The hematology of diploid and triploid transgenic Atlantic salmon (Salmo salar)

This study examined the erythrocyte height/length, hematocrit, total blood hemoglobin concentration and mean cellular hemoglobin content of diploid and triploid transgenic and non-transgenic Atlantic salmon, to clarify the interaction between metabolic rate and hematology in these fish. Triploid erythrocytes were significantly longer and proportionately thinner than diploid erythrocytes for both genotypes. These morphological differences gave triploid erythrocytes an elliptical appearance with the width being similar to53% of the length, whereas diploid erythrocytes tended to be more rounded with the width being similar to62% of the length. As well, diploid and triploid transgenic erythrocytes were significantly shorter and thinner (P<0.0001) than their non-transgenic counterparts. Although not significant, observations using a Channelized Coulter Counter showed that transgenic erythrocytes tended to be higher in count and smaller in volume than non-transgenic erythrocytes of the same ploidy. Transgenics likely produce erythrocytes with higher surface area to volume ratio in response to their elevated metabolic rates. No other major hematological differences were observed between transgenics and non-transgenics of the same ploidy.