QTL for IHNV resistance and growth identified in a rainbow (Oncorhynchus mykiss) × Yellowstone cutthroat (Oncorhynchus clarki bouvieri) trout cross

Infectious hematopoietic necrosis virus (IHNV) is a major constraint to rainbow trout culture. Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) have greater resistance to this virus than do rainbow trout (O. mykiss), but the genetic mechanism of this resistance is not understood. We conducted a genome scan using a backcross of cutthroat trout into a rainbow trout background to estimate the number and locations of quantitative trait loci (QTL) associated with IHNV resistance and growth in trout. IHNV resistance was considered in terms of both survival (binary trait) and days to death (quantitative trait). The genetic map was scanned using interval mapping via two different approaches: one model considered survival alone and a second two-part model combined both survival and days to death. Three QTL were significantly (P ≤ 0.05) associated with virus resistance genome-wide, explaining 32.5% of the phenotypic variation. Cutthroat alleles at two of these QTL resulted in increased resistance to the pathogen, as expected. No growth QTL were detected in this cross. We suggest that these traits are genetically independent.     

不同饲粮对虹鳟鱼卵中矿物质、维生素含量及胚胎发育的影响

试验研究了池塘人工培育下不同饲粮对虹鳟亲鱼所产2种颜色鱼卵中矿物质、维生素含量及对受精率、发眼率、破膜率的影响。结果表明:橘红色鱼卵Ca、Mg、Zn含量略高于淡黄色鱼卵(20.8—67.0—ng/kg),其他6种矿物质均为淡黄卵略高于橘红卵(0.063～46.0 mg/kg);2种颜色鱼卵的维生素含量有差别:淡黄色鱼卵的4种维生素的含量均大于橘红色鱼卵的含量,淡黄色鱼卵中维生素D含量显著大于橘红色鱼卵(P<0.01);2种颜色鱼卵的受精率、发眼率、破膜率差异不显著(P>0.05)。     

虹鳟肌肉纤维组织学特性研究

[目的]为虹鳟肉质评定提供参考。[方法]用显微镜对组织切片进行观察,研究不同体重的虹鳟肌肉纤维组织学特性(背最长肌)。[结果]体重60～90 g虹鳟的肌肉纤维密度达到峰值,为(698.47±9.75)n/mm2;体重90～120 g虹鳟的肌肉纤维密度为(644.31±14.23)n/mm2;体重120～150 g虹鳟的肌肉纤维密度为(610.86±15.45)n/mm2;体重150～180 g虹鳟的肌肉纤维密度为(578.51±16.38)n/mm2;体重180～210 g虹鳟的肌肉纤维密度为(521.22±13.27)n/mm2。体重60～90 g虹鳟的肌纤维直径为(41.13±1.93)μm;体重90～120 g虹鳟的肌纤维直径为(43.67±1.49)μm,体重120～150 g虹鳟的肌纤维直径为(44.92±2.33)μm,体重150～180 g虹鳟的肌纤维直径为(46.38±0.94)μm,体重180～210 g虹鳟的肌纤维直径为(48.22±1.38)μm。[结论]随着体重的增加,虹鳟的肌纤维密度减小、肌纤维直径增加,但其变化幅度由营养状况、年龄和体重决定。     

Effect of crude oil extracts from trout offal as a replacement for fish oil in the diets of the Australian native fish Murray cod Maccullochella peelii peelii

The efficacy of trout oil (TO), extracted from trout offal from the aquaculture industry, was evaluated in juvenile Murray cod Maccullochella peelii peelii (25.4±0.81 g) diets in an experiment conducted over 60 days at 23.7±0.8 °C. Five isonitrogenous (48% protein), isolipidic (16%) and isoenergetic (21.8 kJ g^?1) diets, in which the fish oil fraction was replaced in increments of 25% (0–100%), were used. The best growth and feed efficiency was observed in fish fed diets containing 50–75% TO. The relationship of specific growth rate (SGR), food conversion ratio (FCR) and protein efficiency ratio (PER) to the amount of TO in the diets was described in each case by second‐order polynomial equations (P<0.05), which were: SGR=–0.44TO²+0.52TO+1.23 (r²=0.90, P<0.05); FCR=0.53TO²–0.64TO+1.21 (r²=0.95, P<0.05); and PER=–0.73TO²+0.90TO+1.54 (r²=0.90, P<0.05). Significant differences in carcass and muscle proximate compositions were noted among the different dietary treatments. Less lipid was found in muscle than in carcass. The fatty acids found in highest amounts in Murray cod, irrespective of the dietary treatment, were palmitic acid (16:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6) and eicosapentaenoic acid (20:5n‐3). The fatty acid composition of the muscle reflected that of the diets. Both the n‐6 fatty acid content and the n‐3 to n‐6 ratio were significantly (P<0.05) related to growth parameters, the relationships being as follows. Percentage of n‐6 in diet (X) to SGR and FCR: SGR=–0.12X²+3.96X–32.51 (r²=0.96) and FCR=0.13X²–4.47X+39.39 (r²=0.98); and n‐3:n‐6 ratio (Z) to SGR, FCR, PER: SGR=–2.02Z²+5.01Z–1.74 (r²=0.88), FCR=2.31Z²–5.70Z+4.54 (r²=0.93) and PER=–3.12Z²–7.56Z+2.80 (r²=0.88) respectively. It is evident from this study that TO could be used effectively in Murray cod diets, and that an n‐3:n‐6 ratio of 1.2 results in the best growth performance in Murray cod.     

棉粕及脱毒棉粕替代鱼粉对虹鳟生长、体成分及血清生化指标的影响

用不同比例棉粕(CM)及FeSO4处理的脱毒棉粕(CM+Fe)替代饲料中0(CM0,对照组)、10%(CM10)、20%(CM20)、30%(CM30)、50%(CM50)、70%(CM70)和50%(CM50+Fe)、70%(CM70+Fe)的鱼粉,配置成8种等氮等能的饲料,喂养(9.79±0.13)g的虹鳟(Oncorhynchus mykiss)10周,每组设3个重复,研究棉粕及脱毒棉粕对虹鳟生长性能、体成分及血清生化指标的影响。结果显示:(1)对照组虹鳟增重率(WG)与CM10～CM50以及CM50+Fe组之间差异不显著,CM70组增重率、蛋白质效率(PER)与其他各组相比显著降低,饲料系数(FCR)显著升高。(2)各试验组虹鳟全鱼和肌肉粗蛋白、粗脂肪、粗灰分与对照组差异不显著;CM0～CM70组肌肉中游离棉酚含量也逐渐增加,CM50+Fe和CM70+Fe组肌肉游离棉酚含量显著低于CM50和CM70组。(3)CM70和CM70+Fe组谷丙转氨酶与谷草转氨酶活性与对照组相比显著升高,CM10～CM50和CM50+Fe组与对照组差异不显著,血清甘油三酯含量逐渐升高,血糖含量与总蛋白含量逐渐降低。结果表明,棉粕替代鱼粉的适宜比例为19.62%。     

Passive immunisation of fish against vibriosis, comparison of intraperitoneal, oral and immersion routes

Passive immunisation of fish was conducted to determine whether anti-Vibrio anguillarum whole sera (AVA) and affinity-purified AVA raised in sheep, rabbits and rainbow trout (Oncorhynchus mykiss) were persistent when injected and orally administered into rainbow trout. These responses were compared with active immunisation by immersion in, and intraperitoneal (i.p.) injection with, formalin-killed V. anguillarum cells. Sheep and rabbit AVA were detected in rainbow trout sera for up to 70 days (half-life 21 days) after i.p. injection as determined by an enzyme-linked immunosorbent assay (ELISA). The relative percentage survival (RPS) of passively immunised rainbow trout challenged with virulent V. anguillarum after an injection was comparable to that of active immunisation by immersion after 1 month post-immunisation (p.i). Affinity-purified sheep and rabbit AVA exhibited the same protective potential as whole serum in rainbow trout. Rabbit and sheep immune sera diluted 1:8 and 1:50, respectively, provided equivalent protection as undiluted fish immune serum. An active immune response against passively acquired heterologous immunoglobulins was demonstrated by ELISA, with responses against sheep AVA being less than those against rabbit AVA. Rainbow trout given purified sheep AVA conjugated to LTB (the GM-1-binding subunit of Escherichia coli heat-labile toxin) and administered orally had an RPS of 37.5% at 15 days and 27% at 1 month p.i. In contrast, fish given sheep AVA conjugated to TraT (an internal membrane of E. coli) or in micellar form with Quil-A had RPSs of only 18.7 and 6.2%, respectively, after 15 days, and 13.3 and 0% after 1 month, respectively. The protection conferred by immune sera was shown to be due to the immunoglobulin component alone. Heat inactivation of the complement in sera had no effect on the potency of immune sera.     

虹鳟鱼的养殖技术特点和前景展望

本文阐述了养鳟业的经济意义和价值,并从养鳟用水和生产方式、苗种生产、食用鱼养成、养鳟饲料、海水养鳟,疾病防治等方面总结了养鳟基本技术,同时对我国养鳟历史作了回顾,提出了我国养鳟业的发展前景。     

金鳟发眼卵孵化及苗种培育试验

本首次报道了金鳟发眼卵孵化技术，孵化水温5－11℃，积温达到140－180度日破膜孵出稚鱼，孵化率北京房山78．0％，黑龙江渤海75．8％，经20－40d胚后发育上浮平游开食。同时介绍了苗种培育技术和管理方法。     

植酸酶对金鳟体成分及金鳟椎骨中钙、磷含量的影响

采用喷涂法和预处理两种方法,在豆粕型金鳟饲料中添加不同浓度的植酸酶,通过90 d的饲喂试验,研究植酸酶对金鳟(Oncorhynchus mykiss Walbaum)体成分及其椎骨中钙、磷含量的影响。结果显示:喷涂法和预处理法添加植酸酶的处理组与对照组相比,粗蛋白、粗脂肪的含量均有所下降;喷涂法添加植酸酶的处理组的鱼体粗灰分、磷和钙含量均高于对照组,其中,喷涂法添加1500 U/Kg植酸酶组鱼体磷含量、灰分含量和钙含量显著高于对照组(P(0.05),且此组鱼体磷高于其它试验组;喷涂法各组椎骨中粗灰分、磷含量较对照组提高显著(P(0.05),2500 U/kg植酸酶组椎骨磷含量最高,椎骨中钙含量除D1和D8组外,添加植酸酶的处理组均较对照组提高显著(P(0.05)。预处理法添加植酸酶的处理组与对照组相比,鱼体和椎骨中粗灰分、磷和钙含量均有显著提高(P(0.05),但植酸酶试验组间椎骨中粗灰分、磷含量和钙含量差异均不显著(P(0.05)。结果表明,金鳟饲料喷涂法添加植酸酶1500~2500 U/kg浓度最适,预处理法添加植酸酶500 U/kg浓度较为宜。