Aquaculture America 2021

August 11 - 14, 2021

San Antonio, Texas


Timothy J. Bruce*  Jacob  W.  Bledsoe,  and  Kenneth  D. Cain
Department of Fish and Wildlife Science s
875 Perimeter Dr. MS1136
University of Idaho
Moscow, ID, 83844-1136

At the University of Idaho, recent efforts  have focused on  the  evaluation and selection of optimal  diet formulations for burbot ( Lota lota maculosa) .  Previous findings  demonstrated that juvenile burbot perform well on marine-type commercial diets, whereas subadults  grow equally well on a trout-like diet.   As with many  cultured fish  species,  utilizing  plant-based proteins in aquafeed formulations  is desirable  to  ultimately  reduce the amount of  required fishmeal . A 72 d feeding trial was conducted to  characterize the  growth performance and associated  intestinal microbiota associated with feeding burbot diets containing fishmeal replacement with soybean meal  (SBM)  and dried distillers gains with solubles (DDGS) . As such, young-of the year burbot (8.2±0.1g; triplicate tanks ) were cultured in aerated flow-through tanks  at 13C .  With respect to dietary treatments, an Atlantic cod marine-type (fishmeal-based control; REF) diet was formulated to approximately 48% crude protein and 16% lipid and fishmeal protein content was replaced at 25% with inclusions of SBM and DDGS. In this trial, burbot were fed to apparent satiation to maximize feed intake and obtain accurate data metrics for consumption and conversion. Performance data  collected at 36d and 72d were analyzed using ANOVA and post-hoc testing with Tukey's HSD ( priori=0.05). Growth results from the trial endpoint indicate comparable performance for the FM and SBM diets, while DDGS diet did not show favorable performance when compared  to  the SBM  or FM  diet. For feed conversion ratio (FCR; P=0.019), the burbot fed the REF diet showed the best conversion (0.80±0.01), which was better than the SBM (0.98±0.03) and DDGS (0.96±0 .05) diets. Fecal material (trial start, 36d,  and 72d) was collected for an assessment of the intestinal microbiota via 16S sequencing (V3 and V4 regions) .  Results indicate a difference  in observed amplicon sequence variants (ASVs) across dietary treatments (P=0.030)  and trial sampling timepoints (P=0.013), with the DDGS shifting constituents from 36d  (17.9) to 72d ( 66.1; P=0.039). With respect to alpha diversity analyses, the REF diet display ed an increase  in the Shannon i ndex over time (P= 0.031) and was found to be greater than the SBM group at 72d (P= 0.034).  The results from this feeding trial will be of interest to commercial coldwater aquaculture producers, as  this study better defines a satiation feeding schedule for burbot and demonstrates the potential of  incorporating plant-based protein ingredients into future burbot diet formulations.