No you can't. That is not the correct SPF record, and it is not the correct address of Google's SPF record. Anyone with the control of a reverse DNS domain can make any IP have any name he/she wants, like "google.com", "whitehouse.gov", etc. Allowing reverse matches at all would be very wrong.
The "include" feature of SPF works differently. It does a direct DNS resolution on the given name, and then processes the records that comes from that response. The correct SPF record for Google's e-mail servers is:
v=spf1 include:_spf.google.com ~all
The match is done by IP address from the results returned by a TXT DNS query to
_spf.google.com. Should Google ever change the IP address of their mail servers, this record should be changed too. As of today, a query to that record returns:
~% dig +short txt _spf.google.com
"v=spf1 ip4:126.96.36.199/19 ip4:188.8.131.52/19 ip4:184.108.40.206/20
ip4:220.127.116.11/18 ip4:18.104.22.168/17 ip4:22.214.171.124/20 ip4:126.96.36.199/16
ip4:188.8.131.52/20 ip4:184.108.40.206/20 ip4:220.127.116.11/16 ?all"
Note that the address you are seeing, 18.104.22.168, is included above, in 22.214.171.124/17. So, if your SPF record is configured correctly, it should PASS.
More information on Google Apps Help.