Response of larval and juvenile rudd Scardinius erythrophthalmus (L.) to different diets under controlled conditions 331

Abstract

The growth and survival of rudd <I>Scardinius erythrophthalmus</I> (L.) were evaluated in a laboratory at 25°C. In 20-day Experiment 1, first-feeding larvae at the age of 4 days post-hatch (initially: TL = 5.7 mm, BW = 0.9 mg) were fed live <I>Artemia</I> nauplii or commercial dry feed (Aller Futura Larvae, AFL) or combinations of both. Even the longest period of initial feeding of nauplii (6 days) was insufficient to obtain satisfactory larval growth after weaning to AFL (TL = 12.4 mm and BW = 17.7 mg vs. TL = 18.9 mm and BW = 68.5 mg for the nauplii-fed fish, significant differences). Nauplii-fed older larvae (24 days post-hatch) were then used in Experiment 2, in which they were fed AFL or Ewos AgloNorse (EAN) dry feeds for 40 days. The EAN diet proved to be significantly (<I>P</I> ≤ 0.05) superior to AFL regarding the final fish growth (TL = 36.5 mm and BW = 506.8 mg vs. TL = 33.4 mm and BW = 392.0 mg ), final survival rates (97.6% vs. 100%) and the incidence of spinal deformities (0% vs. 13.5%).