Apollo Investment Corp income down 8 pct

* Net investment income down 8 pct

* Invested $225.8 million during quarter

* Invested $454.1 million a year ago

NEW YORK, Nov 5 (Reuters) - Apollo Investment Corp (AINV.O), a publicly-traded investment firm managed by private equity company Apollo, said on Wednesday net investment income fell 8 percent.

Net investment income totaled $56.5 million or 40 cents per share for the three months ended September 30, compared with $61.6 million or 58 cents per share a year ago.

The Nasdaq-traded unit, known as a business development company, was formed to invest mainly in the debt of small-and medium-sized corporations, but it also has equity investments.

Apollo Investment Corp said that during the quarter it invested $225.8 million, across 5 new and 6 existing portfolio companies. This compares to investing $454.1 million the same time last year.

Its portfolio consists of 78 portfolio companies and is invested 23 percent in senior secured loans, 57 percent in subordinated debt, 4 percent in preferred equity and 16 in common equity and warrants.

Companies it has investments in include European retail chain Alliance Boots, food service distributor US Foodservice and consulting firm Booz Allen Hamilton, according to its Web site.

Apollo Investment Corp is managed by Apollo Investment Management - an affiliate of Apollo Global Management, the buyout firm, run by investor Leon Black.

The parent group raised $930 million in the April 2004 initial public offering of Apollo Investment Corp.

Apollo Investment Corp's shares, which priced at $15 per share at the IPO, on Wednesday closed $1.61 lower at $11.57.

Apollo Global Management itself plans to list on the New York Stock Exchange. It filed with the U.S. Securities and Exchange Commission in April to register securities already traded on a private exchange and said it planned to list them on the NYSE. (Reporting by Megan Davies; editing by Carol Bishopric)