Dietary isoleucine requirement of juvenile blunt snout bream,Megalobrama amblycephala

A 9‐week feeding trial was conducted to estimate the dietary isoleucine requirement of juvenile blunt snout bream. Six isonitrogenous and isoenergetic experimental diets were formulated to contain graded isoleucine levels ranging from 5.3 to 20.1 g kg^?1 dry diet. At the end of the experiment, weight gain (WG), specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) increased with increasing dietary isoleucine level up to 11.1 g kg^?1 dry diet, and dietary isoleucine level above 14.2 g kg^?1 dry diet declined these performances. Dietary isoleucine levels (14.2 and 17.3 g kg^?1 dry diet) significantly improved whole‐body protein content, but decreased whole‐body lipid, plasma triglyceride and cholesterol contents. Significantly lower visceral fat index (VFI) in fish fed with 14.2 g kg^?1 dietary isoleucine was observed compared to those fed with deficient or excessive isoleucine. Dietary isoleucine supplementation significantly increased plasma isoleucine concentration, while plasma valine and leucine concentrations showed a reversed trend. Dietary isoleucine levels regulated the target of rapamycin (TOR) gene expression and improved plasma superoxide dismutase (SOD) activity in juvenile blunt snout bream. Based on second‐order polynomial regression model analysis of SGR and FER, the optimum dietary isoleucine requirement was estimated to be 13.8 g kg^?1 dry diet (40.6 g kg^?1 dietary protein) and 14.0 g kg^?1 dry diet (41.2 g kg^?1 dietary protein), respectively.     

Fatty acid digestibility in gilthead sea bream fed diets containing native,re‐esterified or acid vegetable oils

Re‐esterified vegetable oils are obtained from a chemical esterification reaction between vegetable acid oils and glycerol. Due to their properties, it is expected that they have a higher nutritive value than their corresponding acid oils and a better digestibility than their native counterparts. The aim of this study was to determine the effect of re‐esterified oils with a different monoacylglycerol (MAG) and diacylglycerol (DAG) content, produced from palm or rapeseed, on fatty acid digestibility in gilthead sea bream (Sparus aurata). Triplicate groups of fish were fed nine experimental diets containing different oils during 28 days. For each source, four different types of oil were used: native, re‐esterified low or high in MAG and DAG and acid. A commercial fish oil was used for the control diet. Diets containing re‐esterified oils had better apparent digestibility coefficients (ADC) of total fatty acids than acid oil diets. Re‐esterified oils do not negatively affect apparent digestibility coefficients of fatty acids when compared to their corresponding native oils and could be incorporated as a source of energy in diets for gilthead sea bream. An improvement in digestibility compared to the native oil diet was only obtained in palm re‐esterified oil high in MAG and DAG.     

Fish meal replacement by soy protein from soymilk in the diets of red sea bream (Pagrus major)

Six isoenergetic diets were formulated as follows: fish meal (FM) 700 g kg^–1 (control, C), FM 300 g kg^–1 + soy protein concentrate 300 g kg^–1 (SPC), FM 300 g kg^–1 + enzyme‐treated SPC 300 g kg^–1 (ESC), FM 170 g kg^–1 + soy protein isolate 300 g kg^–1 (SPI), FM 160 g kg^–1 + enzyme‐treated SPI 300 g kg^–1 (ESI) and FM 150 g kg^–1 + conglycinin 300 g kg^–1(CG). Forty fish (3.9 g) were randomly distributed into each of eighteen 300‐L tanks, fed twice daily until satiation for 8 weeks. The final body weight, specific growth rate and condition factor did not show significant differences among the fish fed with diets C, SPC, ESC and ESI (p > .05). The survival was significantly lower in fish fed with diets SPI and CG. Feed efficiency was significantly higher in fish fed with diets SPC and C than in fish fed with other diets (p < .05). There were no significant differences in nutrients retention efficiencies in fish fed with diets C, SPC, ESC and ESI. A significantly higher phosphorus retention efficiency in fish fed with soymilk protein diets resulted in lower phosphorus discharge to the environment (p < .05). These results suggest that the soymilk proteins can comfortably replace 570–770 g FM kg^–1 diet of red sea bream juvenile, which will ensure significant ecological benefits through reducing phosphorus load to the environment.     

Consumption of feeds containing the antibiotic sulfadiazine by gilthead sea bream (Sparus aurata,L.) and rainbow trout (Onchorynchus mykiss,Walbaum)

A method for studying the efficacy of sulfadiazine as a marker to estimate feed intake is presented. Feeding studies were carried out with two species, rainbow trout as a freshwater fish model and gilthead sea bream as a marine fish model, using two temperatures and two sizes of juveniles. The study showed the different feeding behaviour observed in both species, depending on the temperature and the number of days feeding the particles with sulfadiazine, and confirmed a dominant‐subordinate behaviour especially in the case of gilthead sea bream juveniles.     

Physiological responses of reared sea bream (Sparus aurata Linnaeus, 1758) to an Amyloodinium ocellatum outbreak

Amyloodiniosis represents a major bottleneck for semi‐intensive aquaculture production in Southern Europe, causing extremely high mortalities. Amyloodinium ocellatum is a parasitic dinoflagellate that can infest almost all fish, crustacean and bivalves that live within its ecological range. Fish mortalities are usually attributed to anoxia, associated with serious gill hyperplasia, inflammation, haemorrhage and necrosis in heavy infestations; or with osmoregulatory impairment and secondary microbial infections due to severe epithelial damage in mild infestation. However, physiological information about the host responses to A. ocellatum infestation is scarce. In this work, we analysed the proteome of gilthead sea bream (Sparus aurata) plasma and relate it with haematological and immunological indicators, in order to enlighten the different physiological responses when exposed to an A. ocellatum outbreak. Using 2D‐DIGE, immunological and haematological analysis and in response to the A. ocellatum contamination we have identified several proteins associated with acute‐phase response, inflammation, lipid transport, homoeostasis, and osmoregulation, wound healing, neoplasia and iron transport. Overall, this preliminary study revealed that amyloodiniosis affects some fish functional pathways as revealed by the changes in the plasma proteome of S. aurata, and that the innate immunological system is not activated in the presence of the parasite.     

Effect of dietary medicinal herbs on lipid metabolism and stress recovery in red sea bream <Emphasis Type="Italic">Pagrus major</Emphasis>

The effect of dietary medicinal herbs on lipid metabolism and stress recovery was investigated in red sea bream Pagrus major. Fish (mean body weight 24.0 ± 0.2 g) were fed on test fish meal diets supplemented with either Massa Medicata (Mm), Crataegi Fructus (Cf), Artemisia capillaries (Ac), or Cnidium officinale (Co), or with a mixture of the four herbs (HM) for 12 weeks. A control group was fed a diet without herbs in the same manner. A high survival rate was observed in the herbal diet groups. The final mean body weight, feed efficiency, protein efficiency ratio, and apparent protein and lipid retention in the Ac, Co, and HM groups were higher than those in the control and Mm groups. Final carcass, hepatic lipid and triglyceride contents, and plasma triglyceride and nonesterified fatty acid levels were lower in the Ac, Co, and HM groups compared to those of control and Mm groups. However, final hepatic phospholipid, plasma phospholipid, and high density lipoprotein cholesterol levels were higher in the Ac, Co, and HM diets groups than in the control and Mm groups. The Cf, Co, Ac, and HM groups showed faster recovery time in the 2-phenoxyethanol anesthesia test and a higher recovery rate in the 10-min air exposure test than those of the control and Mm groups. Moreover, the Cf, Ac, Co, and HM diet groups had a significantly lower plasma cortisol level than the control and Mm diet group, but the glucose level in the herbal diet groups was higher than that in the control group after a 1-h air exposure. These results indicate that the addition of medicinal herbs to the fish diet improved lipid utilization and stress recovery in red sea bream.     

黄颡鱼吻端细胞培养研究

采用M199培养基对黄颡鱼(Pelteobagrus fulvidraco)吻端组织进行体外培养研究,继代培养细胞传至第8代。实验结果显示:吻端组织接种培养3~5 h,细胞迁移伸展,6 d后生长细胞集落汇合,每4~6 d递次进行继代培养,培养生长的细胞呈纤维样。比较继代细胞在不同温度(15、27、37℃)和血清浓度(0、10%、20%)条件下的生长,27℃、10%血清的培养条件最适宜吻端细胞的增殖。通过染色体组型分析,证明离体吻端细胞为正常的二倍体细胞。研究结果表明,黄颡鱼离体吻端细胞对温度等培养条件有很强的适应性,培养细胞增殖迅速,具有建立连续细胞系的潜力。     

Price and production trends in the marine fish aquaculture in Spain

The Spanish aquaculture sector has undergone a rapid and continuous growth becoming one of the biggest European producers. A wide range of species are farmed and, among them, the sea bass, sea bream and turbot make a significant contribution to the total of the Spanish fish farming output. In this paper, we analyse and predict the medium-term trend of the production and price level for the three leading species previously mentioned. The results obtained show a significant increase in the production of sea bream, sea bass and turbot. The results show also a slight decrease in the sea bream average price, a stable trends for the sea bass and increasing prices for the turbot.     

饲料中添加纤维素酶对团头鲂生长的影响

在 A、B、C、C0 和 D五组团头鲂鱼种 (体均重 2 .35± 0 .2 0 g)的配合饲料中分别加 0、6 0 0、2 4 0 0、2 4 0 0和 4 2 0 0 U/ kg纤维素酶。其中 B、C、D组中加入的纤维素酶都经过适当的预处理 ,而 C0 组饲料则直接添加 2 4 0 0 U/ kg的纤维素酶。经 56天喂养试验 ,结果显示 :投喂 B、C两组饲料的鱼体增重率分别比 A组提高了 14 .59%和 34.18% ,饲料效率也分别提高 6 .0 6 %和13.6 4 % ;而 C0 和 D组的生长性能则与 A组之间没有显著性差异。     

两种养殖模式下黑鲷肠道及养殖水体菌群结构特征的研究

为了研究池塘流水槽循环水黑鲷养殖模式(IP)和传统池塘黑鲷养殖模式(EP)菌群结构特征,运用高通量测序技术,比较分析2种养殖模式黑鲷肠道和养殖水体中菌群组成结构与功能。结果显示：黑鲷肠道和养殖水体中主要由变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、蓝藻细菌(Cyanobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)和绿弯菌门(Chloroflexi)组成,其丰度之和为98.32%~99.22%;在属水平上,菌属差异明显,IP模式下黑鲷肠道显著增加的菌属包括鲁杰氏菌属Ruegeria(14.84%)、聚球藻属Synechococcus(14.24%)、Marivita(3.58%)、norank_o__PeM15(2.97%)、norank_C__KD4-96(2.56%)(P<0.05) (IP>EP);而EP模式下,黑鲷肠道中肠杆菌属Enterobacter(10.31%)、分支杆菌属Mycobacterium(10.30%)、Romboutsia(7.37%)、肠球菌属Enterococcus(6.29%)、乳球菌属Lactococcus(5.38%)显著增加(P<0.05) (IPP<0.05);IP养殖模式水体菌群丰富度和多样性显著高于EP养殖模式(P<0.05),而黑鲷肠道之间无显著性差异(P>0.05)。2种养殖模式条件下菌群结构存在差异,且存在较多丰度差异显著的菌属。IP模式下黑鲷肠道中具有差异显著的优势菌属大多为有益菌,而EP模式黑鲷肠道多为慢性致病菌或条件致病菌属。