Combined effects of temperature and salinity on critical thermal minima of pacific white shrimp Litopenaeus vannamei (Crustacea: Penaeidae)

Critical thermal minima (CTMin) were determined for the Pacific white shrimp Litopenaeus vannamei juveniles from four different acclimation temperatures (15, 20, 25, and 30°C) and salinities (10‰, 20‰, 30‰, and 40‰). The lowest and highest CTMin of shrimp ranged between 7.2°C at 15°C/30‰ and 11.44°C at 30°C/20‰ at the cooling rate of 1°Ch-1. Acclimation temperature and salinity, as well as the interaction of both parameters, had significant effects on the CTMin values of L. vannamei (P<0.01). Yet, the results showed a much more profound effect of temperature on low thermal tolerance of juveniles. Only 40‰ salinity had an influence on the CTMin values (P<0.01). As the acclimation temperature was lowered from 30 to 15°C thermal tolerance of the shrimp significantly increased by 3.25-4.14°C. The acclimation response ratio (ARR) of the Pacific white shrimp exposed to different combinations of salinity and temperature ranged between 0.25 and 0.27. When this species is farmed in sub-tropical regions, its pond water temperature in the over-wintering facilities (regardless of the water salinity level) must never fall below 12°C throughout the cold season to prevent mortalities. © 2010 Elsevier Ltd.SUF2008BAP6This study was financed by the Research Fund of the University of Cukurova ( SUF2008BAP6 )

Thermal tolerance of Litopenaeus vannamei (Crustacea: Penaeidae) acclimated to four temperatures

Critical thermal minima (CTMin) and maxima (CTMax) values were determined for the Pacific white shrimp Litopenaeus vannamei post-larvae and juveniles at four different acclimation temperatures (15, 20, 25, and 30°C). The CTMin of shrimp at these acclimation temperatures were 7.82, 8.95, 9.80, and 10.96°C for post-larvae and 7.50, 8.20, 10.20, and 10.80°C for juveniles, respectively, at 1°Ch-1 cooling rate. The CTMax values were 35.65, 38.13, 39.91, and 42.00°C for post-larvae and 35.94, 38.65, 40.30, and 42.20°C for juveniles at the respective acclimation temperatures. Both acclimation temperature and size of the shrimp affected CTMin values of L. vannamei (P<0.01). Overall, juveniles displayed significantly lower CTMin values than the post-larvae (P<0.0001). However, the CTMax response by post-larvae and juveniles were not significantly different from each other and no interaction was determined between the acclimation temperature and development stage (P>0.01). The area of the thermal tolerance polygon over four acclimation temperatures (15, 20, 25, and 30°C) for the post-larvae of L. vannamei was calculated to be 434.94°C2. The acclimation response ratio (ARR) values were high ranging from 0.35 to 0.44 for both post-larvae and juveniles. L. vannamei appears to be more sensitive to low temperatures than other penaeid species and its cold tolerance zone ranged from 7.5 to 11°C. In successful aquaculture temperature must never fall below 12°C to prevent mortalities. Upper thermal tolerance is less of a problem as in most subtropical regions maximum water temperature rarely exceeds 34°C, but care should be given if shallow ponds with low water renewal rate are being used. © 2010 Elsevier Ltd.SUF2008BAP6This study was financed by the Research Fund of the University of Cukurova (Adana, Turkey) by project code number SUF2008BAP6

The use of nematodes as live feed for larval shrimps

WOS: 000082458200026In this study, the potential of nematodes as an alternative live feed for the omnivorous larva of Penaeus indicus (Crustacea: Penaeidae) and the carnivorous larvae of Macrobrachium rosenbergii and Palaemon elegans (Crustacea: Palaemonidae) was investigated. The results showed that M. rosenbergii and P. elegans larvae were unable to consume the nematodes. The larvae of these species fed Artemia for 8 days, displayed normal development and high survival lover 90%), but, similar to the starved controls. The larvae grown on the nematodes had all died by the 8th day of the experiments. P. indicus larvae fed nematodes from stage Protozoea 3 (PZ3) had similar growth (P>0.05) but higher survival than those fed the control feed (alg/Artemia) until stage postlarvae 1 (PL1) (P<0.05). 51% of PZ1 larvae fed on the nematodes metamorphosed into PL1 compared with 32% of those fed alg/Artemia control diet (P<0.05). In addition to the nematodes, provision of algae for only 1 day significantly improved larval survival and growth of P. indicus larvae. This study demonstrated that nematodes can be used as an alternative live feed for algae and Artemia in the culture of omnivore P. indicus but cannot be used as food in the larval culture of the M. rosenbergii and P. elegans carnivore species

The effect of feed types on survival and trypsin activity in Temora longicornis (Crustacea:Copepoda)

In this study, the effects of different diets on the survival and trypsin-like activity of a calanoid copepod Temora longicornis were investigated in the laboratory. The animals were starved or fed live algae (Diet A), a microencapsulated diet (Diet B), or the microencapsulated diet plus frozen algal cells (Diet C) for 10 days. The highest survival (69%) was obtained with those fed Diet A, whereas the lowest (11%) with the starved control (p<0.05). At the end of the experiment, animals fed Diet C displayed a significantly better survival (53%) than those fed Diet B (32%; p<0.05). Measurement of trypsin-like activity revealed that the animals adapted their digestive enzymes to live or dead algal cells more rapidly (within 24 h of feeding) than to formulated diet particles (after 5 days of feeding). The animals fed Diet A had the highest trypsin-like activity (p<0.05). Addition of frozen algal cells into the culture (Diet C) induced a significantly higher trypsin-like activity over Diet B fed animals (p<0.05). It seems that proteolytic enzymes of copepods feeding on artificial or live feeds have similar responses to other planktonic decapod crustaceans feeding at the primary consumer level

The Use of Nematodes As Live Feed for Larval Shrimps [Karides Larvalarinin Beslenmesinde Nematodlarin Canli Yem Kaynagi Olarak Degerlendirilmesi]

In this study, the potential of nematodes as an alternative live feed for the omnivorous larva of Penaeus indicus (Crustacea: Penaeidae) and the carnivorous larvae of Macrobrachium rosenbergii and Palaemon elegans (Crustacea: Palaemonidae) was investigated. The results showed that M. rosenbergii and P. elegans larvae were unable to consume the nematodes. The larvae of these species fed Artemia for 8 days, displayed normal development and high survival (over 90%), but, similar to the starved controls. The larvae grown on the nematodes had all died by the 8th day of the experiments. P. indicus larvae fed nematodes from stage Protozoea 3 (PZ3) had similar growth (P>0.05) but higher survival than those fed the control feed (alg/Artemia) until stage postlarvae 1 (PL1) (P<0.05), 51% of PZ1 larvae fed on the nematodes metamorphosed into PL1 compared with 32% of those fed alg/Artemia control diet (P<0.05). In addition to the nematodes, provision of algae for only 1 day significantly improved larval survival and growth of P. indicus larvae. This study demonstrated that nematodes can be used as an alternative live feed for algae and Artemia in the culture of omnivore P. indicus but cannot be used as food in the larval culture of the M. rosenbergii and P. elegans carnivore species

The effect of feed types on survival and trypsin activity in Temora longicornis (Crustacea : Copepoda)

WOS: 000072241300003In this study, the effects of different diets on the survival and trypsin-like activity of a calanoid copepod Temora longicornis were investigated in the laboratory. The animals were starved or fed live algae (Diet A), a microencapsulated diet (Diet B), or the microencapsulated diet plus frozen algal cells (Diet C) for 10 days. The highest survival (69%) was obtained with those fed Diet A, whereas the lowest (11%) with the starved control (p<0.05). At the end of the experiment, animals fed Diet C displayed a significantly better survival (53%) than those fed Diet B (32%; p<0.05). Measurement of trypsin-like activity revealed that the animals adapted their digestive enzymes to live or dead algal cells more rapidly (within 24 h of feeding) than to formulated diet particles (after 5 days of feeding). The animals fed Diet A had the highest trypsin-like activity (p<0.05). Addition of frozen algal cells into the culture (Diet C) induced a significantly higher trypsin-like activity over Diet B fed animals (p<0.05). It seems that proteolytic enzymes of copepods feeding on artificial or live feeds have similar responses to other planktonic decapod crustaceans feeding at the primary consumer level