Composition analysis of gastrointestinal contents of laboratory‐reared and wild lake sturgeon ( <i>Acipenser fulvescens</i> )

Abstract This study assessed the composition of digesta from captive and wild Acipenser fulvescens to consider how food availability dietary absorption may influence stocking survival. Non‐lethal gastric lavage colonic flushing were evaluated in laboratory fish then A. caught Tennessee River. Gastrointestinal contents collected at 2, 4, 6, 12, 24, 32 h post‐feeding. The stomach content relative ingested was 36.67% ± 5.09% 2 post‐feeding, peaking 4 (75.82% 14.09%), no recovered after 12 h. solid waste (g/kg) increased with time, highest recovery (5.40 1.30 g/kg) Proximate samples determined using standard colorimetric assay protocols. There a significant reduction protein concentration starting h, glucose concentrations stable both post‐feeding animals, suggesting longer processing times for compared other nutrients. solids very similar between populations (46.17 7.32 vs. 40.00 6.57 mg/dL) (22.99 4.26 19.86 3.95 mg/dL). Lipid concentrations, however, deviated substantially, 40.11 7.71 mg/dL 35.59 7.29 faeces fish, only 18.26 3.47 (stomach) 22.00 5.54 (colonic) fish. Glucose represented relatively small fraction differed based on habitat colon, retaining complex sugars periods. These results indicate that high‐energy diet components are either reduced natural diets or preferentially absorbed within first More use lipid‐dense foods riverine environment provide information improve survival support their reintroduction.