Nutrient concentrations in a diet can be expressed either “as fed,” relative to dry matter (DM), or relative to metabolizable energy (ME). Most published literature evaluates the diet of dolphins by comparing nutrient content relative to DM. Nevertheless, ME requirements, not DM, determine how much food dolphins need to maintain their body condition. The purpose of this paper is to illustrate why it is important to calculate the ME content of fish fed to dolphins and compare nutrient concentrations in dolphin diets relative to ME, not DM. Two studies that compared the nutrient composition of fish species on a DM basis were reevaluated. The ME content of each fish species was calculated and found to vary widely among species, from 0.94 to 1.58 Mcal/kg as fed. Water, mineral, and fat concentrations relative to ME also varied markedly among fish species. To demonstrate the magnitude of nutrient content differences between fish, the percent change in nutrient concentration for each species was calculated relative to herring. The percent changes for DM and ME analyses were then compared. Percent change in nutrient concentration was either over- or underestimated on a DM basis when compared with the percent change on an ME basis. Notable discrepancies were evident among important nutrients, such as crude protein, water, and sodium. Caretakers of managed dolphins must account for differences in energy density when deciding how much to feed and assessing the nutrient composition of the diet.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.