A "regulated trough" is one that the food is released at a time that you set. You set a timer to the time that you want feed to be delivered and a motor will run and dispense food for a period from 1 to 30 seconds. This allows you to beter control how much food is being eaten and when. This is the alternative to "free choice" where the food is gravity feed until it is gone.
You can buy the "regulated trough" kit by itself or as part of a complete feeder.
The round trough regulated delivery system will deliver approximately 1 pound of protein per second of run time. This will vary some by the different types and brands of protein.