Effects of in vitro exposure to ozone and/or hyperoxia on superoxide dismutase, catalase, glutathione and lipid peroxidation in red blood cells and plasma of rainbow trout, Oncorhynchus mykiss (Walbaum)

In aquaculture, ozone is used as a disinfectant. In its production, extensive amounts of oxygen are formed resulting in hyperoxic conditions in culture units. Both ozone and hyperoxia have the potential to be toxic via pro‐oxidant mechanisms and to activate antioxidant defence systems in cultured species. To eliminate systemic effects, blood of rainbow trout, Oncorhynchus mykiss (Walbaum), was exposed in vitro for 5 min to ozone/hyperoxia or hyperoxia, and changes in antioxidant defences and lipid peroxidation were measured after exposure. Ozone exposure caused severe damage in red blood cells (rbc) detected as increased lipid peroxidation and oxidized glutathione (GSSG) levels in both plasma and rbc. Oxygen exposure alone increased intracellular lipid peroxidation and GSSG levels 10 min after exposure and was not evident in the plasma at any time. Ozone, but not oxygen exposure, decreased reduced glutathione (GSH) levels in plasma, and the changes were negatively correlated with increased lipid peroxidation in rbc, indicating that extracellular GSH has a dynamic role in the protection of rbc from direct oxidation by ozone. Both ozone and hyperoxic conditions increased superoxide dismutase (SOD) activity in rbc 3 and 6 h after exposure. In contrast, catalase activity was only increased 10 min after oxygen exposure, suggesting other catalase activation mechanisms rather than enzyme induction. The recovery of lipid peroxidation and GSSG levels in rbc after hyperoxia, but not ozone exposure, indicated a capacity to defend against hyperoxia‐produced oxidative damage, but an overwhelming of antioxidant defences by ozone in rainbow trout rbc in vitro.     

Trypsin enzyme activity during larval development of Litopenaeus vannamei (Boone) fed on live feeds

Larval stages of the Pacific white shrimp, Litopenaeus vannamei (Boone) were fed standard live diets of mixed microalgae from the first to the third protozoea (PZ1 to PZ3), followed by Artemia nauplii until post‐larvae 1 (PL1). Trypsin enzyme activity for each larval stage was determined using N‐α‐p‐toluenesulphonyl‐l ‐arginine methyl ester (TAME) as a substrate. Results were expressed as enzyme content to assess ontogenetic changes during larval development. Tissue trypsin content (IU µg^?1 DW for each larval stage) was significantly highest at the PZ1 stage and declined through subsequent stages to PL1. This contrasts with previously observed patterns of trypsin development in Litopenaeus setiferus (Linnaeus) and other penaeid genera, which exhibit a peak in trypsin activity at the third protozoea/first mysis (PZ3/M1) larval stage. Litopenaeus vannamei larvae transferred to a diet of Artemia at the beginning of the second protozoea (PZ2) stage were significantly heavier on reaching the first mysis stage (M1) than those fed algae, while survival was not significantly different between treatments. At both PZ2 and PZ3 stages, trypsin content in larvae feeding on Artemia was significantly lower than in those feeding on algae. The rapid decline in trypsin content from PZ1 and the flexible enzyme response from PZ2 suggest that L. vannamei is physiologically adapted to transfer to a more carnivorous diet during the mid‐protozoeal stages.     

Activity of digestive enzymes along the gut of juvenile red abalone, Haliotis rufescens, fed natural and balanced diets

Two carbohydrases (cellulase, lysozyme), three proteases (trypsin, aminopeptidase and non-specific protease), a non-specific lipase, and semiquantitative tests of 19 digestive enzymes were assayed in different gut sections of juvenile red abalone, Haliotis rufescens, in order to identify the regions where digestion takes place and investigate the extent to which diet composition can modify the digestive capacity of abalone. The abalone were fed either fresh kelp (K) or balanced diets containing 25 or 38% crude protein for 6 months. Enzyme assays were carried out on different sections of the abalone's gut at the end of this period. On a weight-specific basis, the digestive gland was the site containing most of the enzymes. On a protein-specific basis, two main digestion regions were identified: the digestive gland-stomach region that is characterized by high activities of cellulase and lysozyme, chymotrypsin and protease, and the mouth-intestine region with a typically high activity of lipase and amino peptidase. Significant dietary effects were observed on the activity of enzymes, especially in the digestive gland. Abalone fed with 25 and 38% crude protein diets exhibited higher cellulase (39.8 ± 4.6 and 14.2 ± 0.8 mU mg^− 1 protein, respectively) and lysozyme activities (88.0 ± 20.4 and 56.6 ± 15.7 U, respectively) than those fed with fresh kelp (5.5 ± 0.7 mU mg^− 1 protein and 17.1 ± 1.8 U). In contrast, higher protease activity was found in kelp-fed organisms (234.1 ± 20.4 μg product/mg protein) than those fed the 25 and 38% crude protein diets (109.5 ± 20.7 and 119.5 ± 20.5 μg product/mg protein, respectively). Semiquantitative API ZYM assays resulted in no clear food-specific effects on the activity of carbohydrases, proteases, ester hydrolases or phosphohydrolases, yet organ-specific differences were conspicuous in various cases, and generally agreed with quantitative results. It is suggested that the increased carbohydrase activity exhibited by organisms fed the balanced diets resulted from a combination of an increased number of resident bacteria in the abalone's gut and facilitated contact between dietary substrates and digestive cells. The present results indicate that H. rufescens can adjust their enzyme levels in order to maximize the acquisition of dietary protein and carbohydrates. This characteristic can be advantageously used to search for suitable diets in abalone aquaculture.     

菲律宾蛤仔对镉、铜暴露的蓄积作用及其抗氧化酶系统的响应研究

研究了镉（Cd）、铜（Cu）2种重金属单一暴露下菲律宾蛤仔（Ruditapes philippinarum）肝胰腺和鳃组织内的重金属富集特征和抗氧化酶活力变化特点。结果表明,蛤仔肝胰腺与鳃对Cd、Cu的富集量随重金属浓度与暴靠时间的增加而增火,具有明显的浓度效应与时间效应;菲律宾蛤仔对Cd的富集能力高于Cu,H．肝胰腺中审盖属的蓄积量高于鳃;蛤仔肝胰腺和鳃组织中超氧化物歧化酶（SOD）、谷胱廿肽过氧化物酶（（;Px）和谷胱竹肽硫转移酶（CST）活力在暴露的某些时段被显著诱导（P〈0．05）,似随暴露时问延长或重金属浓度增加,SODf11GST活力则被显著抑制（P〈O．05）,而CPx活力随暴露时问延K逐渐恢复至对照组水平、菲律宾蛤仔肝胰腺和鳃2种组织中SOD和GST的活性变化可作为海洋Cu^2＋Cd^2＋钙染的牛物标志物．     

Cross‐effects of dietary probiotic supplementation and rearing temperature on growth performance,digestive enzyme activities,cumulative mortality and innate immune response in seabass (Dicentrarchus labrax)

Probiotic influence on fish immune response and digestive capacity is extensively discussed in aquaculture. In this experiment, a feeding trial was carried out for 100 days to evaluate the cross‐effects of probiotic supplementation and rearing temperature (17, 20 and 23°C) in juvenile seabass (Dicentrarchus labrax). The experimental diet was supplemented with a commercial probiotic blend (Biomin AquaStar Growout) at 3 g/kg diet (5.23 × 10⁸ CFU/kg diet), and tested against a non‐supplemented diet (control). Growth performance and innate immune responses were analysed at 70 and 100 days of feeding, whereas digestive enzyme activities were determined at 100 days of feeding. At the end of the feeding trial, fish were subjected to a handling stress and cumulative mortality was recorded. Digestive enzyme activities were influenced by temperature, with α‐amylase and lipase activities peaking at the higher temperature (23°C) and trypsin at the lower temperature (17°C). Immune parameters showed a significant temperature versus feeding duration effect, with complement system (ACH50) and peroxidase peaking at 70 and 100 days of feeding, respectively. Poststress cumulative mortality was higher at the lowest temperature (17°C), especially in fish fed the control diet. In conclusion, water temperature was the main variable affecting the studied parameters, whereas the dietary probiotic supplementation had influence on the chymotrypsin activity and survival rate in seabass reared at 17°C.     

镰刀菌毒素对断奶仔猪血清酶、肝脏抗氧化功能及组织病理学的影响

试验旨在研究镰刀菌毒素污染日粮对断奶仔猪血清酶、肝脏抗氧化功能及组织病理学的影响。选择35日龄体重为(8.45±0.94) kg的健康三元杂交(杜×长×大)断奶雌性仔猪40头,随机分为2组,每组20个重复,每个重复1头猪。对照组饲喂基础日粮,试验组饲喂用霉变玉米和霉变玉米蛋白粉替代基础日粮中50%的玉米和玉米蛋白粉配制而成的镰刀菌毒素污染日粮(玉米赤霉烯酮(ZEN) 0.90 mg/kg,呕吐毒素(DON) 1.43 mg/kg,烟曲霉毒素(FUM) 5.85 mg/kg)。仔猪单栏饲喂,预试期7 d,正试期35 d。结果表明:①与对照组相比,试验组断奶仔猪血清中谷草转氨酶(AST)、谷丙转氨酶(ALT)和碱性磷酸酶(ALP)活性均显著升高(P<0.05),肝脏相对重显著降低(P<0.05);②与对照组相比,试验组断奶仔猪血清和肝脏中谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)活性均显著降低(P<0.05),而丙二醛(MDA)含量显著升高(P<0.05);③病理组织学观察发现,试验组断奶仔猪肝脏出现一定程度的组织损伤,部分肝小叶边缘发生明显的炎性细胞浸润,肝细胞发生局部空泡变性。由此可知,镰刀菌毒素污染日粮(0.90 mg/kg ZEN,1.43 mg/kg DON,5.85 mg/kg FUM)饲喂断奶仔猪可引起仔猪血清酶活性改变,肝脏抗氧化功能降低,肝脏组织出现一定程度的病理损伤,从而影响肝脏功能的发挥。     

Effects of Diet and Organic Fertilization on Water Quality and Benthic Macroinvertebrate Populations in Ponds Used to Culture Freshwater Prawn,Macrobrachium rosenbergii

ABSTRACT

Effects of three diets: (1) complete diet; (2) supplemental diet (vitamin and mineral supplements not added); and (3) the supplemental diet with an adjunct organic fertilization regimen (using distiller's dried grains with solubles [DDGS]) on benthic macroinvertebrate populations and water quality in experimental ponds used to culture freshwater prawns, Macrobrachium rosenbergii were investigated. Benthic samples were taken from deep (1.5 m) and shallow (1.0 m) areas of each of nine 0.02-ha ponds every three weeks, using a 0.09-m² Ekman dredge. The abundance of gastro-pods, oligochaetes, total non-insects, chironomids, total dipterans, total insects, and total macroinvertebrates was significantly higher (P <0.05) in ponds receiving the complete diet, possibly due to lower predatory pressure by prawns or direct benefits of micronutri-ents. Total macroinvertebrate abundance was significantly decreased (P <0.05) in ponds receiving supplemental diet (with and without organic fertilization), possibly due to increased predation by prawns to supplement the nutrition not provided by the lower quality diet. Organic fertilization significantly increased (P <0.05) the abundance of oligochaetes and total macroinvertebrates. These data suggest that M. rosenbergii can adjust to reduced feed quality by increasing consumption of benthic fauna.     

Effects of dietary supplementation of fructooligosaccharide on growth performance,body composition,intestinal enzymes activities and histology of blunt snout bream (Megalobrama amblycephala) fingerlings

A feeding trial was conducted to investigate the effects of dietary fructooligosaccharide (FOS) on growth performance, body composition, intestinal enzymes activities and histology of fingerling Megalobrama amblycephala. A total of 1200 fish (1.42 ± 0.01 g) were fed diets containing graded levels of FOS (0, 0.5, 1, 2, 4 and 8 g kg⁻¹ diet) for 8 weeks in a recirculating system indoor. The weight gain, specific growth rate (SGR) and survival rate were all improved in dietary supplementation of FOS fed fish. Increasing FOS levels resulted in both higher whole‐body lipid and lower moisture contents, whereas ash and protein contents showed no significant differences among all the treatments. Intestinal amylase, protease, Na⁺, K⁺‐ATPase, alkaline phosphatase, γ‐glutamyl transpeptidase and creatine kinase activities all increased with dietary FOS levels up to 4 g kg⁻¹ (P < 0.05). Transmission electron microscopy analysis indicated that microvilli length in the mid‐intestine was significantly increased with increased dietary FOS levels (P < 0.05). In conclusion, dietary supplementation of FOS could confer benefits on growth performance, intestinal digestive and absorptive ability, histology of fingerling Megalobrama amblycephala.     

Growth performance and metabolic utilization of diets with native and waxy maize starch by gilthead sea bream (Sparus aurata) juveniles

The effect of dietary starch source and level on growth performance, feed utilization, apparent digestibility coefficients and liver enzyme activities involved in intermediary metabolism of gilthead sea bream juveniles was studied. Five isonitrogenous (47% crude protein) and isolipidic (15% crude lipids) diets were formulated to contain 10% native (diet NS10) or waxy (diet WS10) maize starch; 20% native (diet NS20) or waxy (diet WS20) maize starch or no starch (control). Diets were adjusted with α-cellulose. Another diet was formulated without carbohydrates, and contained 70% crude protein and 15% crude lipids (diet HP). Each diet was fed to triplicate groups of 30 fish (initial weight: 20 g) for 12 weeks. The HP group was fed to near satiation and the other 5 groups were fed on a pair-feeding scheme according to the group that ingested less feed (control diet group). The reduction of dietary protein level from 70% to 47% by the incorporation of 20% starch did not significantly affect gilthead sea bream growth performance or feed efficiency. Compared to the control diet, neither the level nor the nature of starch had any measurable effect on growth performance and feed efficiency. Digestibility of starch was unaffected by source or dietary inclusion level. Diet had no effect on plasma glucose levels, but liver glycogen was higher in diet groups NS20, WS20 and HP. Dietary carbohydrates increased GK and G6PD enzyme activities and decreased ALAT and GDH enzyme activities while had only a minor effect on FBPase activity. The nature of dietary starch tested (native or waxy) had little influence on performance criteria.     

金银花叶片绿原酸提取及工艺参数优化的研究

金银花叶片绿原酸含量仅次于花,通过醇法、超声波法、酶法3种不同方法提取单因素试验和正交试验,结果表明:提取效率酶法优于超声波法,超声波法优于醇法。醇法回流提取的最佳条件是温度90℃,φ=80%乙醇浓度,pH4.0,回流时间2 h,料液比1∶10;超声波法提取的最佳条件是温度50℃,φ=60%的乙醇浓度,pH4.0,超声波功率100 W,料液比1∶8;酶法提取最佳条件是26℃,20 g/L纤维素酶、10 g/L果胶酶,pH4.0,提取4 h,料液比1∶20。粗提取物对革兰氏阴性菌和革兰氏阳性菌均有抑菌和杀菌活性。