Thesis Type: Doctorate
Institution Of The Thesis: Ankara University, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü (Sözleşmeli), Turkey
Approval Date: 2024
Thesis Language: Turkish
Student: HACER ÖZLEM ARSLAN
Supervisor: Ercüment Genç
Abstract:
This doctoral thesis conducted two separate trials. In Trial I, juvenile Procambarus clarkii with an initial weight of 0,241-0,247 g and stocked at a fixed density (51,95 individuals/m²) were subjected to different water renewal rates: 1SY (%1SY/week), 3SY (%3SY/week), 6SY (%6SY/week), and probiotic supplementation: 1SYP (%1SY + Probiotic/week), 3SYP (%3SY + Probiotic/week), 6SYP (%6SY + Probiotic/week). Comparison between 1SY-1SYP showed no significant differences except for final live weight (FW) and protein efficiency ratio (PER). Significant differences were found in FW, live weight gain (WG), specific growth rate (SGR), PER, and feed conversion ratio (FCR) between 3SY-3SYP (p<0,05). No significant differences in growth parameters were observed between 6SY-6SYP (p>0,05). Comparison among SY groups indicated significant differences in WG, SGR, PER, and FCR compared to 1SY (p<0,05), with higher survival rates (SR) noted in 6SY. Among SYP groups, the best growth and survival rates were observed in 3SYP (p<0,05). Abdominal muscle composition analysis did not show significant differences between SY and SYP groups (p>0,05). Total hemocyte count (THC) showed significant differences between 1SY-1SYP, 3SY-3SYP, and 6SY-6SYP groups (p<0,05). In Trial II, using the optimal condition identified in Trial I (3SYP), the effect of increasing stocking densities (51,95; 77,93; 103,90 and 129,88 individuals/m²) was evaluated. Growth improvement was observed in S10-S15 groups (p<0,05). Increasing stocking densities did not significantly affect nutrient composition and THC values (p>0,05). Histomorphological analysis showed no significant differences among groups in all trials. Trial I microbiome analysis revealed dominance of Proteobacteria, Bacteroidota, and Actinobacteriota phyla in SY groups, with a decrease in Proteobacteria and an increase in Bacteroidota in SYP groups. Trial II indicated an increase in Proteobacteria abundance with increasing stocking densities, while other phyla were represented at varying levels. In conclusion, P. clarkii demonstrated adaptability to limited water exchange conditions, with the application of %3 SYP/week enhancing aquaculture productivity, THC, and microbiota profile. This study promotes controlled red swamp crayfish cultivation, contributing to global aquaculture policies and practices.