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AbstractAquaculture programs benefit from feeding protocols that result in large larval body size and high survival. Despite high labor, processing, and material costs relative to alternative foods, feeding live foods generally results in high larval growth and survival. For many species, studies that identify alternative food types or feeding regimens that produce larvae with high survival and size comparable with wild cohorts are lacking. In a 35-d study, the effects of alternative food types (previously frozen Artemiaand trout crumble starter diet (trout diet) on TL, weight per fish, and survival of larval Lake Sturgeon Acipenser fulvescenswere quantified. From days 14 to 21 postexogenous feeding, larvae were transitioned from live Artemiato one of the alternative food types or remained feeding on live Artemiaas the control. At the end of the study, TL and weight per fish of larvae fed live Artemiawere significantly greater than larvae fed the alternative foods. Survival of larvae fed live or frozen Artemiawas higher than larvae fed the trout diet. Lower body growth and survival of larvae fed the alternative foods demonstrate that the frozen and formulated foods are not appropriate diets for Lake Sturgeon larvae.Received January 24, 2017; accepted May 8, 2017Published online August 1, 2017

Aquaculture programs benefit from feeding protocols that result in large larval body size and high survival. Despite high labor, processing, and material costs relative to alternative foods, feeding live foods generally results in high larval growth and survival. For many species, studies that identify alternative food types or feeding regimens that produce larvae with high survival and size comparable with wild cohorts are lacking. In a 35-d study, the effects of alternative food types (previously frozen Artemiaand trout crumble starter diet (trout diet) on TL, weight per fish, and survival of larval Lake Sturgeon Acipenser fulvescenswere quantified. From days 14 to 21 postexogenous feeding, larvae were transitioned from live Artemiato one of the alternative food types or remained feeding on live Artemiaas the control. At the end of the study, TL and weight per fish of larvae fed live Artemiawere significantly greater than larvae fed the alternative foods. Survival of larvae fed live or frozen Artemiawas higher than larvae fed the trout diet. Lower body growth and survival of larvae fed the alternative foods demonstrate that the frozen and formulated foods are not appropriate diets for Lake Sturgeon larvae.

Manipulating feeding rate and protein quality may improve growth and feeding efficiency of cultured species. However, whether feeding rate, protein quality, or their interaction has a greater effect on growth and feeding efficiency response variables is unknown. To determine whether feeding rate and protein quality individually or interactively affect growth and feeding efficiency, juvenile Zebrafish (Danio rerio) were either offered nutritionally similar diet consisting of either menhaden fishmeal protein or a 100% replacement of fishmeal with soybean meal-based protein restrictively or to satiation. Total length, weight, feed intake, and feed conversion ratio (FCR) were measured throughout the duration of the study. Protein quality and feeding rate individually and interactively affected feed intake and FCR: Zebrafish offered feed to satiation had higher growth and FCR than those fed restrictively, and Zebrafish fed soybean meal-based diet showed lower growth and higher FCR and feed intake compared to those fed fishmeal-based diet, although magnitude of response depended on feeding rate. These findings likely indicate lower digestibility of soybean meal or the presence of antinutritional factors in soybean meal that led to impaired nutrient absorption of fish offered soybean meal-based diet. Differences in measured response variables between protein qualities and feeding rates highlight the importance of determining interactive effects in nutritional studies.