Evaluación de la resistencia de postlarvas de litopenaeus vannamei a cambios bruscos de salinidad del agua en condiciones de estrés y sin estrés.

Abstract

The cultivation of white shrimp Litopenaeus vannamei holds significant economic importance in aquaculture, but it faces major challenges due to a lack of studies on the tolerance of larvae to wide changes in salinity. This can result in massive mortalities and considerable economic losses (Poveda & Piedrahita, 2020). The survival and quality of postlarvae depend on multiple factors, including their osmoregulatory capacity, which varies according to ontogenetic development and physiological condition (Burbano-Gallardo et al., 2015). Although L. vannamei is a euryhaline species, its isosmotic point and salinity tolerance can vary significantly (Romano & Zeng, 2012). Physiological stress can alter the ability of postlarvae to cope with sudden environmental changes, such as salinity fluctuations (Li et al., 2017). Therefore, it is crucial to explore the mechanisms underlying inconsistent responses in shrimp survival and growth under different salinity and stress conditions (Li et al., 2008). This project focuses on evaluating the resistance of L. vannamei postlarvae to sudden changes in water salinity under stressed and non-stressed conditions, analyzing physiological responses and determining lethal ranges. The main objective is to examine the impact of sudden exposure to different salinity levels of 3, 10, 15, and 23 ppm on the survival of postlarvae of different ages, both under normal and stress conditions. The methodology included experimental trials with postlarvae of 6, 10, 14, and 16 days old. Test tubes of 20 ml were used as experimental units, with five replicates per treatment. The experiments were conducted under normal conditions for 6- and 10-day-old postlarvae, and under stress conditions for 14- and 16-day-old postlarvae. The results showed that postlarval resistance increases with age and salinity. In 6-day-old postlarvae, maximum resistance was observed at 15 ppm (123 ± 6.46 minutes). For 10-day-old postlarvae, resistance increased dramatically, reaching the experimental maximum of 1440 minutes at 15 and 23 ppm. Under stress conditions, 14- and 16-day-old postlarvae showed higher resistance to higher salinities, with maximum times of 1285.6 ± 199.35 and 1398.4 ± 87.7 minutes at 23 ppm, respectively. The conclusions indicate that stress caused by sudden changes in salinity negatively affects the resistance and survival of L. vannamei postlarvae, regardless of their age. However, more developed postlarvae show greater survival and adaptability to a wider range of salinities compared to younger ones. This study provides valuable information to optimize protocols in larval rearing and increase the resilience of organisms to adverse effects of global climate change and stress conditions in production systems. The results can contribute to improving management practices in the shrimp industry, reducing economic losses associated with stress-related mortalities.