Apparent digestibility coefficients of selected feed ingredients for juvenile snakehead,Ophiocephalus argus

Apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, gross energy, phosphorus and amino acids in Peruvian fish meal, poultry by‐product meal, meat and bone meal, spray‐dried blood meal, hydrolysed feather meal, corn gluten meal, soybean meal, peanut meal, cottonseed meal and rapeseed meal were determined for juvenile snakehead (Ophiocephalus argus) with initial mean body weight of 78.1 g. A reference diet and test diets that consisted of a 70 : 30 mixture of the reference diet to test ingredient were used with 5 g kg^?1 Cr₂O₃ as an external indicator. Fish meal, poultry by‐product meal and corn gluten meal had higher ADCs of dry matter, crude protein, and gross energy among ingredients tested. Dry matter ADCs ranged 61.9–81.5% for animal ingredients and corn gluten meal and ranged 52.2–68.0% for soybean meal, peanut meal, cottonseed meal and rapeseed meal. Energy ADCs of ingredients followed similar trends to differences in dry matter digestibility. Protein ADCs of animal and plant ingredients ranged 73.6–92.8% and 75.3–85.6%, respectively. Amino acid ADCs generally reflected protein digestibility. Lipid ADCs were relatively high for the ingredients tested. Phosphorus ADCs of animal and plant ingredients ranged 39.5–65.2% and 38.7–57.1%, respectively.     

Bacterial Flora in Turbot Scophthalmus maximus Cultured in Deepwell Seawater of Liaodong Peninsula

The microbial flora in turbot (Scophthalmus maximus) cultured in deepwell seawater from Liaodong Peninsula, China was studied for the first time. The total amount of aerobic meso- and psychrophilic microflora from the culturing water, gills, and skin were 3.46–3.82, 3.19–4.28, and 1.70–1.95 log cfu/g, respectively. Out of 204 strains isolated from fresh turbot meat with skin, Gram-positive bacteria accounted for 19.2% of the total aerobic meso- and psychrophilic microflora, and 72.1% were Gram-negative bacteria. Phylogenetic analysis was performed using 16S rDNA sequences of microbial flora isolated from turbot. The predominant bacteria in fresh turbot were Micrococcus, Serratia liquefaciens, and Enterobacteriaceae. Meanwhile, the bacterial flora of refrigerated turbot fish were investigated, and the results indicated that Shewanella putrefaciens was the predominant spoilage bacteria.     

沈阳市水产加工品销售市场调查及展望

本文调查了沈阳市水产加工品销售市场的情况。并提出了沈阳市乃至我省水产加工业的未来设想。     

就地取材养殖青虾技术探讨

河南地处中原,有淮河、长江、黄河、海河四大水系流经我省,尤其是淮河水系上游,大、中、小水库星罗棋布,黄河故道和黄河湿地也大量分布。这些水库和湿地水质清澈,水草丰盛,无污染,盛产青虾。在当前水产养殖业不景气,投入产出比例失调的情况下,利用本地盛产青虾的有利条件,就地取材养殖青虾,是调整水产养殖结构,引导渔农致富的好路子。现将有关技术和经验总结如下。青虾,学名日本沼虾,属广温性动物,主要摄食植物碎片和有机物碎屑。在人工饲养条件下,主要以麸皮、玉米、豆粕等为主食并辅以动物性饲料,如野杂鱼、螺、猪牛羊下脚料。青虾在人工…     

中国观赏鱼产业发展概况

观赏鱼养殖从20世纪80年代开始在我国初具规模,其发展具有产业链延伸较广、产品附加值较高、生产要素集约性较强、产业运营模式较多、单位面积产出较高等五项独特的优点。本文对养殖较为广泛、产业发展带动较强的几大观赏鱼品种进行了剖析:①七彩神仙鱼作为中高档热带观赏鱼的代表种类之一,市场潜力巨大;②锦鲤是大众化的养殖品种,目前规模化的养殖初具规模,产业逐渐走上正轨,但产业附加值和技术含量有待提升;③龙鱼和其他热带观赏鱼品种较多,高端的龙鱼主要来自国外,部分热带观赏鱼可实现国内生产,销往国外。同时,提出了我国观赏鱼产业发展的深层次问题:①要以科技为先,加强新品种的开发;②增强大众意识;加速市场的整顿;③改进市场营销模式;④培育健康的生态养殖模式;⑤拓展市场,开发新领域等,以使观赏鱼产业更好更快地发展。     

Cloning,expression, and induction by 17-β estradiol (E<Subscript>2</Subscript>) of a vitellogenin gene in the white cloud mountain minnow <Emphasis Type="Italic">Tanichthys albonubes</Emphasis>

Vitellogenins (Vtgs), the precursors for the yolk proteins, are very important for the embryonic development of teleosts, and have also been studied extensively as biomarkers for environmental estrogenic mimics. The cDNA for a Vtg was isolated from the liver of the female white cloud mountain minnow (Tanichthys albonubes) by 3′- and 5′-RACE methods. It is 4,171 bp in full length, and encodes a putative protein of 1,326 amino acids. This putative Vtg, designated as wcmmVtg, contains complete portions of LVI and PV, but lacks the C-terminal half of LVII and thus belongs to type I vitellogenin. In addition to the liver of the female fish, wcmmVtg was also shown to be expressed in the ovary. During ovarian development, the mRNA expression of wcmmVtg in both the liver and ovary was continuously increased from the previtellogenic to late vitellogenic stages, but then decreased significantly at post-spawning stage. In the male fish, expression of wcmmVtg mRNA was induced in the liver by treatment with E₂ (10 and 100 ng/l) for 14 days. These results suggest that the Vtg originated from the ovary of the white cloud mountain minnow may also contribute to the accumulation of yolk proteins during oocyte growth, and that the male white cloud mountain minnow is sensitive to the estrogenic treatment in terms of Vtg mRNA expression, which could also be applied to monitor the environmental estrogenic mimics.     

藻类光生物反应器研究进展

微藻在转化太阳能和生产各种代谢产物方面有着广泛的应用价值和潜力。解决藻类大量培养的关键问题是研制和开发出光能利用率较高,成本相对低廉、可以大规模化生产的光生物反应器。本文概述了光生物反应器的研究历史,现状和应用前景。     

Accumulation flux of nitrogen in mudflats and its implications for benthic shellfish culture

In order to evaluate impacts of benthic shellfish culture on sediments in the Daguhe Estuary, surface sediments are sampled in February, May, August and November 2009 and the water content and nitrogen content of sediment, accumulation flux of nitrogen are studied. About 40 % of the mudflat in the estuary is used for bottom sowing culture for Manila clam Ruditapes philippinarum. The seeding density is 1.1–1.5 kg m^?2 in the estuary if the mean weight of juvenile clam is 0.3–0.5 g. Moreover, the stock density of cultivated clam that can be harvested (with mean weight 8 g) is 450–1,600 individual m^?2, and the annual yield of this species of clam is about 3.4 kg m^?2. There is significant spatial difference of water content of sediment from February to November, during which the water content in the uncultured mudflat, the cultured mudflat and the river way is 32.07, 43.95 and 37.69 %, respectively. There is no significant spatial difference of TN (total nitrogen) content of sediment, and the TN content in the cultured mudflat, the uncultured mudflat and the river way is 0.26, 0.22 and 0.29 mg g^?1, respectively. Moreover, the IN (inorganic nitrogen) content of sediment in the cultured mudflat, the uncultured mudflat and the river way is 0.09, 0.08 and 0.14 mg g^?1, which implies that there is no significant spatial difference of IN content. Furthermore, there is no significant spatial difference of EN (exchangeable nitrogen) content of sediment from February to November, during which the EN content in the uncultured mudflat or the river way is about 0.04 μg g^?1 and it is 0.03 μg g^?1 in the cultured mudflat. Thus, the benthic shellfish culture may increase the water content and there is no significant effect of benthic shellfish culture on nitrogen content. The accumulation flux of TN in the cultured mudflat, the uncultured mudflat and the river way is 0.94, 1.13 and 1.40 mg cm^?2 year^?1. The accumulation flux of IN in the cultured mudflat, the uncultured mudflat and the river way is 0.31, 0.39 and 0.66 mg cm^?2 year^?1. Moreover, the accumulation flux of EN in the uncultured mudflat and the river way is nearly equal, which is 0.21 and 0.20 μg cm^?2 year^?1, respectively. The accumulation flux of EN in the cultured mudflat is 0.10 μg cm^?2 year^?1. Thus, the benthic shellfish culture in the estuary does not enhance the accumulation of TN or IN. Nevertheless, it may reduce the accumulation of EN. Furthermore, it is cautious to evaluate the effect of benthic shellfish culture on sediments by the nitrogen content only. The accumulation flux of nitrogen may be one better index to evaluate the impact.     

三种免疫添加剂对草鱼非特异性免疫功能的影响

在饲料中添加不同剂量的Vc、酵母多糖和壳聚糖,连续投喂42d,并在试验的第14、28、35和42天取样检测,研究其对草鱼血清溶菌酶活性、血清超氧化物歧化酶活性（SOD）活性、血清碱性磷酸酶（AKP）活性、补体C3、含量丙二醛（MDA）含量和血液白细胞吞噬活性共6种指标的影响。结果显示：实验组与对照组相比,饲料中添加Vc可以提高血清溶菌酶活性、SOD活性、AKP活性、补体C3含量和血液白细胞吞噬活性高,并降低MDA含量。添加酵母多糖可以提高血清溶菌酶活性、AKP活性、补体C3含量和血液白细胞吞噬活性,并降低MDA含量,但不能提高SOD活性。添加壳聚糖可以提高血清溶菌酶活性、SOD活性、AKP活性、补体C3含量和血液白细胞吞噬活性,但不能降低MDA含量。饲料中添加Vc、酵母多糖和壳聚糖均对草鱼的非特异性免疫功能具有一定的促进作用。     

Physiological response,blood chemistry profile and mucus secretion of red sea bream (<Emphasis Type="Italic">Pagrus major</Emphasis>) fed diets supplemented with <Emphasis Type="Italic">Lactobacillus rhamnosus</Emphasis> under low salinity stress

Environmental stressors caused by inadequate aquaculture management strategies suppress the immune response of fish and make them more susceptible to diseases. Therefore, efforts have been made to relieve stress in fish by using various functional feed additives in the diet, including probiotics. The present work evaluates the effects of Lactobacillus rhamnosus (LR) on physiological stress response, blood chemistry and mucus secretion of red sea bream (Pagrus major) under low salinity stress. Fish were fed four diets supplemented with LR at [0 (LR0), 1 × 10² (LR1), 1 × 10⁴ (LR2) and 1 × 10⁶ (LR3) cells g^?1] for 56 days. Before stress, blood cortisol, urea nitrogen (BUN) and total bilirubin (T-BIL) showed no significant difference (P > 0.05), whereas plasma glucose and triglyceride (TG) of fish-fed LR2 and LR3 diets were significantly lower (P < 0.05) than those of the other groups. Plasma total cholesterol (T-CHO) of fish-fed LR3 diet was significantly (P < 0.05) lower than that of the other groups. Furthermore, total plasma protein, mucus myeloperoxidase activity and the amount of mucus secretion were significantly enhanced in LR-supplemented groups when compared with the control group (P < 0.05). After the application of the low salinity stress test, plasma cortisol, glucose, T-CHO and TG contents in all groups showed an increased trend significantly (P < 0.01) compared to the fish before the stress challenge. However, plasma total protein and the amount of secreted mucus showed a decreased trend in all groups. On the other hand, BUN, T-BIL and mucus myeloperoxidase activity showed no significant difference after exposure to the low salinity stress (P > 0.05). In addition, the fish that received LR-supplemented diets showed significantly higher tolerance against low salinity stress than the fish-fed LR-free diet (P < 0.05). The physiological status and the detected immune responses, including total plasma protein and mucus myeloperoxidase activity in red sea bream, will provide a more comprehensive outlook of the effects of probiotics to relieve stress in fish.