Effects of different levels of sweet potato in feeds on body composition and digestive enzymes activities of Apostichopus japonicas Selenka*

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1 Journl of Ocenology nd Limnology Vol. 36 No. 5, P , Effects of different levels of sweet potto in feeds on body composition nd digestive enzymes ctivities of Apostichopus jponics Selenk* ZHAO Bin ( 赵斌 ) 1, HU Wei ( 胡炜 ) 1, LI Chenglin ( 李成林 ) 1, **, HAN Sh ( 韩莎 ) 1, XU To ( 徐涛 ) 2 1 Mrine Biology Institute of Shndong Province, Qingdo , Chin 2 Shndong Province Fisheries Technology Extension Sttion, Jinn , Chin 3 Homey Foods Co. Ltd., Weihi , Chin Received Feb. 27, 2017; ccepted in principle Jun. 8, 2017; ccepted for publiction Aug. 8, 2017 Chinese Society for Ocenology nd Limnology, Science Press nd Springer-Verlg GmbH Germny, prt of Springer Nture 2018 Abstrct The im of this study ws to test the effects of including sweet potto tuber nd stem powder in feed on the body composition nd digestive enzyme ctivities of the se cucumber Apostichopus jponics Selenk. Different proportions of sweet potto tuber nd stem powders (from 10% to 50%) were dded into compound feeds, which were supplied to A. jponics during 60-dy experiment. The results showed tht the two sweet potto ingredients hd different effects on the nutrient contents of the se cucumber body wll. The group supplied with feed contining 20% sweet potto tuber powder (T2) hd the highest level of crude protein in body wlls ( P <0.05), while there were no significnt differences in the moisture nd sh contents of body wlls mong the groups ( P >0.05). In ll the groups fed with powdered sweet potto tubers (T groups), the proportions of glutmic cid nd lysine in body wlls were higher thn those in the control, wheres the proportion of methionine decresed slightly. Different proportions of sweet potto ingredients in compound feeds lso ffected digestive enzyme ctivities in the se cucumbers. The ctivities of protese nd lipse first incresed nd then grdully decresed with incresing proportions of sweet potto mterils in the feed. The highest protese ctivity ws in the T2 nd the group nd the highest lipse ctivity ws in the 10% sweet potto stem (S1) group. These results show tht feed components cn stimulte digestive enzyme ctivities in se cucumber, nd tht the proportions of tubers nd stems of sweet potto in feed cn be djusted to improve the digestion nd growth of A. jponics in mrine frms. Keyword : Apostichopus jponics Selenk; sweet potto; body composition; digestive enzymes 1 INTRODUCTION Apostichopus jponics Selenk (se cucumber) is n economiclly importnt echinoderm species tht is distributed long the northern cost of Chin. Since 2003, the quculture industry of A. jponics hs developed rpidly, nd it is now one of the min cultured species in Shndong nd Lioning provinces (Li et l., 2010). Mny economiclly vluble mcrolge such s S rgssum spp. hve been used s ingredients of feed for A. jponics, leding to the grdul exhustion of nturl resources. This feed shortge hs incresed the cost of A. jponics nd lso hd negtive effects on the costl environment. Therefore, recent reserch nd development of feed for A. jponics hs focused on lterntive feed sources or dditives. Such mterils must be inexpensive, but ble to meet the nutrient needs of growing A. jponics. The lterntive mterils tested to dte include Zoster mrin (Liu et l., 2013), * Supported by the Nturl Science Foundtion of Shndong Province (No. ZR2014CQ056), the Innovtion Tem Building of Se Cucumber Industry in Shndong Province Modern Agriculturl Technology System (Nos. SDAIT-22-01, SDAIT-22-05), the Tishn Industry Leding Tlents Project (No ), the Agriculturl Seed Engineering Project of Shndong Province (No. 2017LZGC010), the Science nd Technology Development Plnning Project in Shndong Province (No. 2014GNC111022), nd the Sprk Science nd Technology Demonstrtion Project in Shndong Province (No. 2015XH006) ** Corresponding uthor: lcl_xh@hotmil.com

2 1836 J. OCEANOL. LIMNOL., 36(5), 2018 Vol. 36 Tble 1 Composition nd nutrient levels of experimentl diets Group Item CK T1 T2 T3 T4 T5 S1 S2 S3 S4 S5 Ingredient Tuber powders of sweet potto Stem powders of sweet potto Rt til lge Srgssum mel Degumming kelp Deftted fish mel Shrimp mel Compound vitmin Compound minerl Compound enzyme Totl Nutrient level Crude protein Crude ft Crude sh Enteromorph sp. (Lio et l., 2011), Eichhorni crssipes (Wng et l., 2013), lflf (Li et l., 2013) nd Ophiopholis mirbilis (Jing et l., 2012). Those studies hve identified severl mterils tht hve potentil s ingredients to enrich feeds for A. jponics. Sweet potto is n importnt economic crop tht is widely cultivted in Chin. Sweet potto production in Chin ccounts for 80% of the world s totl (Du et l., 2006). In recent yers, there hve been severl studies on the nutritive vlue of sweet potto nd its functionl components (Innmi et l., 1998; Shhidul et l., 2003; Le Vn An et l., 2003). Other studies hve evluted nd nlyzed the nutritive vlues of different prts of sweet potto (Koizumi nd Ysui, 1991; O Sullivn et l., 1996; Wng nd Yeh, 1996; Ishid et l., 2000; Wng et l., 2009), nd hve provided theoreticl foundtion for the use of sweet potto s lterntive feed source or dditive. Preliminry reserch indicted tht ddition of sweet potto ingredients to finl concentrtion of 30% of feed promoted the growth nd food ingestion of A. jponics (Zho et l., 2016). The im of this study ws to expnd the scope of reserch on the use of sweet potto mterils s ingredients in feed for A. jponics, nd to determine whether these mterils ffected the qulity of this importnt mricultured species. Therefore, we determined the effects of dding sweet potto tuber nd stem powders to feed on the body composition of A. jponics. Specificlly, A. jponics fed with different diets were nlyzed to determine their nutrient nd mino cid contents, nd the ctivities of their digestive enzymes (protese, mylse, nd lipse). The overll im of this reserch ws to explore the fesibility of using terrestril plnt mterils (sweet potto tubers nd stems) s the protein source in feed for se cucumber, nd to provide fundmentl dt nd theoreticl support for the development of green nd novel feeds. 2 MATERIAL AND METHOD 2.1 Mteril Helthy se cucumbers with verge weights from 14.2 g to 17 g were obtined from the Germplsm Reserch Center of Mrine Biology Institute, Shndong Province. Sweet potto tubers nd stems were ir-dried nd ground into powder with prticle size of <150 μm. 2.2 Experimentl design nd dily mngement Compound feed ws purchsed from the Qingdo Longer Biologicl Technology Co., Ltd. The composition of the compound feed ws 16% crude protein, 5% crude ft, 8% crude fiber, 6% totl phosphorus, 25% crude sh, 0.8% lysine, nd 10% moisture. To this bsl feed, sweet potto tuber powder (T) or stem powder (S) ws dded to finl concentrtion of 10%, 20%, 30%, 40% or 50%, by weight (Tble 1). Then, wter ws dded to ech

3 No.5 ZHAO et l.: Effects of sweet potto on digestive enzymes of A. jponics 1837 group (40% 60%), nd the mixtures were rolled, pressed into flkes, dried, nd then kept seled until use. The compound feeds contining sweet potto mterils were supplied t 8% of the totl body weight of se cucumbers. Good-qulity dried se mud ws lso supplied (5 g mud:1 g feed). The se cucumbers were fed in plstic boxes (80 cm long, 60 cm wide, 48 cm high). Ech box contined 20 se cucumbers tht were fed once per dy t 17:00. The experiment consisted of five prllel groups. The slinity of se wter ws , the ph rnged from 7.8 to 8.3, nd wter temperture ws mintined t C. Gentle ertion ws supplied to the boxes nd 100% of the wter ws replced dily. The 60-dy experiment begn on April 17, Determintion methods nd dt clcultions The mesure of the growth nd body composition of A. jponics The se cucumbers were strved for 1 dy before the strt of the experiment. The se cucumbers were weighed t the beginning ( W 0 (g); initil body weight) nd t the end of the experiment ( W t (g)), where t indictes the durtion of the experiment. Ech se cucumber ws removed from the wter nd dried in the shde before weighing. The specific growth rte (SGR, %/d) of A. jponics ws clculted s follows: SGR(%/d)=100 (ln W t ln W 0 )/ t. At the end of the experiment, the viscer were tken out nd the digestive trct contents were removed. The rtio of viscer to body wll (RVBW) ws clculted s follows: RVBW%=100 (viscer weight/body wll weight). The crude protein content ws mesured by the Kjeldhl Method, crude ft ws determined by Soxhlet extrction, sh content ws determined by combustion in muffle furnce t 550 C, nd moisture content ws determined fter oven-drying t 103 C. A portion of ech smple ws hydrolyzed with hydrochloric cid (6 mol/l) under nitrogen gs for 24 h before detecting 17 mino cids using n utomtic mino cid nlyzer Determintion of digestive enzyme ctivity To collect coelomic fluid, the se cucumbers were cut open nd the digestive trct nd respirtory tissues were removed. The tissues were wshed with ultrpure wter nd then stored t -80 C until nlysis. The intestinl tissues were homogenized for 20 min in pre-cooled ultr-pure wter using glss homogenizer (10 vol wter:1 vol intestinl tissue), nd the resulting mixture ws centrifuged (0 4 C, r/min) for 30 min. The superntnt ws stored t -20 C until use in nlyses. The ctivities of digestive enzymes including protese, mylse, nd lipse, were mesured using kits developed by the Nnjing Jincheng Bioengineering Institute. Protese ctivity ws detected using the molybdte mmonium method, nd one unit of enzyme ctivity ws defined s the mount of enzyme producing 1 μg mino cids per minute t 37 C. Amylse ctivity ws detected by the turbidimetry method, nd one unit of mylse ctivity ws defined s the mount of protein tht hydrolyzes 10 mg strch in 30 minutes t 37 C. Lipse ctivity ws mesured by the xnthine oxidse method, nd one unit of ctivity ws defined s the mount of enzyme consuming 1 μmol substrte in 1 min t 37 C. The protein content in the enzyme solution ws determined by the Coomssie Brillint Blue G250 Method, with bovine serum lbumen s the stndrd. The ctivities of vrious enzymes were expressed s the number of units per mg soluble protein Dt nlysis Dt were nlyzed by one-wy nlysis of vrince nd multiple comprisons were conducted using SPSS 22.0 softwre, with P <0.05 indicting sttisticl significnce. 3 RESULT 3.1 Effects of sweet potto tuber nd stem powders in feed on growth nd body composition of A. jponics Growth of A. jponics The growth of se cucumbers fed with tuber nd stem powders of sweet potto during the 60-dy experiment is shown in Tble 2. At the end of the experiment, the highest body weight ws in the T2 (20%) group (verge, g). This ws significntly higher thn tht in the control group (CK) ( P <0.05). The body weights of se cucumbers in the T1 (10%) nd T3 (30%) groups (verge, g nd g, respectively) were not significntly different from tht in CK ( P >0.05). The verge weights of se cucumbers in the T4 (40%) nd T5 (50%) groups were lower thn tht of CK ( P <0.05), with the verge

4 1838 J. OCEANOL. LIMNOL., 36(5), 2018 Vol. 36 Tble 2 Effects of feed contining sweet potto tuber nd stem powders on growth of se cucumbers Group Proportion of sweet potto dded (%) Initil body weight (g) Finl body weight (g) SGR (%/d) RVBW (%) CK ± ±1.15 bc 1.260±0.076 b 11.34±0.20 T ± ±1.20 b 1.367±0.096 b 10.47±0.21 T ± ± ± ±0.18 b T ± ± 1.18 bc 1.270±0.069 b 11.25±0.24 T ± ±1.16 c 1.106±0.060 b 11.74±0.22 T ± ±1.21 d 0.997±0.076 c 11.87±0.22 CK ± ±1.15 bc 1.207±0.076 b 10.98±0.23 S ± ±1.20 b 1.241±0.096 b 10.64±0.26 b S ± ± ± ±0.22 b S ± ± 1.18 bc 0.944±0.069 b 12.65±0.26 c S ± ±1.16 c 0.822±0.060 b 13.75±0.33 d S ± ±1.21 d 0.614±0.076 c 13.44±0.32 d Different letters in sme columns indicte significnt differences mong groups ( P <0.05). Tble 3 Effects of tuber nd stem powders of sweet potto on body composition of se cucumbers Group The proportion of sweet potto dded (%) Crude protein (%) Crude ft (%) Crude sh (%) Moisture (%) CK T T T T T CK S S S S S weight in T5 (28.43 g) the lowest mong ll the groups. Among ll the groups fed with feed contining sweet potto stem powder, S1 (10%) hd the highest verge body weight (32.17 g), but it ws not significntly different from tht of CK ( P >0.05). The se cucumbers in the S2 (20%), S3 (30%), S4 (40%) nd S5 (50%) groups hd lower verge body weights thn tht of CK ( P <0.05), with the lowest in the S5 group (22.54 g). The SGR of se cucumbers in the T groups chnged mrkedly during the experiment ( P <0.05) (Tble 2). At the end of the experiment, compred with the SGR in CK, those in T1 nd T2 were significntly higher ( P <0.05), tht in T5 ws significntly lower ( P <0.05), nd those in T3 nd T4 were not significntly different ( P >0.05). In contrst, the SGRs of the S groups decresed during the experiment ( P <0.05). At the end of the experiment, ll S groups except S1 hd notbly lower SGR thn tht of CK ( P <0.05), nd the SGR decresed s the proportion of stem powder in feed incresed. There ws no significnt difference in RVBW mong the T groups ( P >0.05), except tht the RVBW in T2, 9.45%, ws lower thn tht in CK ( P <0.05). The RVBWs were higher in the S groups thn in CK ( P <0.05) nd showed n incresing trend, except for those in S1 nd S2 ( P >0.05) Effects on body composition nd mino cid composition Tble 3 summrizes the body composition of se cucumbers fed diets contining sweet potto tuber nd stem powders. Among ll the components of the body wll, the most bundnt ws moisture (up to 91.1%), followed by crude protein, nd then crude sh. The lest bundnt component ws crude ft (<1.00%). The stem nd tuber of sweet potto hd different effects on the nutrient contents of the body wll. The highest crude protein content in the body wll ws in the T2 group (5.4%), nd this vlue ws significntly higher thn those in other groups. The moisture nd sh contents in the body wll did not differ significntly between the S nd T groups. The CK nd the two groups showing the best growth, T2 nd S1, were selected for mino cid nlyses (Tble 4). The contents of glutmic cid (Glu) nd lysine (Lys) were higher in T2 (0.50% nd

5 No.5 ZHAO et l.: Effects of sweet potto on digestive enzymes of A. jponics 1839 Tble 4 Effects of tuber nd stem powders of sweet potto on mino cids contents in se cucumbers Amino cid contents (%) No. Test item CK T2 S1 01 ASP THR SER GLU GLY ALA CYS VAL MET ILE LEU TYR PHE LYS HIS ARG PRO TAA %), respectively, thn in CK (0.46% nd 0.17%, respectively). The methionine (Met) content ws slightly lower in T2 (0.04%) nd S1 (0.03%) thn in CK (0.07%). 3.2 Effects of sweet potto tubers nd stems in feeds on digestive enzyme ctivities of A. jponics Effects on protese ctivity As the proportion of tuber powder incresed, the protese ctivity in T groups first incresed nd then decresed, with no significnt difference from CK ( P >0.05; Fig.1). The highest protese ctivity ws in T2 (3.75 U/mg prot), significntly higher thn tht in T5 ( P <0.05). However, protese ctivity did not differ significntly mong the other T groups ( P >0.05). The protese ctivity in S groups ws not significntly different from tht in CK ( P >0.05) when less thn 30% stem powder ws included in feed, but ws significntly lower thn tht in CK ( P <0.05) when 30% to 50% stem powder ws included in feed. The protese ctivity did not differ significntly between the S nd T groups when the feed contined less thn 30% sweet potto mterils, but ws significntly lower in S groups thn in T groups when the feed Activity of protese (U/mg prot) b b contined 30% to 50% sweet potto mterils ( P <0.05) Effects on mylse ctivity The sweet potto tuber powder significntly ffected mylse ctivity ( P <0.05, Fig.2). Amylse ctivity ws significntly higher in the groups supplied with feed contining 30% to 40% tuber powder thn in CK. The highest mylse ctivity ws in T4 (0.67 U/mg prot). The mylse ctivity in other T groups ws only slightly higher thn tht in CK ( P >0.05). The effect of sweet potto stem powder on mylse ctivity ws similr. The highest mylse ctivity ws in S3 (0.66 U/mg prot). This vlue ws significntly higher thn tht in CK, wheres the mylse ctivity in other S groups ws not significntly different from tht in CK ( P >0.05). There were no significnt differences in mylse ctivity between the T nd S groups ( P >0.05) Effects on lipse ctivity Figure 3 shows the lipse ctivity of se cucumbers fed with different proportions of sweet potto tuber nd stem powders. The lipse ctivity in T groups tended to decrese with incresing proportion of tuber powder in feeds, but the only significnt difference in lipse ctivity ws between CK nd the T5 group (1.93 U/mg protein); this vlue ws significntly lower thn tht in CK ( P <0.05). The lipse ctivity in S groups lso tended to decrese with incresing proportions of stem powder in feed. When stem powder ws dded to finl concentrtion of 40% or higher, the lipse ctivity ws significntly lower thn tht in CK ( P <0.05). There were striking differences in the lipse ctivity between T nd S groups b Tuber b *b *b Stem CK T1 S1 T2 S2 T3 S3 T4 S4 T5 S5 Dietry tretment Fig.1 Protese ctivity in se cucumbers supplied with feed contining sweet potto tubers nd stems Different letters indicte significnt differences within the sme dietry group; * indictes significnt differences between dietry groups ( P <0.05). b *b

6 1840 J. OCEANOL. LIMNOL., 36(5), 2018 Vol. 36 Activity of AMS (U/mg prot) b b contining sweet potto mterils t 30% to 50% ( P <0.05), but no significnt difference in lipse ctivity between the other T nd S groups ( P >0.05). 4 DISCUSSION Tuber b b b b b b b b CK T1 S1 T2 S2 T3 S3 T4 S4 T5 S5 Dietry tretment Stem Fig.2 Effects of tubers nd stems of sweet potto in feeds on mylse ctivity of se cucumbers Different letters indicte significnt differences within the sme dietry group ( P <0.05). 4.1 Effects of different proportions of sweet potto mterils on nutrient contents of A. jponics Activity of lipse (U/mg prot) Se cucumbers hve mny tiny clcreous ossicles under the surfce. Therefore, their bodies hve higher sh content compred with other qutic nimls including eels, Trionyx sinensis, hirtils, prwns, ricefield eels, mndrin fish, nd Pinctd mrtensii (Liu et l., 2011), while their crude protein nd crude ft contents re lower. The substnces tht increse protein content re exclusively dietry, so the proteins supplied in the feed re key fctor in se cucumber breeding. In this study, the sh content ws high, but it ws not relted to the vritions in the feed. However, the protein content ws closely relted to the proportion of sweet potto tuber nd stem powders in the feed. As one of the terrestril plnts dded into feeds, sweet potto is rich in strch, vitmins, nd minerls (Wng et l., 2005; Bovell- Benjmin, 2007). In tubers of sweet potto, spormin, specil kind of monomer protein in root plnts (Meshim et l., 1985) ccounts for 60% to 80% of soluble protein (Hrvey nd Boulter, 1983). In this experiment, the highest contents of crude protein were in the T2 nd S1 groups, nd the crude protein content ws higher in the T groups thn in the S groups. This is consistent with the reserch results mentioned bove. Sweet potto is n idel feed source of protein becuse its mino cids re bundnt nd wellblnced. In this experiment, the mino cid contents of se cucumbers differed between those fed with sweet potto tuber nd stem powders nd those in the CK group. The glutmic cid nd lysine contents were higher in se cucumbers fed with sweet potto tuber powder thn in those in the CK group, while the methionine contents were slightly lower (0.07% in CK, compred with 0.04% in the T group nd 0.03% in the S group). These results represent the mino cid composition of the se cucumber body wll under these conditions, lthough the composition cn vry depending on the testing methods, environmentl fctors (seson, temperture, slinity), nd the growth stge of se cucumbers. Glutmic cid is importnt for brin cell function, nd for stimulting erythropoiesis. Compred with CK, both the T nd S groups showed higher glutmic cid contents, providing further evidence tht sweet potto s feed ingredient effectively improved the qulity of se cucumbers. 4.2 Effects of different proportions of sweet potto mterils on digestive enzyme ctivities The digestive trct is the most importnt orgn for the digestion of food nd the ssimiltion of nutrients. It is chrcterized by its high plsticity nd strong bility to dpt to chnges in feed composition, ingestion rte, nd metbolic sttus (Hirche, 1989; West-Eberhrd, 1989). The structure nd function of the digestive trcts of nimls in the Holothuroide cn djust to chnges in food sources nd sesons (Fnkboner nd Cmeron, 1985). In this study, there were significnt differences in RVBW between S groups nd CK, indicting tht se cucumbers cn *b Tuber CK T1 S1 T2 S2 T3 S3 T4 S4 T5 S5 Dietry tretment *b Stem Fig.3 Effects of sweet potto tuber nd stem powders in feed on lipse ctivity of se cucumbers Different letters indicte significnt differences within the sme dietry group; * indictes significnt difference between dietry groups ( P <0.05). b b

7 No.5 ZHAO et l.: Effects of sweet potto on digestive enzymes of A. jponics 1841 probbly improve their bility to bsorb protein nd other nutrients from food by djusting the length of the digestive trct. Echinoderms, including se cucumbers, do not hve specilized digestive glnds, but their intestinl trcts perform the sme function. Their intestinl trcts hve bundnt blood sinuses under the midgut epithelium to bsorb nutrients effectively (Frnchini nd Ottvini, 1992), nd promote the digestion nd ssimiltion of nutrients in feeds by secreting vrious digestive enzymes including protese, mylse, nd lipse (Cui et l., 2000). To dte, more thn ten kinds of digestive enzymes hve been detected in the digestive trcts of se cucumbers, including protese, lipse, esterse, glycosidse (mylse, cellulse, lginte lyse, discchridse, invertse, nd chitinse) nd phosphtse (cid phosphtse nd lkline phosphtse) (Choe, 1963). Three importnt digestive enzymes (protese, mylse, nd lipse) were selected nd nlyzed in this experiment. Se cucumbers cn dpt to different food sources by djusting the physiologicl function of the digestive trct nd the ctivities of digestive enzymes. In ddition, the ctivities of vrious digestive enzymes in intestinl trcts were shown to differ mong vrious feeding stges (Fnkboner nd Cmeron, 1985). In this experiment, the ctivities of digestive enzymes differed mong groups fed with different proportions of sweet potto tuber nd stem powders. The protese nd lipse ctivities first incresed nd then decresed, with the highest protese ctivity in T2 (20%) nd the highest lipse ctivity in S1 (10%). This result indicted tht the ddition of tuber nd stem sweet potto into feeds in certin proportions cn ctivte certin digestive enzymes, thereby improving the digestive bility of se cucumbers nd promoting their growth. The chnges in mylse ctivity were not consistent with the proportions of tuber nd stem powders dded to feed. Amylse ctivity incresed s the proportion of sweet potto mterils in feed incresed up to 40%, but then decresed. According to Dybs nd Fnkboner (1986), the increse in mylse ctivity in groups fed with sweet potto ws relted to microbes in the intestine, rther thn the niml itself. Further reserch is required to explore these responses in more detil. 5 CONCLUSION The results of this study show tht sweet potto mterils s feed ingredients cn stimulte digestive enzyme ctivities in A. jponics. Therefore, the ddition of different proportions of tubers nd stems of sweet potto to compound feeds cn improve the digestive bility nd growth of cultured A. jponics. 6 DATA AVAILABILITY STATEMENT The uthors declre tht ll dt supporting the findings of this study re vilble within the rticle nd its supplementry informtion files. References Bovell-Benjmin A C Sweet potto: review of its pst, present, nd future role in humn nutrition. Advnces in Food nd Nutrition Reserch, 52 : Choe S Study of Se Cucumber: Morphology, Ecology nd Propgtion of Se Cucumber. Kibundou Publishing House, Tokyo. 219p. Cui L B, Dong Z N, Lu Y H Histologicl nd histochemicl studies on the digestive system of Apostichopus jponic u s. Chinese Journl of Zoology, 3 5 (6): 2-4. (in Chinese with English bstrct) Du L Q, Zho Y G, Li R F Anlysis nd evlution on the nutritionl components in stem pex of sweet potto. Chinese Agriculturl Science Bulletin, 22 (6): (in Chinese with English bstrct) Dybs L, Fnkboner P V Holothurin survivl strtegies: Mechnisms for the mintennce of bcteriosttic environment in the coelomic cvity of the se cucumber, Prstichopus clifornicus. Development l & Comprtive Immunology, 10 (3): Fnkboner P V, Cmeron J L Sesonl trophy of the viscerl orgns in se cucumber. Cndin Journl of Zoology, 63 (12): Frnchini A, Ottvini E Intestinl cell types in the freshwter snil plnorbrius corneus: histochemicl, immunocytochemicl nd ultrstructurl observtions. Tissue nd Cell, 24 (3): Hrvey P J, Boulter D Isoltion nd chrcteriztion of the storge protein of ym tubers ( Dioscore rotundt ). Phytochemistry, 22 (8): Hirche H J Sptil distribution of digestive enzyme ctivities of Clnus fi nmrchicus nd C. hyperboreus in Frm strit/greenlnd se. Plnkton Reserch, 11 (3): Innmi S, Tbt K, Shimizu J, Kusunoki K, Ishid H, Mtsugum M, Wd M, Sugiym N, Kondo M Dried green lef powders of Jew s mellow ( Corchorus ), persimmon ( Diosphyros kki ) nd sweet potto ( Ipomoe btts poir ) lower heptic cholesterol concentrtion nd increse fecl bile cid excretion in rts fed cholesterolfree diet. Plnt Foods for Humn Nutrition, 52 (1): Ishid H, Suzuno H, Sugiym N, Innmi S, Tdokoro T, Mekw A Nutritive evlution on chemicl components of leves, stlks nd stems of sweet pottoes ( Ipomoe btts poir ). Food Chemistry, 68 (3):

8 1842 J. OCEANOL. LIMNOL., 36(5), 2018 Vol. 36 Jing S H, Ling J, Sun X Study on biochemicl compositions of ophiopholis mirbilis nd its influence on growth nd survivl of Apostichopus jponic u s s feed ingredients. Feed Industry, 33 (16): (in Chinese with English bstrct) Koizumi H, Ysui A Determintion of vitmins polyphenols nd minerls in roots of sweet pottoes. Report of Ntionl Food Reserch Institute, 55 : 1-8. Le V A Frnkow-Lindberg B E, Lindberg J E Effect of hrvesting intervl nd defolition on yield nd chemicl composition of leves, stems nd tubers of sweet potto ( Ipomoe btts L. (Lm.)) plnt prts. Field Crops Reserch, 82 (1): Li C L, Song A H, Hu W, Zhng Y P, Zho B, Li Q C, M D P Sttus nlysis nd sustinble development strtegy of se cucumber Apo s tichopus jponic u s Selenk quculture industry in Shndong province. Progress in Fishery Science, 31 (4): (in Chinese with English bstrct) Li X, Zhng S Y, Chen S Q, Zou A G, Go F, Sun H L, Yn J P, Liu C L Effects of four feedstuffs on the growth, body composition nd digestive physiology of Apostichopus jponicus. Feed Industry, 34 (8): (in Chinese with English bstrct) Lio M J, Ho Z K, Shng D R, Jing Y, Chen G P, Wng Y G Nutrition components nlysis of Enteromorph prolifer nd its preliminry study on feeding Apostichopus jponics. Fishery Moderniztion, 38 (4): (in Chinese with English bstrct) Liu X F, Xue C H, Wng Y M, Li H Y Comprtive nlysis of nutritive composition in body wll nd internl orgns of se cucumber ( Apostichopus jponicus ) t Rushn. Journl of Fisheries of Chin, 35 (4): (in Chinese with English bstrct) Liu X J, Zhou Y, Yng H S, Ru S G Evlution of eelgrss debris s food source for Apostichopus jponics. Mrine Science, 37 (10): (in Chinese with English bstrct) Meshim M, Sski T, Ashi T, Chrcteriztion of mjor proteins in sweet potto tuberous roots. Phytochemistry, 24 (9): O Sullivn J N, Blmey F P C, Asher C J Dignostic criteri for nutrition disorders of sweet potto. Ⅱ: criticl nutrient concentrtions in leves. I n : Minerl Nutrient Disorders of Root Crops in the Pcific: Proceedings of Workshop. Nuku lof, Kingdom of Tong. p Shhidul I M, Yoshimoto M, Ymkw O Distribution nd physiologicl functions of cffeoylquinic cid derivtives in leves of sweetpotto genotypes. Journl of Food Science, 68 (1): Wng H Y, Yeh K W Cultivr differences in trypsin inhibitory ctivities of sweet potto leves nd tuberous roots. Tiwni, 41 (1): Wng W L, Du F L, Xu T C Reserch of nutrition vlue in sweet potto s stems nd leves nd its developments. Food nd Nutrition in Chin, (7): (in Chinese with English bstrct) Wng W X, Bi Y, Hou W J, Wng H Appliction of Eichhorni crssipes sioms in Apostichopus jponicus feed. Cerel & Feed Industry, (8): (in Chinese with English bstrct) Wng X C, Hu X Z, Wng J Z Study on polyscchride extrcting technology from stem of sweet potto ( Ipomoe btts (L.) Lm.). Journl of Agriculturl University of Hebei, 28 (2): 51-53, 60. (in Chinese with English bstrct) West-Eberhrd M J Phenotypic plsticity nd the origins of diversity. Annul Review of Ecology nd Systemtics, 20 : Zho B, Hu W, Li C L, Hn S, Yn F The nutritionl effects of two feedstuffs from sweet potto on feeding nd growth of se cucumber Apos t ichopus jponic u s. Progress in Fishery Sciences, 37 (1):