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Yuanfa He Shuyan Chi Beiping Tan Xiaohui Dong Qihui Yang Hongyu Liu Shuang Zhang 《Journal of the World Aquaculture Society》2021,52(1):171-183
A 4‐week feeding trial was conducted using five groups of hybrid grouper (61.15 ± 0.15 g) to explore the potential effects of three methionine (Met) sources. Five isonitrogenous and isolipidic diets were formulated that included a fishmeal (FM) diet; nonsupplemented (NS) diet; or NS diets with the addition of the L‐methionine (L‐Met), DL‐methionine (DL‐Met), or coated Met (Co‐Met) to obtain the same Met level as the FM diet. Fish were randomly distributed into sea cages (30 fish per cage). Weight gain and specific growth rate in the DL‐Met group and FM group were significantly higher than those in all other groups (p < .05). In the proximal and distal intestines, of the 20 gene and time combinations (10 per gene), there were 14 combinations (70%) in which there were no significant differences in gene expression levels between the FM and DL‐Met groups (p > .05). The main reason for the same growth effect between the DL‐Met and FM groups may be attributed to the synchronized absorption at most time points after feeding, which had similar expression patterns of B0AT1 and ASCT2 of the proximal and distal intestines between two groups. 相似文献
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An 8-week feeding trial was conducted to evaluate the effect of dietary carbohydrate sources on the growth performance and hepatic carbohydrate metabolic enzyme activities of juvenile cobia. Six experimental diets were formulated to contain 20% glucose, sucrose, maltose, dextrin, corn starch and wheat starch respectively. The results indicated that fish fed the wheat starch and dextrin diets showed significantly better weight gain, specific growth rate and protein efficiency ratio compared with those fed the other diets. However, fish fed the glucose diet had a significantly lower survival and condition factor than those fed the other diets. There were significant differences in the total plasma glucose and triglyceride concentration in fish fed diets with different dietary carbohydrate sources. Haematocrit, haemoglobin, red blood cell and leucocytes were significantly affected by the dietary carbohydrate sources. The activities of glucose-6-phosphate dehydrogenase (G6PD), 6-phosphofructokinase (PFK) and fructose-1,6-bisphosphatase (FBPase) were significantly affected by the dietary carbohydrate sources, while fish fed the glucose diet showed higher G6PD, PFK and FBPase activities than those fed the other diets. These data indicated that dextrin and wheat starch were the most optimal carbohydrate sources for juvenile cobia. 相似文献
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试验选用234尾军曹鱼随机分为6个处理,每处理设3个重复,每重复13尾鱼,采用单因素浓度梯度法研究军曹鱼幼鱼商品饲料中锌的最适添加量。在基础日粮(锌含量为75.47mg/kg)中分别添加锌0、30、70、110、150和190mg/kg,制成6种试验日粮,分别投喂军曹鱼幼鱼6周。试验结果表明,基础日粮组鱼成活率、饲料系数、特定生长率、血清碱性磷酸酶(AKP)活性、肌肉和血清锌含量与添加锌组无显著差异(P>0.05)。添加锌组骨骼和肝脏锌含量与基础日粮组差异显著(P<0.05),表现为随锌添加的增加而上升的趋势。以成活率和特定生长率为评价指标,军曹鱼商品日粮中的锌含量可以满足其正常生长需求,不需要额外添加锌。 相似文献
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Growth and energy budget of juvenile cobia (initial body weight ∼ 22 g) at various temperatures (23, 27, 31 and 35 °C) were investigated in this study. Maximal ration level (RLmax, %/day) increased as temperature (T, °C) increased from 23 °C to 31 °C but decreased at 35 °C, described as a quadratic equation: RLmax = −0.023T2 + 1.495T − 17.52. Faecal production (f, mg g− 1 day− 1) increased with increased temperature (T, °C), described as a power function: lnf = 0.738lnT − 0.806. As temperature increased, feed absorption efficiency in dry weight (FAEd, %), protein (FAEp, %) and energy (FAEe, %) all increased first and then decreased, but the variation of feed absorption efficiency was small, with ranges of 89.59-91.08%, 92.91-94.71%, 93.92-95.32%, respectively. Specific growth rate in wet weight (SGRw, %/day), dry weight (SGRd, %/day), protein (SGRp, %/day) and energy (SGRe, %/day) showed a domed curve relative to temperature (T, °C), described as quadratic equations: SGRw = − 0.068T2 + 3.878T − 50.53, SGRd = − 0.079T2 + 4.536T −59.64, SGRp = − 0.084T2 + 4.783T − 63.08 and SGRe = − 0.082T2 + 4.654T − 60.99, and SGRw, SGRd, SGRp and SGRe maximized at 28.5 °C, 28.6 °C, 28.4 °C, 28.5 °C, respectively, as calculated from the regression equations. The relationships between feed conversion efficiency in wet weight (FCEw, %), dry weight (FCEd, %), protein (FCEp, %), energy (FCEe, %) and temperature (T, °C) also took on a domed curve described as quadratic equations: FCEw = − 0.726T2 + 39.71T − 473.8, FCEd = − 0.276T2 + 15.31T − 190.6, FCEp = − 0.397T2 + 22.05T − 277.9 and FCEe = − 0.350T2 + 19.39T − 239.9, and FCEw, FCEd, FCEp and FCEe maximized at 27.4 °C, 27.8 °C, 27.7 °C and 27.7 °C, respectively, as calculated from the regression equations. Energy budget of juvenile cobia fed satiation was 100C = 5F + 67(U + R) + 28G at water temperature 27 °C and 100C = 5F + 70(U + R) + 25G at water temperature 31 °C, where C is food energy, F is faeces energy, (U + R) is excretion energy and metabolism energy, and G is growth energy. 相似文献
5.
Jose Antony Appidi Krishna Reddy Arun Sudhagar Hari Krishna Vungurala Luke A Roy 《Journal of the World Aquaculture Society》2021,52(1):155-170
The suitability of inland saline groundwater as a medium to culture juvenile cobia, Rachycentron canadum, was assessed. In the first experiment, juvenile cobia stocked in raw (unamended) saline groundwater at salinities of 5, 10, and 15 g/L exhibited complete mortality after 108, 176, and 195 hr, respectively. The second experiment evaluated the rearing of juvenile cobia (mean weight ~9.23 ± 0.12 g) in potassium (K+)‐amended saline groundwater (100% K+ fortified) and reconstituted seawater at salinities of 5, 10, and 15 g/L to assess growth and osmoregulation in distinct culture media. Following 60 days of culture, all fish survived the experimental period. Final mean bodyweight of cobia reared in K+‐amended saline groundwater (103.2–115.8 g) and seawater (111.2–113.8 g) of different salinities did not vary significantly (p > .05). No differences (p > .05) were observed in specific growth rate, weight gain (%), and feed conversion ratio between treatment groups. Serum osmolality increased with salinity and was significantly higher (p < .05) for fish in K+‐amended saline groundwater (353–361 mOsmol/Kg) than in reconstituted seawater (319–332 mOsmol/Kg), although differences were not observed between salinities by water type. Cobia stocked in saline groundwater of different salinities were osmoregulating normally, and the higher values observed may be because of variations in ionic composition and other interfering ions in saline groundwater. Trial results suggest that juvenile cobia can achieve optimal growth in K+‐amended saline groundwater of low and intermediate salinities. 相似文献
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T‐C Cheng Y‐S Lai I‐Y Lin C‐P Wu S‐L Chang T‐I Chen M‐S Su 《Journal of fish diseases》2010,33(2):161-169
Establishment and characterization of two cobia, Rachycentron canadum, cell lines derived from cobia brain (CB) and cobia fin (CF) are described. Caudal fin and brain from juvenile cobia were dissociated for 30 and 10 min, respectively, in phosphate‐buffered saline containing 0.25% trypsin at 25 °C. The optimal culture condition for both dissociated cells (primary cell culture) was at 28 °C in Leibovitz‐15 medium containing 10% foetal bovine serum. The cells have been sub‐cultured at a ratio of 1:2 for more than 160 passages over a period of 3 years. Origin of the cultured cells was verified by comparison of their sequences of mitochondrial cytochrome oxidase subunit I genes (cox I) with the cox 1 sequence from cobia muscle tissue. The cell lines showed polyploidy. No mycoplasma contamination was detected. Susceptibility to grouper iridovirus was observed for the CB cell line but not the CF cell line. Both cell lines expressed green fluorescent protein after being transfected with green fluorescent reporter gene driven by the cytomegalovirus promoter. 相似文献
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Minh Van Nguyen Marit Espe Louis E. C. Conceio Hoang Minh Le Manuel Yúfera Sofia A. D. Engrola Ann‐Elise Olderbakk Jordal Ivar Rnnestad 《Aquaculture Nutrition》2019,25(2):495-507
This study determined impacts of dietary methionine concentrations at two temperatures on growth, feeding efficiency and N‐metabolites in juvenile cobia. Methionine concentrations of the experimental diets were deficient (M9; 9 g/kg), sufficient (M12; 12 g/kg) and surplus (M16, 16 g/kg). Water temperature was normal (30°C) or elevated (34°C). Twenty cobia in triplicate tanks were fed the experimental diets for 6 weeks. Both methionine and temperature affected cobia's growth and feeding efficiency. Cobia fed M9 performed lower than the fish fed M12 and M16 diets. Additionally, cobia reared at 34°C performed poorer than at 30°C, probably due to lower voluntary feed intake in the fish reared at 34°C. Protein efficiency ratio and protein productive value in cobia fed M9 diet were less than M12 or M16 diets. This was confirmed with the improved retentions of indispensable amino acids (AAs). No interactions between methionine and temperature were observed in growth and protein accretion. At 30°C, CF improved, while HSI and VSI declined upon methionine supplementation levels. Of which an interaction between temperature and methionine was present. Plasma, muscle and liver free AA and N‐metabolites were affected by methionine and temperature. Furthermore, temperature affected cobia's lipid class composition, resulting in increased phospholipids and cholesterol at 34°C. 相似文献
10.
Genetic characteristics of Streptococcus dysgalactiae isolated from cage cultured cobia,Rachycentron canadum (L.) 
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下载免费PDF全文 Disease outbreaks occurred during 2007–2013 in Taiwan with 2.5–10% mortality among the cage cultured cobia, Rachycentron canadum (L.), characterized by the presence of polyserositis, pericarditis and peritonitis. The micro‐organisms isolated from internal organs were Gram‐positive cocci. The isolates were confirmed as Streptococcus dysgalactiae by a polymerase chain reaction assay that yielded the expected specific 259 bp amplicon. Additionally, partial sequence of the 16S–23S rDNA intergenic spacer region of the GCS strain isolates from fish was also compared and produced 100% sequence identity with S. dysgalactiae (GenBank accession number AB252398 ). The genetic characterization was then determined by pulsed‐field gel electrophoresis (PFGE) analysis. Based on PFGE, the Apa I or Sma I digestion patterns of chromosomal DNA of these isolates were grouped into three main clusters. Taiwanese strains were divided into two clusters, and the tet(M) gene was detected in cluster 1 (pulsotypes: A1–A2 and S1–S3), but not in cluster 2 strains (pulsotypes: A3–A4 and S4–S5). Three Japanese strains from amberjack, Seriola dumerili (Risso), were grouped into cluster 3 (pulsotypes: A5–A7 and S6–S8) and displayed no mortality to cobia in the challenge experiment. Conversely, Taiwanese strains from cobia and snubnose pompano, Trachinotus blochii (L.), displayed a mortality rate of 50–87.5% in cobia. 相似文献