Hi!
Guinea pig guts should always make gurgling noises when you hold you ear against the belly. A silent gut is a life-threatening condition called GI or gut stasis (i.e. the gut has stopped working).
However, when the natural fermentation process goes into overdrive (dysbiosis = bad bacteria taking over) and you can hear the gut rumbling or hear (and smell) a piggy farting from a distance away, then you may want to take your piggy off any fresh food for a day in order to allow the gut to settle down again and avoid acute bloating.
Digestive Disorders: Diarrhea - Bloat - GI Stasis (No Gut Movement) And Not Eating
Too much fresh food and especially too much sugary foods like carrots, sweet corn and fruit can contribute to dysbiosis as the sugar encourages the wrong kind of bacteria to grow and take over. A grass hay and fresh grass based diet supplement by forage or that resemble forage and some high fluid content green veg that is closer to the natural diet guinea pigs have evolved on is best as it helps to avoid these problems and really add 1-2 year to the average life span of a guinea pig to take it from the lower end to the upper or beyond.
Long Term Balanced General And Special Needs Guinea Pig Diets
I hope that this helps you?