Effect of weaning age and diet on pikeperch larviculture

Abstract

The effects of weaning age and diets on survival, cannibalism, deformity and growth were investigated in pikeperch post-larvae Sander lucioperca. In a first experiment, fish were fed Artemia nauplii after hatching and then divided, on days 12, 19 and 26 post-hatch, into groups receiving Artemia nauplii as control or artificial diet. Significant differences were observed on survival, cannibalism, deformity and growth performance between the different weaning age and control groups. The best growth (mean weight gain = 380.8 mg) with the lowest mortality (48.1%) and lowest deformity rate (11.9%) but high cannibalism (36.7%) was obtained in larvae weaned at day 19 post-hatch, whereas the lowest growth (mean weight gain = 218.9 mg) with the highest mortality (68.6%), high deformity (22.3%) and low cannibalism (13.8%) was obtained in fish weaned at day 12 post-hatch. The highest survival but with highest deformity, mainly incomplete mouth development, was observed in control group that was fed Artemia nauplii only. In a second experiment, 19-day old post-larvae were fed different larval feeds (formulated for marine or freshwater fish species) during 18 days and performances (survival, growth, cannibalism, resistance to osmotic stress test) were compared to fish fed standard or HUFA + vitamin C enriched Artemia metanauplii. The best growth was obtained in fish fed Artemia metanauplii (final mean weight = 301.5 and 372.7 mg, in standard and enriched Artemia groups, respectively), while the feeds formulated for freshwater fish species resulted in better growth (final mean weight = 176.6 and 230.8 mg) than those formulated for marine species (final mean weight = 123.8 and 144.5 mg). The highest survival, growth and resistance to saline stress as well as the lowest deformity were found in fish fed HUFA + vitamin C enriched Artemia metanauplii. Significant differences of ascorbic acid content in fish were observed among the dietary treatments, ranging from 17.5 ± 6.4 to 62.5 ± 8.3 μg fish dry matter − 1 . Highly significant correlations were achieved between dietary ascorbic acid content and the ascorbic acid content in larval carcass ( R 2 = 0.91) or the reduction of larval deformity ( R 2 = 0.75).