نوع مقاله : مقاله پژوهشی
1 گروه شیلات، واحد قائمشهر، دانشگاه آزاد اسلامی، قائمشهر، ایران.
2 گروه شیلات، واحد قائم شهر، دانشگاه آزاد اسلامی، قائمشهر، ایران.
عنوان مقاله [English]
Every year, common carp, Cyprinus carpio, fingerlings are released into the northern rivers of Iran to for restocking the Caspian Sea reserves. For artificial reproduction of this fish, hormone injection is inevitable and despite the differences between wild and farmed common carp, the same method is used to induce their sexual maturation in Shahid Rajaei Center in Sari. Therefore, to compare the efficiency of hormone injection in wild and farmed carp, 12 female broodstocks which caught from the Caspian Sea, and 15 farmed broodstocks were injected based on the applied methods of Shahid Rajaei Center in Sari, each in 3 treatments as follows: Two-stage injection of common carp pituitary gland extract at the rate of 4.5 mg per kg of body weight (control), and one- and two-stage injections of sGnRH + domperidone (ovaprim) at a rate of 0.4 ml per kg of weight as the second and third experimental treatments. All 27 wild and farmed female broodstocks responded to hormone injection. The extracted egg weight and working fecundity were significantly higher in farmed broodstocks and the number of eggs per gram and relative fecundity were significantly higher in wild broodstocks (p < /em><0.05). Fertilization, eyeing, and hatching percentages were significantly higher in ovaprim treatments than the pituitary treatment in both farmed (93.20±1.12, 94.36±0.46, 91.87±1.93) and wild (95.51±1.42, 94.90± 0.01, 92.43±0.15) broodstocks (p < /em><0.05). A positive correlation was observed between broodstocks weight, extracted egg weight, and working fecundity with each other in both broodstock groups. However, all three parameters were negatively correlated with the number of eggs per gram and the weight of the broodstocks and the weight of the extracted egg were negatively correlated with the relative fecundity. Also, the percentages of fertilization, eyeing, and hatching rates showed a highly significant positive correlation with each other (p < /em><0.01). In the study of relationships between variables by stepwise regression, no significant relationship was observed between the fertilization, eyeing, and hatching percentages with the weight of broodstocks and the weight of the extracted egg, but in both groups of broodstocks, the quality of eggs had a positive and significant relationship especially with the single-stage injection of ovaprim compared to the pituitary gland. Therefore, the single-stage injection of ovaprim is more suitable for both farmed and wild common carp. Although extracted egg weight and working fecundity were lower in wild than farmed broodstocks due to lower weight of them, hatching percentage in wild broodstocks was higher than farmed broodstocks with a coefficient of 2.18.