不同碳水化合物水平对大口黑鲈鳃组织结构、抗氧化能力和免疫能力的影响

为了探究高碳水化物对大口黑鲈鳃组织结构的完整性、抗氧化能力和免疫能力的影响,设计3种不同碳水化物水平的等氮等脂饲料：7%(L组),12%(M组),17%(H组)。选取初始体重为4.0±0.2g的大口黑鲈360尾,饲喂8周。通过组织切片,抗氧化和免疫酶活的测定及mRNA的表达研究,结果表明：H组能够导致鳃小片基部细胞增生、融合,上皮细胞脱落；H组和M组的丙二醛(MDA)含量显著高于L组(P<0.05)；鳃组织的超氧化物歧化酶(SOD)、过氧化物酶(CAT)在H组和M组显著低于L组(P<0.05)；H组和M组抗氧化酶(CAT,GPX,SOD1,SOD2,SOD3a,SOD3b) mRNA水平也要显著低于L组(P<0.05)；H组和M组酸性磷酸酶(AKP),碱性磷酸酶(ACP)和溶菌酶(LZM)也要显著低于L组(P<0.05)；H组和M组免疫相关基因(IL-1β,IL-10,IL-15,TNF-α和TGF-1β)和抗菌肽(hepcidin-1和hepcidin-2)mRNA水平显著低于L组mRNA水平(P<0.05)；H组凋亡相关的基因(caspase-3,caspase-8,caspase-9)的mRNA水平显著高于L组和M组(P<0.05)；H组的ocluding和claudin-7 mRNA水平显著低于L组和M组(P<0.05)。研究表明：在本实验条件下,饲喂高碳水化物饲料会损伤大口黑鲈鳃组织结构,降低抗氧化能力和免疫能力。     

Effects of dietary carbohydrate to lipid ratio on growth,feed utilization,body composition and digestive enzyme activities of golden pompano (Trachinotus ovatus)

An 8‐week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio (CHO: L) on growth, feed utilization, body composition and digestive enzyme activities of golden pompano, Trachinotus ovatus. Five iso‐nitrogenous (450 g/kg protein) and iso‐energetic (19 MJ/kg gross energy) diets with varying CHO: L ratios of 0.68, 1.02, 1.62, 2.61 and 4.35, respectively, were fed to triplicate groups of 30 fish (average 13.8 ± 0.1 g). Results showed that dietary CHO: L ratios did not show any significant influence on survival of golden pompano (p > .05) but significantly affected its growth performance and feed utilization (p < .05). Fish fed diets with CHO: L ratios at 1.62 and 2.61 exhibited the highest final body weight, weight gain ratio, specific growth rate, feed efficiency ratio and protein efficiency ratio. Fish body lipid and liver glycogen contents were also significantly influenced by CHO: L ratio (p < .05). Hepatic amylase activity increased firstly and then decreased as the dietary CHO: L ratio increased, while lipases activity decreased with increasing dietary CHO:L level. The regression model analysis showed that the most suitable dietary CHO: L ratio (protein 450 g/kg) to reach the highest weight gain ratio is 2.38.     

饲料不同淀粉水平对团头鲂成鱼生长性能、消化酶活性及肌肉成分的影响

为探讨饲料淀粉水平对团头鲂成鱼生长、消化酶活性和肌肉成分的影响,选用初始均重为(161±2.7)g的团头鲂成鱼360尾,随机分成6组(每组3个重复),分别投喂含淀粉17.1%、21.8%、26.4%、32.0%、36.3%和41.9%的等氮等脂饲料9周。结果发现,团头鲂成鱼成活率和特定生长率不受饲料淀粉水平影响,但饲料添加适量淀粉能提高饲料和蛋白利用率,淀粉水平对肝脏和肠道中的总蛋白酶和纤维素酶活性不产生影响,却显著影响淀粉酶活性。肝体比、肝糖原和肌肉粗脂肪含量随饲料淀粉含量的增加而显著增加,血清血糖、胆固醇和甘油三酯含量不受饲料淀粉水平的显著影响,饲料中添加过量淀粉显著降低了血清补体3和补体4含量。以蛋白质效率和饲料效率为评价指标,经折线模型回归分析,得到团头鲂成鱼饲料中淀粉的适宜添加量分别为饲料干重的34.1%和31.4%,但考虑到血清补体的活性,团头鲂成鱼日粮淀粉水平不应超过36.3%。     

不同碳水化合物和蛋白质水平膨化饲料对大规格草鱼生长、肠道消化酶及血清指标的影响

为探究不同碳水化合物和蛋白质水平膨化饲料对大规格草鱼生长、体成分、肠道消化酶和血清指标的影响,以初始体质量(398.6±5.9)g的大规格草鱼为研究对象,设置不同碳水化合物/蛋白质水平分别为C31P30、C34P28、C37P26、C40P24、C43P22、C46P20、C49P18的7组膨化饲料,养殖周期为16周。实验结果显示,各饲料组草鱼成活率(SR)差异不显著,随着蛋白质水平的下降、碳水化合物水平的升高,增重率(WGR)呈下降趋势,蛋白质效率(PER)呈升高趋势;肝体比(HSI)、脏体比(VSI)、肠体比(ISI)、肌肉和肝脏粗脂肪(CF)含量均有随饲料碳水化合物水平升高而升高的趋势。随着饲料中碳水化合物水平升高、蛋白质水平下降,各组间草鱼肌肉粗蛋白质(CP)含量无显著差异;肝糖原、肌糖原含量呈升高趋势,饲料中碳水化合物水平分别高于46%和40%时,肝糖原、肌糖原含量显著升高。肠道胰蛋白酶(PRS)和淀粉酶(AMS)活性随饲料中碳水化合物水平的升高呈先下降后升高趋势,脂肪酶(LPS)活性呈升高趋势;血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白(LDL)、高密度脂蛋白(HDL)含量及谷草转氨酶与丙转氨酶(GOT/GPT)比值都随饲料中碳水化合物水平升高和蛋白质水平下降而呈升高的趋势。本实验结果显示:当饲料碳水化合物水平高于37%、蛋白质水平低于26%时,将显著影响草鱼的生长,饲料中高碳水化合物水平将导致鱼体肝体比、脏体比、肠体比以及肌肉和肝脏脂肪含量升高。     

饥饿对星斑川鲽消化器官形态结构和组织学的影响

在温度(19±1)℃、盐度32±1的条件下,对相同规格体质量为(26.02±0.30)g的星斑川鲽(Platichthys stellatus)分别饥饿5、10、15 d(设为S5、S10、S15组),恢复投喂20 d。采用石蜡切片方法观察星斑川鲽消化器官形态结构,分析饥饿和再投喂对其组织学的影响。形态结构方面,S5组变化相对较小,而S10、S15组变化明显,表现在胃体积缩小,壁变薄;肠管壁变薄变透明,肠系膜因脂肪基本消失而萎缩;肝体积明显缩小,颜色由原来的粉红色变为深黄色。组织结构方面,S5组变化相对较小,而S10、S15组均有不同程度的损伤,表现在胃上皮细胞高度减小,细胞界限变得不清晰,胃腺细胞收缩,分泌颗粒减少;肠皱壁高度下降,上皮细胞高度显著降低,纹状缘高度减小甚至消失,杯状细胞有不同程度的增加;肝组织致密,肝细胞体积缩小,脂质空泡数量减少,细胞界限不明显,排列不规则,细胞内分泌颗粒减少。恢复投喂后,各实验组消化器官形态和组织结构均有不同程度的恢复,恢复投喂结束时,仅S5组恢复到对照组水平,S10、S15组均未达到对照组水平。结果表明,星斑川鲽饥饿耐受时间为5～10 d,超过此范围会对星斑川鲽消化系统组织结构造成不可修复的损害。     

饲料成分与环境温度对奥尼罗非鱼消化酶活性的影响

取相同生长阶段、体重均匀的雄性奥尼罗非鱼(Oreochromis nilotieus×O.aureus)为研究对象,分别设置不同P／E饲料组与不同水温组进行暂养,共3周。在最后一次投喂后2 h进行取样测定。结果表明,饵料蛋白质水平在20％-40％时,肝胰脏和肠道蛋白酶活性变化差异不显著。胃蛋白酶活性随着饵料蛋白水平上升而减低了22.2％和26.0％(P<0.05)。碳水化合物水平由34％上升到42％和50％,肝胰脏淀粉酶活性分别上升了107.1％和106.6％(P<0.01),肠道淀粉酶活性分别提高了67.1％和39.8％(P<0.01)。脂肪水平由1.5％升高7％,肠道脂肪酶活性没有变化,脂肪水平升高到12.5％,肠道脂肪酶活性降低了25.4％(P<0.01)。在水温17-32℃时,罗非鱼消化酶活性均随环境温度的升高而提高。     

温度对波纹龙虾消化酶活力的影响

研究了波纹龙虾温度对不同消化器官中消化酶活力的影响,为人工饲料科学配制依据。用酶学分析方法,设计6个温度梯度(20℃、25℃、30℃、35℃、40℃和45℃),分别测定波纹龙虾胃、肠和肝胰脏的类胃蛋白酶、胰蛋白酶、淀粉酶和脂肪酶的活力。结果显示:在反应温度20℃~45℃范围内,波纹龙虾胃、肠、肝胰脏内的消化酶均随着温度的升高表现为先升后降趋势;不同消化器官中胃蛋白酶活力值出现拐点的温度不一样,胃、肠和肝胰脏的胃蛋白酶活力最大的温度分别是30℃、35℃和40℃;不同消化器官胃蛋白酶的活力有显著差异(P0.05),大小依次为胃肠肝胰脏;波纹龙虾不同消化器官的类胰蛋白酶出现最大酶活力的温度相同,为40℃,但胃的类胰蛋白酶活力明显较肠和肝胰脏的低(P0.05),差值最大可达40 U/mg;波纹龙虾胃、肠和肝胰脏的淀粉酶活力在25℃均出现最大值;在消化器官中,肠道淀粉酶活力最大,与胃和肝胰脏的酶活力有显著性差异(P0.05);波纹龙虾胃、肠和肝胰脏内的脂肪酶活力最大的温度为30℃,活力最高的是肝胰脏,胃内的脂肪酶活力明显的比肠和肝胰脏的要低(P0.05)。     

长鳍篮子鱼的外形特征与消化系统结构

观察并描述了长鳍篮子鱼的外形特征,详细测量了200 ind长鳍篮子鱼的外部形态参数,进行了相关关系分析;并解剖观察了其消化系统结构特征。外部形态参数全长(LT)与体长(LB)、头长(LH)与体长(LB)、体长(LB)与体高(HB)、体重(W)与体长(LB)的相关关系分别为:LT=1.243LB+0.084(R2=0.994);LH=0.218LB+0.370(R2=0.972);LB=2.251HB+1.509(R2=0.896);W=0.011LB3.283(R2=0.991);消化系统结构特征为:口咽腔较小,颌齿发达;食道较短;胃Y形,幽门部肌肉发达,具有2~4个幽门盲囊;肠道细长,肠道系数(CI)为2.64±0.47;肝脏分左右两叶,左肝叶是右肝叶的5倍以上。胆囊位于体腔的后部,肝胆之间通过细长的胆囊管相连,胆囊距肝脏较远。     

施氏鲟幼鱼的饥饿和补偿生长研究——对消化器官结构和酶活性的影响

在20～24 ℃饲养条件下,研究了饥饿和再投喂对施氏鲟(Acipenser schrenckii)幼鱼主要消化器官结构和酶活性变化的影响.幼鱼分别饥饿0 d(对照组)、7 d、14 d和21 d,然后恢复投喂30 d.结果表明,饥饿后,消化道管腔变窄,管腔壁变薄,胃和肠的皱褶减少,变浅,肝脏出现萎缩现象,饥饿组与对照组鱼的比肝重存在极显著差异(P<0.01).同时,饥饿组幼鱼的消化道上皮细胞高度下降,腺细胞缩小,肝细胞内脂滴减少.至饥饿后期,肠上皮细胞和肝细胞的线粒体出现肿胀和脊断裂现象,部分肝细胞核仁解体.恢复投喂30 d后,除饥饿21 d组外,饥饿7 d和14 d幼鱼的胃、肠和肝脏结构基本恢复至正常状态.饥饿对施氏鲟幼鱼的消化酶活性有明显影响,饥饿7 d时,所测的蛋白酶、脂肪酶和淀粉酶的活性均有明显下降,但随饥饿时间的延长,不同的消化酶出现不同程度的变化,原因有待于进一步研究.分析结果还表明,胃中淀粉酶和脂肪酶只是对食物中碳水化合物和脂肪起初步消化作用,它们对食物的消化作用不如胃蛋白酶重要,肝脏中则始终没检测到淀粉酶活性.     

Ontogenetic development of digestive tract and digestive enzymatic activities in Squaliobarbus curriculus larvae

Squaliobarbus curriculus is an economically important freshwater fish. The ontogenetic development of the digestive system of S. curriculus larvae was studied histologically and enzymatically from hatching to 30 days posthatching (DPH). Amylase, lipase, alkaline phosphatase and pepsin activities were detected from the hatching stage, indicating that these enzymes were genetically preprogrammed. Marked increases in intestinal amylase, trypsin and alkaline phosphatase activities between 10 and 20 DPH corresponded to feed acquisition and transformation. Larval development in S. curriculus could be divided into three phases: phase I (endotrophic period): 1–3 DPH; phase II (endo‐exotrophic period): 4–5 DPH; and phase III (exclusively exotrophic period): from 6 DPH onward. At hatching, the digestive tract of the larvae was an undifferentiated straight tube. On 3 DPH, the digestive tract differentiated into the mouth cavity, oesophagus and intestine. On 6 DPH, feeding was totally exotrophic and the yolk sac was completely exhausted. During the growth of S. curriculus larvae, the intestinal mucosa formed and the number of goblet cells and microvilli increased, demonstrating maturation of the digestive system. The study about the digestive development of S. curriculus larvae will contribute to better larval‐rearing strategies.     

低盐胁迫对银鲳幼鱼肠道消化酶活力的影响

通过逐级降低水体盐度的方法,将银鲳幼鱼分别在盐度25、20、15和10的条件下饲养至120 h,检测不同盐度下、不同时间点银鲳幼鱼肠道脂肪酶、淀粉酶、胰蛋白酶和胃蛋白酶的活力。结果表明,随着盐度的降低和处理时间的延长,脂肪酶的活力总体表现出先升后降的变化趋势(P0.05);淀粉酶的活力呈升高的变化趋势(P0.05);胰蛋白酶和胃蛋白酶活力的变化趋势不同,胰蛋白酶的活力呈现升高的趋势(P0.05),而胃蛋白酶活力呈下降的变化趋势(P0.05)。说明盐度降低会对银鲳幼鱼肠道的消化酶产生激活作用,从而促进肠道对营养物质的利用,达到补充机体所损失的能量的目的。但对于不同种酶,激活的顺序和程度却不尽相同,甚至当超出一定的耐受范围后,酶活力反而被抑制。在本研究中,随着盐度的下降和处理时间的延长,脂类物质首先被大量消耗,然后是淀粉类物质,而蛋白类物质在整个过程中的利用率较低。因此建议,在雨季来临之前,提高脂类和淀粉类物质的投喂量,将有助于提高幼体对低盐度的耐受性及其成活率。     

Ontogenic development of enzymatic activity and digestive system in Jullien's golden carp (Probarbus jullieni Sauvage, 1880)

Ontogenic development of the main enzymes and histological structure of digestive organs were studied in Jullien's golden carp (Probarbus jullieni) from hatching until 50 days after hatching (DAH). The larval fish were produced by artificial insemination and fed only Moina sp. till end of experiment. Body weight (mg) and total length (cm) of Jullien's golden carp increased exponentially and linearly. The results indicate the fish weight grew fast with increasing rate, while length increased at a constant rate over the studied period. Up‐regulation of acid protease was observed in newly hatched larvae and the specific activity gradually decreased with time. Trypsin specific activity was relatively stable within the first 35 DAH, while fluctuations in chymotrypsin were observed. Among these three proteolytic enzymes, acid proteases exihibited relatively high specific activity in newly hatched larvae, suggesting a role in yolk protein degradation. Alkaline proteases became more prominent with age and correlated with an abrupt decrease in acid proteases. Increased lipase‐specific activity appeared within 3 DAH and then gradually decreased with time, indicating the capacity to digest yolk lipid reserve. Amylase and cellulase‐specific activities changed in a similar manner, and the sensitivity to time was higher in amylase than in cellulase. The digestive organs and accessory organs developed around 3–5 DAH. However, intestinal histology was almost fully developed around 18 DAH. These findings should be useful for deciding the preferred timing for weaning, as well as on developing artificial diets referenced to the physiological changes of digestive enzymes.     

饲料糖水平对吉富罗非鱼幼鱼生长和肝代谢功能的影响

为研究饲料糖水平对吉富罗非鱼幼鱼生长性能和肝代谢功能的影响,实验配制等蛋白、等脂肪含量的8种不同糖水平(10％、15％、20％、25％、30％、35％、40％和45％)饲料,每个糖水平设3个重复,饲养周期49 d,结果显示:(1)饲料糖水平对吉富罗非鱼幼鱼的增重率、成活率、饲料系数和肝体比均有显著影响(P＜0.05).饲料糖水平为35％时,罗非鱼增重最快;饲料糖水平为40％时饲料系数最低.(2)随着饲料糖水平的升高,鱼体肌糖原、粗脂肪含量逐渐升高,鱼体肝糖原含量先增加后下降.(3)饲料糖水平对各组鱼血清谷草转氨酶、谷丙转氨酶、血清磷酸果糖激酶活性、总蛋白和总胆汁酸浓度均有显著影响(P＜0.05),且随着糖水平的升高,呈上升趋势;而鱼体肝酯酶和脂蛋白脂酶活性则是先上升后下降.(4)饲料糖水平35％时,肝脏组织出现少量细胞脂滴空泡状现象;饲料糖水平40％和45％时,肝脏组织切片有明显的细胞脂滴空泡状、核偏移和细胞质消失现象.肝脏脂滴空泡状面积率与组织脂肪含量具有显著的正相关,与肝脏组织的脂肪肝病变程度成正比.结果表明,吉富罗非鱼苗种饲料以29.10％～ 35.00％的糖水平较利于吉富罗非鱼幼鱼生长及后期的脂肪肝病预防.     

家蝇蛆粉替代鱼粉对凡纳滨对虾消化酶、转氨酶活性和肝胰腺组织结构的影响

试验采用28%鱼粉饲料为基础,以家蝇蛆粉分别替代20%、40%、60%、80%和100%的鱼粉配制5种试验饲料,投喂初始体质量为0.56 g的凡纳滨对虾（Litopenaeus vannamei）45 d,研究了蝇蛆粉对凡纳滨对虾消化酶、转氨酶活性和肝胰腺结构的影响。结果显示,替代组对虾肝胰腺、胃和肠道消化酶活性与对照组相比差异不显著（P＞0.05）。替代组对虾肝胰腺谷丙转氨酶（ALT）、谷草转氨酶（AST）活性均低于对照组,但差异不显著（P＞0.05）;随着替代水平的增加,血清ALT活性在100%替代组、AST活性在60%-100%替代组显著降低（P＜0.05）。与对照组相比,20%-60%替代组肝胰腺上皮细胞中空泡增多,并且出现未知物质;替代水平高于60%时肝胰腺结构损伤严重。结果表明,蝇蛆粉替代水平在60%以下时,对凡纳滨对虾消化酶和转氨酶活性没有显著影响,对肝胰腺结构损伤不明显。     

Effects of dietary lipid levels on the growth, digestive enzyme, feed utilization and fatty acid composition of Japanese sea bass (Lateolabrax japonicus L.) reared in freshwater

Triplicate groups of 40 Japanese sea bass Lateolabrax japonicus reared in freshwater (average weight, 9.52±0.47 g) were fed with six isonitrogenous (∼46% crude protein) diets containing 6%, 8%, 10%, 12%, 14% or 16% lipid for 10 weeks respectively. The results showed that the maximum weight gain (WG), specific growth rate (SGR), feed intake (FI) and protein efficiency ratio (PER) all occurred at the 10% lipid level ( P <0.05) and growth depression occurred when the dietary lipid level was over 12%. Whole body and liver lipid concentrations were enhanced with the increase in the dietary lipid levels, but the muscle lipid content did not significantly change with the increase in the dietary lipid levels. Both liver pepsin and trypsin activities increased with dietary lipid levels ranging from 6% to 10%, and then decreased with a further increase in the dietary lipid content. Liver lipase activities showed a positive correlation with dietary lipid levels, but amylase activities were not markedly influenced by dietary lipid levels. High proportions of 18:1n-9, 20:1n-9, eicosapentaenoic acid (20:5n-3; EPA), 22:1n-11 and docosahexaenoic acid (22:6n-3; DHA), and low concentrations of n-6 fatty acids, particularly 18:2n-6 occurring in the liver and muscle, to some extent, reflected the fatty acid composition in experimental diets.     

Effects of dietary protein levels on the activity of the digestive enzyme of albino and normal Apostichopus japonicus (Selenka)

We evaluated the effects of different proportions of dietary protein (5%, 10%, 15%, 20%, 25% and 30% protein) on the activity of digestive enzymes of normal and albino Apostichopus japonicus. The experimental diets were fed for 60 days, the optimal conditions for digestive enzyme activity in sea cucumbers were studied. The optimal temperature for protease was 29.3°C and the optimal pH was 1.8. The optimal temperature for amylase was 34.3°C and the optimal pH was 6.7. The optimal temperature for cellulase was 56°C and the optimal pH was 5.9. The activity of intestinal protease increased at first and then decreased as the proportion of dietary protein increased, reaching the maximum when the proportion of protein was 19.7%. The activity of protease in the intestine of normal sea cucumber was significantly lower than that of albino sea cucumber, and the activity of amylase was significantly higher than that of albino sea cucumber. This study is expected to provide a basis for further explaining the ecological difference of albino and normal A. japonicus.     

单环刺螠虫消化道组织学和细胞学

对单环刺螠虫(Urechis unicoinctus VonDrasche)消化道的结构进行了组织学和细胞学观察。单环刺螠虫消化道可分为咽、食道、嗉囊、砂囊、胃、中肠、呼吸肠、直肠和排泄腔。咽、食道和直肠管壁由内向外分为粘膜层、粘膜下层、肌层和外膜，嗉囊、砂囊、胃、中肠和呼吸肠壁仅由粘膜层和外膜组成。除食道外，胃之前的消化道及直肠上皮细胞均有发达的纤毛，中肠和呼吸肠上皮主要为微绒毛。消化道上皮主要分为3类细胞，第1种为柱状上皮细胞；第2种为粘液细胞；第3种为分泌细胞。粘液细胞和分泌细胞散布于柱状上皮细胞之间，且结构和数量随部位而异：粘液细胞在咽、食道、嗦囊、胃、中肠和直肠上皮中有较多的分布，分泌细胞在砂囊、胃、中肠和呼吸肠中数量较多。     

饲料糖水平对不同食性鱼类生长及葡萄糖耐受能力的影响

为研究饲料糖水平对不同食性鱼类生长、血浆生化指标、肝/肌糖原的影响及葡萄糖耐受能力的影响,本实验以不同食性的吉富罗非鱼、卵形鲳鲹和军曹鱼为研究对象,糊精为糖源,三种鱼各设置低、中、高（CL、CM、CH;吉富罗非鱼：20%、30%、40%;卵形鲳鲹：13%、26%、39%;军曹鱼：12%、24%、36%）3个不同饲料糖添加水平,依次为进行8周的饲养实验并进行葡萄糖注射实验。结果显示：饲料中不同糖水平对吉富罗非鱼成活率没有显著影响（P>0.05）;饲料系数随饲料糖水平的升高呈现先下降后升高趋势,以CL组最高（P<0.05）;增重率与特定生长率最高值均出现在CH组中,显著高于CL组（P<0.05）。卵形鲳鲹和军曹鱼CH组存活率均显著低于其他各组（P<0.05）;而增重率与特定生长率则均为CM组显著最高（P<0.05）;三种鱼饲料系数随着饲料糖水平的升高呈现先下降后升高趋势,均以CM组最低,分别为1.47（吉富罗非）、1.61（卵形鲳鲹）和1.49（军曹鱼）。饲料中不同糖水平对不同食性鱼类糖代谢相关生化指标有不同程度的影响。随着饲料中糖水平的上升,罗非鱼CH组糖代谢指标均显著高于其他各组（P<0.05）。卵形鲳鲹和军曹鱼CH组血糖、胰岛素、肝/肌糖原、甘油三酯均为最高;军曹鱼CM组肝/肌糖原和甘油三酯均显著高于其他各组（P<0.05）。葡萄糖耐受实验结果显示注射葡萄糖后：（1）卵形鲳鲹组和罗非鱼组在1 h血糖水平达峰值（P<0.05）,并且均在12 h恢复到注射前水平;而军曹鱼组在3 h达血糖峰值后直至24 h才回到注射前水平。（2）军曹鱼组与罗非鱼组血浆胰岛素水平缓慢上升,至3 h达最高水平（P<0.05）,而卵形鲳鲹组在1 h内显著下降（P<0.05）。（3）卵形鲳鲹组与罗非鱼组肝糖原水平缓慢上升,分别在3 h、6 h达峰值（P<0.05）,而军曹鱼组在1 h内呈下降趋势。（4）罗非鱼组与卵形鲳鲹组甘油三酯水平分别在3 h、6 h达峰值（P<0.05）,而军曹鱼组在1 h内显著下降（P<0.05）。本研究表明,饲料糖水平对对三种食性鱼类生长、糖代谢生化指标、葡萄糖利用和耐受能力具有不同程度的影响,杂食性罗非鱼可比肉食性鱼类更好地利用膳食糖物质。葡萄糖耐受能力则以杂食性吉富罗非鱼为最强,卵形鲳鲹次之,军曹鱼葡萄糖耐受能力最低。     

池塘内循环流水养殖模式对大口黑鲈生长性能、抗氧化酶、消化酶及消化道组织结构和菌群的影响

为探究养殖过程中池塘内循环流水养殖模式(inner-pond raceway aquaculture,IPRA)对大口黑鲈生长性能、抗氧化酶、消化酶、消化道组织结构及菌落结构的影响.实验将池塘内循环流水养殖的4条水槽设置为流水组2条和对照组2条,进行为期153d的养殖实验,分别在养殖中期和末期测量大口黑鲈相关生长、生化...     

Histological and histochemical changes in the digestive tract of white sturgeon larvae during ontogeny

Ontogenetic changes in digestive tract histology and digestive enzyme histochemistry were investigated 11 to 36 days post-hatch in white sturgeon Acipenser transmontanus larvae. From initiation of exogenous feeding (12 days post-hatch), larvae were fed a commercial salmonid diet for the ensuing 24 days. The digestive system of white sturgeon displayed a high degree of morphologic organization and functionality at the onset of exogenous feeding. An enhancement of digestive capacities occurred with transition to active feeding. On day 2 of feeding, there was a clear increase of alkaline phosphatase, aminopeptidase M, dipeptidyl peptidase IV, and -glutamyl transpeptidase activity in the brush border of the spiral intestine. This strong activity is an apparent confirmation of the importance of this segment of the intestine for protein digestion and nutrient absorption. The functional development of the pyloric intestine occurred on day 4 and was concomitant with an increase in the activity of brush border and cytoplasmic enzymes such as acetylcholinesterase, dipeptidyl peptidase II, - and -galactosidases. The absence of acetylcholinesterase, lactase, nonspecific esterase, and weak activity of exopeptidases and alkaline phosphatase in the anterior intestine suggests that this segment of the intestine may be less important in nutrient absorption than the pyloric and spiral intestines. The observed quantitative and qualitative differences in enzyme activity along the intestine indicate a high degree of specialization of each segment for specific digestive and absorptive processes.