gnus-treat-strip-leading-blank-lines

gnus-treat-strip-leading-blank-lines is a variable defined in `gnus-art.el'.
Its value is

nil

Documentation:
Strip leading blank lines.
Valid values are nil, t, `head', `first', `last', an integer or a
predicate. See Info node `(gnus)Customizing Articles'.

When set to t, it also strips trailing blanks in all MIME parts.

You can customize this variable.