SUPPLEMENTATION OF ARTIFICIAL DIETS FOR COMMON CARP (CYPRINUS-CARPIO L) LARVAE

Duplicate groups of full-sib carp (Cyprinus carpio L.) larvae were reared at 24 +/- 0.5-degrees-C and fed six artificial diets (A to F) with the same protein sources (yeast powder 59%; dry beef liver 41%) and a diet (G) in which half of the protein source was replaced by egg powder. Diets were supplemented with different levels (0%, 5% or 10%) of cod liver oil (CLO), mineral premix (M) and vitamin premix (V). After 21 days on experimental diets (D0-D21), larvae were fed a commercial feed for 10 additional days (D21-D31). On day 21, survival of larvae fed the yeast-liver diet supplemented with CLO (5%), M (5%) and V (5%) (diet A) was 64% and mean body weight was 169 mg. Compared to diet A, diet B (CLO 10%, M 10%, V 10%) did not improve survival (68%) or mean body weight (170 mg). Larvae fed a nonsupplemented diet (C) containing only yeast and liver had a lower survival rate (42%) and mean body weight (63 mg). Vitamins appeared to be a limiting factor as the larvae fed diet D with CLO 5%, M 5% and no V exhibited a very low survival rate (13%) and mean body weight (28 mg). The mineral premix also seemed necessary as results obtained with diet E (CLO 5%, V 5%, no M) were similar (survival 52%, mean weight 53 mg) to those obtained with the non-supplemented diet (C). Diet F (M 5%, V 5%, no CLO) led to an excellent survival rate (95%) and mean body weight of 189 mg on day 21. Larvae fed diet G (42.5% yeast-liver mixture, 42.5% egg powder, 5% CLO, 5% M, 5% V) reached an individual mean weight of 140 mg. It was concluded that the mineral and vitamin supplementation of the yeast-liver diets was necessary, whilst an addition of 5% CLO in these diets had a negative effect. Survival of larvae initially fed the best diet (F) was 95% and mean body weight was 755 mg after 10 additional days of feeding (D21-D31) a commercial diet. This confirmed the possibility of rearing carp larvae on artificial food with high survival and growth rates.