Transcriptome analysis reveals immune-related genes in tissues of Vibrio anguillarum-infected turbot Scophthalmus maximus

Turbot Scophthalmus maximus is an important mariculture fish species with high economic value.However,the bacterial diseases caused by Vibrio anguillarum infection bring huge economic losses to the turbot aquaculture industry.To understand the immune response of the turbot against V.anguillarum infection and to explore novel immune-related genes,the transcriptome analysis of turbot spleen and gills were conducted after V.anguillarum infection.Differentially expressed genes(DEGs)were identified in spleen and gill of the turbot amounted to 17261 and 16436,respectively.A large number of immunerelated DEGs were enriched in cytokine-cytokine receptor interaction signaling pathway,and the others by the kyoto encyclopedia of genes and genomes(KEGG)enrichment.The gene ontology(GO)classification analysis revealed that V.anguillarum infection had the greatest effect on biological processes and cellular components.Twelve immune-related DEGs were identified in the spleen(cstl.1,egfl6,lamb21,v2rx4,calcr,and gpr78a)and gills(ghra,sh3gl2a,cst12,inhbaa,cxcl8,and il-1b)by heat map.The proteinprotein interaction(PPI)networks were constructed to analyze the immune mechanism.The results demonstrate that the maturation and antigen processing of major histocompatibility complex(MHC)class II molecule,and calcitonin-or adrenomedullin-regulated physiological activity were important events in the immunity of turbot against V.anguillarum infection.In the gills,the protein interactions in TGF-βsignaling pathway,production of inflammatory factors,and endocytosis regulation were most significant.Our research laid a foundation for discovering novel immune-related genes and enriching the knowledge of immune mechanisms of turbot against V.anguillarum infection.

Establishment,Characterization and Expression Pattern of a Spleen Cell Line,SMSP,Derived from Turbot(Scophthalmus maximus)

A turbot(Scophthalmus maximus)cell line named SMSP was obtained from the spleen.The origin of the cells was identified by morphology,chromosome number and COI gene.The optimal basic medium,serum concentration and growth temperature of the cells were detected.SMSP cell line is mainly composed of fibroblast-like cells.Most of the SMSP cells contained 44 chromosomes,and the sequence of COI gene confirmed that the cells were originated from turbot.The optimal culture conditions were 24℃,DMEM+10%FBS.The cell line had high transfection efficiency for siRNA and plasmid.After stimulation with lipopolysaccharide(LPS)or poly(I:C),the expressions of immune-related genes such as TNF-β,IL-12s,IL-10 and IL-1βwere up-regulated significantly in the early stage(P<0.05).This study will provide a model for exploring immune mechanism of turbot against pathogen in vitro.

The ontogeny of acidic digestive tract in larval turbot Scophthalmus maximus based on H+/K+-ATPase and pepsinogen

Acidic digestion is an important digestive process of marine fish.In fish stomach,two enzymes are involved in the secretion of hydrochloric acid(HCl)and proteomic digestion:H^(+)/K^(+)-ATPase and pepsinogen.However,the starting of digestive function in fish is still unclear.To reveal the details of acidic digestion of turbot Scophthalmus maximus in early development,a 40 day of turbot larvae culture was conducted.The H^(+)/K^(+)-ATPase gene from the turbot S.maximus(smH^(+)/K^(+)-ATPase)was identified and characterized.Based on our previous discription on pepsinogen of turbot S.maximus,we combined pepsinogen and H^(+)/K^(+)-ATPase and analyzed the mechanism of acidic digestion in turbot.Results show that the spatial and temporal expression profiles of H^(+)/K^(+)-ATPase agreed with pepsinogen A and C in turbot,indicating a synergetic action between H^(+)/K^(+)-ATPase and pepsinogen during the acidic digestion process.In addition,the turbot juveniles showed a faster growth after the expressions of H^(+)/K^(+)-ATPase gene and pepsinogen gene,demonstrating that pepsin had a higher digestive efficiency,for which a compound diet should be provided to the fish from Day 22 onward.This study provided a reference for biology research and aquaculture of turbot and other marine fishes.

不同铁水平饲养对大菱鲆(Scophthalmus maximus)生长及耐低氧能力影响的研究

铁元素作为细胞色素的重要成分参与鱼类细胞内的氧化还原供能过程,在鱼类应对低氧胁迫时发挥重要作用。以硫酸亚铁为铁源,研究不同铁水平饲养对大菱鲆(Scophthalmus maximus)生长及耐低氧能力的影响。在含铁量为463 mg/kg的基础饲料中添加0(A组)、75(B组)、150(C组)、225(D组)和300(E组)mg/kg铁离子,探究不同铁水平饲喂对大菱鲆常氧下的生长、血清生理生化指标以及抗低氧胁迫的影响。结果显示,常氧情况下,随着饲料中铁含量的增加,上述指标呈先增加后下降的趋势(P<0.05),且C、D组均为峰值显著高于A、B、E三组(P<0.05)。低氧胁迫及耐受实验结果显示,随着低氧胁迫的加剧,C、D两组抗氧化酶活性(SOD,GSH-PX)、低氧[DO=(2.0±0.5)mg/L]死亡率均显著高于或低于其他三组(P<0.05)。铁作为重要的氧载体和电子传递体影响着生物体的物质代谢和能量代谢。研究表明饲料铁水平613~688 mg/kg的饲养对大菱鲆生长性能、抗氧化系统的增强和提高低氧耐受能力具有促进作用,研究结果可为鱼类健康养殖和功能性饵料研制提供新数据支撑。

大菱鲆(Scophthalmus maximus)热休克蛋白SmHsp47相互作用蛋白His-pull down和质谱鉴定

首次克隆了大菱鲆(Scophthalmus maximus)热休克蛋白SmHsp47基因。该基因cDNA序列全长为1927 bp,其中开放阅读框长度为1218 bp,编码一条长度为405个氨基酸的多肽链。结果表明,大菱鲆SmHsp47基因在肝脏、皮肤、鳃和肠等4个组织中都有表达,表达量最高的组织是肝脏,表达量最低组织是鳃;25℃处理6 h后SmHsp47在皮肤中的表达量增加150多倍。利用大肠杆菌原核表达系统表达了SmHsp47的his标签融合蛋白,然后利用His-pull down技术捕获了SmHsp47的相互作用蛋白质,通过质谱分析鉴定出31种候选蛋白,其中大部分蛋白为参与翻译后修饰,蛋白转换及分子伴侣;此外还包括参与脂转运与代谢、能量产生与转换、细胞骨架、防御机制等过程的蛋白质。从31种候选蛋白中进一步筛选出3种分值较高的蛋白:未知蛋白(uncharacterized protein,A0A6A4TFV0)、胎球蛋白B(Fetuin B,A0A2U9C388)和胶原结合蛋白(collagen-binding protein,A0A2U9B608),可为后续的研究提供方向。

Studies on the edwardsiellosis and characterization of pathogenic bacteria from diseased flounder (Paralichthys olivaceus L.) and turbot (Scophthalmus maximus L.)

Edwardsiellosis of flounder and turbot occurring in different mariculture farms during 2001～ 2004 was examined, including the conditions of disease occurrence, clinical signs and pathological changes. The results showed that all diseased fishes expressed bacterial septicaemia. A total of 148 strains were identified using a combination of traditional physiological and biochemical tests and partial 16S rRNA gene analysis. In addition, the mole fraction G ＋ C ratio of the DNA of representative strain of isolates and serum homology were detected, and pathogenicity tests of isolates were conducted by experimental infection. The results revealed that 148 strains were identified as E. tarda of genus Edwardsiella, all the isolates are of serologic similarity, and have strong pathogenicity to flounder and turbot.

Effects of Dietary Carbohydrate-to-Lipid Ratio on the Growth Performance and Feed Utilization of Juvenile Turbot(Scophthalmus maximus)

A 9-week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio(CHO:LIP) on the growth performance and feed utilization of juvenile turbot Scophthalmus maximus(initial body weight 8.75 g ± 0.04 g). Four isonitrogenous and isoenergetic low protein level(39%) diets were formulated with increasing ratios of dietary carbohydrate to lipid(2:18, 6:18, 18:12 and 28:6). A high protein level(50%) diet with the 2:12 ratio of carbohydrate to lipid was used as the control. Results showed that the survival rate, contents of moisture, crude protein and ash in muscle were not significantly affected by dietary treatments. With the dietary CHO:LIP ratio increased from 2:18 to 18:12, weight gain rate significantly increased(P < 0.05). Higher dietary CHO:LIP ratio(28:6) resulted in the significantly decreased weight gain rate(P < 0.05). Meanwhile, this treatment also resulted in the highest daily feed intake and liver glycogen content, as well as the lowest feed efficiency(P < 0.05). Muscle glycogen content in fish fed the diet with 2:12 or 2:18 CHO:LIP ratio was significantly lower than those fed with the other three diets(P < 0.05). The present results confirmed that the juvenile turbot can utilize carbohydrate. Furthermore, the appropriate ratio of dietary carbohydrate to lipid was important to the growth and feed utilization of turbot. The proper CHO:LIP ratio based on the growth performance in the present study was determined to be 18:12 when the dietary protein level was 39%.

Genetic parameter estimation for juvenile growth and upper thermal tolerance in turbot(Scophthalmus maximus Linnaeus)

Twenty-six half-sib groups （53 full-sib families） of turbot,Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring （40-50 individuals/family） and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mor-tality （range： 0.580%-1.391%） between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 （20.232% and 34.377%, respectively）. Mortality was highest on Day 16 （14.145%）. We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods （maximum log L）. Lastly, we estimated phenotypic and genetic correlation between the up-per thermal tolerance limit （UTT） and body weight （BW）. In this study, the positive phenotypic correlation was low between UTT and BW （0.093±0.029）. The genetic correlation between UTT and BW was negative （-0.044±0.239）. The heritability for upper thermal tolerance was low （0.087±0.032）, which is of approximate-ly moderate heritability. The heritability for body weight was high （0.303±0.074）. Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.

Developmental quantitative genetic analysis of body weights and morphological traits in the turbot, Scophthalmus maximus

In order to elucidate the genetic mechanism of growth traits in turbot during ontogeny, developmental genetic analysis of the body weights, total lengths, standard lengths and body heights of turbots was conducted by mixed genetic models with additive-dominance effects, based on complete diallel crosses with four different strains of Scophthalmus maximus from Denmark, Norway, Britain, and France. Unconditional genetic analysis revealed that the unconditional additive effects for the four traits were more significant than unconditional dominance effects, meanwhile, the alternative expressions were also observed between the additive and dominant effects for body weights, total lengths and standard lengths. Conditional analysis showed that the developmental periods with active gene expression for body weights, total lengths, standard lengths and body heights were 15–18, 15 and 21–24, 15 and 24, and 21 and 27 months of age, respectively. The proportions of unconditional/conditional variances indicated that the narrow-sense heritabilities of body weights, total lengths and standard lengths were all increased systematically. The accumulative effects of genes controlling the four quantitative traits were mainly additive effects, suggesting that the selection is more efficient for the genetic improvement of turbots. The conditional genetic procedure is a useful tool to understand the expression of genes controlling developmental quantitative traits at a specific developmental period（t-1→t） during ontogeny. It is also important to determine the appropriate developmental period（t-1→t） for trait measurement in developmental quantitative genetic analysis in fish.

Rearing in intermediate salinity enhances immunity and disease-resistance of turbot (Scophthalmus maximus L.)

Studies were conducted to investigate the non-specific immune responses and disease-resistance of juvenile turbot Scophthalmus maximus,cultured at four different salinities（8,20,32 and 40） . Three concentrations（3.75 × 10 7,3.75 × 10 8 and 3.75 × 10 9 CFU/ml） of Vibrio anguillarum suspension were employed at each salinity to determine the 4-day LD 50 . The serum lysozyme activity,the alternative complement pathway activity（ACH50） and the phagocytosis percentage of head kidney in turbot were tested at 24,48 and 72 h post-challenge of V. anguillarum（1.1 × 10 8 CFU/ml,0.1 ml） ,respectively,to evaluate the non-specific immune responses at the selected rearing salinities. Fish reared at salinity 20 had the lowest mortality,namely,the highest 4-day LD 50 value（8.88 ± 0.17） . Besides,the lysozyme activity,ACH50 and the phagocytosis of turbot were the highest at the salinity 20,but with the lowest at the salinity 40 treatment regardless of sampling time. In addition,the non-specific immune activities kept increasing within 72 h post-challenge of V. anguillarum,except that the lysozyme activity increased from 24 to 48 h,and then decreased from 48 to 72 h at 40 significantly. These results together indicate that rearing in intermediate salinity（20） was able to enhance the immunity and disease-resistance of turbot.

Transcriptomic analysis reveals putative osmoregulation mechanisms in the kidney of euryhaline turbot Scophthalmus maximus responded to hypo-saline seawater

Turbot harbor a relatively remarkable ability to adapt to opposing osmotic challenges and are an excellent model species to study the physiological adaptations of flounder associated with osmoregulatory plasticity.The kidney transcriptome of turbot treated 24 h in water of hypo-salinity(salinity 5)and seawater(salinity 30)was sequenced and characterized.In silico analysis indicated that all unigenes had significant hits in seven databases.The functional annotation analysis of the transcriptome showed that the immune system and biological processes associated with digestion,absorption,and metabolism played an important role in the osmoregulation of turbot in response to hypo-salinity.Analysis of biological processes associated with inorganic channels and transporters indicated that mineral absorption and bile secretion contributed to iono-osmoregulation resulting in cell volume regulation and cell phenotypic plasticity.Moreover,we analyzed and predicted the mechanisms of canonical signaling transduction.Biological processes involved in renin secretion,ECM-receptor interaction,adherens junction,and focal adhesion played an important role in the plasticity phenotype in hypo-stress,while the signal transduction network composed of the MAPK signaling pathway and PI3K-Akt signaling pathway with GABAergic synapse,worked in hypoosmoregulation signal transduction in the turbot.In addition,analysis of the tissue specificity of targeted gene expression using qPCR during salinity stress was carried out.The results showed that the kidney,gill,and spleen were vital regulating organs of osmotic pressure,and the osmoregulation pattern of euryhaline fish dif fered among species.

Genetic parameters and response to selection for body weight in turbot(Scophthalmus maximus, Linnaeus)

Genetic parameters and response to selection were estimated for harvest body weight in turbot. The data consisted of 10 952 individuals of 508 full-sib families from three generations（G0, G1, and G2）. The heritability estimates for G0, G1, and G2 were 0.11±0.08, 0.18±0.09, and 0.17±0.07, respectively. Over three generations, the heritability estimate was 0.19±0.04. Maternal and common environmental effects were 0.10±0.04, 0.14±0.04, and0.13±0.03 within each generation and 0.12±0.01 across generations. The selection differential in growth was 18.24 g in G0 and 21.19 g in G1 corresponding to an average of 19.72 g per generation. The genetic gains were also calculated, they were 22.06 g in G1 and 11.93 g in G2, corresponding to 6.36% and 3.52% body weight. The total genetic gain after two generations was 10.10% body weight, which indicated that the selective breeding program for the body weight trait in turbot was successful.

Estimates of heritability and correlation for growth traits of Turbot(Scophthalmus maximus L.) under low temperature conditions

The objectives of this present research were to assess the heritability of growth traits under low temperature conditions in turbot（Scophthalmus maximus L.）, and to analyze the correlation between body weight（BW） and body length（BL）. There were 536 individuals from 25 full- and half-sib families involved in this study. During the entire 90-day period, which was initiated at 233 dph（day old） and ended at 323 dph, the individuals＇ BW and BL were weighed consecutively six times every 18 days. The heritability of BW and BL and the correlation between these two traits were estimated based on an individual animal model with the derivative-free restricted maximum likelihood（DFREML） method. These results showed that the specific growth rates（SGR） of 25 families was from 0.75±0.11 to 1.05±0.14 under water temperature of 10.5–12°C. In addition, the heritability of BW and BL estimated under low-temperature were 0.32±0.04 and 0.47±0.06, respectively. The BW had a medium heritability（0.2–0.4）, and the BL had a high heritability（〉0.45）, which suggested that selection for increased weight and length was feasible. Moreover, there was potential for mass selection on growth. The genetic and phenotypic correlations between BW and BL were 0.95±0.01 and 0.91±0.01（P 〈 0.01）, respectively. A significant correlation between BW and BL showed that BL could be instead of BW for indirect selection, which could be effectively implemented in the breeding program.

Stocking density effects on growth and stress response of juvenile turbot(Scophthalmus maximus) reared in land-based recirculating aquaculture system

Stocking density is widely recognized as a critical factor in aquaculture and a potential source of long-term stress.The influence of stocking density on growth and stress response of juvenile turbot（Scophthalmus maximus, ~3–75g, initial to final weight） was examined in fish held under low（LD, ~0.21–5.31 kg/m^2, initial to final density）,medium（MD, ~0.42–10.81 kg/m^2） and high stocking density（HD, ~0.63–14.27 kg/m^2） for 120 days in a recirculating aquaculture system（RAS）. In this trial, the growth curve for weight of juvenile turbot in RAS, all fitted by the Schnute model. No significant difference was found in growth performance among the three densities until at the final sampling（Day 120）. The final weight and body weight increase（BWI） in the HD group were significantly lower than in other groups（P〈0.05, weight：（75.83±2.49） g,（75.39±2.08） g,（65.72±2.86） g and BWI：（2 436.12±28.10）%,（2 421.29±4.64）%,（2 097.88±20.99）% in LD, MD and HD groups, respectively）. Similarly, the specific growth rate（SGR）, feed conversion ratio（FCR） and coefficient of variation for weight（CV_w） were adversely affected by high stocking density（P〈0.05）. However, there was no difference in survival and Fulton＇s condition factor（K） of turbot among the different groups. Physiological analyses demonstrated a clear increase in the plasma cortisol level and an obvious decrease in growth hormone（GH） concentration in the HD group on Day120（P〈0.05）. There was no significant effect of stocking density on plasma glucose, Cl– and protein levels. All these findings would provide a reference for selecting the optimal stocking density of juvenile turbot in RAS.

大菱鲆幼鱼视网膜结构及不同光谱下视蛋白基因表达特征的研究

大菱鲆(Scophthalmus maximus)是中国重要的养殖鱼类之一,其生活史经历不同的栖息地和光环境,视觉器官结构及视觉功能也具有适应性发育特征和可塑性。本研究以不同发育阶段的大菱鲆幼鱼为对象,探究了其视网膜结构变化、视蛋白基因的表达特征及其与光谱之间的关系。结果表明,随着大菱鲆幼鱼的生长发育,其视网膜的外核层逐渐变厚;视锥视杆层的厚度变化不明显;而内核层与神经节细胞层逐渐变薄。视紫红质基因rh1与视蛋白基因总表达量的比例上升,由2月龄的57.35%上升到9月龄77.19%;视锥蛋白基因与视蛋白基因总表达量的比例下降;其中红视蛋白基因lws由2月龄的4.49%下降至9月龄的0.13%。将7月龄的大菱鲆幼鱼用不同光谱处理75d后,其视蛋白基因的表达会随光谱环境的变化而发生改变。与全光谱相比, rh2b1、sws2、sws1在红、黄光下的表达量显著下降,而rh2b1在蓝、绿光下表达显著上升、sws2在绿光下表达显著上升,其他则变化不显著(P<0.05)。黄、绿、蓝及全光谱下rh2基因家族与视蛋白基因总表达量的比例最高,而红光下基因rh1的表达量占比最高。大菱鲆幼鱼在不同阶段以及不同光谱处理下表现出了视蛋白基因表达的可塑性以适应不同水层的光谱环境。本研究为探究大菱鲆对光环境的适应机制及工厂化养殖光照调控技术的建立提供理论参考。

水位深度对工厂化流水养殖大菱鲆生长的影响

为探讨水深对工厂化流水养殖水环境的影响,本实验将9000尾初始体质量为141.62±24.47 g的大菱鲆(Scophthalmus maximus)按照低水深(20 cm)、中水深(40 cm)、高水深(60 cm)条件分为3个不同养殖水深组,实验周期为80 d。实验期间,跟踪检测长期和特定时期(投喂后8 h内)不同养殖水深水体中总氨氮(TAN)、亚硝酸盐(NO2–-N)、固体悬浮物(SS)、化学需氧量(COD)等参数,并在实验结束时对大菱鲆成活率、体质量、饲料系数水平进行测量。研究表明,水池内水流速度与水深呈负相关,但各组间无显著性差异。高水深组的固体悬浮物含量显著(P<0.05)低于其他两组,低水深组的化学需氧量显著(P<0.05)低于其他两组,各水深组中氨氮、亚硝酸盐都在大菱鲆幼鱼安全浓度范围内,且无显著性差异。在投喂后,固体悬浮物含量在各水深组中呈先升高后降低趋势,其中低水深组波动最大。氨氮含量在投喂后3 h开始上升,其中低水深组涨幅最大。各水深组中化学需氧量随着投喂时间延长而逐渐积累,而亚硝酸盐含量基本保持不变。实验结束,低水深组中大菱鲆增质量率、特定生长率、体质量变异系数均显著(P<0.05)高于高水深组,而存活率、肥满度、饲料系数在各组之间没有显著差异。研究结果显示,增加水深有利于提高养殖水环境水质恶化的缓冲能力。在保证养殖系统水质指标安全的前提下,低水深在大菱鲆工厂化流水养殖中是一个可行的方案。

芒果叶黄酮浸膏促进大菱鲆生长的研究

该试验以大菱鲆(Scophthalmus maximus)为试验对象,研究芒果叶黄酮浸膏对大菱鲆生长的影响。试验选择一批大小接近、健康度良好的大菱鲆幼苗,共100尾,进行随机分组,分为对照组和试验组两组,每组50尾,对照组饲喂基础日粮,试验组饲喂添加7%芒果叶浸膏的基础日粮,试验期30d,试验过程记录每尾大菱鲆的初始平均体重、试验末期平均体重、存活尾数、初始平均体长、试验末期体长,通过计算成活率、质量相对增长率、饲料系数、体长增重率来判断芒果叶黄酮浸膏促进大菱鲆生长的作用。试验结果显示,添加芒果叶黄酮浸膏组的质量增长率、成活率和对照组相比差异显著(P<0.05),试验组的体长增长率与对照组比也有增长的趋势,但是差异不显著(P>0.05)。研究表明,芒果叶浸膏能促进大菱鲆体重增长、提高其成活率,对其生长起到促进作用。

核糖蛋白替代鱼粉对大菱鲆幼鱼生长性能的影响

该试验旨在研究核糖蛋白替代饵料中鱼粉对大菱鲆(Scophthalmus maximus)幼鱼生长性能的影响,探讨核糖蛋白(Ribosomal protein)替代鱼粉的可行性,并确定最适的替代比例。试验选择体质健壮、体重约为25g的大菱鲆幼鱼400尾,随机分成4组,每组5个重复,每个重复20尾大菱鲆幼鱼。对照组大菱鲆幼鱼投喂基础饵料,试验各组大菱鲆幼鱼分别投喂使用核糖蛋白替代1%、1.5%和2%鱼粉的试验饵料。饲喂8周后,检测各组大菱鲆幼鱼的生长性能。结果表明,在大菱鲆幼鱼饵料中使用核糖蛋白替代1.5%的鱼粉可以显著提高试验末重和增重率,分别比对照组显著提高了5.36%和10.53%(P<0.05);使用核糖蛋白替代1%、1.5%和2%的鱼粉可以使特定生长率分别显著提高7.14%、11.90%、8.73%(P<0.05);使用核糖蛋白替代1.5%的鱼粉可以显著降低大菱鲆幼鱼的饵料系数,显著降低了13.41%(P<0.05)。综上所述,在大菱鲆幼鱼养殖中使用核糖蛋白替代饵料中1.5%的鱼粉对其生长性能效果最优。

中草药对大菱鲆机体非特异性免疫力的影响

该试验以大菱鲆(Scophthalmus maximus)为研究对象,探究不同水平的中草药制剂对其机体非特异性免疫功能的影响,并确定中草药制剂在大菱鲆养殖中的最适添加水平。试验选择120尾体重相近、健康的大菱鲆按照单因素试验设计,分成4组,每组30尾大菱鲆。对照组大菱鲆投喂基础饲料,试验1组大菱鲆投喂基础饲料+0.5%的中草药制剂,试验2组大菱鲆投喂基础饲料+1.0%的中草药制剂,试验3组大菱鲆投喂基础饲料+1.5%的中草药制剂,试验周期为4周。试验结束检测各组大菱鲆血清非特异性免疫指标。结果表明,试验2组大菱鲆血清中的溶菌酶、补体C3和过氧化氢酶水平显著高于对照组(P<0.05),而试验1组和试验3组大菱鲆血清中的溶菌酶、补体C3和过氧化氢酶水平有比对照组提高的趋势,但未达到显著性水平(P>0.05)。研究表明,在大菱鲆饲料中添加适量的中草药制剂可以提高机体的非特异性免疫力,且中草药的最适添加水平为1.0%。

家禽副产物酶解肽对大菱鲆抗氧化功能的影响

试验旨在研究家禽副产物酶解肽对大菱鲆(Scophthalmus maximus)机体抗氧化功能的影响,探讨家禽副产物酶解肽替代基础饵料中鱼粉的最适水平。试验选择400尾体重约为10g的健康、大小均匀的大菱鲆,按照单因素试验设计,分成4个处理组,每组5个重复,每个重复20尾大菱鲆。对照组大菱鲆投喂基础饵料,试验组大菱鲆分别投喂含有5%、10%、15%家禽副产物酶解肽的试验饵料,等量替代基础饵料中的鱼粉。养殖60d。试验结束,每组选择10尾大菱鲆采集血液及肝脏样品,测定抗氧化指标。结果显示,试验2组大菱鲆血清中丙二醛水平显著低于对照组,降低了32.99%(P<0.05);超氧化物歧化酶活性比对照组显著提高了10.79%(P<0.05)。试验2组大菱鲆肝脏中丙二醛水平比对照组显著降低了42.86%(P<0.05)。研究表明,在大菱鲆养殖生产中使用家禽副产品酶解肽替代部分鱼粉可以改善机体的抗氧化性能,且家禽副产物酶解肽替代鱼粉的最佳水平为10%。