Use of Prussian carp, Carassius gibelio, pituitaries in the artificial propagation of female common carp, Cyprinus carpio
Abstract:Background. The usage of common carp pituitaries has been associated with very high costs, resulting from sacrificing the valuable broodstock. A close taxonomic proximity between the Common carp, Cyprinus carpio L., and Prussian carp, Carassius gibelio (Bloch, 1782), reflected in the presence of high levels of the homologous carp LH hormone in Prussian carp pituitaries, was recently demonstrated. This prompted the present authors to evaluate the Pruss ian carp pituitaries as a less expensive alternative to carp pituitaries, for inducing spawning in common carp.
Materials and Methods. Prussian carp were fished in Lake Pamvotis (NW Greece) on April 4, 2007 and 204 pituitaries were extracted and processed. Accordingly, the prepared pituitary liquid extract was injected in 30 female common carp (experimental group) in the State Carp Hatchery in Psathotopi, (western Greece). Common carp pituitary extract was used for the hypophysation of female common carp in the control group (n = 30). In both groups, standard hatchery procedures were followed concerning broodstock handling during the artificial propagation of common carp. Fertilized eggs were incubated in 7-L Zugar jars after removing the sticky substrate and hatching percentage was calculated.
Results. Spawning success was 73.3%, total egg yield was 5.94 kg, total relative fecundity was 112.5 g · kg−1 of body weight (150.0 g · kg−1 of body weight based on fertile broodstock), and hatching percentage reached 85.2 %. Statistically, all the above performance values were not significantly different compared to the controls.
Conclusion. Taking advantage of a natural resource practically unexploited, the use of Prussian carp pituitaries in the artificial propagation of common carp was equally effective to common carp pituitaries, contributing to lower running costs in the hatchery.