The synergistic influence of water salinity and temperature on the routine oxygen consumption and apparent heat increment of Penaeus vannamei (Boone, 1931) juveniles

Osmoregulation Oxygen consumption Salinity fluctuation White shrimp

Authors

  • Michael Andam
    michael.andam@dnsc.edu.ph
    Institute of Aquatic and Applied Sciences-Fisheries Department, Davao del Norte State College, New Visayas, Panabo City, 8105, Philippines.
February 25, 2025

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The open-thelycum Pacific white shrimp, Penaeus vannamei (Boone, 1931), is a precious species in aquaculture due to its increasing market demand. This study evaluated the routine oxygen consumption rate (OCR) and apparent heat increment (AHI) of P. vannamei juveniles at four salinities of 5, 15, 25, and 35 ppt and two temperatures of 28 and 32°C levels to understand their respiratory adaptations to salinity fluctuations, which is essential for optimizing their culture conditions. The results indicated that white shrimp juveniles are well-adjusted to withstand salinity changes up to 35 ppt, as evidenced by a 100% survival rate following exposure to various salinity levels (5, 15, 25, and 35 ppt) at 28 and 32°C, respectively. However, the findings show that salinity significantly influenced the metabolic rate of P. vannamei juveniles. Penaeus vannamei juveniles exposed to various salinity levels exhibited higher oxygen consumption and AHI at 32°C compared to 28°C. Oxygen consumption (fasting and feeding) elevated as salinity reduced, with the maximum values at 5 ppt and the minimum at 25 ppt at both temperatures. When salinity was lowered from 25 to 5 ppt, the OCR of shrimp after feeding increased. At low salinity (5 ppt), oxygen consumption increased by 160.78% and 197.48% at 28°C and 32°C, respectively. However, OCR increased with increasing salinity from 25 to 35 ppt at both temperatures. A surge in metabolic rate at low salinity (5 ppt) was likely due to a decreased ability to maintain ionic and osmotic balance as temperature increased. The study also demonstrated that the oxygen consumption of unfed P. vannamei juveniles significantly depends on salinity, with no significant influence from temperature and the interaction between the two factors (temperature x salinity). However, the OCR of P. vannamei juveniles after feeding was significantly influenced by salinity, temperature, and their interaction. These findings suggest that to optimize the production of P. vannamei in controlled conditions, the shrimp should be cultivated at a salinity range of 15 to 25 ppt at 28 and 32°C, respectively.