Intensive rearing of the nase Chondrostoma nasus (L.) larvae using dry starter feeds and natural diet under controlled conditions

We performed intensive rearing of larvae of the nase Chondrostoma nasus (L.) in a feeding experiment until 21 days from the initiation of exogenous nutrition under laboratory conditions at a temperature 26°C. Two dry starter feeds (a feed for salmonids and a starter feed of the artificialplanktontype)differinginthecompositionof nutrients (50% and 60% of proteins, 12% and 16% of fat, respectively) and natural food (Artemia salina nauplii) were used. Cumulative survival rate, individual weight (w), total length (TL), specificweightgrowthrate(SWGR),specificlengthgrowthrate(SLGR)andconditionfactor(CF)wereassessed.One-wayanalysisofvariance(ANOVA)was used for statistical processing of data. High survival rate 99.3% and the highest (P < 0.01) growth rate of nase larvae (TL = 22.0 mm, w = 69.2 mg) were found when feeding the natural food. The application of dry feed of the artificialplanktontyperesultedinhighersurvival(98.8%)andsignificantlyhigher(P < 0.01) growth of both length and weight (TL = 17.5 mm, w = 42.5 mg) compared to the nase fed with dry feed for salmonids (survival rate 77.3%, TL = 15.9 mm, w = 24.5 mm). In the course of the experiment the value of Fulton's coefficientincreasedfrominitial0.57 to 0.79 in fishfedwithartificialplanktonto0.65infishfedwithnaturalfoodandto 0.61if dryfeedforsalmo-nids was used. We conclude that with an appropriate starter feed the successful intensive rearing of larval nase can be carried out under controlled conditions.