饲料中植物油替代鱼油对中华绒螯蟹肝胰腺和性腺气味的影响

为探究中华绒螯蟹肝胰腺和性腺的气味受饲料中植物油替代鱼油的影响,采用植物油(豆油:菜籽油=3:1,W/W)替代不同水平鱼油(0、50%和100%)的3种等氮等脂饲料(F1、F2和F3)喂养成体雌蟹70 d后,用感官评价结合电子鼻分别分析肝胰腺和性腺的气味差异,并进一步采用气相色谱-质谱法-嗅闻法(GC-MS-O)技术具体分析其气味物质。结果显示,电子鼻可以分别有效区分3组中华绒螯蟹肝胰腺和性腺的气味轮廓,感官评价得F2组肝胰腺和性腺的肉香味强于其他两组,同时土腥味最低。肝胰腺和性腺分别鉴定出57、39种挥发性物质,25、17种嗅感物质,且F2组的这两个部位的挥发性物质种数相对于其他两组均较多,结合OAV评价表明醛类物质对这两个部位的气味贡献最大,其中壬醛和癸醛是这两个部位的主要气味物质,分别呈现奶香、生蟹黄味。使用F2组饲料在一定程度上增加愉悦气味的嗅感强度同时减弱不愉悦气味的嗅感强度。综上,饲料中使用50%植物油替代鱼油最合适,在降低养殖成本的同时对肝胰腺和性腺的气味有一定改善作用。本研究为优化育肥饲料中鱼油替代源配比以及进一步改善中华绒螯蟹风味品质等提供了一定的理论依据。

Effects of Dietary Replacement of Fish Oil by Vegetable Oil on Odor of Hepatopancreas and Gonads of Chinese Mitten Crab(Eriocheir sinensis)

In order to study the effects of dietary replacement of fish oil by vegetable oil on the odor quality of hepatopancreas of Chinese mitten crab,vegetable oil(soybean oil:rapeseed oil=3:1,W/W)was used to replace different levels of fish oil(0,50% and 100%)to make three kinds of feeds with equal nitrogen and fat(F1,F2 and F3)to feed adult female crabs for 70 days.In this study,the overall odor differences by using electronic nose were analyzed in combination with sensory evaluation,and odor substances were analyzed by gas chromatography-mass spectrometer-olfactometry. The results showed that electronic nose could effectively distinguish the odor profiles of the three groups of hepatopancreas and gonads of Chinese mitten crab. The meat flavor of the hepatopancreas and gonads in the F2 group was stronger than that of the other two groups,and the earthy smell was lowest by sensory evaluation. 57,39 volatile substances,25,17 olfactory substances were identified in the hepatopancreas and gonads,respectively,and the kinds of volatile substances in these two parts of the F2 group were more than that of the other two groups. Aldehydes contributed the most to the odor of these two parts,among which nonanal and decanal were the main odorants of these two parts,showing milky flavor and raw crab odor respectively. The use of the F2 group feed increased the olfactory intensity of the pleasant odor to a certain extent while reducing the olfactory intensity of the unpleasant odor. In summary,it was the most appropriate to use 50% vegetable oil in the feed instead of fish oil,which could improve the odor of the hepatopancreas and gonads while reducing the cost of breeding. The above results would provide a reference for the improvement of the odor quality of cultured Chinese mitten crabs and the development of fish oil substitute sources in fattening feed.