Description: Brown shrimp, Crangon crangon (L.), is the most valuable target of coastal fisheries in the southern North Sea. Annual landings exceeded 30,000 tons in the last decade, yielding up to 100 Mio Euro. The shrimp are boiled immediately after capture onboard the fishing vessel for preservation and easy peeling. After landing, the shrimp are collected by traders and exported for manual peeling. Only the muscle of the pleon is returned and sold as regional delicacy. The remains, comprising the cephalothorax, the shell of the pleon, and, in case, adhering eggs, account for up to 70% of the total body mass. This potential resource, for example as aquaculture feed, has not yet been considered for exploitation. In this respect, the fatty acid (FA) profile and the share of essential FAs are crucial quality factors. Since boiling alters the quality of shrimp, this study evaluates changes in the FA composition of shrimp muscle and remains by comparing frozen and boiled samples. Major FAs in C. crangon were the saturated palmitic acid (PA, 16:0), accounting for 16.6%–19.1% of total fatty acids (TFAs), and the long-chain polyunsaturated FAs (LC-PUFAs) eicosapentaenoic acid (EPA, 20:5(n-3), 16.1–21.6%TFA ) and docosahexaenoic acid (DHA, 22:6(n-3), 11.5–13.6%TFA ). Frozen muscle and frozen remains showed similar FA profiles. Boiling changed the FA profile. PA, EPA, and DHA decreased by up to 25%, whereas palmitoleic acid 16:1(n-7) and oleic acid 18:1(n-9) increased by 2% to 3% each. Boiled muscle and boiled remains showed similar FA profiles. Despite the loss of FAs, the boiled shrimp remains are suggested to be a suitable PUFA supplement for aquaculture feeds, deserving further investigation.

Description: Processing remains of brown shrimp, Crangon crangon, account for up to 60 % of the catch while only the small muscle fraction is used for human consumption. Incorporation into aquafeeds for high-valued species would reduce waste, create by-product value and promote sustainable aquaculture development. A detailed chemical characterisation of the remains from mechanically peeled brown shrimp was made and apparent nutrient digestibility coefficients in Litopenaeus vannamei were investigated. Brown shrimp processing remains (BSPR) contain substantial amounts of key nutrients (521 g⋅kg-1 crude protein, 74 g⋅kg-1 total lipid, 15 MJ⋅kg-1 gross energy) and valuable functional ingredients were detected (cholesterol, astaxanthin). Apparent energy (82 %) and protein (86 %) digestibility coefficients reveal good bioavailability of these nutrients. Dry matter digestibility was lower (64 %) presumably due to the high ash content (244 g⋅kg-1). The amino acid profile meets dietary requirements of penaeid shrimp with high apparent lysine and methionine digestibility coefficients. Analysis of macro- and micro minerals showed reasonable levels of required dietary minerals (phosphorus, magnesium, copper, manganese, selenium, zinc) and apparent copper digestibility was high (93 %). Contamination levels present in BSPR were below European standards acceptable for human consumption. Processing remains of brown shrimp have a high potential as alternative feed ingredient in sustainable diets for L. vannamei in recirculating aquaculture systems.

Description: Brown shrimp, Crangon crangon, is the most valuable target of coastal fisheries in the southern North Sea. Landings approach 40,000 tons p.a., yielding up to 100 Mio Euro. The shrimp are boiled immediately after capture on board ship for preservation and easy peeling. After landing, the shrimp are collected by traders and sent for manual peeling. Only the meat of the pleon is returned and sold as regional delicacy. The remains, comprising the cephalothorax, the shell of the pleon and, in case, adhering eggs, accounts for 70 % of the body mass. This potential resource for e.g. aquaculture feeds has not yet been considered for exploitation. Shrimp peeling remains were obtained from a shrimp trader, operating a mechanical peeling device. The remains were dried, ground to a powder, and analyzed for gross composition, nutrients, and contaminants. The shrimp meal was used as substitute for commercial fishmeal in custom-made feed pellets. These pellets were fed to Whiteleg shrimp, Litopenaeus vannamei, held in a recirculating aquaculture system. The acceptance of the pellets was excellent and the apparent digestibility high. Mortality decreased along with the rising share of shrimp meal. Concomitantly, growth of L. vannamei increased by up to 70 %. Brown shrimp remains proved to be a suitable complement for shrimp feeds. Commercial utilization of such remains would gain value to shrimp fisheries, encourage local processing, and may reduce transport emissions.

Description: Introduction Brown shrimp, Crangon crangon, present the major coastal fishery in the southern North Sea with annual landings of up to 40,000 t (ICES, 2022). While only the abdominal muscle fraction is used for human consumption, the unused processing remains account for up to 60 % of the shrimp biomass. Incorporation of the remains into aquafeeds for high-valued species like L. vannamei would create by-product value, reduce waste, and promote circular economy approaches. This study aims to assess the suitability of brown shrimp processing remains (BSPR) as a sustainable feedstuff for L. vannamei to replace fishmeal. A detailed biochemical characterization was made and key apparent nutrient digestibility coefficients of BPSR examined. Controlled feeding trials with juvenile L. vannamei were conducted to determine effects on growth performance, feed utilization, digestive enzyme activities, and immunological parameters. Materials and Methods Frozen remains of mechanically peeled brown shrimp were obtained from a shrimp trader in northern Germany, dried at 60 °C, and ground to a homogenous meal. A detailed biochemical characterization of the meal was made using established methods (AOAC, 2010; Folch et al, 1957; Percot, Viton and Domrad, 2003) and by certified laboratories. To measure apparent nutrient digestibility coefficients, a reference and test diet was prepared using yttrium as inert marker. A 40-day feeding trial with 192 juvenile shrimp (6.5 ± 1.3 g) was conducted using pelleted diets replacing 0, 50 and 100 % of the fishmeal content with BSPR. Survival, molting frequency, growth, digestive enzyme activities, and muscle proximate composition of L. vannamei was determined. Based on the first trial, a second feeding trial with 720 shrimp (4.31 ± 1.0 g) was performed with six extruded feeds replacing the fishmeal content in steps of 20 % from 0 to 100 % to obtain an estimate for the optimal substitution level. The high water stability of the extruded pellets allowed for accurate measurements of feed intake and assimilation efficiency. Hemolymph was analyzed for phenoloxidase and prophenoloxidase activities and protein content. Results and Discussion Brown shrimp processing remains contain substantial amounts of key nutrients (521 g·kg-1 crude protein, 74 g·kg-1 total lipid, 15 MJ·kg-1 gross energy), minerals (phosphorus, magnesium, copper, manganese, selenium, zinc, and valuable functional ingredients (cholesterol, astaxanthin, chitin). Apparent digestibility coefficients of energy, protein, methionine, lysine, and copper exceeding 80 %, demonstrated excellent nutrient bioavailability of BSPR. In the first feeding trial, shrimp showed best growth with diets containing a mixture of 50 % fishmeal and 50 % BSPR. No negative effects on muscle quality (moisture, protein, lipid) appeared and digestive enzyme activities were not affected by diet. The daily molting ratio increased with higher BSPR inclusion levels and a higher molting synchronicity was observed. The second feeding trial showed significantly enhanced growth when the BSPR substitution level exceeded 60 %. Based on the polynomial regression of the BSPR substitution level and shrimp weight gain, best growth is expected at 85 % inclusion level (Figure 1.). Different crustacean meals have been shown to stimulate growth in penaeid shrimp (Cordova-Murueta & Garcia-Carreno 2002; Williams et al. 2005; Nunes et al., 2019 ). This has been attributed to well-balanced nutrient profiles, increased palatability and even unknown growth promoters. Yet it remains unclear what the underlying mechanisms are. The shrimp hemolymph parameters (protein, phenoloxidase, prophenoloxidase) and digestive enzyme activities were not affected by the diets. Therefore, the enhanced growth performance might primarily be related to superior nutritional value and not immunological or digestive enzymatic improvements. We observed a reduced feed intake at concomitantly improved growth with diets containing 80 – 100 % BSPR. This supports the hypothesis that inherent component(s) of BSPR may promote growth in L. vannamei. Since the molting behavior of shrimp was also affected by the dietary treatment, it is possible that chitin-oligomers or chitin-protein derivatives in the BSPR are beneficial for shrimp growth. Good bioavailability and supply of key dietary nutrients further underline the suitability of BSPR as excellent feedstuff for L. vannamei. References Aline Percot, C. V., and Alain Domard. (2003). Optimization of Chitin Extraction from Shrimp Shells. Biomacromolecules, 4. doi:https://doi.org/10.1021/bm025602k AOAC (2010). Official Methods of Analysis of AOAC international. 18th edition. AOCA International, Gaithersburg, Maryland, USA. ICES. 2022. Working Group on Crangon Fisheries and Life History (WGCRAN; outputs from 2021 meet-ing). ICES Scientific Reports. 4:14. 77 pp. http://doi.org/10.17895/ices.pub.10056 Córdova-Murueta, J. H., & Garcıìa-Carreño, F. L. (2002). Nutritive value of squid and hydrolyzed protein supplement in shrimp feed. Aquaculture, 210(1-4), 371-384. Folch, J., Lees, M., & Sloane Stanley, G. H. (1957). A simple method for the isolation and purification of total lipids from animal tissues. J biol Chem, 226(1), 497-509. Nunes, A. J., Sabry‐Neto, H., Oliveira‐Neto, S., & Burri, L. (2019). Feed preference and growth response of juvenile Litopenaeus vannamei to supplementation of marine chemoattractants in a fishmeal‐challenged diet. JOURNAL OF THE WORLD AQUACULTURE SOCIETY, 50(6), 1048-1063. Williams, K. C., Smith, D. M., Barclay, M. C., Tabrett, S. J., & Riding, G. (2005). Evidence of a growth factor in some crustacean-based feed ingredients in diets for the giant tiger shrimp Penaeus monodon. Aquaculture, 250(1-2), 377-390.