Troughs, say, in middle of pigsty (7)

I believe the answer is:

gutters

'troughs' is the definition.
('gutter' can be a synonym of 'trough')

'say in middle of pigsty' is the wordplay.
'say' becomes 'utter' (I've seen this before**).
'in' is an insertion indicator.
'middle of' means to look at the middle letters.
The central letters of 'pigsty' are 'gs'.
'utter' inserted into 'gs' is 'GUTTERS'.

(Another definition for gutters that I've seen is " They carry off rainwater".)

I've seen this clue in The Telegraph.

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