Browsing by Author "Parish, George Rod"

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    Quantifying Digestion in California Yellowtail (Seriola lalandi dorsalis), Technological Advances Towards the Development of the Aquaculture Sector
    (2016-12) Parish, George Rod; Garcia, Armando; Tropical Conservation Biology & Environmental Science
    Tracing the path of nutrient incorporation from the moment of ingestion through the later phases of excretion and growth has proven extremely difficult due to the nature of marine species. Numerous studies have attempted to quantitatively describe feed efficiency in fish however no method more accurately embodies this process as respirometry. Respirometry has been a valuable tool to monitor variability in respiration rates and offers a quantitative approach to measure specific dynamic action. The term specific dynamic action encompasses the energy expenditures during ingestion, digestion, absorption, and assimilation of a meal. This type of analysis produces an estimate of both the baseline and postprandial metabolic rate, which can be later compared with the initial meal energy to provide an estimate towards the efficiency during digestion. Yellowtail were placed in a 30L flume and maintained at a velocity of 1 body length per second as well as a 1237L static respirometer to determine their “fasted” baseline metabolic rate. After the fish consumed a meal equivalent to 5% body weight, their postprandial metabolic response (SDA) was calculated based on the difference in oxygen consumption between their “fasted” and “digestive” states. Baseline routine metabolic rates and SDA were calculated for both a sardine flesh and a commercially available pelleted feed treatment. The results of this work indicate a considerably large percentage of the total energy of a meal placed towards digestion in yellowtail, a common theme for a number of other active pelagic fish of similar proportion.