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The article presents information on a study on the effects of early suppression of cyst supplementation and different preparations of decapsulated Artemia cysts as a dietary supplement for juvenile tech. The supplements are for growth performance as well as body deformities reduction. It is stated that no significant differences were found in survival when different cyst supplements were provided.

Two 120-day experiments with 5-month-old juvenile tench ( Tinca tinca L.) were conducted to evaluate different photoperiod conditions. In the first experiment, juveniles were exposed to natural winter photoperiod (ca. 11 h light: 13 h dark), continuous light or continuous darkness. In the second experiment, two photoperiods were tested: natural winter or an extended photoperiod (16 h light: 8 h dark). In all cases, survival was high (95.8-100%). In the first experiment, tench under the natural winter photoperiod had the highest growth (52.3 mm TL, 1.84 g W, 1.28% d−1 SGR). In the second experiment, the extended photoperiod enabled a significantly higher growth (56.8 mm TL, 2.51 W g, 1.75% d−1 SGR) than in the natural winter photoperiod. Percentages of deformed fish ranged from 1 to 31.2%. [ABSTRACT FROM AUTHOR]

Two 60-day experiments were carried out on tench ( Tinca tinca L.) from day 5 post-hatch. Density was 20 larvae L−1 and temperature 24 ± 0.5°C. In experiment 1, Artemia nauplii were the sole food, testing nauplii amounts and feeding frequency. High survival rates (between 79.5% and 95.5%) were obtained. Growth was faster as nauplii amounts were greater; the highest growth rate (11.00), weight (265.5 mg) and Fulton’s coefficient (1.40) were obtained when fish were fed in excess once a day, without significant differences from the growth obtained by feeding in excess of eight times a day. In experiment 2, a dry diet for marine fish was tested as a replacement for Artemia nauplii, following two transition protocols, one faster than the other; high survival rates (between 77.7% and 87.1%) were again obtained. The slower transition allowed a growth rate of 10.14, length of 23.1 mm, weight of 158.3 mg and a Fulton’s coefficient of 1.28, without significant differences from the faster transition. At all stages, growth values were significantly higher from feeding nauplii in excess as the sole food, but the required nauplii quantity was six times higher than the amount supplied to the animals fed the dry diet. [ABSTRACT FROM AUTHOR]