Growth promoting effects of carp serum components on goldfish culture cells

The growth promoting effect of carp Cyprinus carpio serum was investigated in a medium for goldfish Carassius auratus cell culture. The cell growth rate was decreased in the L-15 medium containing carp serum free from low molecular weight (LMW) fraction of less than 10 000. The addition of this fraction to the medium recovered the original growth rate, whereas the fraction itself did not enhance cell growth. Similar experiments were carried out with carp serum lipoprotein and albumin-like protein fractions. The high density lipoprotein (HDL) fraction containing apolipoprotein (apo) A-I and apoA-II enhanced cell growth at 20 degrees C and 35 degrees C when added with the above-mentioned LMW fraction. A good proliferation was observed at both 20 degrees C and 35 degrees C with the HDL fraction at 0.58 mg/mL. Carp albumin-like protein fraction, mainly containing a 71 kDa-component, also enhanced goldfish cell growth with the LMW fraction at the two temperatures. These results suggest that HDL and albumin-like proteins play an important role in the goldfish cell growth cooperatively with LMW substances contained in carp serum.