Effect of genetics and maternal dietary iodide supplementation on turkey embryonic growth.
Embryonic growth of a turkey lines selected for 16-wk BW (F) or 180-d egg production (E) was measured and compared to randombred controls (RBC2 or RBC1). Egg weight at setting relative to poult weight at hatching indicated increased growth in F as well as E embryos compared to randombred controls. Eggs from F weighed 10 g more than those of RBC2 (P < or = 0.0001) but the poults at hatching were only 8 g heavier (P < or = 0.0001). Water vapor loss during incubation indicated that only 0.9% of the difference could be accounted for by water vapor loss. Selection for increased 16-wk BW resulted in decreased embryo growth rates relative to hatchling mass (P < or = 0.0001) beginning at Day 16 of incubation compared to that of RBC2. Eggs from E weighed 15 g less than RBC1 (P < or = 0.0001) but produced poults weighing only 7 g less (P < or = 0.0001). Incubation water vapor loss was depressed in E compared to RBC1 (P < or = 0.0001) but accounted for only 1.4% of the difference between hatchling weights. Selection for egg production increased embryo growth rates (relative to hatchling mass) measured at 4-d intervals compared to those of the RBC1 line (P < or = 0.05). Iodide supplementation of the maternal diet depressed (P < or = 0.05) glycogen in F embryos but interacted with line to generally increase glycogen in E embryos. Increased glycogen was related to increased growth rates in E but not F line embryos. It may be concluded that iodide supplementation of the material diet and genetics are determinants of embryonic growth in turkeys.
Christensen
V L
VL
Department of Poultry Science, North Carolina State University, Raleigh 27695-7608, USA. vern_christensen@ncsu.edu
Donaldson
W E
WE
Nestor
K E
KE
McMurtry
J P
JP
D000822:Animal Husbandry; D000818:Animals; D001835:Body Weight / Q000235:genetics; D019587:Dietary Supplements; D004531:Eggs; D005260:Female; D007454:Iodides / Q000008:administration & dosage*; D008297:Male; D012641:Selection, Genetic; D014422:Turkeys / Q000196:embryology / Q000235:genetics*; D014882:Water-Electrolyte Balance
D007454:Iodides