Effects on growth performance and survival rate of black sea trout larvae (Salmo trutta labrax, Pallas 1811) fed with annelida and nematoda worms

In this study, 1800 Salmo trutta labrax larvae with a mean weight of 0,109 ± 0.01 g were fed with two sources of live feeds and commercial diet as a control group during the first feeding transition phase to determine the survival success of live feeds. During the trial, growth performance and some histological parameters (liver, intestine) were also determined. Experiment was designed as 3 groups with 3 replicates and lasted 30 days to the point where all larvae adapted to external feeding. Panagrellus redivivus and Enchytraeus albidus were chosen as live feed sources where a well-known commercial feed was used as control feed (300-500µm and 500-800µm). Highest survival rate was measured for Enchytraeus albidus fed groups with a mean % 84 survival where the lowest was calculated % 58,5 for Panagrellus redivivus. Mean total weight gain was highest (26,06 ± 6,80 g) in control groups which was significantly different than P. redivivus and E. albidus groups. Lowest mean was calculated as 11,93±5,95 g for P. redivivus group. Specific growth rate measurements were similar to total weight gain where commercial diets had the highest mean SGR (2.6134) and P. redivivus had the lowest (1.3796). Commercial diets showed the best FCR values (0.5508) with the lowest (4.5803) being for P. redivivus group. Histological evaluation of the intestines revealed fat vacuoles in E. albidus and commercial feed fed groups. This was linked to the higher fat content found in commercial feeds and E. albidus where P. redivivus samples did not show fat vacuoles.