Feeding juvenile Artemia enriched with ascorbic acid improves larval survival in the spiny lobster Jasus edwardsii.

Newly hatched Jasus edwardsii phyllosoma were fed unenriched Artemia [endogenous ascorbic acid (AA) concentration of 166 μg g−1 dry weight (dw)], Artemia supplemented with algae (AA concentration 594 μg g−1 dw) or with ascorbyl-2-polyphosphate (A2P) (AA concentration 11 737 μg g−1 dw) to examine possible benefits of AA enhancement on culture. Plain or algal-enriched Artemia were fed continuously for 28 days in two treatments during the study. Four other treatments received A2P-enriched Artemia on a progressive basis starting from the commencement of the trial (D-0), the third (D-3), sixth (D-6) or ninth day (D-9) of Stage I (14 days) and similarly during Stage II (14 days). Prior to the commencement of A2P supplementation, plain Artemia were supplied to these animals. By Stage III (28 days feeding), algal, D-0 and D-3 phyllosoma had attained the largest size. The uptake and retention of AA by Stage III phyllosoma appeared to be dose-dependent with the highest concentration of AA incorporation evident in D-0 phyllosoma (1816 μg g−1 dw), while algal and plain phyllosoma contained the lowest concentrations (600 and 300 μg g−1 dw, respectively). Survival at Stage III was highest in D-0 phyllosoma (89%) and lowest in plain phyllosoma (51%). There was a positive relationship between phyllosoma AA concentration and larval survival ( R2 = 0.8328, P < 0.0001). D-0 phyllosoma had the lowest stress index when subjected to an osmotic/temperature activity test, indicative of better survival in culture compared to plain, algal and D-9 phyllosoma, which had consistently higher indices. A negative relationship existed between phyllosoma AA concentration and stress indices at Stage III ( R2 = 0.9263, P < 0.0001), suggesting that AA from the Artemia diet conferred stress resistance. [ABSTRACT FROM AUTHOR]