Dietary soya allergen β‐conglycinin induces intestinal inflammatory reactions,serum‐specific antibody response and growth reduction in a carnivorous fish species,turbot Scophthalmus maximus L.

This study was conducted to investigate the effects of dietary β‐conglycinin on the growth performance, digestion, gut morphology and immune responses of juvenile turbot (Scophthalmus maximus L.). Four diets were formulated to contain 0%, 2%, 4% and 8% purified β‐conglycinin. Triplicate groups of 30 fish were fed to apparent satiation twice daily for 12 weeks. Fish fed 4% and 8% dietary β‐conglycinin showed significantly reduced specific growth rate, feed efficiency ratio, apparent digestibility coefficient of nutrients and whole‐body lipid contents, as well as a profound infiltration of mixed leucocytes in the lamina propria and a significant decrease in the absorptive surface of distal intestine. The expression of pro‐inflammatory cytokines, TNF‐α and IL‐1β, in the distal intestine was significantly upregulated by 4% dietary β‐conglycinin, whereas a significantly lower expression level of IgM and anti‐inflammatory cytokine TGF‐β1 was observed in fish fed 8% dietary β‐conglycinin. Serum lysozyme and alternative complement pathway activity were first significantly enhanced by 2% dietary β‐conglycinin and then rapidly declined by 4% and 8% dietary β‐conglycinin. Respiratory burst activity of head kidney macrophages and serum superoxide dismutase activity were significantly suppressed by 4% and 8% dietary β‐conglycinin. Dietary β‐conglycinin (2–8%) significantly increased the level of specific antibody against β‐conglycinin in serum. Collectively, these results suggested that higher levels of dietary β‐conglycinin (4–8%) induced a variety of non‐specific and specific immune responses and intestinal mucosal lesions in turbot, resulting in inferior feed utilization and poor growth performance.     

1H NMR‐based metabolomics studies on the effect of size‐fractionated fish protein hydrolysate,fish meal and plant protein in diet for juvenile turbot (Scophthalmus maximus L.)

This study was designed to evaluate changes in the metabolic profile of liver and muscle of turbot (Scophthalmus maximus L.) fed fishmeal‐based diet, diets containing size‐fractionated fish protein hydrolysate and plant protein‐based diet using ¹H NMR‐based metabolomics approach combined with the growth. Fish protein hydrolysate (FPH) was obtained by enzymatic treatment, permeate fraction was obtained as UF by ultrafiltered step, and retentate fraction was retained as RF. FM diet contained fish meal used as a single protein source. Four other diets (PP, UF, FPH and RF) contained 180 g kg^?1 diet fish meal. 54, 55 and 55 g kg^?1 dry diet UF, FPH and RF were supplemented to UF, FPH and RF diets. All diets were formulated to be isolipidic and isonitrogenous fed to five triplicate groups of turbot (16.05 ± 0.03 g) for 68 days. O‐PLS‐DA in FM versus UF, FM versus FPH, FM versus RF and FM versus PP resulted in a reliable model for muscle and liver tissue, while O‐PLS‐DA in UF versus FPH and UF versus RF only showed metabolites changes in liver tissue. Results indicated that metabolite changes among the different treatments were consistent with the growth tendency.     

Dietary nucleotides improve the growth performance,antioxidative capacity and intestinal morphology of turbot (Scophthalmus maximus)

A growth trial was conducted to evaluate the effects and safety of nucleotides in low fish meal diets on the growth performance, antioxidative capacity and intestinal morphology of turbot (Scophthalmus maximus). High fish meal control diet was formulated with 500 g kg^?1 fish meal. Seven levels (0.075, 0.15, 0.225, 0.300, 1.5 and 3.0 g kg^?1, respectively) of nucleotides were added to a low fish meal basal diet, which was formulated with 400 g kg^?1 fish meal. The eight experimental diets were fed to groups of juvenile turbot (initial weight: 6.0 ± 0.03 g) for 60 days. Results showed that compared with high fish meal control diet, low fish meal basal diet treatment had lower total antioxidative capacity (T‐AOC), glutathione peroxidase activity, fold height of proximal and distal intestine, enterocyte height of all evaluated enteric section and microvillus height of mid‐intestine and distal intestine (P < 0.05). However, supplemented nucleotides in diets could significantly improve growth (specific growth rate, SGR), feed utilization, antioxidative capacity and intestinal morphology of turbot (P < 0.05). Broken‐line regression analysis of SGR and T‐AOC showed that the optimal supplemental levels of dietary nucleotide for juvenile turbot were 0.366 and 0.188 g kg^?1, respectively. In summary, 0.300 g kg^?1 of dietary nucleotides was helpful in improving growth, feed utilization, antioxidative capacity and intestinal morphology of turbot fed with low fish meal diet. Excessive dietary nucleotides (3.0 g kg^?1) might cause oxidative stress and morphological damage in intestine and then reduce the growth of turbot.     

Nutrient digestibility profile of premium (category III grade) animal protein by-products for temperate marine fish species (European sea bass, gilthead sea bream and turbot)

Three trials, with classical experimental designs for in vivo digestibility studies, were conducted to determine the apparent digestibility coefficient (ADC) of protein (ADCp), lipid (ADCl), energy (ADCe) and amino acids (AA) in selected animal by-products fed to European sea bass, Dicentrarchus labrax (Trial 1), gilthead sea bream, Sparus aurata (Trial 2), and turbot, Psetta maxima (Trial 3). In each trial, five experimental diets [including a reference diet (RD)] where fish meal (FM) was used as the sole protein source were fed ad libitum to the fish for a period of 4 weeks. Test diets were based on the FM RD and obtained by replacing 30% of the RD with a category III designated European animal by-products (fit for human consumption), namely: steam hydrolysed feather meal (HFM), enzyme-treated feather meal (EFM), poultry meat meal (PMM) and spray-dried haemoglobin meal (SDHM). Faecal material was collected using the 'Guelph system', and nutrient and energy digestibility coefficients were related to the measurement of chromic oxide (Cr₂O₃) incorporated into the diet at a rate of 0.5%. Without any exception, FM diets yielded the best digestibility values for all macro-nutrients and by all fish. Among the test ingredients, ADCp was consistently higher for PMM and SDHM in the three species (85.5%, 91.1% in sea bass; 79.2%, 82.8% in sea bream; and 78.4%, 74.8% in turbot). Conversely, ADCp of HFM and EFM were less efficiently digested (67.2%, 68.2% in sea bass; 21.5%, 21.7% in sea bream; and 46.6%, 36.0% in turbot). However, the novel processing method applied to feather meal did not considerably influence the digestibility of most of the nutrients in this feedstuff. The current investigation yielded valuable numerical ADC for EAA considered to be of prime importance in generating balanced diet formulations.     

有水与无水保活运输对大菱鲆生理应激及鱼肉品质的影响

为探究大菱鲆分别在有水及无水条件下运输过程中生理生化指标及肌肉品质的变化,为大菱鲆的保活运输提供参考。将大菱鲆进行暂养、降温、充氧包装后进行模拟运输,并在运输不同时间段取样,检测大菱鲆生理生化指标及肌肉指标。结果显示,模拟运输18 h后,有水运输组和无水运输组中的大菱鲆存活率仍为100%。大菱鲆肌肉中水分含量、粗脂肪、pH、糖原、三磷酸腺苷(ATP)和腺苷酸(AMP)含量显著降低,乳酸和肌苷酸(IMP)含量升高。其中,有水运输组中的大菱鲆AMP含量降低了38.65%,IMP含量增加了29.1%,无水运输组中的大菱鲆AMP含量降低了12.83%,IMP含量增加了28.47%。大菱鲆血液生化指标中,葡萄糖、尿素氮和皮质醇含量显著升高。运输过程后,无水运输组中大菱鲆生理应激及能量代谢指标的变化幅度均小于有水运输处理组中的大菱鲆。此外,低温无水运输组大菱鲆肌肉中呈味核苷酸IMP和AMP含量显著高于有水运输组,表明低温无水运输增加了大菱鲆呈鲜味物质的含量,提高了鱼肉风味。研究表明,低温无水保活技术在活鱼运输中具有广泛的应用前景。     

Application of amplified fragment length polymorphism markers to assess molecular polymorphisms in gynogenetic haploid embryos of turbot (Scophthalmus maximus)

Among the variety of cultured marine species, the turbot Scophthalmus maximus is a fish of growing importance in European aquaculture. In this paper, an advanced application of AFLPs to estimate the genetic diversity of haploid gynogenetic families with the aim of obtaining a preliminary genetic map is presented. Ten EcoRI/TaqI primer combinations were tested in four families comprising diploid mothers and their haploid progenies. The amplified fragment length polymorphism (AFLP) analysis revealed an average of 6.8 polymorphic bands per primer combination and a total number of 88 polymorphisms out of 579 fragments. Among various primer pairs, seven combinations were selected in relation to the quality of profiles and number of polymorphic fragments, to be used in the determination of genetic linkage relationship between AFLP markers within the largest haploid family. Co‐migration of non‐homologous fragments was also investigated in one primer combination adding a fourth selective nucleotide to the three used in the classic TaqI AFLP protocol. Surprisingly, a rate of 38.7% of non‐homologous fragments co‐migrating with monomorphic bands was identified, due to the combined effect of homoplasy and the protocol used. Additional polymorphic markers discovered by this protocol were included in the linkage map. The turbot AFLP linkage map comprises 52 AFLP markers distributed in 12 linkage groups. On the basis of this map, turbot expected total genome length sums up to 1225.6 cM. The results confirm the usefulness of AFLPs in revealing genome segregation in haploid turbot progeny.     

Transition from endogenous to exogenous nutritional sources in larval Black Sea turbot Psetta maxima

ABSTRACT: Early growth, yolk and oil globule absorption, early morphological development and initial feeding were studied in the Black Sea turbot Psetta maxima . Based on energy transition and morphological development, the nutritional transition process from endogenous to exogenous sources was divided into six phases: (i) primordial phase (from hatching to ≈ 30 h after hatching, HAH); (ii) organogenesis phase (to ≈ 90 HAH); (iii) onset of feeding (to ≈ 110 HAH); (iv) early feeding (to ≈ 190 HAH); (v) intensified feeding (to ≈ 230 HAH); and (vi) completion of oil globule absorption (to beyond 345 HAH). Based on comparisons with early life stage features of other marine species, the turbot larvae were shown to possess the following characteristics: (i) oil globule remaining for a long period, resulting in an extended mixed feeding period; and (ii) feeding rate extremely high in larvae immediately following final absorption of the oil globule. These features in early turbot larvae were regarded as advantageous for survival in a rearing condition, although the coincidence of initial feeding with completion of yolk absorption signaled a period of leveled-off growth rate.     

微米纯氧气泡增氧技术养殖大菱鲆效果初探

试验旨在分析新型微米纯氧气泡增氧养殖大菱鲆的效果。试验采用微米纯氧气泡增氧和机械增氧2种方式,设置机械增氧组(溶解氧6~9 mg/L)、微米纯氧增氧Ⅰ组(溶解氧6~9 mg/L)和微米纯氧增氧Ⅱ组(溶解氧15~20 mg/L)3个试验组。结果表明,微米纯氧Ⅰ组大菱鲆的体重增长、成活率、肥满度及饵料转化率高于机械增氧组;微米纯氧Ⅱ组各指标低于机械增氧组。7个月的大规模生产试验(800 m2水面,溶解氧6~9 mg/L)表明,采用微米纯氧气泡增氧养殖大菱鲆,各测定指标均显著高于机械增氧,可以加快大菱鲆生长,提高成活率和饵料转化率。     

Reproduction, gamete supply and larval rearing of New Zealand turbot Colistium nudipinnis (Waite 1910) and brill Colistium guntheri (Hutton 1873): a potential new aquaculture species

New Zealand turbot Colistium nudipinnis (Waite 1910) and brill Colistium guntheri (Hutton 1873) were studied to assess their potential for aquaculture development. The reproductive cycle of wild fish showed a long spawning season from winter to summer, during which it is possible to obtain gametes. Both species have a diurnal ovulatory cycle, and gamete collection, by stripping and fertilizing at sea, was most successful within 2–3 h before and after sunset. Male reproductive anatomy suggests that these flatfish spawn in close proximity and that pair formation is highly likely. The eggs of both species have multiple oil droplets, turbot eggs being slightly larger (0.99 mm diameter) with more droplets (18–55) than brill eggs (0.97 mm, 13–26 droplets). Hatching occurred approximately 84 h after fertilization at 14 °C. Newly hatched turbot averaged 2.2 mm in length, and brill averaged 2.1 mm. First feeding began 4 days post-hatch (DPH). During larval rearing, rotifers were replaced by Artemia nauplii at 10 DPH. Metamorphosis commenced at 12–15 DPH and was completed and the larvae settled by 45 DPH. Weaning to inert foods began at 20–22 DPH (50 mg weight) and was completed by 57 DPH. Survival of turbot was 22.8% from fertilized egg to hatching, 7.3% through incubation to 22 DPH and 2.1% through incubation to fully weaned juveniles. Weaning success for turbot from metamorphosis to 57 DPH was 31.5%.