Changes in fatty acid profiles in different lipid classes during late development of turkey embryos from two genetic lines

Abstract

Fatty acid (FA) profiles in embryonic yolk sacs (YS) and livers were studied in embryos from a randombred turkey line (RBC2) and a line selected for body weight at 16 wk (F line). There were no differences in FA profiles of fresh yolk lipids. During the course of incubation, oleic acid (C18:1) was higher and linoleic acid (C18:2) was lower in YS triglyceride (TG) and phospholipid (PL) subclasses in F line compared with RBC2 embryos. In both lines, the C18:1 content of YS cholesteryl esters (CE) increased from 58 to 63% during the last 6 d of incubation. From 22 to 28 d of incubation, there was a constant C18:1 concentration in hepatic CE, which was > 60% of total hepatic CE FA. As incubation proceeded, palmitic acid (C16:0) and C18:1 in hepatic TG decreased from 27 to 16% and 37 to 34%, respectively. The stearic acid (C18:0) in TG increased from 12% at Day 22 to 32% of total FA at hatch (Day 28) in RBC2 embryos compared with a lesser increase in the F line (11.8 to 18.6%). In hepatic PL, arachidonic acid (C20:4) decreased, whereas both C16:0 and C18:0 increased from 22 to 28 d of incubation. During this same time period, there was an overall decline in docosahexaenoic acid (C22:6) only in the RBC2. On Days 26 and 28, F line embryos had greater concentrations of C22:6 and C20:4 in hepatic PL than did RBC2. These results suggest that selection for increased BW has changed the proportional incorporation of different FA into embryonic lipids.

Rapid embryonic accretion of docosahexaenoic acid (DHA) in the brain of an altricial bird with an aquatic-based maternal diet

“…Not shown here is the process of selective uptake of the phospholipid class relative to triglycerides, which can also contribute to the high selective uptake of DHA in turkeys, chickens and pigeons (Vansheel et al, 1981;Noble and Cocchi, 1990;Ding et al, 1995) but has not been measured here. Data are calculated from: Moore (1964, 1965);Vansheel et al (1981); Lin et al (1991); Ding et al (1995); Ding and Lilburn (1997); Groscolas et al (2003); Speake et al (2003); Speake and Wood (2005); Pappas et al (2007); and the present study. For the chickens of Lin et al (1991), we used data from animals fed the control diet, and for the turkeys of Ding and colleagues (1995) and Ding and Lilburn (1997), we averaged selective uptake calculated for the two breeding lines.…”

“…Data are calculated from: Moore (1964, 1965);Vansheel et al (1981); Lin et al (1991); Ding et al (1995); Ding and Lilburn (1997); Groscolas et al (2003); Speake et al (2003); Speake and Wood (2005); Pappas et al (2007); and the present study. For the chickens of Lin et al (1991), we used data from animals fed the control diet, and for the turkeys of Ding and colleagues (1995) and Ding and Lilburn (1997), we averaged selective uptake calculated for the two breeding lines. Eggs hatch on the 11th day of incubation (age 0 on the x-axis, indicated by 'H').…”

“…penguins and coots) can achieve these high levels by the time of hatching because the maternal diet is aquatic or marine based, and thus they produce DHA-rich egg yolks Pappas et al, 2007). Other precocial species, such as terrestrial chickens and turkeys, have DHA-poor egg yolks, but instead have the ability as embryos to selectively transfer DHA from the yolk, thus concentrating their small maternal endowment of DHA (Lin et al, 1991;Ding and Lilburn, 1997). Not all precocial birds have this capability, however; ducks, for example, are not able to accumulate high levels of DHA in the brain by the time of hatching if the maternal diet was DHA-poor (Maldjian et al, 1996).…”