Effect of genetics and maternal dietary iodide supplementation on glycogencontent of organs within embryonic turkeys

In prior studies it was shown that the growth of turkey embryos was depende nt upon maternal dietary iodide as well as genetic selection. The current s tudy posed the question of which organ systems respond to these variables. Embryos from lines selected for 16-wk BW grew at the same rate as unselecte d embryos from the randombred population serving as the initial source of t he selected line until approximately 21 d of incubation (selected = F; rand ombred control = RBC2). Line differences in growth of F embryos could be ac counted for increased liver and heart growth at the expense of muscle growt h. Muscle growth increased in the growth-selected line Frier to pipping. Mu scle growth was affected less when darns were selected for egg production ( selected = E; randombred control = RBC1). Muscle growth was slowed in E lin e embryos compared to that of RBC1, and liver and heart growth were slowed at internal and external pipping stages in E embryos compared to RBC1. Early muscle growth was augmented when F dams were fed supplemental iodide. A similar response was observed in E line embryos but occurred at a later stage of development. Measurements indicated decreased tissue glycogen in l iver, heart, and muscle of selected lines may be one possible mechanism by which growth or organ function may come in conflict.