Lipids and FA analysis of canine prostate tissue

It is widely reported that an association exists between dietary fat intake and the incidence of prostate cancer in humans. To study this association, there is a need for an animal model where prostate carcinogenesis occurs spontaneously. The canine prostate is considered a suitable experimental model for prostate cancer in humans since it is morphologically similar to the human prostate and both humans and dogs have a predisposition to benign and malignant prostate disease. In this study, the FA and lipids profiles of the normal canine prostate tissue from nine dogs were examined. The total lipid content of the canine prostate tissue was 1.7 +/- 0.5% (wet weight). The lipid composition analysis using TLC-FID showed that the two major lipid classes were phospholipids and TAG. Total FA, phospholipid, and TAG FA analysis showed that the major FA were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2n-6), and arachidonic acid (20:4n-6). The n-3 FA were present at <3% of total FA and included alpha-linolenic acid (18:3n-3) (in total and TAG tissue FA), EPA (20:5n-3) (not in TAG), and DHA (22:6n-3) (not in TAG). The n-3/n-6 ratio was 1:11, 1:13, and 1:8 in total, phospholipid, and TAG FA, respectively. This study shows the canine prostate has a low level of n-3 FA and a low n-3/n-6 ratio. This is perhaps due to low n-3 content of the diet of the dogs. FA analysis of dogfoods available in Australia showed that the n-3 content in both supermarket and premium brand dogfoods was <3% (wet weight), and the n-3/n-6 ratio was low.