I am in agreement with everything brought up in this article:
Citadel Tibetan Mastiffs Heartworm Timing
I only suggested the Denamarin because of my experience and investigation of what it can do to protect the liver during stressful times. I could not relocate the beagle/mushroom study, but I did see it a while back. I did find where Dr Dodds recommends giving it for one week following an 'every 6 weeks dose' of Heartworm preventative. I was suggesting it may be helpful to give during the Immiticide treatment, but I do not know how that drug is metabolized. As Liver and kidney tests were performed on these dogs prior to even Heartworm preventative dosing, I will assume these drugs can affect the liver, in which case the Denamarin would help protect the liver.
(Dr Dodds received her D.V.M. in 1964 from the Ontario Veterinary College.)
I do question going 6 months without Heartworm preventative. I think 3 months if one uses Heartgard, and 2 months for all others, but do read the small print on the package... (main concern if the mosquito follows your dog into the house, when the temps are higher than outside)
Here a link to a thread that contains some 'research' I did a few years back:
http://www.yorkietalk.com/forums/yor...-med-rant.html