盐度对花鳗鲡和太平洋双色鳗鲡幼鳗生长性能及消化酶活力的影响

文章研究了不同盐度对花鳗鲡(Anguilla marmorata)幼鳗和太平洋双色鳗鲡(A. bicolor pacifica)幼鳗生长性能及消化酶活力的影响。将花鳗鲡幼鳗(9.760.36) g和太平洋双色鳗鲡幼鳗(11.820.04) g分别在淡水(盐度0)与盐度5、10、18水体中养殖30d, 测量每组实验鱼总重后检测胃、肠道和肝脏蛋白酶、淀粉酶和脂肪酶的活力。结果表明, 花鳗鲡和太平洋双色鳗鲡在各盐度处理中存活率均为100%, 未出现死亡。两种鳗鲡在淡水中生长良好, 特定生长率最高, 而饵料系数最低。盐度对花鳗鲡幼鳗和太平洋双色鳗鲡幼鳗消化酶活力的影响存在差异, 其中花鳗鲡胃、肠道和肝脏蛋白酶活力在各盐度处理中均无显著变化(P0.05), 淀粉酶和脂肪酶活力均随盐度的增加而下降; 太平洋双色鳗鲡胃蛋白酶活力在盐度10时最大, 肝蛋白酶活力在盐度18时最大, 而淀粉酶和脂肪酶活力在各盐度处理组无显著变化(P0.05)。这表明盐度对花鳗鲡胃、肠道和肝脏的淀粉酶和脂肪酶活力具有抑制作用, 对太平洋双色鳗鲡的蛋白酶活力有一定的激活作用。在相同盐度条件下, 不同消化器官中同种消化酶活力存在差异, 各盐度的两种鳗鲡肠道中淀粉酶和脂肪酶的活力均显著高于肝脏和胃(P0.05), 胃中蛋白酶活力高于肝脏和肠道, 但不显著(P0.05)。研究发现两种鳗鲡体内脂肪酶活力相对较高, 表明其对脂肪具有较强的消化能力。建议在配制花鳗鲡幼鳗和太平洋双色鳗鲡幼鳗饲料时, 适当提高粗脂肪比例, 有助于促进对营养物质的消化吸收, 提高养殖效益。       

Polymorphism and partial characterization of digestive enzymes in the spiny lobster Panulirus argus

We characterized major digestive enzymes in Panulirus argus using a combination of biochemical assays and substrate-(SDS or native)-PAGE. Protease and amylase activities were found in the gastric juice while esterase and lipase activities were higher in the digestive gland. Trypsin-like activity was higher than chymotrypsin-like activity in the gastric juice and digestive gland. Stability and optimal conditions for digestive enzyme activities were examined under different pHs, temperature and ionic strength. The use of protease inhibitors showed the prevalence of serine proteases and metalloproteases. Results for serine proteases were corroborated by zymograms where several isotrypsins-like (17-21 kDa) and isochymotrypsin-like enzymes (23-38 kDa) were identified. Amylases (38-47 kDa) were detected in zymograms and a complex array of non-specific esterases isoenzymes was found in the digestive gland. Isoenzyme polymorphism was found for trypsin, amylase, and esterase. This study is the first to evidence the biochemical bases of the plasticity in feeding habits of P. argus. Distribution and properties of enzymes provided some indication on how the digestion takes place and constitute baseline data for further studies on the digestion physiology of spiny lobsters.     

Digestive enzymes of three teleost fishes.

The activity of amylase, sucrase, protease and lipase has been examined in Wallago attu, Clarias batrachus and Labeo rohita. The optimum pH value for carbohydrases ranges from 5.0 to 7.0 and that for trypsin between pH 6.8 and 7.8. Lipase is active at a slightly more alkaline medium. The optimum pH for a given enzyme varies in different sections of the alimentary canal of the same fish and also from species to species. Variations are also found in the optimum substrate concentration for a given enzyme in the different sections of the alimentary canal. The activity of carbohydrases is higher in the herbivorous fish Labeo, than in the carnivorous fish Wallago, and the omnivorous fish Clarias. As for protease, maximum activity is found in Wallago. The difference is not so well marked for the activity of lipase. There is a correlation between the normal diet of the fishes and the relative activity of the digestive enzymes.     

Postprandial changes in pH and enzyme activity from the stomach and intestines of Tilapia rendalli (Boulenger, 1897), Oreochromis mossambicus (Peters, 1852) and Clarias gariepinus (Burchell, 1822)

The ability to utilise dietary components differs among fish species. Digestive enzymes may be used to determine the efficiency of the digestive process. In this study, the activities of the digestive enzymes in Tilapia rendalli, Oreochromis mossambicus and Clarias gariepinus were explored. Protease, amylase, lipase and cellulase activities were measured in different parts of the digestive tract of the three fish species. The pH dynamics along the digestive tract were monitored. In all fish species, the presence of food led to a reduction in stomach pH, whereby pH values of 1.54, 1.58 and 2.01 were recorded 12 h after feeding in O. mossambicus, T. rendalli and C. gariepinus, respectively. Protease and amylase activities were significantly higher (P < 0.05, anova ) in the tilapias than in C. gariepinus. The tilapias may be pre‐adapted to produce more protease and amylase to digest plant material, which is more difficult to digest than animal matter. In all species amylase activity was significantly higher in the proximal intestine than in the other parts of the digestive tract (P < 0.05, anova ). The highest protease activity was recorded in the distal intestines. This is because of the alkaline pH recorded in the proximal and distal intestines, which favours amylase and protease activity, respectively. Lipase activities were significantly higher (P > 0.05) in C. gariepinus than in both tilapias. Marginal cellulase activities were recorded in all species. It is inferred here that phylogeny and not diet may be the main factor influencing enzyme activities, as all fish were fed a similar diet.     

Changes in digestive enzymes through developmental and molt stages in the spiny lobster, Panulirus argus

Changes in major digestive enzymes through developmental and molt stages were studied for the spiny lobster Panulirus argus. There were significant positive relationships between specific activity of trypsin and amylase enzymes and lobster size, whereas esterase and lipase specific activities decreased as lobsters aged. No relationship was found between amylase/trypsin ratio and lobster size. Positive trends were found, however, for trypsin/lipase and amylase/lipase ratios. Results suggest that changes in enzyme activity respond to the lobsters' physiological needs for particular dietary components although multivariate analysis suggested that enzyme activities could be not totally independent of diet. On the other hand, the pattern of changes of major enzyme activities through molt cycle was similar for most enzymes studied. Following molt, trypsin, chymotrypsin, amylase, and lipase activities gradually increased to maximal levels at late intermolt (C4) and premolt (D). There were no variations in the electrophoretic pattern of digestive enzymes through developmental and molt stages and thus, it is demonstrated that regulation is exerted quantitatively rather than qualitatively. Further studies on the effect of other intrinsic and extrinsic factors on digestive enzyme activities are needed to fully understand digestive abilities and regulation mechanisms in spiny lobsters.     

红螯螯虾胚胎发育期主要消化酶和同工酶的活性变化

采用生物化学方法测定了红螯螯虾(Cherax quadricarinatus)胚胎发育各期主要消化酶(胃蛋白酶、胰蛋白酶、淀粉酶、纤维素酶和脂肪酶)的比活力及主要同工酶(乳酸脱氢酶、苹果酸脱氢酶、葡萄糖-6-磷酸脱氢酶和酯酶)的活力。结果显示,5种消化酶各自表现出不同的变化模式,胃蛋白酶和胰蛋白酶的比活力早期均逐渐上升,到发育后期胃蛋白酶出现快速下降,而胰蛋白酶却仍保持较高水平;淀粉酶比活力呈“V”字型变化趋势,晚期活性较高;纤维素酶和脂肪酶的比活力则均较低。4种同工酶酶谱随胚胎的发育渐趋复杂,酶活性也随之增强。结果表明,消化酶和同工酶活力的高低均受其基因的调控,并随胚胎发育适时表达,为胚胎组织、器官和系统的形成以及未来仔虾的开口摄食提供物质保证。     

Digestive enzymes and metabolic profile of Pseudoplatystoma corruscans (Teleostei: Siluriformes) in response to diet composition

Digestive enzyme responsiveness to feeding and associated adjustments of metabolism can be used to derive nutritionally effective diet formulations. Juvenile pintado (Pseudoplatystoma corruscans) were fed different diets. After feeding, fish were killed and blood, liver and white muscle were collected to evaluate metabolites. Stomach along with anterior, middle and posterior intestine were sampled for enzyme analysis. Non-specific protease, trypsin, chymotrypsin, amylase and lipase were assayed. Crude protein (CP) did not induce proteolytic activity; highest protease activities were observed in the stomach. Amylase was higher in the stomach in fish feeding on diets containing 13-25% starch. Lipase activity was observed along the gastrointestinal tract, with the highest activities observed in the middle section. The metabolic profile of white muscle was not affected by CP. In contrast, some plasma and liver metabolites were altered concomitant with changes in the digestive enzymes. Amino acid catabolism was increased. Digestion in pintado was responsive to cornstarch, reflected in intermediary metabolism; proteolytic activities of the digestive tract seem to be sufficient to deal with large amounts of dietary protein. As a result, we are able to recommend a balance between protein and energetic compounds, such as lipids and carbohydrates, in the diet to optimize fish growth.     

云斑尖塘鳢消化酶活力的研究

本文采用酶学分析方法研究了云斑尖塘鳢在正常摄食状态与饥饿的状态下胃、肠及肝胰脏组织中蛋白酶、淀粉酶和脂肪酶的活性。结果显示,在30℃的条件下,正常摄食组样本在酸性条件下的蛋白酶活力表现为:胃后肠肝胰脏前肠,中性和碱性条件下:后肠肝胰脏前肠及胃;饥饿组样本仅有胃表现出较高的酸性蛋白酶活性,其他器官的蛋白酶活性均很低。在正常和饥饿实验组中肝胰脏的淀粉酶活性均高于其他器官,胃肠的淀粉酶活性均较低。正常摄食组中脂肪酶活力后肠肝胰脏;而在饥饿组中仅有肝胰脏检测到脂肪酶活性。结果表明,云斑尖塘鳢适度饥饿组较正常摄食组消化酶活性大幅降低;其高蛋白酶活力及中等脂肪酶活力与其肉食性相一致;此外云斑尖塘鳢也具备少量的淀粉消化能力。     

The effect of adipokinetic hormones on the activity of digestive enzymes

The role of the adipokinetic hormone (AKH) in the control of protease, amylase and lipase activities is examined using the cockroach Periplaneta americana and the fruit fly Drosophila melanogaster as model species. The effects of Peram‐CAH‐I and ‐II on the activity of cockroach digestive enzymes in the gastric caeca and midgut are measured both in vivo and in vitro. The results show the activity of proteases, amylases and lipases in both parts of the gut: amylase activity is higher in the gastric caeca than in the midgut; lipase activity presents the opposite trend; and protease activity is similar in both organs. The applied hormones stimulate the activity of all digestive enzymes, although this stimulation is not uniform; AKHs affect enzymes selectively, and in some cases unequally, in the gastric caeca and midgut. No substantial differences between Peram‐CAH‐I and ‐II stimulation are recorded. The in vitro results demonstrate that AKH stimulates digestive enzyme activity directly. In agreement with the cockroach results, enzymatic activity in D. melanogaster larvae producing nonfunctional AKH is lower than that in the larvae with ectopically expressed Akh gene, where enzyme activity reaches or even exceeds that of the controls. Overall, the results demonstrate the active role of AKHs in the stimulation of digestive enzyme activity in insects.     

Digestive enzyme profiles reveal digestive capacity and potential energy sources in fed and starved spiny lobster (Jasus edwardsii) phyllosoma larvae

The impact of starvation on the digestive enzyme (protease, trypsin, lipase and amylase) activities of Stage I and IV Jasus edwardsii phyllosoma larvae was used to identify the nutrients metabolised or conserved during food deprivation, highlighting the most critical energy reserves. Protease activities increased significantly in both Stages I and IV phyllosoma, suggesting that protein catabolism provided energy during food deprivation. Lipase activity decreased significantly in starved Stages I and IV larvae indicating that lipid may be spared for fuelling later developmental moults. The use of protein, while sparing lipid, may provide immediate energy but not at the expense of long-term lipid energy stores which are known to be important during their lengthy larval phase. The preferential use of protein during short-term periods of starvation suggests that particular attention must be given to providing sufficient protein in artificial diets at all times. Amylase activity in starved Stage I larvae was lower than in fed animals, suggesting that the starved animals are not gaining sufficient carbohydrate. However, amylase activity was similar in fed and starved Stage IV larvae, possibly due to the catabolism of accumulated glycogen stores that were not sufficiently developed in Stage I animals.     

卤虫投喂下长吻(鱼危)仔稚鱼消化酶发育和口宽变化的研究

采用酶学和形态学测定方法, 研究在投喂卤虫条件下长吻(鱼危)仔鱼4种主要消化酶: 胃蛋白酶、胰蛋白酶、脂肪酶和淀粉酶的活性变化以及长吻(鱼危)仔鱼口宽、全长变化。实验共进行13d, 实验结果表明: (1)长吻(鱼危)仔鱼全长、口宽的发育与其日龄表现出明显的线性正相关(R_TL²=0.974, R_MW²=0.964)。口宽与全长比值(MW/TL)在仔鱼开口后急剧下降, 并自7日龄开始维持在0.07—0.08, 口宽和全长处于同步发育期并表现出明显的相关性(R²=0.948), 说明7日龄(/h, days post hatching)后口宽和全长处于同步发育期, 标志仔鱼转食的开始。(2)长吻(鱼危)仔鱼初次开口时即可检测出四种消化酶的活性。5—7/h时胰蛋白酶显著高于初孵仔鱼, 与此时仔鱼开始开口摄食的行为相一致。胃蛋白酶、脂肪酶活性在仔鱼孵化后第7天即开口的第3天, 淀粉酶活性在孵化后第6天, 显著高于初次孵化出来的仔鱼。8—13/h时, 胃蛋白酶、胰蛋白酶、脂肪酶和淀粉酶活性均在较高水平平稳的波动, 标志着消化道发育逐渐健全。     

Insectivore to frugivore: ontogenetic changes in gut morphology and digestive enzyme activity in the characid fish Brycon guatemalensis from Costa Rican rain forest streams

Brycon guatemalensis , a Neotropical characid fish, consumes an entirely terrestrial diet, shifting from eating insects as juveniles to fruits and leaves as adults. Juvenile and larger‐sized fish collected in the Rio Puerto Viejo at the La Selva Biological Station in Costa Rica were studied to test the hypotheses that, with ontogeny, (1) relative gut length increases, (2) pyloric caeca arrangement and number remain unchanged and (3) pepsin, trypsin and lipase activities decrease, while α‐amylase activity increases. These hypotheses were mainly supported in that larger fish had longer guts, unchanged pyloric caeca arrangement but fewer caeca, and, at both environmental and standard temperatures for the enzyme assays, lower pepsin and trypsin activities but higher α‐amylase activities than the juveniles. Only lipase, among the digestive enzymes, exhibited the unexpected outcome of either not differing significantly in activity (per g of tissue) between juveniles and larger fish or being significantly higher (per mg of protein) in larger fish. The overall results support the view that B. guatemalensis is specialized morphologically and biochemically to function first as a carnivore and then as a herbivore during its life history.     

Temporal changes in digestive enzyme activities in the gastrointestinal tract of European eel (Anguilla anguilla) (Linneo 1758) following feeding

Changes occurring after feeding in the digestive enzyme activities of European eel were investigated to provide some insights into the digestive physiology of this fish. Total and specific proteases, amylase and lipase activities were measured using standard biochemical assays over a 24 h cycle in fed eels, compared to starved ones, under the same rearing conditions. In the gastrointestinal tract of fed eels quantitative changes started 4 h after feeding and continued later on; conversely, in starved eels enzyme activities remained unchanged over time. In fed eels, total and specific protease activities showed an overall increasing trend in the intestine, while in the stomach they progressively decreased to values 22–50% lower than those measured at the pre-feeding time; this behaviour probably reflected the progression of digesta along the intestinal tract. The prolonged secretory response of European eel to food ingestion proved its extended activity in the digestive process.     

Digestive enzymes of two freshwater fishes (Limia vittata and Gambusia punctata) with different dietary preferences at three developmental stages

The variation of activity of some digestive enzymes was studied in three age groups of two freshwater endemic fishes from Cuba: Limia vittata and Gambusia punctata. Trypsin, chymotrypsin and amylase activities showed a different pattern between both species. Trypsin and chymotrypsin activity increased with the age of fishes, while amylase activity decreased. The highest activity of trypsin and chymotrypsin was registered in G. punctata while the highest amylase activity was detected in L. vittata. Zymograms revealed proteases with molecular masses similar to trypsin and chymotrypsin reported for other fish species. Amylase electrophoresis showed the presence of this enzyme; in L. vittata amylase zymograms showed two bands with molecular masses of 175 and 100 kDa and in G. punctata four bands of 175, 100, 46 and 30 kDa respectively were found. The activity of the digestive enzymes can be used as an effective indicator of the feeding habits and the development of the digestive tracts in L. vittata and G. punctata.     

Profile of Digestive Enzymes Activity During Early Development of Featherback <Emphasis Type="Italic">Chitala chitala</Emphasis> (Hamilton, 1822)

The ontogenetic development of the key digestive enzymes of featherback Chitala chitala was assayed during the early development. Amylase, lipase, trypsin and chymotrypsin activities were detected on 1 days after hatch (DAH), (during endotrophic stage) but pepsin activity was detected on 12 DAH (exotrophic phase) correlated with the improvement of gastric secretion at the beginning of flexion stage. The gradual shift of alkaline protease activity (trypsin and chymotrypsin) to more efficient acidic digestion indicated a change in the digestive physiology as a result of metamorphosis acquiring the juvenile characteristic during the postflexion or extrophic phase. The initial high level of amylase (i.e. from 1 DAH to 9 DAH) during endotrophic and endoexotrophic feeding stage could be better explained as a result of programmed gene expression. But a constant decrease in activity after the 12 DAH i.e. on the onset of flexion and exotrophic stage of featherback fish in the present study may be possibly due to the developmental changes in the gut morphology and increased protein level in the tissue. These fluctuations of the enzymatic activities in featherback larvae reflect the ability of the fish to adapt with the diet during ontogenetic shift. This information can lead to the possibility of developing an age specific formulated feed for intensive farming of this new candidate species.     

Effect of formulated diet on digestive enzymes of Labeo rohita (Ham.)

Six sets of feeding experiments were carried out using formulated diets containing prawn head waste (PW), chicken intestine waste (CW), banana flower (BF), cauliflower waste (CAU) Dolicos lab lab (DLL) and groundnut leaf (GNL) in four levels of inclusion (15, 30, 45 and 60%) to assess the pattern of distribution and activities of digestive enzymes like cellulase, amylase, maltase, invertase, protease and lipase in the digestive tracts of Labeo rohita fingerlings. A control group of fish was fed with diets containing antibiotics to destroy the digestive tract microflora which may induce digestive functions. In general, the activity of digestive enzymes depended on the amount and type of the ingredients present in the diets ingested by the fish. Test animals showed both endogenous and bacterial cellulase activities which suggests the necessity for including cellulose (plant protein source) as dietary ingredient. Occurrence of higher amount of cellulase in the foregut and amylase in the fore and midgut influenced by DNL and GNL diets revealed the possibility of including less than 40% of the respective ingredients in the diet of rohu. Maltase and invertase were highly influenced by GNL, DLL and BF diets than PW and CW diets. More than 40% inclusion of PW and CW was found to increase protease and lipase secretion in the midgut and hindgut regions. The higher secretion of lipase in the midgut suggested the physiological versatility for lipid digestion in rohu fingerlings.     

丽斗蟋翅二型雄虫食物消化能力及消化酶活性比较

【目的】丽斗蟋Velarifictorus ornatus具明显的翅二型现象,为探讨翅型分化对丽斗蟋翅二型雄虫消化能力及中肠内消化酶活性产生的影响,对长翅型与短翅型雄虫食物消化能力及中肠内消化酶活性进行了检测比较。【方法】我们采取重量营养指数测定了羽化后12 d内丽斗蟋两型雄成虫增长量、相对增长率、取食量、食物利用率、近似消化率和食物转化率。为进一步明确丽斗蟋翅二型成虫食物消化能力与中肠内消化酶活性的关系,我们采用4种专用底物测定了中肠内用于分解蛋白质、脂肪和碳水化合物的总蛋白酶、胰蛋白酶、脂肪酶和淀粉酶的活性。【结果】结果表明,丽斗蟋两型雄虫取食量、食物转化率、食物利用率与增长量均无统计差异,但中肠内消化酶活性变化规律不同。成虫羽化后4 d时,长翅型雄虫中肠内总蛋白酶与胰蛋白酶活性显著高于短翅型雄虫,相反,羽化后0 d时,短翅型雄虫中肠内总蛋白酶与胰蛋白酶活性则显著高于长翅型雄虫,而羽化后12 d时,虽然短翅型雄虫总蛋白酶活性高于长翅型雄虫,但胰蛋白酶活性在两型雄虫间并无差异。成虫羽化后0 d时,两型雄虫脂肪酶活性无差异,但无论是羽化后4 或 12 d,长翅型雄虫中肠内脂肪酶活性皆显著大于短翅型雄虫。成虫羽化后4 d时,短翅型雄虫中肠内淀粉酶活性显著高于长翅型雄虫,而羽化后0与12 d时,两型雄虫间无显著差异。【结论】丽斗蟋翅二型雄虫食物消化能力无显著差异,但羽化后不同时间,中肠内消化酶活性存在差异,该差异可能与成虫羽化后不同时期,翅二型雄虫在飞行与繁殖投资中对不同能源物质的需求有关。     

不同生态环境中铜绿丽金龟幼虫肠道细菌产消化酶活性比较

目的 测定不同生态环境中铜绿丽金龟幼虫肠道细菌产消化酶活性。方法 采用平板透明圈法和分光光度计法。结果 平板透明圈法测得废弃菜园和花生田中铜绿丽金龟幼虫肠道细菌产蛋白酶和淀粉酶活性差异无统计学意义（F=1.089、0.4963,P>0.05）,而细菌的产纤维素酶活性有显著差异,其中花生田铜绿丽金龟幼虫肠道中分离到的粘质沙雷菌产酶活性显著高于其他菌株;分光光度计测得的不同生态环境中铜绿丽金龟幼虫肠道细菌的产蛋白酶、淀粉酶和纤维素酶活性差异均有统计学意义（F=461.565、42.349、18.7673,P<0.05）。从变异系数来看,分光光度计法测得的蛋白酶、淀粉酶和纤维素酶的变异程度较低,而脂肪酶测定时平板透明圈法的变异系数较低。结论 平板透明圈法和分光光度计法均可用于铜绿丽金龟幼虫肠道细菌产消化酶活性测定。通过分析研究比较,分光光度计法适于测定细菌的产蛋白酶、淀粉酶和纤维素酶活性,平板透明圈法适于测定细菌的产脂肪酶活性。     

温度对南疆沙蜥和密点麻蜥消化酶活性的影响

为探究不同温度对南疆沙蜥Phrynocephalus forsythii和密点麻蜥Eremias multiocellata消化酶活性的影响,本研究测定了不同温度下南疆沙蜥和密点麻蜥的肝脏、胃及十二指肠的消化酶——淀粉酶(碘-淀粉比色法)、脂肪酶(比浊法)及胰蛋白酶(紫外线吸收法)的活性。结果显示,南疆沙蜥和密点麻蜥消化酶活性在4～45℃随着温度升高呈现先上升、后下降的趋势;40℃驯化的南疆沙蜥、35℃驯化的密点麻蜥肝脏、胃及十二指肠的淀粉酶、脂肪酶及胰蛋白酶活性最高。南疆沙蜥和密点麻蜥消化酶活性具有温度依赖性,这与机体在不同温度下的生理机能是密切相关的。同时,2种蜥蜴的消化酶活性最大时的驯化温度明显不同,这与它们偏好的环境温度密切相关。