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Feeding frequency and water temperature impact apparent digestibility coefficients of sablefish (Anoplopoma fimbria) Pace, Steven Alan

Abstract

Integrated multi-trophic aquaculture (IMTA) is a sustainable form of polyculture that holds promise in alleviating sustainability and environmental concerns facing current aquaculture practices. For sablefish (Anoplopoma fimbria) to be considered for use in IMTA systems, information on the digestibility of the diets by this species is needed. These data are critically important in establishing the necessary relationships between various species in IMTA networks. The effects of feeding frequency and water temperature on the apparent digestibility coefficients of juvenile sablefish were assessed in two separate experiments. In experiment 1 the effect of feeding frequency on apparent digestibility of a commercial feed (supplemented with chromic oxide as an indigestible marker) was determined by feeding juvenile sablefish either once, twice, or three times per day. In experiment 2 the effect of water temperature on apparent digestibility coefficients of the feed was determined in groups of sablefish reared at 8 ºC and 11.5 ºC. In both experiments the feed and faeces were analyzed for chromic oxide, ash, moisture, protein, and energy content and the resulting data were used to calculate apparent digestibility coefficients (ADC) for crude protein (CP), gross energy (GE), and organic matter (OM). Results from Experiment 1 indicate that feeding frequency had an effect on all ADC; with lower values of digestibility found with higher feeding frequencies (p ≤ 0.05). In Experiment 2 fish maintained at 11.5 ᵒC had higher ADC compared to those at 8.0 ˚C (p ≤ 0.05). This new information will be applied to a future IMTA ecosystem model, in an effort to enhance system efficiency.

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Attribution-NonCommercial-NoDerivatives 4.0 International