Taurine Supplementation of All-plant Protein Diets for Rainbow Trout (Oncorhynchus mykiss)

Abstract.— Taurine has been demonstrated to be conditionally indispensable for several carnivorous fish species. Current trends in trout production include decreasing levels of fish-meal content in feeds, along with faster growing strains of fish. Taurine may be a limiting nutrient in support of elevated planes of growth for rainbow trout. A 9-wk feeding trial was conducted using a factorial treatment design with protein source (fish meal or plant) and taurine supplementation (four levels) as the main effects. The fish-meal diet series included 23% herring meal and contained 1.76% total sulfur amino acids (TSAA). The plant diet series did not contain any animal proteins and substituted protein from soy protein concentrate in place of the herring-meal protein and contained 1.5% TSAA. Taurine was supplemented at 0, 5, 10, and 15 g/kg dry diet to each of the diets in the plant series and the fish-meal series of diets. All diets were formulated to contain 43.8% crude protein and 20% lipid with an estimated physiological fuel value of 4.2 kcal/g. Fifteen fish were stocked in each of 24 tanks with a mean initial weight of approximately 26.8 g per fish. The unsupplemented fish-meal diet contained 2 g/kg taurine, and the unsupplemented plant diet had taurine levels below the detection limit of 0.1 g/kg diet. Taurine supplementation improved growth, feed conversion ratios, protein retention efficiencies, and energy retention efficiencies of fish fed the plant protein diets. No effects of taurine supplementation were observed for these response factors in fish fed the fish-meal series diets. This study demonstrates that taurine supplementation may be necessary for rainbow trout fed plant-protein-based feeds.     

Evaluation of Yellow Lupin Lupinus luteus Meal as an Alternative Protein Resource in Diets for Sea-Cage Reared Rainbow Trout Oncorhynchus mykiss

The performance of sea-water reared rainbow trout Oncorhynchus mykiss fed three isonitrogenous and iso-energetic diets based on either fishmeal, solvent-extracted soybean meal or yellow lupin ( L luteus cv. Wodjil) kernel meal was evaluated. Over the course of a 10-wk study, the fastest growing fish were those fed the diet containing 50% yellow lupin kernel meal (YLM), which grew from 83.6 ± 0.7 g to 322.8 ± 3.2 g (mean ± SEM). This was not significantly faster than growth of fish fed the diet based on 50% solvent-extracted soybean meal (SBM), though it was significantly ( P < 0.05) faster than the growth of fish fed the fishmeal based diet (FSM). Growth of fish fed the experimental diets was comparable to growth of fish fed a range of commercial diets as a reference. Survival of fish fed the FSM diet was poorest of all the treatments (47.4%), though this was only significantly poorer than that of fish fed the YLM diet (88.9%). Feed intake was highest by fish fed the YLM diet (5.58 g/d) and lowest for fish fed the FSM diet (336 g/d). Reasons for these differences in feed intake were not clear, though they may be related to different levels of buoyancy and palatability among the diets. Feed conversion rate (FCR) was consistent between treatments at about 1.6:1, though given that this study was a sea-cage based experiment it is likely that considerable unaccounted feed losses occurred, thereby inflating the feed conversion value. Sensory evaluation of fish fed the three test treatments showed no overall difference in the acceptability of the fish, further supporting that solvent-extracted soybean meal and yellow lupin kernel meal both have considerable potential to replace fishmeal as a protein resource in diets for rainbow trout.     

虹鳟鱼对挤压膨化饲料的养分消化率

膨化技术已在食品工业中应用了将近100年。挤压膨化造成物料的物理和化学变化，如粒度减小、淀粉糊化及酶的失活。温和的挤压加工通常会提高动物对植物蛋白的消化率，但对虹鳟鱼是否如此，尚有待研究。     

诺氟沙星在金鳟体内的药物代谢动力学研究

实验水温为15±2℃,金鳟（Oncorhynchus mykiss）（平均体质量100±10g）单剂量肌肉注射30.0 mg/kg诺氟沙星后,应用高效液相色谱（HPCL）法于0.15,0.25,0.5,0.75,1,1.5,2,4,6,8,12,24,48,72 h测定了鱼血浆、肝脏和肾脏组织中药物的浓度,研究了诺氟沙...     

诺氟沙星在金鳟体内的药物代谢动力学研究

实验水温为15±2℃,金鳟（Oncorhynchus mykiss）（平均体质量100±10g）单剂量肌肉注射30.0 mg/kg诺氟沙星后,应用高效液相色谱（HPCL）法于0.15,0.25,0.5,0.75,1,1.5,2,4,6,8,12,24,48,72 h测定了鱼血浆、肝脏和肾脏组织中药物的浓度,研究了诺氟沙星在金鳟组织中的分布及药物动力学规律。结果表明,诺氟沙星在金鳟体内吸收分布迅速,符合药物动力学一级吸收二室开放模型,但消除缓慢。诺氟沙星在金鳟血浆、肝脏和肾脏中的主要动力学参数如下：分布半衰期（T1/2α）分别为0.866、1.985、0.388h;消除半衰期（T1/2β）分别为31.369、36.402、30.975h;药时曲线下面积（AUC）分别为：308.005μg/mL.h、622.721μg/g.h、794.362μg/g.h。     

Spray-Dried Blood Cells as a Partial Replacement for Fishmeal in Diets for Rainbow Trout Oncorhynchus mykiss

Abstract.— The objective of this study was to evaluate growth of juvenile rainbow trout Oncorhynchus mykiss (81.4 mm initial length and 6.4 g initial weight) fed a diet containing 47.5% herring meal (FM diet) and a test diet containing 34.5% herring meal and 8.75% spray-dried animal blood cells (SBC diet). Both diets were formulated to be isonitrogenous (48.5 and 48.0% protein) and isocaloric (3,977 and 3,927 kcal DElkg). At the end of the 12-wk feeding trial, differences in growth rate and feed conversion ratios were not statistically significant between the two dietary treatments. Apparent crude protein digestibility was 89.7% for the SBC diet and 88.1% for the FM diet. Apparent net protein utilization and iron retention values were not different, but phosphorus retention was higher for fish fed the SBC diet. Whole body iron content of the fish decreased in both groups from 23.3 mg/ kg in an initial sample to 16.5 mg/kg in fish fed the FM diet and 18.4 mg/kg in fish fed the SBC diet at the end of 12 wk. The diet containing 8.75% SBC replaced 27.4% of the crude protein supplied by herring meal, and it had 22.7% less total phosphorus (P) than the fishmeal diet. The cost of gain for the FM diet was $0.508/kg gain compared to $0.512/kg gain for the SBC diet.     

Performance of Post-juvenile Rainbow Trout Oncorhynchus mykiss Fed Diets Manufactured by Different Processing Techniques

Four different methods of pelleting—extruded (EXT), steam pelleted (STM), using a Universal Pellet Cooker (UPC), and expanded (EXP)—were performed on subsamples of a single batch of mash to determine the effects on feed pellet characteristics, in vivo feed digestibility, and performance of rainbow trout Oncorhynchus mykiss fed the diets for 16 wk. Results indicated that the STM feed was the most (851 g/L) and UPC feed the least (672 g/L) dense, and that UPC feed had the highest % float (8.3%) and, of the pellets that sank, the fastest sink rate (15.1 cm/sec). While some differences occurred among pelleted diets in loss of dry matter (% dry loss) after incubation in a water bath for up to 10 min, the overall % dry loss was only approximately 1–2%. The method of pelleting did not affect fish weight gain, feed conversion ratio, or specific growth rate. Measurement of the apparent digestibility coefficient of dry matter of the test diets using Cr₂O₃ as the marker ranged from 71–89%. While it appeared that the method of pelleting can affect feed characteristics and the amount of feed offered to the fish, fish performance was not affected.     

虹鳟营养需求的研究进展

简要介绍了近年来国内外虹鳟的营养研究,包括蛋白质、脂肪、维生素、矿物质等方面,提出一些虹鳟养殖中的注意事项,为虹鳟养殖、饲料生产和科研开发提供参考。     

二倍体和三倍体虹鳟精液低温保存寿命的研究

与二倍体（2n组）精原液做比较,以不同密度为组别,研究了4℃下两组（3n-HD和3n-LD）三倍体虹鳟（Oncorhynchus mykiss）精原液的保存时限。结果发现,随着保存时间的延长,精液中精子的活力和寿命逐渐降低。2n组、3n-HD组和3n-LD组虹鳟精原液中精子分别在保存5d、4.5d和12.5d后失去活力;在7d、15d和14.5 d后死亡,即三倍体虹鳟精原液4℃保存时间约为二倍体的2倍,说明低温短期保存三倍体虹鳟精原液可以取得较好效果。     

Fisheries By-Catch and By-Product Meals as Protein Sources For Rainbow Trout Oncorhynchus mykiss

Abstract— Fisheries by-catch and by-product meals are portrayed as ingredients having a great potential as ingredients in aquaculture feeds. The present study was designed to evaluate the nutritional value of shrimp by-catch meal, shrimp processing waste meal, and two fish meals made from Pacific whiting (meal with and without solubles) for rainbow trout by determining apparent digestibilityof these ingredients and conducting a 12-wk feeding trial with juvenile fish (average initial weight 20 g/fish). Apparent digestibility coefficients (ADCs) for protein in diets containing by-catch and processing by-products were 76% for shrimp by-catch meal, 79% for shrimp processing waste meal, 88% for Pacific whiting meal without solubles, and 92% for Pacific whiting meal with solubles. ADCs for lipid were higher than 94% for all the diets. ADCs for energy were 57% for shrimp by-catch meal, 73% for shrimp processing waste meal, 70% for Pacific whiting meal without solubles, and 73% for Pacific whiting meal with solubles. Growth performance was significantly affected by dietary protein source. Fish fed the shrimp by-catch meal diet had weight gain and feed conversion ratios similar to that of fish fed the control diet with anchovy fish meal. Fish fed diets containing shrimp processing waste and Pacific whiting meal with solubles had significantly lower weight gain and higher feed conversion ratios than the control diet. Growth was significantly lower in fish fed the Pacific whiting meal diet compared to fish fed the anchovy fish meal. The lower growth of fish fed diets containing Pacific whiting meal appeared to be a result of lower feed intake, indicating perhaps a lower palatability of this ingredient. Additional research addressing processing methods, nutritional manipulations, and palatability enhancement is needed to improve potential of some fisheries byproduct meals as ingredients in the diets of rainbow trout.     

Effects of Oral Administration of Specific Antibodies to Rainbow Trout Oncorhynchus mykiss

A new product called oralized fish serum concentrate (OFSC) was evaluated for a possible effect against various bacterial pathogens in rainbow trout. The OFSC produced from immune trout sera was found to contain fully functional antibodies and complement component C3. The antibodies detected in the serum concentrate were specific to Vibrio anguillarum (O1 and O2) and Aeromonas salmonicida , which had been used for vaccination of the fish prior to serum collection. The functionality of the specific antibodies in OFSC was not reduced after 6 wk storage at -20 C, 5 C, and 20 C. The serum was mixed with commercial trout feed and used for feeding rainbow trout fry (first feed period). After oral delivery of OFSC to rainbow trout for 1 mo, samples of gut content and gut tissue contained functional antibodies. In gutted fish no functional antibodies were found. This suggests that antibodies from OFSC are unable to be transferred across the gut wall in a functional state. Oral administration of OFSC did not increase survival of rainbow trout in an immersion challenge with Vibrio anguillarum .     

金鳟养殖试验

在辽宁省凤城市四门子镇新农水产养殖场进行金鳟鱼的养殖试验。养殖用水为当地山涧冷泉水,养殖水面为100m2,共投放单重20g的鱼种12000尾。试验期间,金鳟生长良好,成活率为99%,利润为12万元。试验结果表明,金鳟作为良好水环境的指示生物,具有极高的生态附加值,可以为进一步开发辽东山区的生态资源和冷水资源提供有效途径,为促进生态经济的协调发展奠定良好基础。     

二倍体和三倍体虹鳟精液低温保存寿命的研究

与二倍体(2n组)精原液做比较,以不同密度为组别,研究了4℃下两组(3n-HD和3n-LD)三倍体虹鳟(Oncorhynchus mykiss)精原液的保存时限。结果发现,随着保存时间的延长,精液中精子的活力和寿命逐渐降低。2n组、3n-HD组和3n-LD组虹鳟精原液中精子分别在保存5d、4.5d和12.5d后失去活力;在7d、15d和14.5 d后死亡,即三倍体虹鳟精原液4℃保存时间约为二倍体的2倍,说明低温短期保存三倍体虹鳟精原液可以取得较好效果。     

Evaluation of Soybean Meal-Red Blood Cell Coextruded Feed Ingredient in Diets Fed to Rainbow Trout Oncorhynchus mykiss

Abstract.— Fish meal is one of the predominant sources of crude protein used in practical feeds for most cultured species. However, with overfishing and increasing demand for protein feedstuffs, new competitively priced sources of dietary protein are needed. A coextruded soybean meal-red blood cell (SBM-RBC) ingredient was evaluated as a source of crude protein for rainbow trout Oncorhynchus mykiss . The SBM-RBC ingredient was incorporated at either 0, 21, 42 or 63% of the dietary protein, replacing an isoni-trogenous amount of fish meal. All diets were fed for 8 wk to triplicate groups of juvenile rainbow trout (average initial weight 49.5 g) stocked into a recirculating system consisting of 48, 114-L aquaria. There were no significant differences in weight gain, feed conversion ratio, protein efficiency ratio, apparent crude protein digestibility, apparent gross energy digestibility, dress-out percentage, or fillet protein and fat concentrations in fish fed any of the experimental diets. Based on these data, extruded SBM-RBC appears to be a suitable ingredient in diets fed to rainbow trout.     

Fly Prepupae as a Feedstuff for Rainbow Trout, Oncorhynchus mykiss

Fly larvae may provide an effective method to mitigate two large and growing global concerns: the use of fish meal derived from capture fisheries in aquaculture diets and manure management in livestock and poultry facilities. A 9‐wk feed trial was conducted to determine whether fly larvae could be used as a partial fish meal and fish oil replacement in rainbow trout, Oncorhynchus mykiss, diets. A trout diet was formulated to contain 40% crude protein and 15% fat. Sixty‐seven percent of the protein in the control diet was derived from fish meal, and all the fat was derived from fish oil. Two of the test diets included using the black soldier fly, Hermetia illucens, prepupae, which are 40% protein and 30% fat, as 25 and 50% replacement for the fish meal component of the control diet. The total protein derived from black soldier fly prepupae in these two test diets was 15 and 34%, respectively. A third test diet included using housefly, Musca domestica, pupae, which is 70% protein and 16% fat, as 25% replacement for the fish meal component of the control diet. Data suggest that a rainbow trout diet where black soldier fly prepupae or housefly pupae constitute 15% of the total protein has no adverse effect on the feed conversion ratio of fish over a 9‐wk feeding period. In addition, the diet with black soldier fly prepupae permitted a 38% reduction in fish oil (i.e., from 13 to 8%); however, fish fed black soldier fly diets low in fish oil had reduced levels of omega‐3 fatty acids in their muscle fillets. The findings from this study suggest that either the black soldier fly or the housefly may be a suitable feedstuff for rainbow trout diets.     

The Toxicity of Hydrogen Peroxide to Rainbow Trout Oncorhynchus mykiss and Cutthroat Trout Oncorhynchus clarki Fry and Fingerlings

Fungal and parasitic infections of fish can significantly impact the survival of cultured fish. Formalin is currently used to control such infections; however, concern has arisen over its safety to users and to the environment. Hydrogen peroxide has been designated as a low priority fungicidal drug by the United States Food and Drug Administration (FDA), yet, little information is available on treatment concentrations or its toxicity to trout. Rainbow trout Oncorhynchus mykiss and cutthroat trout Oncorhynchus clarki fry and Angerlings were exposed to hydrogen peroxide concentrations of 0, 70, 170, 280, 420 and 540 ppm for 30, 60 or 120 rnin at 15 C to determine the chemical's toxicity. Rainbow trout fry and fingerlings experienced elevated mortalities (>20%) during treatments using 420 and 540 ppm for 30 min; 280, 420 and 540 ppm for 60 min; and >170 ppm for 120 min. Cutthroat trout fry experienced elevated mortalities (>23%) during treatments using 540 ppm for 30 min; 420 and 540 ppm for 60 min; and >170 ppm for 120 min. Cutthroat trout fingerlings experienced elevated mortalities (>60%) during treatments using 540 ppm for 60 min and >280 ppm for 120 min. No control mortalities were encountered for both life stages of either species. The lethal concentrations (LC₅₀) of both age classes and species for each of the three durations ranged from 514–636 ppm for 30 min treatments, 322–506 ppm for 60 min treatments, and 189–280 for 120 min treatments. Mortalities for all four toxicity tests which occurred during a 96-h post-treatment period were centered around the following treatments: 30 min, 540 ppm; 60 min, 280–540 ppm; 120 min, 170 ppm. Tissue damage to gills was found only among fish that did not survive the initial chemical exposure. Test concentrations proved to be relatively stable during a 24-h period, retaining better than 85% of their original strength for all five dilutions. At a water temperature of 15 C concentrations should not exceed 280 ppm for a 30-min treatment.     

新型锌制剂对虹鳟生长及免疫功能的影响

为研究纳米锌及纳米锌多糖复合体对虹鳟生长及免疫功能的影响,选取平均体质量(120.0±3.0) g的虹鳟300尾,随机分成5组,每组3个平行,每个平行20尾,按1μL/g进行尾部肌肉注射纳米锌及纳米锌多糖复合体溶液,含量分别为1000、3000 mg/kg,试验周期为10 d。试验结果显示,纳米锌及纳米锌多糖复合体可不同程度提高虹鳟特定生长率(P>0.05)。1000 mg/kg纳米锌多糖复合体组虹鳟血液NBT阳性细胞数量百分比在第3 d最高,达22.3%(P<0.05);3000 mg/kg纳米锌多糖复合体组白细胞吞噬能力在第6 d最强(P<0.05)。3000 mg/kg纳米锌组虹鳟血清杀菌能力第3 d最高(19.4%),而3000 mg/kg纳米锌多糖复合体组血清杀菌能力第6 d最高,达32.43%(P<0.05)。第3 d,1000 mg/kg纳米锌多糖复合体组过氧化氢酶活性、一氧化氮合成酶活性分别为26.39、43.38 U/mL (P<0.05);第6 d,超氧化物歧化酶、酸性磷酸酶活性最高,分别为29.91 U/mL、201.4 U/L(P<0.05),微量丙二醛浓度最低,为3.19 nmol/mL。试验结束后通过杀鲑气单胞菌攻毒感染,7 d内观察虹鳟累积死亡率,1000 mg/kg纳米锌多糖复合体组累积死亡率仅30%。由试验结果可知,纳米锌和纳米锌多糖复合体均能对虹鳟免疫功能产生促进作用,以1000 mg/kg纳米锌多糖复合体效果最佳。     

Determination of Salt Diffusion Coefficient in Rainbow Trout (Oncorhynchus mykiss)

ABSTRACT

The diffusion properties of sodium chloride in rainbow trout muscle during dry salting at 10°C were investigated. The average initial dry matter content of the samples increased from 27.80 ± 0.10 to 36.01 ± 0.16%, and the average salt content increased to 17.98 ± 0.38 g NaCl/100 g dry matter at the end of the 10-h dry salting process. The analytical solution of Fick’s second law considering one-dimensional diffusion through an infinite slab was used to calculate effective salt diffusion coefficients (D_eff). The D_eff values in rainbow trout fillets decreased with increasing salting time and ranged from 6.64 × 10^?10 to 16.45 × 10^?10 m²/s.     

Enzymatic and Histological Evaluations of Gut and Liver in Rainbow Trout,Oncorhynchus mykiss,Fed with Rice Protein Concentrate‐based Diets

This study was carried out in order to investigate the histological and biochemical responses in the gastrointestinal tract (GIT) of rainbow trout fed a rice protein concentrate (RPC). A stock of 360 juvenile rainbow trout (62.4 ± 0.3 g) were randomly distributed into 12 fiberglass tanks and fed with four experimental diets obtained by including graded levels of RPC (RPC: 0, 20, 35, and 53%) replacing fish meal on dry weight basis. The experimental plan was balanced and monofactorial, with four treatments and three replicates. At the end of the experiment, 15 fish per treatment were killed, and different tissues were sampled for biochemical and histological analyses. The results showed that total alkaline proteases were unaffected by RPC inclusion level. Amylase and lipase activities showed slight differences between the groups for all examined tracts. No histopathological changes were observed in GIT for any of the dietary treatments. Liver samples of fish fed with RPC‐based diets were characterized by a slight decrease in lipid vacuolizations and a decreasing trend in the Ceroid Substances Presence Index. In conclusion, RPC did not show detrimental effects on the intestinal morphology and modification of tissue enzyme activity in rainbow trout.     

Incidence of Pathogenic Microorganisms in Aquacultured Rainbow Trout (Oncorhynchus mykiss)

ABSTRACT

Quantitative levels of six known pathogens (Listeria monocytogenes, Clostridium botulinum, Salmonella species, Vibrio cholerae, Yersinia enterocolitica, and Y. pseudotuberculosis) and aerobic plate counts were measured at five aquaculture facilities. The farmed rainbow trout (Oncorhynchus mykiss) and trout fillets were sampled at two different growing seasons to monitor for microbial hazards. Listeria spp. was identified in both whole trout and trout fillets from all five facilities sampled from both growing seasons. Presumptive Clostridium botulinum spores were also identified from all five facilities for both seasons. The growing season did not affect pathogen levels and there was no evidence that any one aquacultural system was superior to the others. Salmonella spp., Vibrio cholerae, and Yersinia spp. were not isolated from any of the trout samples analyzed.