Effect of fecal retrieval timing on digestibility of nutrients in rainbow trout diet with the guelph and TUF feces collection systems

The effect of feces collection intervals on the digestibility of feed in rainbow trout was determin-ed in order to substantiate nutrient loss from the feces collected by the Guelph System and TUF column. Feeding experiments were conducted using two different diets, and feces and surround-ing water were collected at 3, 6, 9, 12, and 15h after the final feeding. There was no significant difference in the apparent digestibility coefficient (ADC) of crude protein and lipid during collection intervals between data obtained from the Guelph System and TUF column. The ADC of dry matter and energy by the Guelph System exhibited the same trend as protein, but the ADC of dry matter and energy by TUF column at 3h was slightly lower than that at 6h or above. The results obtained have demonstrated that the effect of fecal retrieval intervals on the ADC is very minimal, and hardly and leaching of nutrients occurs from the feces collected with either the Guelph System or TUF column. Thus, it is proved that the Guelph System and TUF column are suitable equipment for collecting feces from salmonid fish to test digestibility.