The grass carp is a subtropical and temperate fish species, belonging to
family Cyprinidae and genus Ctenopharyngodon. Rivers and lakes in Asia
represent the native habitat of this species, especially the Amur River. In
Egypt, this fish species is exotic and it is used as biological control. It has a
short spawning season extending from May till the end of June.
Remarkably, this fish species does not spawn naturally in the captivity state.
Thus, for a successful spawning process, the injection of hormones is
necessary. The biochemical composition including the changes in the ovary
during the maturation process was addressed using different indices. The total
protein content in the ovarian tissues varied with maturation stages, showing
a significant difference (P>0.05). The value ranged from 60.65 + 0.299g/
100g dry weight in the immature stage and increased to 66.44 + 0.420g/ 100g
dry weight in maturing stage. On the other hand, lipid content in the ovary
with the maturation process fluctuated from the lowest value (5.77 + 0.070g/
100g) of dry weight in the immature stage to the highest value (12.77 + 0.070g/
100g) of dry weight. The level of cholesterol during the ripe stage of the ovary
is attributed to the available cholesterol consumed in the synthesis of steroid
hormones. All these items coordinate are important for maturation, covering
the need of broodstock for sufficient proteins and lipids that must be
supplied in fish food.