View metadata,Downloaded citation and from similar orbit.dtu.dk papers on:at core.ac.uk Apr 01, 2019 brought to you by CORE provided by Online Research Database In Technology Annual variation in the composition of major nutrients of the common starfish (Asterias Rubens) van der Heide, Marleen Elise; Møller, Lene Friis; Petersen, Jens Kjerulf; Nørgaard, Jan Værum Published in: Animal Feed Science and Technology Link to article, DOI: 10.1016/j.anifeedsci.2018.02.007 Publication date: 2018 Document Version Peer reviewed version Link back to DTU Orbit Citation (APA): van der Heide, M. E., Møller, L. F., Petersen, J. K., & Nørgaard, J. V. (2018). Annual variation in the composition of major nutrients of the common starfish (Asterias Rubens). Animal Feed Science and Technology, 238, 91-97. 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Accepted Manuscript Title: Annual variation in the composition of major nutrients of the common starfish (Asterias Rubens) Authors: Marleen Elise van der Heide, Lene Friis Møller, Jens Kjerulf Petersen, Jan Værum Nørgaard PII: S0377-8401(17)31469-4 DOI: https://doi.org/10.1016/j.anifeedsci.2018.02.007 Reference: ANIFEE 13947 To appear in: Animal Feed Science and Technology Received date: 17-11-2017 Revised date: 8-2-2018 Accepted date: 9-2-2018 Please cite this article as: van der Heide, Marleen Elise, Møller, Lene Friis, Petersen, Jens Kjerulf, Nørgaard, Jan Værum, Annual variation in the composition of major nutrients of the common starfish (Asterias Rubens).Animal Feed Science and Technology https://doi.org/10.1016/j.anifeedsci.2018.02.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Annual variation in the composition of major nutrients of the common starfish (Asterias Rubens) Marleen Elise van der Heidea, Lene Friis Møllerb, Jens Kjerulf Petersenb, Jan Værum Nørgaarda* a Department of Animal Science, Aarhus University, Foulum, DK-8830 Tjele, Denmark. b Danish Shellfish Centre, National Institute of Aquatic Resources, Danish Technical University, DK-7900 Nykøbing Mors, Denmark. * Corresponding author at: Aarhus University, Blichers Alle 20, DK-8830 Tjele, Denmark. E- mail address: [email protected] (J.V. Nørgaard) Highlights: Nutrient composition of starfish changes during the year. Starfish caught from February to May had highest crude protein and lowest ash. Fat content did not show a clear seasonal variation. Small starfish had the poorest nutrient composition. The geographical locations did not significantly affect the nutrient composition. ACCEPTED MANUSCRIPT ABSTRACT To study the annual variation in the composition of nutrients relevant to pig and poultry feeding, monthly samples of starfish (Asterias Rubens) were taken in Denmark. The effect of 1 different locations and starfish sizes was also assessed. Crude protein (CP) and phosphorus were high from February to May and lower thereafter. The AA profile remained constant and followed the same pattern as CP. An opposite pattern of CP was observed for both ash and calcium. Fat followed no clear annual pattern. Starfish within the smallest size group had the lowest fat and CP levels and the highest ash and calcium levels. The most profound differences between locations were observed in May. The seasonal pattern in chemical composition seemed related to spawning and gonadal developments. Large and medium sized starfish caught between February and May will be most suitable for pig and poultry feed. Abbreviations: AA, amino acids; Ca, calcium; CP, crude protein; DM, dry matter; P, phosphorus. Keywords: Feed, marine protein, minerals, nutrients, seastar, starfish meal 1. Introduction Recently, efforts have been made to use the common starfish Asterias Rubens as a feed ingredient in pig and poultry diets (Afrose et al., 2016; Sørensen and Nørgaard, 2016). Starfish have a crude protein level from around 270-450 and up to 700 g/kg in the dry matter (DM) and a high quality amino acid (AA) profile (Levin et al., 1960; Nørgaard et al., 2015; Sørensen and Nørgaard, 2016). The calcium (Ca) level of above 100 g/kg, however, disturbs the balance between Ca and phosphorus (P) in pig diets. Furthermore, the nutrient compositionACCEPTED of starfish caught in different month MANUSCRIPTs has been found to be variable. Both factors can make the use of starfish in feed formulation challenging. Knowledge on changes in nutrient composition of starfish will allow identification of the optimal fishing period as well 2 as the circumstances that make starfish meals most suitable for use in animal nutrition and will enable production of a uniform feedstuff. Different aspects can affect the chemical composition of starfish. Firstly, environmental factors such as temperature, feed source and feed availability can alter availability and requirement of nutrients and utilisation of energy (Ferguson, 1975).Secondly, starfish nutrient composition is believed to be dependent on starfish size (Levin et al., 1960). Lastly, nutrient composition can change between seasons which is partly related to the reproductive cycle. During the reproductive cycle, the gonads vary largely in size and nutrient composition due to deposition and release of nutrients, mainly protein and fat (Oudejans and Sluis, 1979; Rubilar et al., 2008). In Asterias rubens, gametogenesis and gonadal developments start around September-October (Oudejans and Sluis, 1979). Ovaries are fully matured and ready for spawning between April-May. Pre-vitelogenesis, a sexual rest period, follows from June to September. The pyloric caeca has a nutrient storage function and will therefore also influence nutrient levels (Jangoux and van Impe, 1977). No research has been published on the annual changes in nutrient composition of the intact starfish body. Nonetheless, annual changes in nutrient composition of starfish have been studied on different body compartments, i.e. the gonads, the pyloric sphincter and the somatic body (Oudejans and Sluis, 1979; Mcclintock et al., 1990; Rubilar et al., 2008). The objective of this study was to describe the variation in the composition of major nutrients in starfish. Differences in nutrient composition attributed to month, starfish size and harvesting locations were measured and compared in order to find the optimum catching circumstancesACCEPTED of starfish for their use in animal MANUSCRIPT feed. 2. Material and methods 2.1. Sampling and characterisation 3 Starfish (Asterias rubens) were caught monthly between February 2016 and January 2017 and sent for posterior nutrient analysis. Sampling was performed in Limfjorden in the North of Denmark. Starfish were collected by dredging at three different positions: position 1: at a depth of 5.5 m and 56° 46,807; 008° 54,512; position 2: at a depth of 6 m and 56° 47,763; 008° 55,485; position 3: at a depth of 5 m and 56° 48,327; 008° 53,552. Because these locations were part of blue mussel production sites, as they should be according to EU legislation (European Commission, 2017), the water was under continuous quality analysis and declared free of toxins. Samples were stored at 5 ºC during transport and subsequently at -18 ºC until nutrient analyses were performed. In April, May and October 2016, additional sampling was performed in Lillebælt, which is in the central part of Denmark. Starfish were collected by dredging by fishermen. In Limfjorden, additional sampling was performed in April (N=312), June (N=206) and December (N=202) 2016 where size and weight of the sampled starfish were measured immediately after fishing. Starfish were allotted to one of three size groups; small (≤7.5 cm), medium (7.5-15 cm) and large (> 15 cm). The nutrient composition of starfish was analysed separately for each size class during these three months. 2.2. Chemical analyses Chemical analyses were performed on intact starfish, i.e. a mixture of the solid phase and the liquid phase leaked during the hours from fishing until freezing. All analyses, with the exception of AA analyses, were performed in duplicates. To assess DM, samples were freeze driedACCEPTED for two to three days at -80 °C until a constant MANUSCRIPT weight was reached (Christ Gamma 2-16 LSC, Germany). Crude protein (CP, N x 6.25) level was analysed using the Kjeldahl method (AOAC, 2000). Crude fat was analysed by hydrolysing the sample with hydrochloric acid before extraction with petroleum ether (European Commission, 2009). To get the ash level, 4 the samples were oven dried at 525 °C for 6 h. The minerals P and Ca were analysed after ashing at 450 °C and treatment with hydrochloric acid/nitric acid. Phosphorus was measured using spectrophotometry after reaction with vanadomolybdate (Stuffins, 1967). Calcium was measured using atomic absorption spectrophotometry (model SP9, PyeUnicam Ltd, Cambridge, UK). For other mineral than Ca and P, the samples were destroyed using Ultrawave Microwave Acid Digestion System (Milestone Inc, Shelton, USA) at 230 °C and 1500 watt for 35 minutes, acidified with 5 ml of nitric acid (67-69%).