon (Fabricius) in chilled sawdust, for live transportation. Three chilling rates of 1.38 ± 0.16 °C h?1 within 8 h (slow), 2.76 ± 0.32 °C h?1 within 4 h (moderate) and 5.52 ± 0.64 °C h?1 within 2 h (fast) were tested to cold anaesthetize 144 farm‐raised P. monodon (22–25 g) in each chilling rate at 15 g L?1 salinity, from 25 °C down to 14 ± 1 °C in plastic net boxes kept in a refrigerated chilling tank provided with aeration. Eight cold‐anaesthetized shrimps subjected to each chilling rate were packed in an insulated cardboard box (triplicate) between two layers of moist and chilled (2–3 °C) sawdust, and kept inside a chilled storage cabinet at 14 ± 1 °C for durations of 16, 20, 24, 28, 32 and 36 h. Survival was determined by revitalizing the shrimps in aerated water with an initial temperature of 20 °C, which was raised to 28 ± 1 °C at 2.7 °C h?1 within 3 h. Statistically valid, safe durations for obtaining 100% survival were 22.9 ± 1.1, 19.1 ± 0.4 and 14.6 ± 1.1 h, using probit analysis at the slow, moderate and fast chilling rates respectively. The weight loss (1.5–8.8%) due to cold anaesthetization and subsequent revitalization of the packed shrimp was insignificant. Sensory evaluation showed significant improvement in general appearance, and also in colour as well as in flavour of the meat when compared with that of the freshly harvested dead shrimps. The texture as well as odour of the raw and cooked meat between treated and untreated shrimps was unaffected. The effects of chilling rates and shipping durations on sensory quality were insignificant. One hundred per cent survival was obtained for 24, 20 and 16 h for the slow, moderate and fast chilling rates respectively. Percentage survival of the shrimps at different durations was significantly different among the chilling rates, but pair‐wise comparison revealed that the slow and moderate chilling rates were identical. Hence, the moderate chilling rate, which took only 4 h, can be considered the optimum, though the choice of different chilling rates depends on the duration of live storage desired.  相似文献   

10.
This study investigated short‐term effects of increasing water temperature from 27 to 41°C on survival and feed consumption of Penaeus indicus at three different ages: PL25 (postlarvae 25 days old), PL50 and PL90. For each age group, water temperature was maintained at 27°C in the control, but increased to 32, 35, 38 and 41°C at a rate of 1°C every eight hours. The temperature was then kept stable until the end of the 7‐day experiment. Results showed that increasing water temperature affected both survival and feed consumption of the experimental shrimps (p < .01). Survival was highest at 32 and 35°C ranging from 93.8% to 100%, but significantly reduced to 40.0%–81.6% at 38°C. No shrimp survived the 41°C treatment. PL25 were more tolerant to 38–41°C than PL50 and PL90 in terms of survival. Increasing water temperature had no effects on feed consumption of PL25 (p > .05). For PL50 and PL90, feed consumption significantly increased at 38 and 41°C (p < .01) and was similar within the range of 27–35°C. This study suggests that P. indicus in tropical areas can tolerate water temperatures of at least 35°C and should be considered for farming during the summer time.  相似文献   

11.
The present study assessed the effects of different types of feeds and salinity levels on water quality, growth performance, survival rate and body composition of the Pacific white shrimp, Litopenaeus vannamei, juveniles in a biofloc system. Shrimp juveniles (2.56 ± 0.33 g) were cultured for 35 days in 300 L fibreglass tanks (water volume of 180 L) with a density of 1 g/L in six treatments. Three sources of feed (100% formulated feed, mixture of 66.6% formulated diet and 33.3% wet biofloc, and 100% wet biofloc) and two levels of salinity (10 and 32 ppt) were considered in two control groups and four biofloc treatments. Water quality parameters in the biofloc treatments were significantly better than control groups (p < .05). The highest increase in growth performance and survival rate were obtained in salinity of 32 ppt and mixed feed sources. Analysing the proximate composition of body shrimp indicates an increase in lipid and ash levels in biofloc treatments, which was more evident in the salinity of 32 ppt. In addition, the proximate analysis of shrimp body showed significant differences between biofloc treatments and control groups (p < .05). The highest FCR was found in the treatment with salinity level of 10 ppt and fed only with floc. Overall, it was found that the artificial diet supplemented with biofloc at the salinity of 32 showed better performance in the juvenile stage of Pacific white shrimp.  相似文献   

12.
This study aimed to analyse the effects of different water temperatures on the growth, survival and blood physiological parameters of Lophiosilurus alexandri. Juveniles measuring 12.6 ± 0.5 cm and weighing 30.6 ± 3.6 g were subjected to four water temperature regimes: 23, 26, 29 and 32°C with four replicates. The animals were fed twice daily with formulated diet. The experiment lasted for 35 days. Survival was 100% at all water temperatures, and the best temperature for growth was estimated to be 27.8°C using a quadratic regression model. The estimated temperatures for the best feed conversion and highest feed consumption rates were 26.2 and 28.8°C respectively. The fat visceral‐somatic index was highest at 32°C. The highest haemoglobin and haematocrit values were 29.4 and 32.1°C respectively. For plasma protein and cholesterol, the lowest values estimated were 23.9 and 24.1°C respectively. Glucose and liver nitrogen content increased with rising temperature. Higher values of total ammonia in the water were observed at higher temperatures. No effects of temperature were seen on the amounts of muscle dry matter, nitrogen, energy content and triglycerides or on the hepatosomatic index. Water temperature has an important role in the developmental and blood physiological parameters of juvenile L. alexandri, and the quadratic regression model showed that the appropriate temperature for growth is between 27 and 28°C.  相似文献   

13.
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14.
Calanoid copepods, including species of the genus Acartia, are commonly used as larval diets for marine finfish. This study aimed to determine the separate effects of water temperature (18, 22, 24, 28° ± 0.5°C) and photoperiod (24L:0D; 18L:6D; 12L:12D; 8L:18D; 0L:24D) on Acartia grani egg production (EP), hatching rate (EHR) and population growth. Egg production rate was not affected by the two abiotic parameters. A. grani eggs incubated at T24°C and T28°C were the first to achieve 50% hatching rate (23–25 hr), with significant differences at the end of the experiment (48 hr) between T28°C treatment (EHR 88 ± 5%) and T18°C treatment (EHR 65 ± 2%). However, different temperature regimes did not affect final number of individuals in population growth experiment. Still, when eggs were excluded from data, population at lower temperatures (18°C) was mainly composed by the nauplii stage (72%), while at higher temperatures (24°C and 28°C) more than 60% of the population was composed by copepodites and adults. A. grani subjected to long‐day photoperiods had significantly lower EHR (16.7% at 24L:0D; 20.8% at 18L:6D) than at short‐day photoperiods (52.6% at 6L:18D; 50.0% at 0L:24D). In population growth experiment, eggs were the most common life stage after 12‐day culture. Lowest population number was found at constant light conditions (665.0 ± 197.1), suggesting higher metabolic rates and depletion of energy reserves in long‐day conditions. This study expanded knowledge on the biological response of A. grani to separate temperature and photoperiod regimes, and provided ground to improve the culture of this potential life feed species for hatcheries.  相似文献   

15.
In this study, we aimed to investigate the effects of water temperature and stocking density on the survival, feeding and growth of the juveniles of the hybrid yellow catfish from Pelteobagrus fulvidraco (♀) × Pelteobagrus vachelli (♂) using the parameters as follows: survival rate (%), feeding rate (% day?1), feed conversion ratio, specific growth rate (% day?1), coefficient of variation (%), productivity (P, g m?3 day?1) and condition factor. We reared the juvenile fish (3.25 ± 0.21 g) at 12 water temperature levels and six stocking density levels (each level included three aquaria in two batches of experiments). The results showed that all groups survived at a temperature range of ≤35°C during a 46‐day experimental period, and they could achieve a high growth at a water temperature range of 26–32°C. The optimal temperature for growth was 29.8°C. Productivity peaked at a stocking density of 1.9 kg m?3. Our results indicated that the hybrid is very suitable for commercial aquaculture.  相似文献   

16.
The present study evaluates the effect of two temperatures, 14°C (T14) and 18°C (T18), on yield and the presence of cranial abnormalities during early development in north palm ruff (Seriolella violacea). Different time indices – days post‐hatching (DPH), degree‐days (D°) and effective degree‐days (D°eff) – were used to analyse growth during cultivation. Several ontogenetic events were achieved in less time during cultivation at 18°C. Additionally, a larger total length and final weight, as well as a higher survival rate, were achieved after 80 days of culture at higher temperatures (T18 = 55.5 ± 1.5 mm; 2.87 ± 0.21 g; 1.80 ± 0.18% and T14 = 24.3 ± 2.2 mm; 0.26 ± 0.08 g; 1.33 ± 0.12%). D° and D°eff were valid as independent temperature indices for predicting the growth response of S. violacea against thermal variations. The frequencies of cranial skeletal abnormalities (mouth and opercular complex) were evaluated in the pre‐flexion, flexion, post‐flexion and juvenile stages. However, the frequency of cranial skeletal abnormalities at the end of this study was not significantly influenced (P > 0.05) by temperature, and values below 21% were recorded in both treatments. These results can be of practical use for optimizing culture conditions to maximize the yield and quality of S. violacea juveniles.  相似文献   

17.
The basal diet (C), with 0.20% medicinal herbs (M) and 0.30% Bacillus (BM1), with 0.10% medicinal herbs and 0.15% Bacillus (BM2), and with 0.30% Bacillus (B), was used to feed white shrimps (Litopenaeus vannamei) (1.91 ± 0.03 g) in order to assess survival, growth, body composition, and digestive enzyme activity. At the end of the feeding trial, survival ranged from 95.83 to 98.33% with no significant difference (P > 0.05) among all groups. Growth measured as weight gain was significantly (P < 0.05) higher in shrimp fed with BM2, BM1, and M compared to that of C. However, no significant differences were found among B, BM1, and M. In the case of specific growth rate, the shrimp fed with BM1 and BM2 exhibited significantly (P < 0.05) higher values than that of C. The contents of body moisture, crude protein, and ash seemed to be unaffected by the feed supplements, though lipid content was found to be significantly (P < 0.05) different among the treatments. The shrimp fed with BM1 and BM2 had the lowest and highest lipid contents, respectively. The digestive enzyme activity assessed using shrimp hepatopancreas revealed that the activities of amylase and protease in shrimp fed with BM2 were significantly (P < 0.05) higher than those of C at the end of the 2nd and 6th weeks. However, better performance of the specific amylase activity was shown by the shrimp fed with B at the end of the 8th week.  相似文献   

18.
《Aquaculture Research》2017,48(6):2803-2811
The brown shrimp Farfantepenaeus californiensis and the seaweed Ulva clathrata, both native to north‐west Mexico, were co‐cultured in lined ponds during 18 weeks. The aim of this study was to evaluate different stocking densities (10, 20, 30, 40 and 50 per m2) in terms of shrimp yield to see if the co‐culture method results in shrimp yields suitable for commercial production. The presence of Ulva results in good water quality and allows culture of brown shrimp with low water exchange (10% weekly) and with low nitrogen and phosphorus content in discharged water. The final weight and specific growth rate (SGR) in shrimp between 10 and 30 per m2 were significantly higher (12.5–12.0 g and 4.56–4.53% day−1 respectively) than 40 and 50 per m2 (9.1 and 8.6 g, and 4.31% and 4.26% day−1 respectively). Total shrimp biomass generated in 30 or more shrimp per m2 was significantly higher (2.7–3.1 t ha−1) compared with 10 and 20 shrimp per m2 (1.0 and 2.0 t ha−1 respectively). The lowest feed conversion ratio (FCR) (0.97) was shown in the 10 shrimp per m2 case, and the highest FCR was seen with 50 shrimp per m2 (1.37). Shrimp survival ranged between 71% and 81%, where the highest mortality was shown in 50 shrimp per m2. The results show that the co‐culture method can result in commercially interesting yields, suggesting that 30 shrimp per m2 is the best stocking density for co‐culturing F. californiensis with U. clathrata, based on the shrimp performance.  相似文献   

19.
ABSTRACT

The effect of photoperiod (24L:00D, 12L:12D, and 00L:24D) and temperature (22 ± 1°C and 28 ± 1°C) on performance of Clarias gariepinus larvae was tested. Larvae weighing 3.2 ± 0.24 mg were cultured in aquaria at a stocking density of 20 fish L?1 and fed twice a day on catfish starter diet (40% CP) at 10 % BW day?1. Highest mean weight gain (31.00 mg), SGR (7.56% day?1), and survival (83%) were achieved at photoperiod and temperature combination of 00L:24D and 28 ± 1°C. Percent survival of larvae differed significantly (p < .05) among treatments with optimal survival of (83%) in treatment combination of 28 ± 1°C and 00L:24D, while lowest survival (40%) in treatment combination of 22 ± 1°C and 24L:00D.  相似文献   

20.
Natural spawning, early development and larviculture of the ornate goby Istigobius ornatus in captivity were studied for the first time. I. ornatus spawned 46 times from 31 October 2013 to 31 October 2014. Fecundity ranged from 246 to 10,214 eggs per clutch, with an average hatching rate of 77.8% ± 9.9% (M ± SEM). Fertilized eggs (1.31–1.54 × 0.46–0.50 mm in diameter) were adhesive demersal and oval‐shaped. Embryonic development lasted 84 hr at 27.5 ± 0.5°C. Newly hatched larvae [2.12 ± 0.04 mm in total length (TL)] transformed to the juvenile stage completely when TL was 7.79 mm. Effects of different water temperatures (24, 28 and 32°C) and salinities (10, 15, 20, 25, 30, 35 and 40 g/L) on per cent survivals (%) and survival activity indices (SAIs) were tested. Survival was not significantly different under different temperatures; SAIs was significantly higher at 28°C. Larvae showed the significantly higher survival and SAIs at salinities 10–30 g/L than at 35 and 40 g/L. Effect of different prey densities on survival was significantly higher in 7 days post hatch larvae fed 20 and 30 rotifers/ml. These findings could guide future programs in captive breeding technology development and commercial production of other marine ornamental gobies.  相似文献   

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