Swine shredded tough tissue (5)
I believe the answer is:
sinew
'tough tissue' is the definition.
(I've seen this in another clue)
'swine shredded' is the wordplay.
'shredded' indicates anagramming the letters.
'swine' is an anagram of 'SINEW'.
(Other definitions for sinew that I've seen before include "power source" , "Muscular strength" , "Cord of tissue connecting muscle to bone" , "Tough material" , "Tendon - ligament" .)