Larviculture output and stress tolerance of Farfantepenaeus paulensis postlarvae fed Artemia containing different fatty acids

Fatty acid nutrition is known to play a vital role on survival, growth and stress tolerance of aquatic animals. In this study, we assessed whether the enrichment of Artemia franciscana (GSL strain, USA) with emulsions containing different fatty acid profiles would affect larviculture output and tolerance to salinity, temperature and total ammonia (TAN) of the shrimp Farfantepenaeus paulensis. From mysis I up to postlarvae 10 (PL10), three replicate groups of shrimp were reared in 40-l tanks at an initial density of 60 l− 1. They were fed one of the following diets: (1) newly hatched Artemia nauplii; (2) Artemia metanauplii enriched with a saturated fatty acid (SFA) emulsion (ICES enrichment emulsion 0/–/C); and (3) Artemia metanauplii enriched with an emulsion containing 50% n − 3 highly unsaturated fatty acids (n − 3 HUFA) (ICES emulsion 50/0.6/C). Newly hatched Artemia nauplii were enriched for 24 h with two doses of 0.3-g emulsion per liter added at 12 h intervals. Larval feeding was carried out daily at 10:00 and 22:00 hours. Survival and total length (TL; from the tip of rostrum to the tip of the telson) were estimated. Tolerance to salinity, temperature and total ammonia (TAN; NH4+ + NH3) were assessed by exposing PL10 to 10‰ salinity for 1 h, 16–17 °C for 1 h and increasing total ammonia levels (0, 15, 30, 45 60 and 90 mg TAN l− 1) for 24 h, respectively. Tolerance to salinity and temperature were expressed as cumulative stress indexes (CSI; sum of cumulative mortalities over 1 h), while tolerance to ammonia was estimated as the median lethal concentration for 50% of the population during 24 h (LC50). All data were subjected to ANOVA and Tukey's test, except LC50 values, which were compared graphically. Survival of shrimp fed n − 3 HUFA-enriched Artemia was significantly higher than in the other treatments. TL of PL1 was not significantly different, but PL10 fed Artemia nauplii were significantly longer. No differences were found in terms of tolerance to salinity and temperature. PL10 fed n − 3 HUFA enriched Artemia presented a higher tolerance to ammonia. Results indicate that feeding n − 3 HUFA-enriched Artemia to F. paulensis larvae increases survival and tolerance to ammonia, which may be advantageous under adverse rearing conditions.