If a trust makes an overall loss in an income year, the loss is retained in the trust - there is no amount of net income available for distribution.
However, in some cases you are required to report a loss on your tax return. This happens if you are eligible to use the averaging provisions available to primary producers and the trust has made a loss from its primary production activities but has an overall net income amount, part or all of which it distributes to you.
Your distribution advice or statement from the trust will separately identify your share of any primary production loss (which is needed for averaging purposes) and your share of other income.
A loss made by the trust is 'retained' in the trust and there's no income to distribute. However, in some cases you are required to enter a loss on your tax.