Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Vertical bars in the histograms represent the standard error. Means within a row with different superscripts differ (a, b = P < 0.05) while means within an ascot present a trend (* = P < 0.10).
