If a slave claims paternity of a foundling, is the lineage established?

Primary text

If the claimant is a slave, the lineage is attached to him because his lineage carries sanctity. This is the position of Al-Shafi'i and others. However, no right of custody (hadhanah) is established for him because he is occupied with serving his master, nor is maintenance imposed upon him or his master because the child is judged to be free, so his maintenance falls upon the public treasury (bayt al-mal).