Egg collection is a critical stage in rainbow trout (Oncorhynchus mykiss) propagation. Traditional manual stripping poses risks including altered ovarian fluid pH and physical injury to broodstock. This study optimized pneumatic extraction as an efficient alternative, evaluating the effects of gas type, flow rate, pressure, and needle specifications. Eighty 4-year-old female broodstock with a mean weight of 3783.5 ± 0.0035 g were allocated to experimental groups. Survival rate, stripping duration, ovarian fluid pH, fertilization rate, eyed egg stage, and hatching rate were measured. Pneumatic extraction at 1.5 L/min flow rate showed comparable survival to manual stripping (85-90%, p>0.05), while significantly increasing egg yield (497.1 ± 21.3 g vs. 345.0 ± 18.7 g, p<0.01). Gas type had no differential effect on reproductive indices (p>0.05). The method reduced stripping time by 32% (39.8 ± 5.2 s vs. 46.0 ± 6.1 s, p>0.05) and achieved complete abdominal evacuation. Findings establish pneumatic extraction as a standardized and operator-independent technique that enhances hatchery productivity while improving fish welfare by body surface manipulation and repeated anesthesia.
Mahmoudi R. Optimization of Pneumatic Egg Stripping Method in Rainbow Trout (Oncorhynchus mykiss) with Emphasis on Improving Efficiency and Reproductive performance. JAIR 2025; 13 (1) :51-60 URL: http://jair.gonbad.ac.ir/article-1-922-en.html