CAJ | 학술논문

二十二碳六烯酸(C22：6n-3, DHA)对甲壳动物生长、蜕壳、性腺发育、免疫保护和抗环境胁迫具有重要的调节作用,探讨饲料中脂肪酸营养与中华绒螯蟹幼蟹生长和耐低氧胁迫的调控关系具有重要的理论意义和现实意义。通过单个体养殖试验、生化分析、低氧胁迫及生理指标测定等方法,研究了饲料中DHA含量对中华绒螯蟹幼蟹(初始均重为0.6g左右)成活、生长、脂类组成和低氧胁迫下生理指标的影响,探讨幼蟹饲料中适宜的 DHA含量。结果表明：(1)饲料中 DHA含量对中华绒螯蟹幼蟹的成活、生长、蜕壳和肝胰腺指数无显著影响；(2)饲料中DHA含量对幼蟹肝胰腺水分、肌肉水分及总脂含量均无显著影响,但饲料中过量DHA(0.81%)导致幼蟹肝胰腺总脂含量显著升高；(3)幼蟹肝胰腺和肌肉中的DHA均随着饲料中DHA含量升高而显著上升,但 DHA相对保留率(组织中 DHA与饲料中 DHA的比值)随着饲料中 DHA含量上升而显著下降,整体上肌肉中各 PUFA的相对保留率远高于肝胰腺。无论饲料中 DHA/EPA比值如何变化,肌肉中DHA/EPA均小于1,这说明幼蟹肌肉需要更多的 EPA；(4)饲料中添加适量的 DHA(0.18%-0.28%)可以提高低氧胁迫下幼蟹血淋巴中超氧化物歧化酶的活性,降低其乳酸和丙二醛含量,从而提高幼蟹的抗低氧胁迫能力。综上,中华绒螯蟹幼蟹饲料中适宜DHA含量为0.2%左右。
이십이탄륙희산(C22：6n-3, DHA)대갑각동물생장、세각、성선발육、면역보호화항배경협박구유중요적조절작용,탐토사료중지방산영양여중화융오해유해생장화내저양협박적조공관계구유중요적이론의의화현실의의。통과단개체양식시험、생화분석、저양협박급생리지표측정등방법,연구료사료중DHA함량대중화융오해유해(초시균중위0.6g좌우)성활、생장、지류조성화저양협박하생리지표적영향,탐토유해사료중괄의적 DHA함량。결과표명：(1)사료중 DHA함량대중화융오해유해적성활、생장、세각화간이선지수무현저영향；(2)사료중DHA함량대유해간이선수분、기육수분급총지함량균무현저영향,단사료중과량DHA(0.81%)도치유해간이선총지함량현저승고；(3)유해간이선화기육중적DHA균수착사료중DHA함량승고이현저상승,단 DHA상대보류솔(조직중 DHA여사료중 DHA적비치)수착사료중 DHA함량상승이현저하강,정체상기육중각 PUFA적상대보류솔원고우간이선。무론사료중 DHA/EPA비치여하변화,기육중DHA/EPA균소우1,저설명유해기육수요경다적 EPA；(4)사료중첨가괄량적 DHA(0.18%-0.28%)가이제고저양협박하유해혈림파중초양화물기화매적활성,강저기유산화병이철함량,종이제고유해적항저양협박능력。종상,중화융오해유해사료중괄의DHA함량위0.2%좌우。
Docosahexaenoic acid (C22:6n-3, DHA) is one of the important highly unsaturated fatty acids (HUFAs) for the regulation of growth, molting, gonadal development, immunity and environmental stress resistance of crustacean. We investigated the effects of dietary DHA levels on survival, growth, molting period, lipid composition and hypoxia stress of juvenile Eriocheir sinensis. Five experimental diets were formulated containing 0.06%, 0.18%, 0.28%, 0.55%and 0.81% of DHA. Each diet was randomly assigned to triplicate groups of juvenile crabs with initial body weight around 0.6g, and each group contained 20 individually cultured crabs. The results showed that, (1) Dietary DHA had no significant effect on survival, growth, molting period and hepatosomatic index for juvenile E. sinensis; (2) excessive diet DHA (Diet 5, DHA=0.81% dry weight) led to significantly higher lipid contents in the hepatopancrea. Despite hepatopancrea or muscle, the tissue DHA percentage was significantly increased with the increase of dietary DHA levels. However, the relative retention ratio (tissue particular fatty acid percentage/dietary respective fatty aid percentage) of tissue DHA deceased dramatically from Diet 1 to Diet 5 treatment;(3) despite of dietary DHA/EPA ratio, the DHA/EPA ratio of muscle remained less than one, which indicated crab muscle required less DHA than EPA; (4) among eight physiological indices of juvenile E. sinensis under hypoxia stress, malondialdehyde (MDA), lactic acid (LA) and superoxide dismutase (SOD) were good indicators for the evaluation of crab hypoxia stress resistance. The optimal dietary DHA content (Diet 2 and Diet 3) led to lower MDA and LA levels and higher SOD activity than the Diet 1 without DHA supplementation did. In conclusion, our results indicated the optimal dietary DHA level was around 0.2%of dry diet or 3%of total fatty acids.