Liver Lipid Accumulation in Duck Embryos and Hatchlings Change with Parental Age¹

Abstract

The purpose of this study was to investigate the effects of duck breeder age on liver lipid accumulation and yolk absorption and utilization in duck embryos (day 25 of incubation) and newly hatched ducklings. One breeder flock was monitored at 24 (young breeders), 31 (mature breeders and near peak egg production) and 47 (post peak egg production) weeks of age. Electron microscopy images of duck embryo liver slices revealed a significant change in hepatic lipid accumulation as a function of breeder age. More specifically, as breeder age increased both the relative number of liver lipid droplets as well as the size of the lipid droplets increased in duck embryos (day 25 of incubation). At hatch, however, newly hatched ducklings from 31-week-old breeders exhibited the lowest number as well as the smallest sized lipid droplets when compared to ducklings from 24 or 47-week-old breeders. The trend in yolk absorption at day 25 as a function of breeder age paralleled that in liver lipid accumulation. That is, day 25 maintained a higher percentage of unabsorbed yolk when compared to embryos from 31- or 47-week-old breeders. In contrast to breeder age, time of incubation (day 25 vs. day 28 or hatch) had little effect on yolk fatty acid profiles when compared to breeder age. Although there were no clear trends in yolk fatty acid usage among the various ages of breeders, newly hatched ducklings from 31-week-old breeders did have a significantly higher proportion of 18:2 n6 compared to those from breeders at 24 or 47 weeks of age. These data would suggest that breeder age subsequently affects the relative number and size of liver lipid droplets in embryos and newly hatched ducklings.

Effect of incubation humidity and flock age on hatchability traits and posthatch growth in Pekin ducks

“…The results of viability rate in this work were in partial agreement with those reported by Washburn and Guill (1974) and Mc-Naughton et al (1978) that mortality rate appeared to be higher in chicks from young chicken breeders. Also, Braun et al (2001) reported that mortality was highest in ducklings from young breeders. The present results were slightly different in that viability of the ducklings initially increased with increased parental age and then decreased again at the older parental age.…”

The Circulating Levels of Lipoproteins in Embryos and Newly Hatched Ducklings Change with Parental Age¹

“…As shown in the current study, VLDL particles were altered in terms of components, i.e., lower CE:PRO and TG:PRO ratios for ducklings originating from 24-week-old breeders. This lower level of lipid components may partly explain the greater than expected yolk sac weights observed in these ducks as well as the reduction in liver lipid accumulation [11]; that is, we demonstrated in these ducklings that remnant yolk absorption is impaired, so this may have altered composition and level of lipoproteins derived from the yolk. The changes observed in VLDL may have resulted from differences in gene expression.…”

“…We [11] recently reported, however, that duck embryos from young parents have significantly less liver lipid accumulation as compared with duck embryos from older parents; therefore, suggesting that circulating lipoproteins may be altered. The present study was designed to investigate the changes in lipoprotein subfractions (VLDL and LDL) and their constituents, i.e., protein (PRO), TG, total cholesterol (TC), CE, phospholipids (PL), and the ratios of CE:PRO and TG:PRO.…”