豆粕对松浦镜鲤肠黏膜能量代谢、肠道健康相关基因表达的影响及α-酮戊二酸缓解作用

为探究豆粕对松浦镜鲤肠道健康及能量水平的影响及AKG缓解肠道损伤的作用机制。选取初始体重为(9.51±0.06)g松浦镜鲤幼鱼609尾，随机分为7组，每组3个重复，每缸29尾鱼。对照组(FM)饲喂30.8%鱼粉为蛋白源饲料，实验组以40%豆粕为基础饲料(SM),AKG组、Met组和Com组分别在SM基础上添加1%AKG、300 mg/kg Metformin和0.2 mg/kg Compound-c,Met+AKG组和Com+AKG组为在AKG组上分别添加Metformin和Compound-c。实验共59 d。结果显示，与FM组比，SM组后肠黏膜ATP和ADP含量显著升高；前肠ACC、TNF-α、IL-1β、TGFβ2、caspase9、Claudin7、Claudin11、Claudin3c、Occludin，中肠AMPK-α、TOR、ACC、IL-1β、TGFβ1、Caspase8、Claudin7、Occludin及后肠TGFβ1、Caspase8、Caspase9基因表达显著降低；后肠TNF-α、Claudin11、Claudin3c和Occludin显著升高。与SM组比，A...     

氧化鱼油诱导草鱼Ctenopharyngodon idellus肝胰脏谷胱甘肽/谷胱甘肽转移酶通路的应激反应

在水温25~33℃下,将平均体质量74.8±1g的草鱼Ctenopharyngodon idellus放养在池塘网箱中,投喂以豆油、鱼油、氧化鱼油为饲料脂肪源的5组等氮等能半纯化饲料(豆油组6S、鱼油组6F、2%氧化鱼油组2OF、4%氧化鱼油组4OF,及6%氧化鱼油组6OF),采用荧光定量PCR(q RT-PCR)方法,测定了草鱼肝胰脏中谷胱甘肽(GSH)/谷胱甘肽转移酶(GST)通路中GCLC、GSR、GSTPI、MGST1基因的表达活性及GSH的含量和超氧物歧化酶(SOD)的活性,研究了氧化鱼油对草鱼肝胰脏抗氧化防御能力的影响。72d的养殖结果显示:6F组GCLC的表达活性显著下调(P<0.05),其余各组间均无显著差异(P>0.05);各试验组GSR的表达活性均下调,6F和4OF组间显著下调(P<0.05);GSTPI的表达活性均显著下调(P<0.05),与饲料中(EPA+DHA)含量呈线性负相关关系;除6F组外,其余各组MGST1的表达活性均较6S组显著下调(P<0.05),且MGST1的表达活性与饲料丙二醛(MDA)含量呈二项式关系,与6S组相比,其余各组肝胰脏中GSH含量及SOD活性均显著下调(P<0.05)。氧化鱼油引起草鱼GSH/GST合成通路基因表达相适应,肝胰脏GSH合成相关基因和MGST1的表达活性下调,而GSTPI的表达活性增强。GSH/GSTs通路基因表达活性和GSH含量随饲料中氧化鱼油的增加呈梯度变化。     

氧化鱼油对黄颡鱼幼鱼肠道健康的影响及精氨酸的干预作用

为研究饲料中添加氧化鱼油对黄颡鱼幼鱼肠道免疫、抗氧化和其他功能指标、组织结构的影响及添加精氨酸对其的干预作用,采用2×3设计方式,在饲料中分别添加新鲜鱼油(FF)∶氧化鱼油(OF)按照(m/m)2.5∶0、1.5∶1.0和0.5∶2.0的比例配制3种基础饲料(FF,OF1,OF2),在基础饲料中分别添加0.48%精氨酸(Arg)盐酸盐配制3种精氨酸饲料(FFA,OFA1,OFA2),选取初始体质量为(4.41±0.05)g的黄颡鱼600尾,随机分为6组,每组4个重复,分别投喂6种实验饲料,饲养56 d。结果显示,在OF2组中,黄颡鱼肠道酸性磷酸酶(ACP)、碱性磷酸酶(AKP)活性和白细胞介素-6(IL-6)含量显著升高;与OF2组相比,OFA2组AKP活性和IL-6含量均显著下降。在FF、OF1、OF2三组中,肠道超氧化物歧化酶(SOD)活性呈下降趋势,谷胱甘肽过氧化物酶(GSH-PX)和过氧化氢酶(CAT)活性呈现上升趋势,总抗氧化能力(T-AOC)呈现先下降后上升的趋势,但差异均不显著;在OF2组中,丙二醛(MDA)含量显著升高;添加精氨酸后,除SOD活性有显著升高外,其他抗氧化指标的组间均无显著性差异。双因素方差分析显示,精氨酸对黄颡鱼肠道CAT活性的影响达到显著水平,饲料中氧化鱼油和精氨酸对黄颡鱼肠道GSH-PX活性的影响存在交互作用。在FF、OF1、OF2三组中,肠道二胺氧化酶(DAO)活性呈现下降趋势,一氧化氮合酶(i NOS)活性呈现上升趋势,但差异均不显著;与OF2组相比,OFA2组的DAO和i NOS活性分别显著升高和下降;双因素方差分析显示,精氨酸(Arg)对黄颡鱼肠道DAO、i NOS活性的影响分别达到显著水平。在OF1组中,肠道皱壁高度、肌层厚度和杯状细胞数量均明显升高;与OF2组相比,OFA2组皱壁高度和杯状细胞数量明显升高;与FF组相比,FFA组肌层厚度明显增加。双因素方差分析显示,氧化鱼油对黄颡鱼肠道皱壁高度的影响达到显著水平。研究表明,在饲料中添加一定水平的氧化鱼油会抑制黄颡鱼幼鱼肠道免疫及抗氧化指标,损伤肠道组织结构,但添加一定量的精氨酸可以缓解氧化鱼油对黄颡鱼幼鱼肠道免疫、抗氧化和组织结构的抑制作用。     

抗菌素对草鱼肠道免疫和菌群的影响

为探究抗菌素对草鱼免疫和肠道菌群的影响，本实验以草鱼为研究对象，设置基础饲料(对照组)、基础饲料添加恩诺沙星或氟苯尼考3组饲料，投喂草鱼2周后，通过肠道酶活检测、荧光定量PCR (qRT-PCR)和高通量测序技术分析饲料中添加抗菌素对草鱼肠道免疫及肠道菌群多样性影响。分析结果显示，(1)饲料中添加恩诺沙星和氟苯尼考降低了草鱼肠道谷胱甘肽过氧化物酶(GPx)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)的含量，提高丙二醛(MDA)的含量，导致草鱼肠道氧化应激。(2)氟苯尼考组中的TNF-α、IL-1β、IL-12、NF-κB-P65、MHCⅡ、s IgM等免疫因子和ZO-1、ZO-2、occludin、CLDN-1、JAM3等黏膜相关蛋白的mRNA表达量显著下降，恩诺沙星组的免疫因子TNF-α、IL-1β、IL-12、TLR4、MHCⅡ和黏膜相关基因ZO-2、occludin、CLDN-1、JAM3的mRNA表达量显著下降。(3)通过16S rRNA高通量测序来揭示拌食投喂抗菌素对草鱼肠道微生物群落结构的影响，分析结果显示，饲料中添加恩诺沙星或氟苯尼考对草鱼肠道α多样性无显著差异，但对...     

棉籽蛋白源对大口黑鲈生长、体组成及健康的影响

为评价棉籽蛋白在大口黑鲈饲料中应用的可行性,用4种不同质量的棉籽蛋白替代30%鱼粉配制成5种等氮等脂的实验饲料(CPC_0为对照组,CPC_1, CPC_2, CPC_3,CPC_4),在室内循环养殖系统饲喂大口黑鲈[平均体质量(12.20±0.11) g] 8周。结果显示,4种棉籽蛋白的营养组成、棉酚、棉籽糖和水苏糖含量不同,以CPC_3棉籽蛋白质量最优。CPC_3组鱼的终末体质量、增重率和特定生长率显著高于其他组,而各实验组全鱼常规营养成分和肌肉氨基酸组成没有显著差异。CPC_3组肝脏SOD、GSH-Px活性以及CAT和SOD mRNA表达水平最高,MDA含量最低。CPC_3组肝脏抗炎因子IL-10、TGF-β的相对表达量最高,而促炎因子IL-1β、IL-8和TNF-α的相对表达量最低。此外,棉籽蛋白源会显著影响大口黑鲈肝脏蛋白质代谢,CPC_3组ALT、AST活性以及基因P13K、AKT、m-TOR、S6K1、4E-BP表达水平最高。同时发现,CPC_3组大口黑鲈肠道SOD酶活性最高、MDA含量最低,且肠道通透性指标(二胺氧化酶活性、D-乳酸和内毒素含量)也最低。棉籽蛋白源也影响了肠道紧密连接蛋白相关基因ZO-1、Claudin-1和Occludin的表达。研究表明,棉籽蛋白质量对大口黑鲈生长和健康会产生显著影响,其中棉籽蛋白CPC_3效果最佳,显著改善大口黑鲈的肝脏和肠道健康,进而促进其生长。因此,棉籽蛋白CPC_3可以作为大口黑鲈饲料的优质蛋白源。     

国产鸡肉粉替代鱼粉对大口黑鲈生长性能、肝脏健康及肠道屏障的影响

为评价鸡肉粉替代鱼粉的可行性，用不同水平国产鸡肉粉(PBM)等蛋白替代基础饲料中的鱼粉，配制成5种等氮等脂的实验饲料(对照组、PBM 12.5、PBM 25.0、PBM 37.5及PBM 50.0)，在室内循环系统饲喂初始体重为(9.25±0.13) g的大口黑鲈8周。结果显示，各处理组大口黑鲈的增重率(WGR)、特定生长率(SGR)和摄食率(FR)均无显著差异。同对照组相比，实验组肝脏超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著增加，而丙二醛(MDA)含量显著降低。随鸡肉粉替代水平的增加，肝脏抗炎细胞因子基因(IL-10、TGF-β)相对表达量显著上调，而促炎细胞因子基因(IL-8、TNF-α)相对表达量显著下调，但肝脏的组织结构无显著临床症状变化。此外，随替代水平的增加，肠道抗氧化基因(sod、cat)和肠道紧密连接蛋白基因(Occludin、ZO-1和Claudin-1)相对表达量也显著上调，而血清D-乳酸(D-lac)和脂多糖(LPS)含量显著降低。研究表明，鸡肉粉替代基础饲料(基础饲料中含有40%的鱼粉) 50%的鱼粉不会抑制大口黑鲈的生长，同时还会增强鱼体的抗氧化...     

不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响

以鱼粉和豆粕为蛋白源,鱼油和豆油等比例混合油为脂肪源,共配制4个蛋白水平(20%、25%、30%、35%),每一蛋白水平设4个脂肪水平(4.5%、8%、11.5%、15%),共16组饲料。每组设3个重复,在水温23~29℃下,连续投喂初始体重为(16.84±0.28)g的草鱼(Ctenopharyngodon idellus)10周,研究不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响。结果显示:肠道蛋白酶的活性随着饲料蛋白含量的升高而显著升高(P<0.05),饲料蛋白水平在20%~30%时,饲料中的脂肪水平对蛋白酶活性影响不显著(P>0.05),蛋白水平在35%时,高脂肪抑制了蛋白酶活性,肝胰脏的蛋白酶变化规律类似于肠道;肠道和肝胰脏淀粉酶活性在饲料蛋白含量相同的情况下,随着脂肪含量的升高呈现显著的下降趋势(P<0.05),但饲料中蛋白(30%,35%)和脂肪(8%,11.5%,15%)含量较高时,淀粉酶活性较稳定;肠道和肝胰脏的脂肪酶活性在饲料蛋白含量相同的情况下,随着脂肪含量的升高,呈显著上升的趋势(P<0.05),但在蛋白含量(30%,35%)和脂肪含量(8%、11.5%,15%)的6个试验组之间差异不显著(P>0.05);在脂肪含量分别为4.5%、8%和11.5%时,饲料的蛋白含量对肠道的脂肪酶活性无显著性影响(P>0.05),当脂肪含量为15%时,随着蛋白含量的升高,肠道的脂肪酶活性显著降低(P<0.05)。结果表明,草鱼饲料中蛋白含量为30%和脂肪为8%(即蛋白能量比21.7 mg/kJ)的试验组草鱼获得较高的消化酶活性。     

壳寡糖对虎龙斑的生长、免疫及肠道菌群的影响

壳寡糖（Oligochitosan,OCS）,作为绿色饲料添加剂,具有许多重要的生物活性功能,如促进生长、抗氧化等,但对石斑鱼免疫调控机制的研究还未解读。本试验通过在基础试验饲料中添加0（对照组）、100、200、400、800、1600 mg/kg的壳寡糖,配制出5种试验饲料并投喂虎龙斑（Epinephelus fuscoguttatus ♀× Epinephelus lanceolatu ♂）4周后,分析饲料中添加壳寡糖对虎龙斑的生长、非特异性免疫、肠道菌群多样性以及抗病力的影响。结果显示：（1）壳寡糖能显著提高石斑鱼的增重率、降低饲料系数,但对肥满度和存活率无显著影响。（2）采用实时荧光定量PCR（qRT-PCR）技术对虎龙斑中肠的免疫基因表达进行检测,结果显示壳寡糖可显著提高免疫相关基因表达水平（p < 0.05）,激活炎症因子TNF-α、IL-1β、TGF-β1、TOR、TLR3的表达,提高GPx、CAT、MnSOD的表达来改善抗氧化能力,并增加紧密连接蛋白ZO-1、ZO-2、ZO-3、Claudin-3α的表达。（3）通过微生物组高通量测序来揭示壳寡糖投喂石斑鱼的肠道微生物群落结构,结果表明,实验组和对照组肠道细菌优势类群丰度和α多样性无显著差异（p > 0.05）;但是800 mg/kg组的益生菌所占丰度增加,细菌群落β多样性差异明显,可改变其群落组成结构。（4）以哈维氏弧菌（Vibrio harveyi）攻毒7 d后,800 mg/kg组的累积死亡率显著低于对照组和其他实验组（p < 0.05）,并显著改善肠道形态。综上所述：饲料中添加适量的壳寡糖能促进虎龙斑的生长、提高免疫力、改善肠道菌群及增强抗病力。     

饲料中添加大豆皂甙对大菱鲆幼鱼生长和肠道健康的影响

为研究大豆皂甙对大菱鲆幼鱼生长性能、消化酶活性、肠道组织结构完整性和肠道菌群结构的影响，在以鱼粉为蛋白源的基础饲料中分别添加0%和0.3%的大豆皂甙，配制成鱼粉组和大豆皂甙组2种等氮等脂的实验饲料来投喂体质量为(4.63±0.01) g的大菱鲆进行12周的摄食生长实验。结果显示，饲料中添加0.3%的大豆皂甙对大菱鲆的生长性能没有产生显著影响，但显著降低了胃蛋白酶及肠淀粉酶活性；2组实验中大菱鲆肠道组织形态无明显差异，但大豆皂甙组肠道紧密连接蛋白的基因表达量显著降低。肠道菌群分析结果显示，大菱鲆肠道中相对丰度最高的门和属分别为变形菌门和盐单胞菌属。LEfSe和MetaStat分析显示，饲料中添加大豆皂甙后显著提高了大菱鲆肠道内优势菌(变形菌门及希瓦氏菌属)，皂甙水解相关的肠道微生物(鞘脂单胞菌属、普氏菌属、栖瘤胃普雷沃菌以及普通拟杆菌)及潜在致病菌(莫氏杆菌属和发光杆菌属)的相对丰度，同时显著降低了Caenimonas、Niastella和条件致病菌罗尔斯通菌属的相对丰度。研究表明，0.3%大豆皂甙抑制了大菱鲆消化酶活性及肠道紧密连接蛋白的基因表达，且引起了大菱鲆肠道菌群结构的显著改变。因此，大豆皂甙对鱼类肠道健康尤其是肠道菌群的影响不容忽视，值得进一步研究。     

饲料中添加丁酸钠对草鱼生长、消化酶活性、血清生化指标和肠道组织学的影响

为了探究饲料中补充不同水平丁酸钠对草鱼生长性能、肠道消化酶活性、血清生化指标和肠道组织形态的影响，分别添加0 mg/kg (SB0)、1 000 mg/kg (SB1)、2 000 mg/kg(SB2)和3 000 mg/kg (SB3)的微囊丁酸钠(含50%丁酸钠)至基础饲料中，设计4组等氮等脂的实验饲料。选取300尾体质健康的草鱼(10.0±0.1) g，分成4组，每组3个重复，每个重复25尾鱼，放置在水泥池中养殖8周。结果显示，各组草鱼增重率为273.7%～279.9%，饲料系数为1.55～1.60，饲料中补充丁酸钠对草鱼生长性能和体成分无显著影响。与对照组相比，添加不同水平的丁酸钠均显著提高了肠道蛋白酶活性和血清超氧化物歧化酶(SOD)活性，降低了血清谷草转氨酶(AST)活性，SB1组血清碱性磷酸酶(AKP)活性显著升高，而SB2和SB3组血清谷丙转氨酶(ALT)活性显著降低。各组肠道淀粉酶活性、血清酸性磷酸酶(ACP)、甘油三酯(TG)、葡萄糖(GLU)、总蛋白(TP)和D-乳酸(D-LA)无显著差异。在肠道组织学方面，各丁酸钠补充组肠道绒毛高度和SB1、SB2组肌层厚度显著...     

Effects of ferulic acid on growth performance,immunity and antioxidant status in genetically improved farmed tilapia (Oreochromis niloticus) fed oxidized fish oil

A study was conducted to characterize the effects of dietary oxidized fish oil on the growth performance, immunity and antioxidant status of genetically improved farmed tilapia (Oreochromis niloticus) and to determine the role of ferulic acid on the oxidative damage induced by the oxidized fish oil. The tilapia (13.73 ± 0.31 g) were fed four experimental diets containing untreated (peroxide value, POV: 2.2 meq/kg) and highly oxidized (POV: 120.6 meq/kg) fish oil either with or without ferulic acid (0 or 400 mg/kg) supplementation for 12 weeks. From the results, the oxidized fish oil treatments increased antioxidant enzyme activities and MDA values but decreased the weight gain and the immunological parameters in tilapia. Meanwhile, the serum biochemical indices were significantly affected by the oxidized fish oil. Besides, the addition of ferulic acid partially counteracted the free radical‐induced damage and improved the health status of tilapia. In conclusion, the oxidized fish oil may induce oxidative stress, destroy liver, dysregulate lipid metabolism as well as reduce non‐specific immunity, and eventually result in growth inhibition of tilapia. The ferulic acid supplementation partially offset the negative effects of the oxidized fish oil on tilapia.     

A study of the damage of the intestinal mucosa barrier structure and function of <Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis> with <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis>

The aim of this study is to explore the effect of Aeromonas hydrophila on the intestinal mucosal barrier structure and intestinal permeability in grass carp (Ctenopharyngodon idella). Histopathological examinations showed that A. hydrophila induced severe intestinal lesions, including inflammatory cell infiltration and intestinal villus fusion and swelling. Messenger RNA (mRNA) expression of the inflammatory cytokines TNF-α, IL-1β, IL-8, IL-10 and MyD88 was significantly increased after infection with A. hydrophila. The permeability of intestinal mucosa was determined using Evans blue (EB) and d-lactic acid. The results indicated that the levels of EB and serum d-lactic acid were significantly increased after infection with A. hydrophila (p < 0.05). Our results also indicated that the intestinal mucosal barrier injury induced by A. hydrophila infection was closely associated with the expression of the tight junction (TJ) protein zonula occludens-1 (ZO-1), occludin, claudin b and claudin c as well as the activity of Na⁺, K⁺-ATPase and Ca²⁺, Mg²⁺-ATPase. Lower mRNA levels of occludin and lower Na⁺, K⁺-ATPase and Ca²⁺, Mg²⁺-ATPase activity in the intestines were observed after challenge. ZO-1 and claudin c were significantly increased 24 h after infection with A. hydrophila. The most interesting finding was that claudin b also significantly increased 24 h after challenge and then decreased to lower levels at 72, 120 and 168 h post-infection compared to the PBS-treated control group. The results demonstrated that grass carp infection with A. hydrophila induced intestinal inflammation and impaired the structure and function of the intestinal mucosal barrier.     

Effect of dietary oxidized fish oil on growth performance,body composition,antioxidant defence mechanism and liver histology of juvenile largemouth bass Micropterus salmoides

Four isonitrogenous and isolipidic diets containing fresh fish oil (peroxide value, POV: 11.5 meq kg^?1, diet FR) and three degrees of oxidized fish oil (POV: 132, 277 and 555 meq kg^?1, diet OX₁₃₂, OX₂₇₇ and OX₅₅₅, respectively) were formulated to investigate the effects of dietary oxidized fish oil on growth performance, body composition, antioxidant defence mechanism and liver histology of juvenile largemouth bass. After a 12‐week feeding trail, a proportion of approximately 9% of Micropterus salmoides showed inflammation and haemorrhage at the base of dorsal, pectoral and tail fin in both groups OX₂₇₇ and OX₅₅₅. Fish fed oxidized oil diets obtained significantly higher (P < 0.05) weight gain and specific growth rate because of their remarkable higher feed intakes, compared with the fresh oil receiving group. The analysis of biometric parameters and body composition indicated significant differences (P < 0.05) in various test diets. The activities of hepatic catalase and superoxide dismutase were significantly stimulated (P < 0.05) by oxidized oil ingestion. Hepatic glutathione peroxidase, glutathione reductase and glutathione‐S‐transferase activities were significantly higher (P < 0.05), and liver glutathione content was markedly lower (P < 0.05) in group OX₅₅₅ than the other treatments. Oxidized oil consumption resulted in marked depletion (P < 0.05) of vitamin E concentration in plasma, liver and muscle tissue, increased plasma and muscle malondialdehyde content along with decreased haematocrit value. Histological examinations indicated that hepatocytes with lipid vacuoles and nuclear migration were shown in groups OX₂₇₇ and OX₅₅₅. The overall results in this study suggested that an increased oxidative stress in M. salmoides fed oxidized lipid may account for their stimulated hepatic antioxidant defences, vitamin E depletion in plasma and certain tissues, and pathological changes. The detrimental effect of oxidation products on fish health and the unexpectedly enhanced feed intake of oxidized feeds in M. salmoides underline the importance that cares should be taken to minimize dietary oxidation products to the greatest extent possible.     

暗纹东方鲀心型脂肪酸结合蛋白H-FABP基因克隆与表达分析

为深入了解心型脂肪酸结合蛋白(heart-type fatty acid-binding protein,H-FABP)的结构与功能,采用RACE技术克隆得到暗纹东方鲀H-FABP的全长cDNA序列,共772 bp,开放阅读框为402 bp,编码133个氨基酸。生物信息学分析表明,暗纹东方鲀H-FABP基因具有一个脂质转运蛋白家族保守结构域和多个蛋白激酶磷酸化位点。NJ法系统进化分析显示,暗纹东方鲀与红鳍东方鲀亲缘关系最近,其次是鲈形目。经荧光定量PCR检测,H-FABP基因在暗纹东方鲀所有被检测的组织中都有表达,其中肝脏中的表达量最高,其次为肌肉和心脏,预示H-FABP主要参与脂肪酸氧化分解过程。为探究豆油作为脂肪源的可行性,采用不同比例(0、25%、50%和75%)豆油替代鱼油的饲料投喂初始体质量为(8.31±0.20)g的暗纹东方鲀8周。结果显示,全鱼油组肝脏中H-FABP基因的表达量显著高于50%豆油组和75%豆油组,但与25%豆油组无显著性差异,且随着饲料中豆油比例的增加,暗纹东方鲀肝脏中H-FABP基因的表达量呈下降趋势。研究表明,富含n-3多不饱和脂肪酸的鱼油可以促进脂肪酸氧化分解,能预防脂肪肝。因此,为不影响暗纹东方鲀肝脏脂肪代谢,饲料中豆油替代鱼油的比例应控制在50%以下。     

Molecular cloning,characterization and nutritional regulation of key enzymes required for the effective utilization of marine wax esters by Atlantic salmon (Salmo salar L.)

Previous studies had shown that wax ester‐rich lipid extracted from calanoid copepods could be a useful alternative to fish oil as a provider of long‐chain n‐3 polyunsaturated fatty acids in diets for use in salmon aquaculture. Effective utilization of wax ester requires digestion and metabolism in the intestine with the fatty alcohol component being oxidized to fatty acid in intestinal cells through the combined activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). We studied wax ester utilization in Atlantic salmon using a candidate gene approach, focusing on ADH and ALDH as sequence information was available for these genes, including fish sequences, facilitating isolation of the cDNAs. Here, we report on the isolation and cloning of full‐length cDNAs for ADH3 and ALDH3a2 genes from salmon intestinal tissue. Functional characterization by heterologous expression in the yeast, Saccharomyces cerevisiae, showed the products of these cDNAs had long‐chain ADH and ALDH enzyme activities. Thus, ADH3 was capable of oxidizing long‐chain fatty alcohol, and ALDH3a2 was capable of oxidizing long‐chain fatty aldehyde to the corresponding fatty acid. The genes were highly expressed in intestinal tissue, particularly pyloric caeca, but their expression was not increased in salmon fed dietary copepod oil in comparison to fish fed fish oil.     

饲料脂肪源和碘酸钾对中华鳖稚鳖生长、存活率、肝肠组织形态和脂类代谢的影响

为了比较饲料中添加鱼油、茶籽油、亚麻籽油以及碘酸钾对中华鳖（）稚鳖生长和脂类代谢的影响，本研究配制了4种油脂含量为10%的饲料，分别为鱼油料（FO，对照组）、鱼油+碘酸钾料（FO+PI，碘酸钾添加量为75 mg/kg）、茶籽油料（TO）和亚麻籽油料（LO），饲喂初重为（5.06±0.05）g的中华鳖66 d。FO+PI组和LO组中华鳖稚鳖的存活率显著低于FO组（<0.05）。各组中华鳖稚鳖血浆中葡萄糖、总胆固醇和甘油三酯水平无显著差异（ACACA）的表达水平，上调了中华鳖-499的表达水平（-23b的表达水平（<0.05）。FO+PI组和TO组的稚鳖肝脏细胞内脂滴空泡较少，同时TO显著影响了肠道组织的黏膜褶。结论认为，相比于鱼油组，在饲料中添加10%茶籽油、亚麻籽油和添加75 mg/kg碘酸钾不会引起稚鳖生长差异，但是亚麻籽油和碘酸钾降低了稚鳖的存活率，茶籽油和碘酸钾影响肝脏的脂类代谢。