植酸酶对金鳟粪磷及水环境中磷含量的影响

通过喷涂和预处理两种方法将不同浓度植酸酶添加到豆粕型金鳟(Oncorhynchus mykissW albaum)饲料中,研究了植酸酶对金鳟粪磷及养殖水环境中磷含量的影响。金鳟粪磷分析结果显示,喷涂法添加植酸酶,对照组中粪磷含量最高,其他各试验组较对照组差异显著(P<0.05),但500~2000 U/kg组中粪磷含量差异显著(P<0.05),2500~6000 U/kg组中粪磷含量无显著差异(P(0.05);预处理法添加植酸酶,对照组粪磷含量最高,其他各试验组粪磷含量较对照组降低显著(P<0.05),但添加植酸酶的各试验组之间差异不显著(P(0.05)。通过水中磷含量试分析结果显示,无论是喷涂法添加植酸酶还是预处理法添加植酸酶,各试验组水体总磷含量分别较其对照组差异不显著(P(0.05),各试验组的活性磷含量均未检出。实验结果表明,金鳟饲料中添加植酸酶可以降低粪磷含量,对养殖生产过程中控制磷的排放,减少磷污染具有重要的意义。     

山泉水人工养殖金鳟肌肉营养成分分析

为了解金鳟(Oncorhynchus mykiss Walbaum)在贵州省山泉水养殖条件下的营养特点,采用生化方法测定了山泉水养殖金鳟肌肉中营养成分。结果显示:金鳟含肉率为79.60%,肌肉中水分、粗蛋白质、粗脂肪、灰分含量分别为75.45%、20.30%、2.61%、1.08%。肌肉中所测到的18种氨基酸总量为63.76%,其中8种必需氨基酸占26.07%,非必需氨基酸占37.69%,鲜味氨基酸占23.39%。肌肉中含有25种脂肪酸,其中饱和脂肪酸占20.83%,单不饱和脂肪酸占31.25%,多不饱和脂肪酸占47.92%。矿质元素中常量元素以钾和磷较高,分别为19 030.00 mg/kg和8 913.00 mg/kg;微量元素以铁和锌含量较高,分别为35.03 mg/kg和12.31 mg/kg。结果表明:与甘肃省养殖金鳟相比,贵州省山泉水养殖金鳟肌肉中肌肉的含肉率和常规营养成分含量与其相当,必需氨基酸总量/氨基酸总量(∑EAA/∑TAA)和必需氨基酸总量/非必须氨基酸总量(∑EAA/∑NEAA)均低于甘肃省养殖金鳟,但符合WHO/FAO提出的参考蛋白模式,且贵州省山泉水养殖金鳟肌肉中不饱和脂肪酸含量和微量元素含量均高于甘肃省养殖金鳟,说明山泉水养殖下的金鳟肌肉具有更好的营养价值。     

甘肃金鳟生长激素基因多态性与生长性状的相关分析

生长激素（ GH）基因能够影响动物的生长,是一个与生长性状有关的基因。以315尾甘肃金鳟（ Oncorhyn-chus mykiss）为研究材料,分析了GH基因外显子区域多态性,并对基因型与生长性状进行了关联性分析。 PCR-SSCP分析结果显示B等位基因在外显子2区域第903 bp处发生G/C突变,存在3种基因型AA、 AB和BB。 D等位基因在外显子5区域第3049 bp处发生T/G的突变,在3094 bp处发生C/A的突变,其中第3049 bp处发生的T/G的突变导致第157位氨基酸由组氨酸变为谷氨酰胺,为有义突变,共检测到3种基因型CC、 CD和DD个体。最小二乘法分析表明, BB基因型的全长值和体长值都显著高于AA和AB基因型（ P＜0.05）。 T3049 G和C3094 A突变点对全长、体长和体重均有显著性影响（ P＜0.05）,其中CC基因型的全长值、体长值和体重值都高于DD和CD基因型。在标记辅助育种中,这些分子标记可以为甘肃金鳟遗传改良提供基础的数据和参考。     

金鳟日本品系不同家系提纯复壮后生长性能的比较

本实验通过人工授精技术和苗种标准化培育方法建立16组金鳟(Oncorhyncus mykiss)日本品系全同胞家系。运用方差分析、多重比较等方法分析不同家系不同时期的生长性能。结果显示:不同时期各组家系间平均体长、体重存在显著性差异,其中在5月龄阶段,J7家系增重最快,绝对增重率比全部家系的均值高38.83%,比增重最慢的家系J25高98.66%,表现出明显的生长优势;9月龄阶段,J7家系增重最快,绝对增重率比全部家系均值高25.93%,比增重最慢的家系J27高85.37%;12月龄时,J7家系增重最快,绝对增重率比全部家系均值高27.68%,比增重最慢的家系J25高58.27%,但不同月龄阶段各组家系的绝对增重率及体重值排序并不一致;金鳟日本品系个体体重性状的变异系数高于体长性状的变异系数,1月龄、5月龄、9月龄、12月龄体重的变异系数分别为34.34%、30.60%、27.91%、27.06%,体长的变异系数分别为10.34%、10.31%、9.91%、9.40%。在整个生长测量过程中,J7、J11、J15三个家系,无论是体长还是体重都表现出较优的生长速度和增长量,生长优势明显,可以判断J7、J11、J15家系为优秀家系。研究结果为进一步的选育提供了良好的材料。     

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%。     

无鱼粉饲料中添加磷和植酸酶对奥尼罗非鱼生长性能及体成分的影响

奥尼罗非鱼(Oreochromis niloticus×O.aureus)幼鱼的初始体重约5.0 g,试验共设5组饲料,以全鱼粉饲料为对照组(D0),以豆粕和花生粕完全替代鱼粉为试验组,其中两组为不补充磷酸二氢钙的情况下不添加植酸酶(D1)和添加植酸酶(D2),另两组为在补充磷酸二氢钙的情况下不添加植酸酶(D3)和添加植酸酶(D4)。每一饲料组设3个重复,每箱养鱼30尾,在流水系统中饲养,表观饱食投喂,投喂率为5%~6%。饲养实验周期为8周。试验结果表明,添加磷组(D3、D4)和全鱼粉组(D0)的特定生长率和饲料系数在组间差异不显著(P>0.05),但显著高于不添加磷组(D1、D2)(P<0.05);磷的表观消化率在添加植酸酶组(D2、D4)均显著高于不添加植酸酶(D1、D3),但与全鱼粉组(D0)差异不显著;鱼体粗蛋白含量在不添加磷和植酸酶组(D1)显著低于其他4组;体粗脂肪含量在不添加磷(D1、D2)组显著高于其他组;体灰分含量由高到低依次为全鱼粉组(D0)、添加磷和植酸酶组(D4)、添加磷不添加植酸酶组(D3)、不添加磷添加植酸酶组(D2)和不添加磷不添加植酸酶组(D1),且两两组间差异显著;体钙、磷、镁、锌含量和脱脂骨灰分、钙、磷含量在全鱼粉组(D0)最高。不添加磷组(D1、D2)血清磷含量显著低于其他3组,而血清碱性磷酸酶活性显著地高。试验结果说明,无鱼粉饲料中补充磷可保持奥尼罗非鱼幼鱼生长率,饲料利用和全鱼可食部分营养成分含量;同时添加植酸酶,能显著提高饲料中磷的利用率,促进磷、锌和镁在鱼体内沉积,并有进一步提高奥尼罗非鱼幼鱼生长和饲料利用的趋势。[中国水产科学,2006,13(1):112-118]     

植酸酶对异育银鲫生产性能及鱼体成分的影响

选用360尾体重为(12.0±0.2)g的异育银鲫(Carassius auratus gibelio)鱼种,随机分为Ⅰ、Ⅱ、Ⅲ、Ⅳ四个组,每组设置3个重复,其中Ⅰ为对照组,饲喂基础日粮,Ⅱ、Ⅲ、Ⅳ为试验组,分别在基础日粮中添加500 U/kg、1000 U/kg、1500 U/kg的植酸酶。饲喂60 d,试验结果表明:(1)与对照组比较,添加1000 U/kg植酸酶的试验组鱼增重率提高8.8个百分点,饲料系数下降0.18,植酸磷利用率提高20.6个百分点,说明在异育银鲫鱼种配合饲料中添加适宜的植酸酶能促进鱼的生长,提高植酸磷的利用;(2)添加植酸酶各组异育银鲫鱼种的鱼体成分中,粗灰分、粗蛋白、钙、磷及部分矿物质元素(铁、铜、镍)含量显著提高,表明植酸酶能释放植酸的螯合物,促进矿物质元素在动物体内的沉积。     

盐度对金鳟幼鱼肌肉品质的影响

探讨了盐度驯化对金鳟(Oncorhynchus mykiss)幼鱼肌肉品质的影响.结果表明,盐度驯化对金鳟肌肉硬度、胶着性和咀嚼性无显著影响,但盐度为32时,回弹性最高,盐度为24时,金鳟肌肉的白度最高,显著高于对照组,亮度无显著性差异,但盐度为16时,肌肉颜色偏红.盐度驯化对金鳟肌肉水分、粗脂肪和粗蛋白含量无显著影响...     

嗜水气单胞菌灭活疫苗对虹鳟免疫力和抗病力的影响

为研究嗜水气单胞菌(Aeromonas hydrophila)灭活疫苗对虹鳟(Oncorhynchus mykiss)(250 g±12 g)免疫力和抗病力的影响,给试验鱼腹腔注射0.2 mL的灭活嗜水气单胞菌悬液(1.0×108cfu/mL)。分别在注射前(0 d)和注射后7、14、21、28、35、42 d取样,测定血液白细胞吞噬活性、血清溶菌酶(LZM)活力、补体C3含量以及头肾和脾脏中IgM、IgT基因表达情况。结果表明:注射嗜水气单胞菌疫苗能显著提高白细胞吞噬率(PP)和吞噬指数(PI)、LZM活力和补体C3含量,注射后21 d达峰值,PI、LZM和补体C3在42 d仍显著高于对照组。免疫后21 d头肾和脾脏中IgM基因上调表达,35 d达峰值(分别上升24倍和26倍),42 d下降但仍极显著高于对照组。头肾和脾脏中IgT的上调表达比IgM弱得多,头肾35 d达峰值(上升6.2倍),脾脏28 d达峰值(上升6.1倍)。免疫42 d后嗜水气单胞菌攻毒结果表明,嗜水气单胞菌灭活疫苗对虹鳟有较高的免疫保护作用,免疫保护率达到71.43%。     

复合免疫增强剂对金鳟非特异性免疫力的影响

在水温(13±1)℃下,将体质量(98.6±5.3)g的金鳟Oncorhynchus mykiss饲养在循环水系统中,投喂在基础饲料中分别添加0.5%、1%和2%的复合免疫增强剂,1周、2周、3周和4周后测定血清中溶菌酶(LYS)和超氧化物歧化酶(SOD)的活性及补体C3的含量。投喂4周后,每尾鱼注射0.2mL浓度为3×10~8cfu/mL的杀鲑气单胞菌Aeromonas salmonicida,统计各组金鳟14d内的免疫保护率。结果显示:金鳟血清中LYS和SOD的活性及补体C3含量均呈现先升高后降低的趋势,投喂2周后达到最高值,显著高于对照组(P0.05);人工感染杀鲑气单胞菌后3个实验组14d内的死亡率显著低于对照组,表明该复合免疫增强剂能显著提高金鳟对细菌病的抵抗力。     

Dietary microbial phytase supplementation and the utilization of phosphorus, trace minerals and protein by rainbow trout [Oncorhynchus mykiss (Walbaum)] fed soybean meal-based diets

Effects of thermal and enzymatic treatments of soybean meal on apparent absorption of total phosphorus, phytate phosphorus, nitrogen (protein), ash, calcium, magnesium, copper, iron, manganese, strontium and zinc were examined using rainbow trout, Oncorhynchus mykiss (Walbaum), as the test species. Absorption of the test nutrients was estimated using yttrium as an inert non-absorbable indicator. Thermal treatments (microwaving, dry roasting, steam heating, cooking) had no measurable effect on the apparent absorption of phosphorus and other minerals. Phytase supplementation increased the apparent absorption of phosphorus, nitrogen (protein), ash, calcium, magnesium, copper, iron, strontium and zinc in low-ash diets containing soybean meal, but had little effect in high-ash diets containing both soybean and fish meal. In low-ash diets, the apparent absorption of phosphorus increased in accord with the level of phytase added to the diet, from 27% (no phytase added) up to 90% (phytase added, 4000 units kg⁻¹ diet) or 93% (predigested with phytase, 200 units kg⁻¹ soybean meal). In high-ash diets, dietary acidification with citric acid decreased the effect of phytase, whereas in low-ash diets, acidification markedly increased the effect of the enzyme. Excretion of phosphorus in the faeces of fish fed a low-ash diet containing phytase-treated soybean meal was 0.32 g per kg diet consumed, a 95%−98% reduction compared with phosphorus excretion by fish consuming commercial trout feeds.     

虹鳟IL-17多克隆抗体的制备及初步鉴定

本研究根据NCBI已发表序列设计引物,提取经植物血凝素刺激后的虹鳟Oncorhynchus mykiss头肾细胞总RNA,采用RT-PCR方法扩增IL-17成熟肽基因,测序结果表明所获得的序列与发表序列相一致。将该基因重组至原核表达载体pET32a中,并转化大肠杆菌Escherichia coli Rosetta,进行诱导表达。SDS-PAGE电泳结果表明:目的蛋白以包涵体形式表达,大小约为32k Da,重组蛋白经Ni-NTA系统纯化、复性后纯度达90%以上,以其免疫小鼠制备虹鳟IL-17多克隆抗体。ELISA结果显示其效价为1∶25 600,而间接免疫荧光结果显示所制备的多克隆抗体能够特异性地识别真核细胞中瞬时表达的虹鳟IL-17。本研究成功制备虹鳟IL-17多克隆抗体,为下一步IL-17在虹鳟黏膜免疫中的作用及其佐剂效应研究奠定基础。     

Interaction between diet and genetic aptitude for weight and growth in juvenile rainbow trout, Oncorhynchus mykiss (Walbaum)

Samples of rainbow trout, Oncorhynchus mykiss (Walbaum) alevins from 17 independent families (full‐sib‐groups) were raised from the start of feeding until the age of 18 weeks post‐hatching with three diets (C, G and S) differing in protein content (fish soluble protein concentrate: 84% in C, 54% in G and 44% in S) and carbohydrates (none in C, 30% glucose in G and 40% crude corn starch in S). Fish were fed to near satiation, and their body weight and growth were measured. Diet effect was highly significant (G< C < S), as well as the familial effect. The major part of the familial variance (80–90%) was common to the three diets. However, a minor part of the familial variance was observed to be diet dependent (family × diet interaction), and was found to result mainly from relative performances with carbohydrates (G and S diets) vs. pure protein (C diet). These results indicate that genetic improvement of growth should suffer little impairment from possible changes in future feed formulations.     

Covariation between diploid and triploid progenies from common breeders in rainbow trout, Oncorhynchus mykiss (Walbaum)

The covariation between diploid and triploid progenies from common breeders was investigated in various progeny-testing experiments where either dams or sires were sampled from rainbow trout, Oncorhynchus mykiss (Walbaum), stocks. Triploidiza tion was found to frequently reduce the performance in the traits studied: body length and weight, growth, coefficient of condition and pyloric caeca number. Triploidization also generated significant interactions with the parental breeding value. These interactions were caused in part by the familial variance not being the same in triploids as in diploids, but also by actual ranking differences between diploid and triploid familial performances. However, the effect of these interactions was minor as compared with the amount of variation common to both ploidy levels (genetic correlations averaged 0.7–0.9). Therefore, selection of diploid breeders appeared efficient enough for improving triploid progeny, unless family selection methods including triploid progeny testing were preferred for other reasons. Lastly, it was observed that variances from maternal origin tended to be larger in triploids, whereas variances from paternal origin tended to be smaller, as compared with diploids. This point was discussed referring to the genetic make-up of triploids and in the scope of dams and sires for selective breeding.     

Myosin expression levels in trout muscle: a new method for monitoring specific growth rates for rainbow trout Oncorhynchus mykiss (Walbaum) on varied planes of nutrition

Fish growth is manifested by a number of measurable physical changes. We have developed a sensitive method for monitoring the growth rate of fish fed at four different planes of nutrition. This technique consists in measuring expression levels of myosin RNA isolated from the muscle of experimental animals. Using PCR (polymerase chain reaction) primers, and a fluorescence-labelled single-stranded DNA probe that hybridizes specifically to a region within the myosin mRNA of rainbow trout Oncorhynchus mykiss (Walbaum), we were able to detect differences in the relative level of myosin expression between groups of fish. This method also allows for the determination of absolute expression levels when reactions are performed with standards consisting of known levels of in vitro-transcribed myosin RNA. With the proper equipment, this novel procedure can be performed rapidly on large numbers of individuals, and with the procurement of non-invasive muscle biopsies the same experimental animal could theoretically be sampled multiple times throughout the course of the study. This new method could be used to measure differences in muscle synthesis in fish associated with various nutrient intake levels, environmental parameters, life-history stages and health status.     

The use of AquaMats® to enhance growth and improve fin condition among raceway cultured rainbow trout Oncorhynchus mykiss (Walbaum)

AquaMats® are a type of artificial seaweed designed to provide structure in ponds used for fish culture and as a substrate for the growth of aquatic plants and invertebrates which in turn are a source of nutrition to cultured species. In two separate tests AquaMats® were placed into raceways used to rear rainbow trout Oncorhynchus mykiss (Walbaum) to evaluate their effect on fish growth and fin condition. In the first test, the AquaMats® were placed perpendicular to the raceway length similar to a baffle design. One treatment consisted of AquaMats® that were cleaned on a regular basis, and the other treatment consisted of AquaMats® that were not cleaned throughout the test. By the end of the test no differences were found between treatments with respect to final fish weight, specific growth rate, or feed conversion ratio. The use of AquaMats® did not improve fin condition, in fact several fins measured were significantly better among control fish. In the second test AquaMats® were placed on the raceway bottom parallel to their length and to the water flow. AquaMats® were also hung from the side of the raceway to provide cover. At the conclusion of this test no differences were found between treatments with respect to final fish weight, specific growth rate, or feed conversion ratio. The placement of AquaMats® did have a transitory impact on fin condition. Mid‐way through the test, treatment fish generally exhibited longer fins compared with the controls. However, by the end of the test, these differences were no longer detectable. The results from both tests indicate that fish were not provided with additional nutrition to the extent it improved growth. However, the use of AquaMats® did make a significant, albeit transitory, impact on fin condition.     

The effect of different numbers of feeding days on feed consumption and growth of rainbow trout [Oncorhynchus mykiss (Walbaum)]

A trial was conducted to evaluate the effects of the number of feeding days on feed consumption and growth of rainbow trout, Oncorhynchus mykiss (Walbaum) (initial mean weight 53.6 ± 11.3 g). Fish were held under natural winter–spring (40°57′N) photoperiod (L:8 D:16 – L:14 D: 10) and ambient water temperatures (4–12 °C) for 128 days, and fed on day 7 (F₇), day 5 (F_5.1: no feeding on weekends and F_5.2: no feeding on Sundays and Wednesdays) or every other day (F_EOD). Feeding treatments were replicated with 50 fish held in 200‐L tanks. Number of feeding days affected final live weight, with fish in group F₇ achieving a mean weight of 285.6 g, followed by F_5.1 (256.6 g), F_5.2 (247.6 g) and F_EOD (223.2 g). Final condition factors (CF) differed between the F_EOD group and the others. Feed conversion ratios (FCR) exhibited significant differences among some of the groups. The results suggest that depriving rainbow trout of feed for more than 1 day a week has a negative effect on growth, but little influence on feed conversion.     

Radiological examination of the spinal column in farmed rainbow trout Oncorhynchus mykiss (Walbaum): experiments with Flavobacterium psychrophilum and oxytetracycline

Flavobacterium psychrophilum and oxytetracycline have both been associated with spinal deformities in salmonids. Experiments were carried out to investigate whether infection with F. psychrophilum or medication with oxytetracycline (OTC) at the fry stage would result in an increased occurrence of vertebral column deformities in rainbow trout, Oncorhynchus mykiss (Walbaum). Fish were on‐grown for 9 months and examined by radiology at the end of the experiments. There was a relationship between infection by F. psychrophilum and deformities of the spinal column, if fish with more than 10 affected vertebrae were classified as deformed. The deformities found among infected fish were often visible externally and were more severe than those seen among control fish (most deformities foun among controls were only seen on X‐ray photographs). Deformities were evenly spread along the vertebral column of infected fish. OTC treatments of up to 200 mg of OTC (kg fish)^?1 day^?1 for 10 days and repeated three times did not result in increased spinal deformities relative to untreated control groups; therefore, medication of rainbow trout with oxytetracycline did not cause deformities of the spinal column under our treatment conditions.     

Reproductive performance of female rainbow trout Oncorhynchus mykiss (Walbaum) kept under water temperatures and photoperiods of 13° and 51°N latitude

At Doi Inthanon Fisheries Research Unit (DIFRU), Thailand (13°N), rainbow trout were exposed to natural (13°N) and artificial (51°N) photoperiods, and natural water (NW) temperatures and cooled water (CW) 8 months before first spawning. In group I (51°N, CW), water temperatures of 18°C were never reached. In group II (51°N, NW) and group III (13°N, NW), the mean water temperatures in May exceeded 20°C, and 19°C in June and July. Eggs from 94% of all females in group I were obtained before January. This percentage diminished to 84% and 68% in groups II and III. The weight of the spawners and the size of the eggs were significantly lower in group III than in the other groups. No significant differences were observed for egg number per kg body weight of spawners between the groups. The mean fertilization rate of eggs was the highest, with 71%, in group I, and the lowest, with 50%, in group II. For hatching rates, on average 27%, 24% and 30% in groups I, II and III, respectively, differences were not significant. In group III, 37% of all batches reached fertilization rates above 80% and 16% of egg batches showed hatching rates of more than 60%.