The Israeli Journal of Aquaculture - Bamidgeh 54(1), 2002, 5-11

EPITOPES OF TILAPIA RED BLOOD CELLS.
I.SPECIES-SPECIFIC ANTIBODIES FOR THE CONTROL
OF TILAPIA BREEDING STOCKS


Bracha Timan, Andrey Shirak, Ruth Segal, Ziv Machnes and Ramy R.Avtalion

Laboratory of Fish Immunology and Genetics, Faculty of Life Sciences, Bar Ilan University, Ramat Gan 52900, Israel

(Received 26.11.01, Accepted 6.1.02)

Key words: antigenic markers, erythrocytes, hemagglutination, identification, tilapia

Abstract

Specific antisera against red blood cells of some tilapia species were obtained by reciprocal interspecific and intergeneric immunizations. The antisera were used to confirm co-dominant expression of epitopes in F1 interspecific hybrids and to identify the parental origin of three red tilapia strains. The antisera in all hybrids (Oreochromis niloticus x O.mossambicus, O.aureus x O.horno rum, O.niloticus x S.galilaeus and O.niloticus x O.aureus) were positive to both parental strains. However, while all F1 hybrids of O.mossambicus x O.hornorum were positive to anti-O.mossambi cus antiserum, only 50% were positive to anti-O.hornorum antiserum. In most cases, these results point to co-dominant expression of the species-specific epitopes in hybrids.

In addition, the triple parental origins of the Philippine red tilapia (positive for O.aureus, O. mossambicus and O.niloticus epitopes) and of mossambicus red tilapia (positive for O.hornorum, O.mossambicus and O.niloticus epitopes) were assessed. The O.niloticus red tilapia, described as a purebred red variant of O.niloticus, was positive for both anti-O.niloticus and anti-O.aureus antibodies, with a significantly more intense reaction to the latter. A possible genetic basis of this last finding is discussed.

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