条斑紫菜优良品系(LC-14)的筛选与特性分析

从条斑紫菜(Pyropia yezoensis)绿色突变体和红色突变体种内杂交产生的F_1叶状体中,分离出新品系LC-14。该品系的F_1叶状体在生长速度和品质等方面均显著优于条斑紫菜野生型栽培品系(WT)。日龄70 d的叶状体平均长度和湿重,LC-14品系分别为106.53 cm和3.07 g,分别是WT品系的4.39和10.27倍。培养至第55天,LC-14品系的3种主要光合色素(叶绿素a、藻红蛋白和藻蓝蛋白)含量分别为9.85 mg/g、52.09 mg/g和23.26 mg/g,分别比WT品系提高了65%、65%和49%,而其藻体的平均厚度(20.89μm)反而降低了32%。此外,LC-14品系的壳孢子放散总量为761.32×10~4 ind/壳,是WT品系的1.28倍。上述结果表明,LC-14品系具有生长快、品质优、壳孢子放散量大的优点,藻体颜色与野生色(棕褐色)相近,是条斑紫菜的优良品系,有望在生产中应用。     

印度产紫菜Pyropia chauhanii优良品系的选育与特性分析

为培育出藻体薄且适合在我国南方高水温海区栽培的紫菜新品种,利用~(60)Co-γ射线辐照和高温胁迫处理印度产紫菜Pyropia chauhanii野生型品系(PC-WT)的叶状体,分离出优良品系PC-M,随后通过研究2个品系在耐高温性、生长、主要光合色素含量、单孢子和壳孢子放散量等方面的差异后发现,在18和23°C温度组中,2个品系的壳孢子存活率、分裂率和假根发生率均无显著性差异,但在27和29°C温度组中,PC-M品系的壳孢子存活率比PC-WT品系分别提高了250.7%和305.4%,分裂率分别提高了42.4%和67.1%,假根发生率分别提高了86.6%和175.3%;将在23°C下培养30 d的叶状体分别置于18、23、27和29°C下培养10 d,在18、23和27°C组中,PC-M品系的叶状体绝对生长率分别是PC-WT品系的5.1、5.3和7.5倍,特定生长率分别是PC-WT品系的1.3、1.3和1.8倍;在27°C下培养15 d或在29°C下培养10 d,PC-WT品系的叶状体均放散了大量的单孢子,藻体流失严重,仅剩下基部,而PC-M品系的叶状体均没有放散单孢子、藻体形态完整、光泽好、生长速率快,培养至30 d后才发生轻微的卷曲。与PC-WT品系相比,常温组(23°C)的PC-M品系的3种主要光合色素(chl.a、藻红蛋白和藻蓝蛋白)含量以及壳孢子放散量分别提高了39.4%、209.8%、94.8%和36.7%,但藻体的平均厚度反而减少了31.6%。上述结果证实,与PC-WT品系相比,PC-M品系具有藻体薄、色素含量高、生长快、耐高温、壳孢子放散量大、单孢子不放散等优点,有望被培育成适宜栽培的新品种。     

Improvement of fish meal replacements by soybean meal and soy protein concentrate in golden pompano diet through γ‐ray irradiation

A 5‐week feeding trial was conducted to examine the effect of γ ‐ ray irradiation on the inclusion of soybean meal (SBM) and soy protein concentrate (SPC) in diets of juvenile golden pompano (Trachinotus ovatus). One diet containing 320 g kg^?1 fish meal served as a reference (C), and another four diets were formulated with 75% of the fish meal replaced by SBM (SM), SPC (SC), SBM irradiated with γ ‐ ray at 30 kGy (SM30) or SPC irradiated with γ ‐ ray at 30 kGy (SC30). The weight gain was higher in fish fed diets SM30 and SC30 than in fish fed diets SM and SC, respectively, whereas fish consumed more diet SM30 than diets SM, SC or SC30. No significant differences were found in feed conversion ratio, nitrogen retention efficiency (NRE), phosphorus retention efficiency (PRE), condition factor, hepatosomatic index (HSI), body composition, waste outputs of nitrogen (NWO) and phosphorus (PWO) either between fish fed diets SM and SM30 or between fish fed diets SC and SC30. The weight gain and PWO were higher, but the PRE and the body phosphorus content were lower in fish fed diet C than those in fish fed diets SM30 or SC30. No significant differences were found in the NRE, condition factor, HSI and body composition (i.e. moisture, crude protein, crude lipid and ash) between fish fed diets C and SM30 or between fish fed diets C and SC30. Macromolecular proteins in SBM and SPC were degraded, whereas the contents of peptides with molecular weight <6.5 kDa were increased by γ‐ray irradiation. This study reveals that γ ‐ ray irradiation can improve the performance of SBM and SPC as a fish meal substitute in the golden pompano diet.     

Artificial substratum consisting of poly‐β‐hydroxybutyrate‐based biodegradable plastic improved the survival and overall performance of postlarval tiger shrimp Penaeus monodon

The use of artificial substratum consisting of poly‐β‐hydroxybutyrate (PHB)‐based biodegradable plastic for penaeid shrimp culture was investigated in the present study. The survival of postlarval tiger shrimp Penaeus monodon (30 ± 5 mg) provided with PHB substratum made out of PHB type DP9002 (Metabolix GmbH, Köln, Germany) was 88.7 ± 3.4% and this was significantly higher as compared to postlarvae provided conventional substratum consisting of polyvinylchloride (PVC) pipes (67.3 ± 6.5%). However, no significant weight improvement was observed for the postlarval tiger shrimp indicating that PHB could not be used as growth promoter. Nevertheless, a trend of improved robustness against adverse environmental conditions (lethal ammonium chloride concentration) and increased resistance to pathogenic Vibrio was observed in postlarval tiger shrimp provided with PHB substratum as compared to postlarvae provided with PVC substratum. Results indicate higher preference by postlarvae on PHB substratum over PVC substratum. Overall, this study indicates the potential of artificial substratum consisting of PHB‐based biodegradable plastic as replacement for conventional substratum consisting of PVC pipes in enhancing the survival of postlarval tiger shrimp and improving its performance against adverse environmental conditions and disease resistance.     

Characterization of β‐catenin 1 during the gonad development in the common carp (Cyprinus carpio)

β‐catenin gene is a pivotal gene for gonad development and maintenance of ovarian function in mammals. However, little is known about its expression and function in gonad development of fish. In this study, a complete cDNA (3342 bp) sequence of β‐catenin 1 was cloned from the common carp, Cyprinus carpio, by RACE PCR, which encodes a 780‐amino‐acid protein. Quantitative real‐time PCR demonstrated that β‐catenin 1 mRNA expressions were high in the testis and ovary tissue and the expression increased as the testes developed and the early stage ovaries developed. Western blot results revealed a single immunoreactive band with an estimated molecular weight of 90 kDa in testes. Immunohistochemistry analysis revealed that the β‐catenin 1 protein was concentrated mainly in the cytoplasm of early development stage of oocyte cells and in the cytomembrane of developing and mature sperm cells. 17β‐Ethinylestradiol injecting intraperitoneally into the fish decreased the relative β‐catenin 1 mRNA expression level except 1 μg/g 72 hr and 5 μg/g 48 hr of treatments in the ovary by real‐time PCR. These results suggest, for the first time, that β‐catenin 1 is an essential protein in gonad development and might be involved in ovarian early development of C. carpio.     

坛紫菜与Pyropia radi种间杂交重组优良品系的选育与特性分析

为获得具明显杂交重组优势的紫菜优良品系,实验以印度产紫菜Pyropia radi野生型品系(Pr-WT01,特点:藻体厚、生长慢、韧性好、壳孢子放散量多)为父本,坛紫菜诱变品系(Ph-HMC5,特点:藻体薄、生长快、韧性差、壳孢子放散量少)为母本进行种间杂交,从杂合丝状体产生的F1叶状体中选出4个综合性状优良的杂交重组品系,HR-6品系为其中的最优良品系。父本品系叶状体的绝对生长率最大值为0.39 cm/d,母本品系为5.24 cm/d,而HR-6品系高达9.27 cm/d,在日龄30~50 d期间,它的平均绝对生长率比母本品系的最大生长率还大。日龄60 d的叶状体平均体长父本品系为13.18 cm,母本品系为85.67 cm,而HR-6品系已达218.57 cm,分别是父、母本品系的16.58倍和2.55倍。日龄35 d的HR-6品系叶状体的叶绿素a含量高达9.43 mg/g,比父、母本品系分别增加了50%和20%;另外,它的总藻胆蛋白含量高达99.62 mg/g,分别是父、母本品系的2.18倍和1.74倍。日龄35 d的HR-6品系的叶状体平均厚度为26.22μm,比父本品系降低了37%,比母本品系增加了30%,叶状体的韧性明显增加。HR-6品系的壳孢子放散总量达167.72万个/贝,分别为父、母本品系的1.13和2.65倍。上述研究结果表明,HR-6品系具有生长快、品质好、壳孢子放散量大等优良性状,表现出良好的生产适用性。     

Comparative effect of Freund's adjuvant and Aloe vera L. gel on the expression of TNF‐α and IL‐1β in vaccinated Cyprinus carpio L. with Aeromonas hydrophila C. bacterin

The comparative effects of Freund's and Aloe vera gel as adjuvants on the expression of IL‐1β and TNF‐α genes were studied in vaccinated common carp (Cyprinus carpio) with Aeromonas hydrophila bacterin. Fishes were intraperitoneally immunized with A. hydrophila bacterin in combination with Aloe vera gel or Freund's and also without any adjuvant. At day 28 after immunization, all groups were challenged by lethal dose of A. hydrophila (10⁷ cells/fish). Changes in the expression of IL‐1β and TNF‐α genes were evaluated in anterior kidney before challenge and 12, 24, 72 and 7 days postchallenge using quantitative real‐time PCR. Higher expression levels of both genes were observed in all vaccinated groups compared with non‐immunized group. Fishes which received Aloe vera gel showed higher expression of IL‐1β and TNF‐α in relation to animals which vaccinated with or without Freund's adjuvant. We concluded that Aloe vera gel in compared with Freund's adjuvant had a more stimulatory effect on the expression of immune‐related genes in vaccinated common carp and it can use as a novel adjuvant in aquaculture.     

The effects of different proportions of the 17β‐estradiol and 17α‐methyltestosterone on growth,sex reversal and skin colouration of the electric blue hap (Sciaenochromis ahli Trewavas, 1935)

This study was performed to investigate the effects of 17β‐estradiol (ES) and 17α‐methyltestosterone (MT) on growth, development, survival, sex ratio and colour change in the electric blue hap (Sciaenochromis ahli Trewavas, 1935). The hormones were not supplemented to the control feed, while six other feeds were prepared by adding 20, 40 and 60 mg kg^?1 17β‐ES or 20, 40 and 60 mg kg^?1 17α‐MT to each, resulting in seven different feed treatments. Average live weight of the fish supplemented with these diets was 0.42 ± 0.04 g. At the end of the study, the highest weight gain was observed in fish fed 60 mg kg^?1 17α‐MT group (2.62 ± 0.11 g) and the difference with the groups fed with 17β‐ES was found to be significant. All fish fed 17α‐MT were male, while the rates of feminization in fish fed 17β‐ES at 20, 40, 60 mg kg^?1 were 91.11%, 88.88% and 93.33% respectively. Survival rates were respectively determined as 80%, 95.56%, 84.44%, 93.33%, 77.78%, 84.44% and 84.44% for the control, 20, 40, 60 mg kg^?1 17β‐ES and 20, 40, 60 mg kg^?1 17α‐MT treatments. The best colouration was achieved in the 17α‐MT groups (P < 0.05). The L* values varied between 32.98 ± 4.44 and 61.35 ± 2.19, a* values between ?7.06 ± 0.22 and ?3.42 ± 0.11, and b* values between ?7.74 ± 0.10 and 11.65 ± 0.03, while Chroma (C*) and Hue (H°_ab) angle values varied between 7.54 ± 0.22 and 13.60 ± 0.01 and between 119.76 ± 0.05 and 239.73 ± 4.86. In conclusion, the 17α‐MT feeding was found to have a greater effect on the growth, feed conversion ratio, masculunization and pigmentation of the electric blue haps than the 17β‐ES treatment.     

坛紫菜杂交重组品系的选育与特性分析

坛紫菜选育品系(HR-6)具有叶状体快速生长期的前期生长较快,色素蛋白含量高,但成熟较早,生长期短,丝状体的壳孢子放散量较少等特性;坛紫菜另一个选育品系(HR-5)具有叶状体快速生长期的前期生长较慢,色素蛋白含量高,但成熟晚,生长期较长,丝状体的壳孢子放散量多等特性。为改善HR-6品系叶状体成熟较早,壳孢子放散量较少的弱点,本文以HR-6品系为父本,HR-5品系为母本进行种内杂交,从杂合丝状体产生的F1叶状体中选育出了综合性状更加优良的品系(WD-7)。在叶状体的快速生长前期(日龄30~45d),父本品系的绝对生长率为6.68cm/d,母本品系为3.63cm/d, WD-7品系为6.67cm/d;在叶状体的快速生长中后期(日龄46~60d),父本品系的绝对生长率降至5.15cm/d,母本品系则升至7.27cm/d,而WD-7品系高达11.54cm/d。父本品系的叶状体成熟最早,培养35d左右,大部分个体已成熟;WD-7品系遗传了母本品系成熟较晚的优点,日龄55d之后,大部分个体才出现成熟。日龄35d的叶状体平均厚度,WD-7品系为29.87μm,分别比父、母本品系增加了10%和16%,藻体的韧性明显增强。WD-7品系的壳孢子放散总量为183.42万个/壳,分别是父、母本品系的1.17倍和0.57倍。上述结果证实,WD-7品系不仅遗传了父本品系叶状体快速生长期的前期生长较快的特性,同时又遗传了母本品系叶状体成熟晚、生长期长、中后期生长快的优点,壳孢子放散量也比父本品系有所增加,此品系有望被培育成适宜大规模栽培的新品种。     

Effects of continuous and alternate administration of β‐glucan and mannan‐oligosaccharide on the growth,immunity and resistance against Vibrio splendidus of sea cucumber Apostichopus japonicus (Selenka)

A 4‐week growth trial was conducted to compare the effects of different feeding strategies of dietary immunostimulants on the growth, immunity and resistance against Vibrio splendidus of sea cucumbers Apostichopus japonicus (Selenka). Six feeding strategies were set, including feeding immunostimulants‐free diet continuously (control), feeding dietary β‐glucan (1.25 g kg^?1 diet) continuously, feeding dietary mannan‐oligosaccharides (MOS; 2.00 g kg^?1 diet) continuously, feeding β‐glucan 2 days followed by MOS 5 days alternately, feeding β‐glucan 5 days followed by MOS 2 days alternately and feeding β‐glucan 7 days followed by MOS 7 days alternately. The sea cucumbers fed immunostimulants showed higher specific growth rate (SGR) and lower cumulative mortality than control (P < 0.05). When sea cucumbers were fed with β‐glucan continuously, total coelomocytes counts and superoxide anion were significantly higher than control on the 4th day (P < 0.05). However, these two immune parameters were not significantly higher than those in control after the 18th day (P > 0.05). While sea cucumbers continuously fed MOS, these two immune parameters were not significantly higher than control until the 15th day. All immune parameters of the sea cucumbers fed with β‐glucan and MOS alternately were significantly higher than those in control during the experiment (P < 0.05). The sea cucumbers fed with β‐glucan 7 days followed MOS 7 days alternately showed the highest SGR and second lowest cumulative mortality. It was suggested that this feeding strategy is most suitable for sea cucumbers.     

Purification and characterization of a β–glucan binding protein from the haemolymph of freshwater prawn Macrobrachium rosenbergii

β‐glucan binding protein (βGBP), a pattern recognition protein was purified from the haemolymph of freshwater prawn Macrobrachium rosenbergii by heparin affinity chromatography that showed a single band in native gradient PAGE. The β‐glucan binding property of the purified protein was confirmed in a phenoloxidase (PO) assay, where addition of βGBP along with β‐glucan increased the specific PO activity compared with that of β‐glucan alone. The molecular weight of the βGBP was found to be ~316 kDa on gel filtration chromatography. In SDS‐PAGE, βGBP molecule was reduced to one polypeptide chain of molecular weight ~113 kDa. Thus the βGBP in M. rosenbergii is possibly a homotrimeric molecule. The purified sample run on unreduced condition in SDS‐PAGE also revealed a similar size band (~113 kDa) and hence, the polypeptide chains of βGBP are held by non‐covalent interactions. The purified βGBP samples run in native PAGE was stained positively with alcian blue for carbohydrates and Sudan black for lipids indicating the βGBP to be a glycolipoprotein. With rabbit polyclonal anti‐βGBP serum developed, an indirect ELISA was standardized and the normal βGBP concentration in adult M. rosenbergii serum was quantified to be ~2 mg mL^?1. Furthermore, the applicability of the developed ELISA is discussed.     

Influence of dietary linoleic acid (18:2n‐6) and α‐linolenic acid (18:3n‐3) ratio on fatty acid composition of different tissues in freshwater fish Songpu mirror carp,Cyprinus Carpio

Six isonitrogenous and isoenergetic purified diets were formulated to feed Songpu mirror carp for 60 days. The control diet (CD) was only supplemented with soybean oil. The other five experimental diets contained soybean oil, linseed oil and lard oil blended at various inclusion levels to attain different linoleic acid (LA)/α‐linolenic acid (LNA) ratios (0.53, 1.04, 2.09, 3.95, 6.82) with a constant total C₁₈ polyunsaturated fatty acids (PUFA; LA+LNA, 2% dry weight) content. The fatty acid (FA) profiles of hepatopancreas, dorsal muscle, intestine, intraperitoneal fat (IPF), spleen and kidney reflected those of the diets, but with some differences. The spleen showed the lowest correlation with diet compared with other tissues, followed by the hepatopancreas (P < 0.05). The intestine and IPF showed relatively higher correlation. On the other hand, the control group had the lowest tissue‐diet correlation, followed by the LA/LNA0.53 group (P < 0.05), whereas the LA/LNA2.09 showed the highest. The LA/LNA ratios in the tissues were up‐regulated in the LA/LNA0.53, 1.04 groups and down‐regulated in the LA/LNA3.95, 6.82 groups. This was due to when LA (or LNA) was highly added in diet, the decrease in this FA was huge in tissue. The contents of saturated fatty acids and monounsaturated fatty acids increased in the control group, but seemed not influenced by dietary LA/LNA ratios. These results demonstrated that the FA deposition was tissue‐specific, and also influenced by the dietary FA composition in the experimental fish. Finally, we suggest that 2.09 is the optimal LA/LNA ratio (2% C₁₈ PUFA) of Songpu mirror carp for fillet FA composition.     

Effects of γ‐aminobutyric acid supplementation on the growth performance,serum biochemical indices and antioxidant status of pharaoh cuttlefish,Sepia pharaonis

This study evaluated the effects of dietary γ‐aminobutyric acid (GABA) on the growth performance, serum biochemical indices and antioxidant status of pharaoh cuttlefish, Sepia pharaonis. Cuttlefish were cultured in open‐culturing cement pool systems for 8 weeks. Six practical diets supplemented with graded levels of GABA (0, 20, 40, 60, 80 and 100 mg/kg) were formulated. Each diet was randomly assigned to triplicate groups of 60 cuttlefish (mean weight: 10.33 g), the cuttlefish were fed two times per day to apparent satiation. The results showed that the specific growth rate (SGR), weight gain (WG) and feed efficiency (FE) significantly increased with dietary GABA supplementation (p < .05). The survival rate (SR) and protein content in muscle significantly increased when 58.9 mg/kg GABA supplied. Moreover, the nitric oxide (NO) content and acid phosphatase (ACP) activity in serum were significantly increased with dietary GABA supplementation (p < .05), while the activity of aspartate aminotransferase (AST) in serum decreased significantly when supplied with GABA at 58.9 mg/kg (p < .05). In addition, dietary GABA improved antioxidation activity by significantly increasing the activities of superoxide dismutase (SOD) and catalase (CAT) but decreasing malondialdehyde (MDA) levels in the liver and gill (p < .05). On the basis of the quadratic regression analysis of FE, the optimum content of dietary GABA in S. pharaonis was estimated to be 55.3 mg/kg. The findings of this study demonstrated that dietary GABA had a positive effect on the growth performance, serum biochemical indices and antioxidant status of S. pharaonis.     

Algal density alleviates the elevated CO2‐caused reduction on growth of Porphyra haitanensis (Bangiales,Rhodophyta), a species farmed in China

Growing of Pyropia haitanensis, a commercially farmed macroalga, usually increases their densities greatly during cultivation in natural habitats. To explore how the increased algal densities affect their photosynthetic responses to rising CO₂, we compared the growth, cell components and photosynthesis of the thalli of P. haitanensis under a matrix of pCO₂ levels (ambient CO₂, 400 ppm; elevated CO₂, 1,000 ppm) and biomass densities [low, 1.0 g fresh weight (FW) L^?1; medium, 2.0 g FW L^?1; high, 4.0 g FW L^?1]. Under ambient CO₂, the relative growth rate (RGR) was 5.87% d^?1, 2.32% d^?1 and 1.51% d^?1 in low, medium and high densities, and elevated CO₂ reduced the RGR by 27%, 25% and 12% respectively. Maximal photochemical quantum yield of photosystem II (F_V/F_M) was higher in low than in high densities, so were the light‐utilized efficiency (α), saturation irradiance (E_K) and maximum relative electron transfer rate (rETR_max). Elevated CO₂ enhanced the F_V/F_M in low density but not in higher densities, as well as the α, E_K and rETR_max. In addition, elevated CO₂ reduced the content of chlorophyll a and enhanced that of carotenoids, but unaffected phycoerythrin, phycocyanin and soluble proteins. Our results indicate that the increased algal densities reduced both the growth and the photosynthesis of P. haitanensis and alleviated the elevated CO₂‐induced negative impact on growth and positive impact on photosynthesis. Moreover, the elevated CO₂‐induced reduction on growth and promotion on photosynthesis indicates that rising CO₂ may enhance the loss of photosynthetic products of P. haitanensis through releasing organic matters.     

Characterization of a γ‐aminobutyrate type A receptor‐associated protein gene,which is involved in the response of Portunus trituberculatus to CO2‐induced ocean acidification

The γ‐aminobutyrate type A receptor‐associated protein (GABARAP) is a ubiquitin‐like modifier implicated in membrane trafficking and fusion events involving the γ‐aminobutyrate type A receptor, autophagy and apoptosis. In this study, the gene encoding GABARAP was cloned from swimming crab Portunus trituberculatus (PtGABARAP) based on the expression sequence tag (EST). The full‐length cDNA of 664 bp includes a 5′ untranslated region (UTR) of 87 bp, a 3′ UTR of 223 bp with a poly(A) tail, and an open reading frame (ORF) of 354 bp encoding a polypeptide of 117 amino acids with a predicted molecular weight of 13.96 kDa. The deduced amino acid sequence shares high similarity (93%–100%) with GABARAPs from other species and includes a conserved Atg8 domain. In a phylogenetic analysis PtGABARAP clustered with GABARAPs from other species, and more widely with other GABARAP family proteins. The impact of elevated ocean acidification (OA) on P. trituberculatus behaviours was investigated, and real‐time RT‐PCR revealed that PtGABARAP expression was up‐regulated after OA exposure. Ocean acidification also caused crabs anxiety‐like behaviours, like the shoal average speed increase, preference for dark environment (scototaxis) and fast exploration. The results indicated that GABARAP might be involved in the interactions of GABA_A receptors and elevated‐CO₂ seawater.     

Dietary soybean β‐conglycinin suppresses growth performance and inconsistently triggers apoptosis in the intestine of juvenile grass carp (Ctenopharyngodon idella) in association with ROS‐mediated MAPK signalling

The current study aimed to investigate the effects of dietary soybean β‐conglycinin on growth performance and intestine apoptosis in juvenile grass carp (Ctenopharyngodon idella). For fish fed with the 80 g β‐conglycinin/kg diet for 7 weeks, the specific growth rate and feed intake were decreased. In the proximal intestine, dietary β‐conglycinin did not induce DNA fragmentation, tended to decrease the reactive oxygen species (ROS) content, and decreased ROS‐generating enzyme (NADPH oxidase [NOX]) activity. Subsequently, in the mid‐intestine, dietary β‐conglycinin caused DNA fragmentation, tended to increase the ROS content, increased caspase‐3, caspase‐8 and caspase‐9 activities, upregulated the mRNA levels of proapoptotic molecules (apoptotic protease‐activating factor‐1 [Apaf1] and Bcl‐2‐associated X protein [BAX]) and mitogen‐activated protein kinase (MAPK)‐related signal molecules (Jun N‐terminal kinase (JNK) and p38 MAPK) and increased the protein levels of p38 MAPK and phospho‐p38 MAPK. Moreover, in the distal intestine, dietary β‐conglycinin induced DNA fragmentation, elevated NOX activity and the ROS content and increased caspase‐3, caspase‐8 and caspase‐9 activities, death ligand (TNF‐α) mRNA expression level, and p38 MAPK and phospho‐p38 MAPK protein levels. In summary, dietary soybean β‐conglycinin suppressed fish growth and inconsistently caused apoptosis among the different intestinal segments which was partially associated with ROS‐mediated MAPK signalling.     

Effect of β‐glucooligosaccharides as a new prebiotic for dietary supplementation in olive flounder (Paralichthys olivaceus) aquaculture

β‐Glucooligosaccharides (BGO), produced from barley β‐glucan, were used as a feed supplement (0.1%) for juvenile olive flounder (Paralichthys olivaceus) to identify and quantify its oral administration effects on innate immunomodulation and infectious disease protection. Juvenile flounders (14 ± 0.5 g) were divided into two groups fed either 0.1% BGO (treatment) or a standard diet (control) for 8 weeks. At the end of the experiment, investigation of the effects was carried out through systemic studies on growth performance, serum and mucus biochemical parameters, innate immunity, microvillus length, and relative pro‐inflammatory cytokine gene expression. The results demonstrated that the BGO diet produced slightly higher levels of growth performance, serum protein, microvillus length and pro‐inflammatory cytokine gene (tumour necrosis factor‐α, interleukin [IL]‐1β, and IL‐6) expression without any significant differences (p > .05). All innate immunity parameters were up‐regulated by BGO administration and, among these, respiratory burst, lysozyme and superoxide dismutase (SOD) were significantly different (p < .05). Fish in the both groups were challenged with Streptococcus iniae (1.35 × 10⁸ CFU/ml), and BGO group was focused to confirm the promotion of innate immunity parameters. The results showed a significantly (p < .05) lower death rate compared with that of the control. Therefore, BGO could be used as a new prebiotic in future olive flounder aquaculture as well as to control streptococcosis.     

坛紫菜优良品系的选育与特性分析

利用体细胞克隆技术,从象山湾采集回来的坛紫菜叶状体的体细胞再生群体中筛选出细长型生长快的叶状体,再次进行体细胞克隆,从它的体细胞再生体中再次选育出生长最快的叶状体,依此法连续筛选3次,最后获得一个快速生长的优良品系(XS-1),其F1代的叶状体在生长速度、成熟期、3种主要光合色素含量等方面明显优于野生型品系(wt)。在相同条件下培养80d,XS-1品系的F1代叶状体平均体长达128.8cm,是wt品系的10.45倍;XS-1品系的F1叶状体群体的成熟高峰出现时间比wt品系推迟20d;在波长350～750nm之间,两个品系的叶状体活体吸收光谱中均出现5个吸收峰,但XS-1品系的各峰峰值均远高于wt品系;XS-1品系的叶状体总藻胆蛋白含量高达80.4mg/g,比wt品系提高了188%,而它的Chl.a含量比wt品系提高了32%;XS-1品系的叶状体平均厚度为32.2μm,比wt品系减少15%。研究结果表明,XS-1品系是一个生长快、颜色和品质好、遗传稳定的优良品系,有望在生产中得到应用。     

Effects of α‐lipoic acid on growth performance,body composition,antioxidant profile and lipid metabolism of the GIFT tilapia (Oreochromis niloticus) fed high‐fat diets

The wide use of lipid as a non‐protein energy substitute has led to lipid metabolic problems in cultured tilapia. Therefore, studies that reduce the effects of high‐fat diets in genetically improved farmed tilapia (GIFT) are required. This study evaluated the optimum level and effects of dietary α‐lipoic acid (α‐LA) on growth performance, body composition, antioxidant capacity and lipid metabolism of GIFT tilapia. The basal diet (120 g/kg lipid) was supplemented with six concentrations of α‐LA at 0 (control), L300, L600, L900, L1200 and L2400 mg/kg diet to make the experimental diets, which were fed to GIFT tilapia juveniles (initial body weight: 0.48 ± 0.01 g) for 8 weeks. The weight gain of fish improved significantly in the L300 than other dietary treatments. The intraperitoneal fat index and lipid content of fish fed on the L2400 diet decreased significantly than those fed on the control diet. The activities of superoxide dismutase and glutathione peroxidase (GSH‐Px) in serum and liver were significantly higher in fish fed on the L300 diet than the control. The reduced GSH content of fish fed on the L300 in serum and liver was significantly higher than those fed on control diet. The malondialdehyde content in serum and liver was significantly lower in L300 than in the control. The adipose triglyceride lipase gene was significantly up‐regulated in fish fed on the L2400, but the diacylglycerol acyltransferase 2 gene was down‐regulated in adipose. The liver‐type fatty acid‐binding protein gene in the liver was significantly up‐regulated in fish fed on the L300 and L600 diets. Moreover, the acyl‐coenzyme A oxidase gene in liver was significantly up‐regulated in fish fed on the L300, L600, L900 and L1200 diets. Polynomial regression analysis indicated that 439–528 mg/kg α‐LA is an appropriate dosage in high‐fat diet to improve growth performance and relieve lipid oxidative damage by accelerating lipid catabolism and reducing lipid synthesis in GIFT tilapia.