... phoeniceus ), an altricial species that breeds in aquatic habitats. We also manipulated diet by feeding nestlings fish oil or sunflower oil. Finally, we assessed selective uptake of yolk by comparing the yolk fatty acid composition of freshly laid eggs and day-old hatchlings. Relative to other altricial...

... of supercooling capacity fundamentally requires elimination of ice-nucleating agents (INA) of endogenous origin: summer turtles, but not winter turtles, produced feces(perhaps derived from residual yolk) that expressed ice-nucleating activity. Ingestion of vermiculite or eggshell, which had modest ice-nucleating...

... in urea cycle enzyme activities. Total amino acid levels in the embryonic tissues were unaltered by chronic ammonia exposure, but levels of most individual amino acids and total amino acid levels in the yolk were significantly lower (by 34–58%) than in non-exposed controls. The data indicate that trout...

... of yolk precursors (vitellogenin and very-low density lipoprotein, VLDL) by the liver, and of albumen by the oviduct. We gave European starlings ( Sturnus vulgaris ) silastic implants containing estradiol prior to egg formation, which we predicted would increase egg mass. As expected, exogenous estradiol...

... O 7 .10H 2 O), 2.5 mmol l −1 Hepes, 0.1 mmol l −1 amiloride] for 30 min and ammonia excretion rates, ammonia concentration in the perivitelline fluid (PVF) and yolk, and the pH of the PVF, yolk and USL were measured. The rate of ammonia excretion was dependent, in part, on the partial pressure...