Gut morphology in growth hormone transgenic Atlantic salmon

As growth hormone transgenic Atlantic salmon consume more food to support their rapid growth, a study was conducted to determine if the morphology of the digestive tract would reflect these accelerated processes. Offspring from a non-transgenic cross that was spawned on the same day as the test fish were used as the control. Test fish were F2 generation fish, derived from eggs from a transgenic F1 female fertilized with milt from a non-transgenic male. The length of the gastrointestinal (GI) tract and pyloric caeca in transgenic salmon was greater than in control salmon. More folds were observed in the anterior intestine of transgenic salmon. No difference in the GI tract wall was observed between the 2 groups. The results indicate that transgenic salmon have a digestive system with a greater inner surface area.