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1.
The reliability of several in vitro steps as compared with the conventional in vivo method to determine the dry matter and protein digestibilities of several raw ingredient by discus juveniles was assessed. In vitro studies were conducted based on a 12-h digestion method and measurement of pH drop involving four different substrate–enzyme mixtures, namely the Lazo single enzyme, Hsu multi-enzyme, Saterlee multi-enzyme and discus extract enzyme system. Results from both methods showed that fishmeal was highly digestible in terms of dry matter (67.22–87.52%) and protein (76.8–91.18%). With the exception of poultry offal meal, findings also indicate that discus digests dry matter in feedstuffs of animal origin (fish meal and beef heart) more efficiently compared with plant materials (soybean and wheat meal) with no obvious trend observed for protein digestibility in any of the ingredients tested. Apparent digestibility coefficients of not less than 40% suggest that all the ingredients tested were potential ingredients for development of formulated feed for discus culture. A comparison between the different in vitro enzyme systems tested showed that the Saterlee method, which used commercial mammalian and bacterial enzymes, was best in terms of its ability to differentiate the digestibilities of the various ingredients and correlation ( r 2 =0.85–0.90) with the in vivo results. The use of a crude enzyme extract from discus digestive tract also provided values consistent with in vivo and Saterlee in vitro methods ( r 2 =0.72–0.87), indicating the potential and need for further investigation to develop a more accurate in vitro assay based on discus digestive enzymes. 相似文献
2.
In a 8-week production-scale experiment at a commercial trout farm, the effects of dietary lipid level and phosphorus level on phosphorus (P) and nitrogen (N) utilization of rainbow trout (initial mean weight 99 g) were assessed. A low-phosphorus, high-lipid experimental diet (457 g protein, 315 g lipid, 9.1 g P kg–1 dry diet) was compared with a commonly used commercial diet (484 g protein, 173 g lipid, 13.6 g P kg–1 dry diet). P and N budgets were constructed using data from the production-scale experiment and digestibility data for the two diets. In addition, orthophosphate and ammonia-N waste were measured in effluent over one 24-h period. Relative to the commercial diet, the experimental diet resulted in significantly increased feed efficiency ratio, N retention and P retention, and substantially reduced dissolved, solid and total P waste (g kg–1 dry feed). Although N retention resulting from the experimental diet was higher, this was attributable to higher N (protein) digestibility of the experimental diet. Solid N waste (g kg–1 dry feed) resulting from the experimental diet was substantially lower, but dissolved N waste (g kg–1 dry feed) was not significantly different relative to the commercial diet. Mean effluent orthophosphate production (mg day–1 kg–1 fish) of fish fed the experimental diet was substantially lower than that of fish fed the commercial diet ( P < 0.05), but effluent ammonia-N production (mg day–1 kg–1 fish) was not significantly affected by dietary treatment. 相似文献
3.
Microbial phytase (Natuphos 5000G) was supplemented into barley, canola meal, wheat and wheat middlings at 500 FTU kg–1 diet to test the effectiveness of the phytase on digestibility of crude protein (CP), gross energy (GE) and minerals for rainbow trout. A total of 180 rainbow trout (initial mean body weight 223.8 ± 17.9 g) were stocked into ten 40-L fibreglass digestibility tanks with 18 fish per tank. Duplicate tanks were assigned to a reference diet and a single tank was assigned randomly to each of the eight diets made from these four ingredients supplemented with and without phytase. The collection of faeces lasted for 2 weeks. Faeces collected in each week represented a replicate and they were analysed separately. The mean apparent digestibility coefficients (average of four ingredients) in phytase supplemented and nonsupplemented ingredients were: CP, 97.3% and 96.5%; GE, 62.8% and 53.1%; calcium (Ca), 38.3% and –5.3%; magnesium (Mg), 72.4% and 50.3%; manganese (Mn), 31.0% and –4.2%; total-phosphorus (total-P), 71.1% and 47.6%; phytate-phosphorus (phytate-P), 87.5% and 22.3%; copper (Cu), 38.3% and 26.4%; potassium (K), 97.1% and 97.0%; sulphur (S), 90.2% and 88.6%; zinc (Zn), 12.3% and –16.6%. A two-tailed t -test indicated that phytase supplementation significantly ( P < 0.05) improved the digestibility of Ca, Mg, Mn, total-P, phytate-P, and GE. The efficacy of phytase on nutrient digestibility also depended on the type of ingredient as measured in rainbow trout. 相似文献
4.
Abstract. An enzootic, Australian, atypical strain of Aeromonas salmonicida isolated from diseased goldfish, Carassius auratus (L.), was inoculated into Atlantic salmon, Salmo salar L., brown trout, S. trutta L., rainbow trout, S. gairdneri Richardson, and brook trout, Salvelinus fontinalis (Mitchill), fingerlings by intraperitoneal injection (i.p.) and by bath challenge, the latter with and without prior abrasion of skin. The 10-day LD50 (i.p.) was estimated to be 7·4 × 10-3 colony forming units (cfu) for Atlantic salmon, 3·0 × 10-2 cfu for brown trout, 3·7 × 102 cfu for brook trout and 6·4 × 103 cfu for rainbow trout. Brown, rainbow and brook trout succumbed to bath challenges with between 105 –106 cfu/ml, developing ulcers of the skin and septicaemia. The organism was trasmitted from inoculated fish to five of 195 within-tank control fish via water and established a carrier state in one of 14 Atlantic salmon. It was concluded that the organism poses a significant threat to the salmonid farming industry and wild salmonid fisheries in Australia. 相似文献
5.
Rainbow trout, Oncorhynchus mykiss (Walbaum), were exposed continuously to infectious pancreatic necrosis virus (IPNV) at 0, 101 , 103 or 105 plaque forming units (pfu) L−1 of water to estimate the effects of chronic IPNV exposure on early life stages. Fish density averaged 35 fish L−1 (low density) or 140 fish L−1 (high density), and the tank flow rate was 250 mL−1 min. Virus exposure began at 6 days before hatch and continued until fish were 44 days old. Cumulative per cent mortality, analysis of survival and hazard functions, and discrete-time event analysis were used to explore the patterns of survival and mortality. In eggs and fish exposed to IPNV, mortality significantly greater than in the 0 pfu L−1 exposure did not occur until IPNV concentration was 105 pfu L−1 at low fish density and 103 pfu IPNV L−1 at high fish density. These results suggest that in the natural aquatic environment, where rainbow trout densities are likely to be considerably lower than in this study, mortality resulting from infection with IPNV will very likely not occur when ambient concentrations of virus are ≤103 pfu IPNV L−1 . In aquaculture rearing units, trout density is likely to be as high or higher than the densities used in this study. Therefore, continuous inputs of virus at concentrations greater than 101 pfu L−1 may result in IPN epidemics in aquaculture facilities. 相似文献
6.
Abstract. The pathogenicity of Renibacterium salmoninarum to carp, Cyprinus carpio L., and rainbow trout, Salmo gairdneri Richardson, was investigated. All carp injected with 4·8 × 108 cells/fish, or 4·8 × 107 cells/fish survived for 38 days. R. salmoninarum was isolated from all moribund fish, but not from the kidney of surviving fish, although R. salmoninarum antigen was detected in several of these fish by the dot blot assay. On the other hand, mortality in rainbow trout was 95% in the fish injected with 4·8 × 108 cells/fish, and 15% in those which received 4·8 × 107 cells/fish. R. salmoninarum antigen was detected by the dot blot assay in all surviving rainbow trout. The number of R. salmoninarum cells was immediately decreased by carp or rainbow trout serum, and the serum bactericidal activity of carp was higher than that of rainbow trout. Carp blood leucocytes had higher phagocytic activity than those of rainbow trout. 相似文献
7.
Nutritional strategies to reduce both phosphorus (P) and nitrogen (N) excretion relative to growth of rainbow trout were tested in a 2 × 3 factorial experiment. The two factors were `dietary P level' and `dietary lipid level.' Reduction in dietary P from 14 to 8 g kg–1 dry diet was achieved by partial substitution of dietary fish meal with a combination of full-fat soyabean meal, corn gluten and spray-dried blood meal. Triplicate tanks of 35 rainbow trout per tank were fed experimental diets for 16 weeks and grew from approximately 40 to 250 g, in 15 °C spring water. All tanks were fed the same percent biomass per day. Diets were isonitrogenous, and dietary energy varied with dietary lipid. Diet digestibility data and results of the experiment were used to construct N and P budgets for the fish fed the various diets. A reduction in dietary fish meal from 500 to 200 g kg–1 dry diet, corresponding to a reduction in dietary P from 14 to 8 g kg–1 dry diet, resulted in >50% reductions in both solid and dissolved P waste, but did not affect growth, feed efficiency ratio (FER) or sensory characteristics of rainbow trout. Increasing dietary lipid from 170 to 310 g kg–1 dry diet led to higher growth rate and FER, and lower total N waste relative to weight gain, but did not change protein retention. Increasing dietary lipid level increased deposition of lipid in whole bodies of rainbow trout, and resulted in discernible differences in sensory characteristics of trout fillets. 相似文献
8.
J. SALES 《Aquaculture Nutrition》2009,15(5):537-549
Values for the digestible contents of nutrients in diets and feed ingredients are of utmost importance in nutritional strategies for fish. Prediction from dietary composition would eliminate lengthy, tedious and demanding digestibility experiments with fish. Apparent digestible lipid (DL) content [range 7.6–353.4 g kg−1 dry matter (DM)] in compound diets can be predicted with high accuracy ( n = 610; studies =127; fish species = 34; R 2 = 0.9515; RMSE = 16.9504) from dietary crude lipid (CL) content (range 12.0–388.7 g kg−1 DM) by the linear regression equation DL =−2.7303 + 0.9123 CL. Validation of this equation against 65 values from 15 independent studies presented R 2 and mean prediction error (MPE) values of 0.9947 and 0.0671, respectively. The corresponding equation for 37 individual feed ingredients evaluated in 24 studies with 18 fish species ( n = 180) was found to be DL = −1.5824 + 0.8654 CL ( R 2 = 0.9717; RMSE = 8.3765). However, validation of the latter is currently hampered by a lack of independent values. 相似文献
9.
Hongyue Zhao Dong Han Shouqi Xie Xiaoming Zhu & Yunxia Yang 《Aquaculture Research》2009,40(16):1864-1872
The present study was carried out to investigate the influence of water temperature on the growth performance and digestive enzyme (pepsin, trypsin and lipase) activities of Chinese longsnout catfish. Triplicate groups of Chinese longsnout catfish (35.6±0.48 g, mean±SE) were reared at different water temperatures (20, 24, 28 and 32 °C). The feeding rate (FR), specific growth rate (SGR) and feed efficiency ratio (FER) were significantly affected by water temperatures and regression relationships between water temperature and FI, SGR as well as FER were expressed as FR=−0.016 T 2 +0.91 T −10.88 ( n =12, R 2 =0.8752), SGR=−0.026 T 2 +1.39 T −17.29 ( n =12, R 2 =0.7599) and FER=−0.013 T 2 +0.70 T −8.43 ( n =12, R 2 =0.7272). Based on these, the optimum temperatures for FR, SGR and FER were 27.66, 26.69 and 26.44 °C respectively. The specific activities of digestive enzymes at 24 or 28 °C were significantly higher than that at 20 or 32 °C. In addition, there was a significant linear regression between FR or SGR and specific activities of pepsin and lipase, which indicated that pepsin and lipase played important roles in regulating growth through nutrient digestion in Chinese longsnout catfish. 相似文献
10.
Abstract. Viral haemorrhagic septicaemia (VHS) is reported for the first time in sea-water cultured rainbow trout. Heavy mortalities with typical signs and lesions A VHS virus (serotype 1) was isolated from the diseased fish. The mortalities were caused only by the VHS virus and 80 days post transfer of trout to sea-water the mortalities reached 85%, of the initial population.
The disease was experimentally transmitted to rainbow trout, both in sea-water 3·104 pfu/ml of virus or by intramuscular injection of various doses of VHS1 (7·101 7·104 or 7·104 pfu per fish). Death occurred in all infected groups and started earlier in sea-water. Typical signs of VHS were observed in moribund fish. Viral multiplication was demonstrated to have occurred in fish organs. 相似文献
The disease was experimentally transmitted to rainbow trout, both in sea-water 3·10
11.
K Pedersen H F Skall A M Lassen-Nielsen L Bjerrum N J Olesen 《Journal of fish diseases》2009,32(5):465-472
A selection of 16 field isolates of Photobacterium damselae from marine rainbow trout farms in Denmark was subjected to phenotypic and genotypic characterization and pathogenicity to fish. All isolates belonged to the subspecies damselae , being positive for haemolysis, motility and urease. There were considerable differences in haemolytic properties, some isolates presenting a broad zone of haemolysis and others only a narrow zone. Pulsed-field gel electrophoresis revealed a high diversity indicating that P. damselae subsp. damselae is an opportunistic, not clonal pathogen in Danish marine rainbow trout. Virulence of the strains to rainbow trout was highly variable with LD50 values ranging from 3.9 × 103 to 1.5 × 108 cfu at 20 °C. The virulence was significantly higher at 20 °C than at 13 °C. The strains with the strongest haemolytic properties were the most virulent suggesting a strong involvement of haemolysin in the pathogenesis. The pathological changes were consistent with a bacterial septicaemia and the haemorrhages were more pronounced than for most other bacterial infections. 相似文献
12.
Dietary formic acid enhances apparent digestibility of minerals in rainbow trout, Oncorhynchus mykiss (Walbaum) 总被引：1，自引：0，他引：1
The effect of dietary formic acid on the availability of phosphorus (P) from a fishmeal-based diet by rainbow trout, Oncorhynchus mykiss (Walbaum), reared in brackish water (5–6 g L−1 ) was determined. Diets containing a low amount of P (6.0 mg P g−1 dry matter) were acidified with 0, 4 and 10 mL kg−1 formic acid and fed to trout (average weight, 520 g) for 4 weeks. The measured pH of the diets were 6.3, 5.8 and 5.3, respectively. The intestinal solubility of P and the digestibility of P were measured by stripping the faecal matter from the fish. The apparent digestibility coefficient (ADC) of P significantly ( P < 0.05) increased from 69.5% to 75.0% of the basal diet in fish fed diets containing 10 mL kg−1 formic acid. The solubility of P in the intestine was highly variable within each treatment, and the differences were not significant. The pH of intestinal content increased with the increase in dietary formic acid concentration. The ADC of magnesium and calcium also showed a significant ( P < 0.05) increase with the acidification of diet by formic acid. 相似文献
13.
J M Fregeneda Grandes M Fernández Díez & J M Aller Gancedo 《Journal of fish diseases》2001,24(6):351-359
Juvenile rainbow trout, Oncorhynchus mykiss (Walbaum), were experimentally infected to investigate the pathogenicity of 20 isolates of two morphotypes of long-haired Saprolegnia obtained from wild brown trout, Salmo trutta L., and river water in Spain. The trout were exposed to 2 × 105 and 3 × 105 L–1 zoospores. Saprolegnia infection could not occur without 'ami-momi' treatment. Pathogenicity varied greatly among isolates as mortality ranged from 0 to 100% of the fish. There was a statistically significant difference ( P < 0.001) between the mortality caused by morphotype I isolates and that produced by those of morphotype II. The most pathogenic isolates usually belonged to morphotype II, consisting of isolates which had secondary cysts with bundles of hooked hairs which were shorter and less numerous than those of morphotype I; the morphotype I isolates usually had low pathogenicity. Lesions were most frequently found on the fins. Cultures detected the presence of Saprolegnia in internal organs. Histopathology of the intestine suggests that Saprolegnia may reach this and other organs via the blood stream from surface lesions. 相似文献
14.
A method to evaluate protein quality using in vivo methods was developed for larval fish. FluoSpheres® fluorescent microspheres (10 μm) were incorporated into two test diets, our standard zein microdiet (ZMD) and a microdiet with identical ingredients except for the replacement of high quality fish meal with the same product cooked for 24 h at 80 °C (ZMD-CF). Several trials were performed to design a reliable method to test digestibility using FluoSpheres® as a marker. The developed in vivo technique was tested on 35 days posthatch (dph) larval Atlantic cod ( Gadus morhua L.) and two tropical fish species in the early juvenile stage. The method took into account loss of total protein to the faecal pellet and water column. Apparent digestibility of protein in larval cod fed ZMD was significantly higher than that of larvae fed ZMD-CF ( P < 0.05). A growth study to validate differences between the two diets showed significant differences in growth and survival of larvae fed ZMD versus ZMD-CF ( P < 0.05). Further validation of our results was indicated through the use of a pH-stat method using enzymes extracted from 35 dph larval cod guts. This novel technique will be advantageous for researchers to evaluate feed ingredients for larval marine fish and is adaptable to many different areas of larval fish nutrition. 相似文献
15.
Abstract. Juvenile rainbow trout (initial mean body weight 17 g) reared on practical trout diets containing different levels of available carbohydrate for 8–24 weeks were assayed for liver function based on the time required to recover from the anaesthetics tricaine methanesulphonate (MS222), 2-phenoxyethanol (2PE) and tertiary-amyl alcohol (TAA), as well as plasma clearance of 35 S-sulphobromo-phthalein (BSP), Liver/body weight ratios (LBW) and percentage liver glycogen content (LG) increased in a linear manner with increased available carbohydrate. The mean recovery time (MRT) of trout anaesthetized with 2PE and TAA increased linearly with increased LBW and LG. No difference was observed in the MRT of trout anaesthetized with MS222 which is not metabolized in the trout liver. There was a significant linear regression of the biological half-life of plasma BSP on LBW (MR2 = 95.7) and LG (MR2 = 99.6). The results indicate that increased liver glycogen and liver weight due to higher levels of available carbohydrate affect the liver function of rainbow trout. These liver function tests may be applicable in determining acceptable levels of available carbohydrate in practical trout diets. 相似文献
16.
A Decostere E D'Haese M Lammens H Nelis & F Haesebrouck 《Journal of fish diseases》2001,24(8):481-487
The intracellular behaviour of a Flavobacterium psychrophilum strain, ingested by spleen phagocytes of rainbow trout, Oncorhynchus mykiss , of different ages, was assessed in vivo . Three groups of rainbow trout weighing 1 g (aged 10 weeks), 25 g (aged 20 weeks) and 300 g (aged 15 months), respectively, were injected intraperitoneally with 1 × 106 cfu of a F. psychrophilum strain. It was found that only fry, aged 10 weeks, displayed clinical signs and suffered mortality. Bacteriological colony plating of different organs demonstrated that the spleen and to a lesser extent the kidney of only the fry were affected. The number of colony forming units per gram of spleen tissue increased with time. No bacteria were found in the trout aged 5 months and older. Light microscopical examination and epifluorescence microscopy revealed that the fry spleen phagocytes contained an increasing number of viable intracellular F. psychrophilum bacteria over time. Again, no bacteria were encountered in the phagocytes collected from older fish. 相似文献
17.
In the present study, effects of sulfamerazine on some haematological and immunological parameters of rainbow trout ( Oncorhynchus mykiss ) were examined. Four groups of rainbow trout were fed experimental diets containing either no sulfamerazine (control) or supplemented with sulfamerazine at 100 mg kg−1 (Exp-A), 200 mg kg−1 (Exp-B) or 400 mg kg−1 (Exp-C) for 21 days. Blood samples were taken for the haematological and immunological parameters from fish on the third, seventh, 14th and 21st days of feeding. Haematological parameters [haematocrit, leucocrit, numbers of erythrocytes (RBC) and leucocytes (WBC), haemoglobin (Hb), mean corpuscular volume (MCV), mean haemoglobin concentration (MHC) and mean corpuscular haemoglobin concentration (MCHC)] and immunological parameters [phagocytic ratio (PR) and index (PI), glass-adherent NBT-positive cell activation, total plasma protein and total immunoglobulin (Ig)] were evaluated during the experimental trial. It has been observed that MCV ( P <0.05), PR and PI ( P >0.05) were increased and haematocrit and leucocrit value, numbers of erythrocytes and leucocyte, haemoglobin, MHC and MCHC values and total plasma protein and total Ig levels were decreased in rainbow trout after application of three different doses of sulfamerazine. 相似文献
18.
Yuzo Yamamoto Carol A Woody Takayuki Shoji & Hiroshi Ueda 《Aquaculture Research》2008,39(10):1019-1027
Two anaesthetics, clove oil and methane sulphonate (MS-222), were examined for their effects on the olfactory nerve response of masu salmon ( Oncorhynchus masou Brevoort) and rainbow trout ( O. mykiss Walbaum). Exposing both species to clove oil for 3 min at concentrations of 50 and 100 mg L−1 , or for 10 min at 50 mg L−1 , did not significantly reduce their olfactory response. Directly applying clove oil anaesthesia to the olfactory epithelium significantly reduced olfactory response though after 20 min, olfactory response recovered to 70% and 52% of pre-treatment levels in masu salmon and rainbow trout respectively. Compared with the post-anaesthetic recovery of responses after clove oil (50 mg L−1 ), buffered MS-222 (100 mg L−1 ) with NaHCO3 (100 mg L−1 ), and unbuffered MS-222 (100 mg L−1 ) treatment for 3 min, the response after MS-222 treatment declined gradually and significantly, but not after clove oil and MS-222+NaHCO3 treatments. Clove oil appears to be an effective and relatively safe anaesthetic for salmonids with little long-term impact on their olfactory response, which plays a crucial role in their life history. 相似文献
19.
Pathogenicity of Saprolegnia species associated with outbreaks of salmonid saprolegniosis in Japan 总被引：2，自引：0，他引：2
The present study was conducted to evaluate the pathogenicity and pathology of Saprolegnia salmonis NJM 9851 and Saprolegnia parasitica NJM 9868, isolated from outbreaks of saprolegniosis, against the immature stages of five species of salmonids. The cumulative mortalities of the tested fish groups that were exposed to 2 × 10 5 spore/L concentrations of S. salmonis NJM 9851 were 90% for brown trout, 93.3% for sockeye salmon and 100% for rainbow tout, masu salmon, and Japanese char. In contrast, all salmonid species exposed to 2 × 10 5 spore/L concentrations of S. parasitica NJM 9868 experienced cumulative mortalities of 100%. The histopathological changes of the saprolegniosis lesions found in all sites of infection were loss of the epidermis, edema of the hypodermis and different degrees of degenerative changes in the underlying musculature. It is clear from our results that S. salmonis NJM 9851 and S. parasitica NJM 9868 are highly pathogenic species to five species of salmonid fishes 相似文献
20.
James M. Myers William K. Hershberger Robert N. Iwamoto 《Journal of the World Aquaculture Society》1986,17(1-4):1-7
The induction of tetraploidy was attempted in three intraspecies crosses (autotetraploid) of sal-monid: chinook salmon ( Oncorhynchus tshawytscha ), coho salmon ( O. kisutch ) and rainbow trout ( Salmo gairdneri ), and in the interspecies hybrid (allotetraploid) coho × Atlantic salmon ( Salmo salar ).
Pressure treatments of 6.2 × 104 kPa (9,000 psi) were applied for six minutes at intervals from 50% of the time to cleavage to beyond first cleavage. Analysis of eyed stage embryos via flow cytometry indicated two periods of tetraploid induction existed corresponding to 55–75% and 100–110% of the first cleavage interval (FCI).
The effects of different pressures and the times of application were analyzed in a study with rainbow trout. Treatments of 4.8 × 104 kPa (7,000 psi) for eight minutes, and 5.5 and 6.2 × 104 kPa (8,000 and 9,000 psi) for four minutes, were applied at 65, 78, and 100% FCI. Tetraploids were found in the 5.5 and 6.2 × 104 kPa group treatments only when applied at 65% FCI.
The results indicate that, while tetraploidy is inducible in salmonids, further experimentation is necessary to discern the appropriate time and treatment for optimal tetraploid induction in each species. 相似文献
Pressure treatments of 6.2 × 10
The effects of different pressures and the times of application were analyzed in a study with rainbow trout. Treatments of 4.8 × 10
The results indicate that, while tetraploidy is inducible in salmonids, further experimentation is necessary to discern the appropriate time and treatment for optimal tetraploid induction in each species. 相似文献