An investigation on the gamete quality of black sea trout (Salmo trutta labrax) brodstock fed with mealworm (Tenebrio molitor)

In this thesis, the effect of feeding mealworm larvae (Tenebrio molitor) for 50 days before the breeding period in addition to commercial feed on gamete quality Black Sea trout (Salmo trutta labrax) broodstocks was investigated. Female and male fishes of similar weight and size were placed in a total of six tanks, each containing 5 fishes. While the control group was only fed with commercial feed, mealworm larvae were given as an additional protein source two days a week and three days a week to the experimental groups formed from female and male individuals. Broodstocks were fed with 8-mm diameter commercial feed twice a day at 0.5-1% ratio of body weight and; larvae were given with the commercial feed as an addition, at 20-25% ratio of the feed. In addition to the growth parameters in the experimental groups, the number of eggs (number/individual) in the female fish and the egg diameter (mm) in the eggs obtained were examined. In male individuals; sperm volume (ml), density of spermatozoa (x109 cell/ml), total motility of spermatozoa (%), progressive motility of spermatozoa (%) and average curvilinear velocity (VCL, µm/s) of these motility values were determined. At the end of the study, the live weight gain of the female fish was calculated as 128.2 g in the control group and 72.6 g in the two days group and 37.6 g in the three days group. The highest live weight gain was found as 46.2 g in the control group of male. Fecundity values were found as 4362 ± 1638 numbers/individuals in the control group, 3436±1016 numbers/individuals in the two days group and 3797 ± 1130 numbers/individuals in the three days group. The egg diameters were 4.3 ± 1.8 mm in the control group; 4.5 ± 1.4 mm in the worm group and 4.5 ± 1.8 mm in the worm group. Values of sperm volume; 5,8±1,6 ml, 10±2,9 ml, 12±3 ml, spermatozoa concentration 3,96±0,2x109 cell/ml, 4,04±0,1x109 cell/ml, 3,92±0,1x109 cell/ml were determined from control group, two days group and tree days group respectively. Sperm motility were analyzed by CASA sysem and Total motility %72,1±26 , %82,47±8, %85,7±8,2; progressive motility %28,74±15; 30,5±18,4 ve 23,7±9,8; VCL 97,9±36 µm/sec, 122,7±26 µm/sec, 93,9±11,7 µm/sec; progressive VCL 143±28 µm/sec, 140±34,3 µm/sec , 115,7±17,6 µm/sec were determined from control group, two days group and tree days group respectively. As a result, it was determined that giving mealworm larvae as an addition to the commercial feed in female individuals did not have an effect on the amount of eggs (p˃0,05) but the egg diameters were smaller in the control group and were different with the mealworm groups (p<0,05). In spermatological characteristics, it was observed that only the amount of sperm was different between the groups (p<0,05); all other parameters were found to be similar to each other statistically (p˃0,05). It was determined that the amount of sperm was increased by increasing the amount of mealworm.