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Turkish Towel Chondracanthus exasperates and taurine were added to alternative plant‐based feeds for juvenile sablefish Anoplopoma fimbria to evaluate the effect of these ingredients, alone or combined, on fish growth, feed intake and efficiency, whole body nutrient composition, and liver histomorphology. Fish growth was significantly increased with the addition of taurine, and to a lesser extent, Turkish Towel to the experimental feeds. Feed efficiency and protein retention were significantly improved with the addition of taurine, but were unaffected by Turkish Towel addition. As expected, whole body taurine content was significantly affected by taurine addition. Increases in whole body lipid were observed with both taurine and Turkish Towel addition, with a significant interaction between the two factors. Liver histomorphology was generally normal; however, histopathologic changes were observed in some fish at the end of the experiment. The occurrence of hepatocellular nuclear pleomorphism and clear cell foci was less among fish that had received the Turkish Towel feeds. The addition of taurine had no effect on the number of fish with a histopathologic change. Overall, results from this study reaffirm taurine supplementation is beneficial to sablefish receiving plant‐based feeds and indicate Turkish Towel may be a promising feed ingredient for this species. [ABSTRACT FROM AUTHOR]

To quantify the efficacy and cost of different soya protein ingredients, heated soya beans (HSB) and underprocessed (SB) full‐fat soya beans (FFSB), soya protein concentrate (SPC) and trim waste from Pacific whiting (Merluccius productus) were incorporated into feeds for the cold water marine sablefish (Anoplopoma fimbria). Feed ingredients for this study were processed using an experimental heated ball mill with demonstrated potential as an affordable process for rural or small‐scale feed production. The three feed treatments were formulated with equal amounts of soya protein and Pacific whiting process trim. The three feed treatments contained 46% protein and 18% lipid as dry matter. Three 480‐L tanks of 10 fish were used to evaluate each of the three feed treatments. Fish were fed to satiation every 2 days for 8 weeks. Weight gain of the treatment groups ranged between 56% and 105% over the course of the study. Fish growth was significantly better among fish receiving the feeds containing HSB and SPC than a feed containing SB. At the conclusion of the study, histomorphologic evaluations of the distal intestines of final fish were conducted. Varying levels of inflammation were measured for all three treatments. Fisher's exact test showed a significant reduction in mononuclear cell infiltration among fish fed heat‐treated full‐fat soya beans vs those receiving underprocessed full‐fat soya beans. Fish receiving HSB feed had significantly lower intestinal inflammation than SB fish. Based on our results, cost savings of $ 0.253/kg were calculated for the HSB feed over the SPC feed. [ABSTRACT FROM AUTHOR]

Development of a highspeed and high-yield water-powered fish evisceration system (FES) to efficiently preprocess smallfish and bycatch for producing minced fish meat is described. The concept of the system is propelling fish in a stream of water through an arrangement of cutting blades and brushes. Eviscerated fish are separated from the viscera and water st ream in a dual screen rotary sieve. The FES processed head off fish, weighing 170-500 g, at the rate of 300 fish/min when used with an automatic heading machine. Yields of mince produced from walleye pollock, Theragra chalcogramma; and Pacific whiting, Merluccius productus; processed by the FES ranged between 43% and 58%. The maximum yield of minced muscle from fish weighing over 250 g was 52%, and the yield of mince muscle from fish weighing less than 250 g was 58%. Test results indicated that surimi made from minced meat recovered from fish processed with the FES was comparable in quality to commercial grade surimi from conventional systems. Redesigned for commercial operation in the Faeroe Islands (Denmark), the system effectively processed North Atlantic blue whiting, Micromesistius poutassou, with an average weight of 110 g at a constant rate of 500-600 fish/mm, producing deboned mince feeding a surimi processing line at a rate of 2.0 t/h. Yields of mince ranged from 55% to 63% from round fish. Surimi made from the blue whiting mince meat produced by the FES was comparable to surimi commercially produced from blue whiting by Norway and France and sold into European markets. [ABSTRACT FROM AUTHOR]

The small size and high surface area to volume ratio of larval fish feed presents challenges for nutrient retention in micro-particulate diets. A method for the accurate and rapid measurement of nutrient retention or loss from micro-particulate feed in water is needed to help develop micro-particulate feeds with good nutrient retention characteristics. The present study developed and validated an instrument method using fibre optic technology that measures protein leaching in real time. Larval fish feed particles of different sizes (100–500 μm) and formulations were measured. Under consistent experimental conditions, a feed could be assayed for the rate of mass loss and the half-life or time of 50% total soluble mass loss. The results closely approximated natural decay models with coefficients of determination ( r2) >0.95. The end result is a fast and accurate method to quantify and provide solid reference data for a feed formulation or particle size. Using this method allows different feeds to be compared and conclusions drawn for relative performance. [ABSTRACT FROM AUTHOR]

Abstract: A technique was developed to determine apparent digestibility coefficients (ADCs) of protein in microparticulate and live feeds for marine fish larvae. The technique is analogous to methods used for larger fish and allows for an in vivo measurement of protein digestibility by employing a spectrophotometric protein assay for protein determination and rare earth oxides as inert digestibility markers. Either a microbound microparticulate diet developed in our laboratory or Artemia nauplii were fed to 8-week-old Atlantic cod as a single 30-min feeding and fecal solids collected 6 h later. Protein ADCs for the two diets were significantly different (P =0.016) with determined ranges of 47 to 58% and 76 to 86%, (Artemia and microparticulate diets, respectively). Measured ADCs are presented as a range to account for the possibility of leaching of protein from the microparticulate diet, and the evacuation (loss) of marker from the live prey during the 30-min feeding. It is suggested that this new technique will assist researchers in selecting experimental larval feeds with the most nutritive potential for extended feeding studies. Detection limits for this technique were determined to be 8.6 μg for protein and 0.020 and 0.038 μg for yttrium (Y2O3) and dysprosium (Dy2O3) markers, respectively, in collected fecal solids. [Copyright &y& Elsevier]

Juvenile sablefish were fed a low taurine, basal feed with seven graded levels of supplemental taurine to determine taurine requirements for growth and feed efficiency. The basal feed was plant based, formulated primarily with soy and corn proteins with a minimal (9%) amount of fishmeal. The unsupplemented, basal feed contained 0.14% taurine. Experimental feeds were supplemented with 0, 0.25, 0.50, 1.0, 1.5, 3.0, and 6.0% taurine. Using the five parameter, saturated kinetic model (5 SKM), peak weight gain was predicted at 1.5% dietary taurine. Optimum weight gain, as defined as the region of the 5 SKM curve corresponding to at least 95% of peak, was predicted between 0.4% and 5.8% dietary taurine. Peak feed efficiency was predicted at 1.1% dietary taurine with optimum weight gain predicted between 0.4% and 4.2%. Whole body and muscle tissue protein and lipid content were not affected by taurine supplementation. Tissue taurine content increased asymptotically with increasing dietary taurine supplementation. Whole body tissue became saturated at 0.25 ± 0.02% taurine, expressed on a wet weight basis. Muscle tissue became saturated at 0.34 ± 0.02% taurine. Results from this study should increase the performance of alternative, plant based feeds formulated for sablefish and enable regulatory agencies better estimate the potential human exposure to taurine from the consumption of sablefish receiving these feeds. [ABSTRACT FROM AUTHOR]