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1.
A multiple-batch study was conducted using stocker catfish (0.09 kg/fish) and carryover fish (0.39 kg/fish) to look at the effects of different stocker densities on fish production. Twelve 0.1-ha ponds were stocked with 7,400; 11,120; or 14,825 stockers/ha, and equal weights of carryover fish (2,268 kg/ha). Fish were fed once daily to apparent satiation with a 32% protein floating feed and aerated with a single 0.37-kW electric paddlewheel aerator. No significant differences were detected for gross, net, and net daily yields, growth (g/d), or survival. Sub-marketable yield (<0.57 kg) increased as stocking density increased. However, marketable yields (≥0.57 kg) were not affected by density. Carryover fish in high-density ponds had a significantly lower (P < 0.05) mean weight at harvest, but mean stocker weight was not different across densities. Economic analysis found breakeven prices increased and net returns decreased with increased stocking density when sub-marketable fish were not considered as revenue. The study indicated the possibility that stockers compete with large carryover fish, particularly at higher densities. 相似文献
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Previous work suggested that feeding catfish, Ictalurus punctatus, more frequently over the winter might reduce weight loss. Twelve 0.10-ha ponds were stocked with 987 kg/ha market-sized fish and 2,960 kg/ha sub-marketable fish in November 2008 with treatments of: (1) unfed, (2) fed daily (fed 90 d), and (3) temperature-threshold feeding (fed 62 d). Total gross yield was significantly greater for the temperature-threshold feeding treatment than the unfed control, but survival and mean weight of fish at harvest were not. Net yield was negative for all treatments, due primarily to mortality of market-sized fish. Plasma glucose and insulin-like growth factor-1 did not differ significantly, but plasma osmolality was significantly lower in fasted than in fed fish. Mean feed consumption rates in vats provided evidence to support more frequent feeding over the winter. Overwintering costs were $0.11/kg with temperature-threshold feeding. Research on strategies to reduce winter mortality has potential to reduce overwintering costs. 相似文献
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《Journal Of Applied Aquaculture》2013,25(3):17-30
Abstract Two studies were conducted to determine if temporary sequestration of fingerling channel catfish, Ictalurus punctatus, in cages improves production of multiple-crop ponds. In the first study, 0.04-ha ponds were stocked with 295 large (mean weight = 566 g) and 780 fingerling (mean weight = 21 g) catfish. Fingerlings were stocked into cages or open ponds. At 120 days after stocking, fish in cages were released. After an additional 40 days, ponds were clean-harvested to remove large (>500 g) and small (<500 g) fish. In the second study, ponds (0.08-ha) were stocked with 750 large (mean weight = 46 g) and 750 small (mean weight = 20 g) fingerling catfish. Small fingerlings were stocked into cages or open ponds. At 60 days after stocking, fish in cages were released. Market-ready fish were selectively harvested at five and nine months after stocking. Results from the first study indicated that individual weight, weight gain, and yield of both size classes of fish raised in sequestered ponds were significantly greater (P< 0.05) than that of fish raised in open ponds. In addition, total weight gain and yield of fish in sequestered ponds was significantly greater (P< 0.05) than those in non-sequestered ponds. Results from the second study indicated that a significantly greater (P< 0.05) number of market-ready fish were harvested from sequestered ponds than from non-sequestered ponds. Mean yield of sequestered ponds was 31% greater than that of non-sequestered ponds; however, differences were not significant (P> 0.05). Amount of feed fed to fish raised in sequestered ponds was significantly greater (P< 0.05) than amount of feed fed to fish raised in non-sequestered ponds in both studies. It is unclear which factor or factors were responsible for the enhanced production of sequestered ponds; however, temporary sequestration may reduce agonistic behavior and competition for feed between fish size groups. 相似文献
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Cynthia Ware Lester H. Khoo Terrence E. Greenway David J. Wise Brian G. Bosworth Mark L. Lawrence Matt J. Griffin 《Journal of the World Aquaculture Society》2018,49(1):197-204
Members of the genus Edwardsiella are important pathogens of cultured and wild fish globally. Recent investigations into the phenotypic and genotypic variation of Edwardsiella tarda have led to the segregation of E. tarda into three distinct taxa: E. tarda, Edwardsiella piscicida, and Edwardsiella anguillarum. In catfish aquaculture in the southeastern USA, E. piscicida has been more commonly associated with disease than E. tarda or E. anguillarum, and recent research has demonstrated E. piscicida to be more pathogenic in channel catfish than E. tarda or E. anguillarum. Anecdotal reports from industry suggest an increased prevalence of E. piscicida associated with the culture of channel (♀) × blue (♂) hybrid catfish. This work investigated the comparative susceptibility of channel catfish, blue catfish, and their hybrid cross to molecularly confirmed isolates of E. tarda, E. piscicida, and E. anguillarum. There was significantly higher mortality in hybrid catfish compared to channel catfish following intracoelomic injection of E. piscicida. To our knowledge, E. piscicida is the first bacterial pathogen to demonstrate increased pathogenicity in hybrid catfish compared to channel catfish. 相似文献
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《Journal Of Applied Aquaculture》2013,25(2):75-83
Abstract This study was conducted to determine if channel catfish could be cultured at an increased density in the Partitioned Aquaculture System (PAS) without significantly affecting performance. Channel catfish fingerlings (36.53±6.76 g; mean ±SD) were initially stocked into six 9.15 m3 sections at 3,461±317 fish per section, twice the designed carrying capacity, and fed twice daily to satiation. After 75 days, the density of three units was reduced by approximately 50% and all six units were fed for another 97 days. There was no significant difference (P > 0.05) in mean growth rate, feed conversion ratio, or production between fish grown at the low- and high-density treatments. Also, length variation (CV) and condition factors (K) were similar (P > 0.05) between fish grown at the low and high-density. Increasing density by twice the designed carrying capacity did not affect performance of channel catfish in the PAS. 相似文献
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利用m tDNA控制区序列对1984、1997年引进的斑点叉尾鮰群体遗传多态性进行了分析。通过PCR产物测序法,测定了40尾斑点叉尾鮰线粒体DNA的一段包括部分Cytb基因、tRNAThr、tRNAPro、D-loop控制区和部分tRNAThe长度为1256 bp的核苷酸序列,经过比对分析得到7个序列单元型。7个单元型中共有13个碱基转换位点,全部发生在控制区,其序列相似度平均为99.58%。群体总的序列单元型多态性比例为17.5%,其中1997年群体的单元型多态性比例为35%,是1984年群体单元型多态性比例(15.0%)的2倍多。初步表明1984年引进的群体遗传多样性较低。 相似文献
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通过Percoll密度梯度离心法分离斑点叉尾[鱼回]头肾巨噬细胞,经含2%胎牛血清的L-15培养液中培养,在光镜和电镜下观察其形态和超微结构;采用MTS法研究酵母细胞壁对巨噬细胞体外作用的合适浓度和最佳时间。结果表明:使用34%、51%的密度梯度分离斑点叉尾[鱼回]头肾细胞,经过3~12小时培养,巨噬细胞纯化率95%以上;分离的头肾巨噬细胞具有巨噬细胞的形态特征。酵母细胞壁对斑点叉尾[鱼回]的巨噬细胞最适的作用浓度为0-500pg/ml,作用时间为12小时。本研究为进一步探讨酵母细胞壁对鱼类免疫细胞的作用机理奠定了基础。 相似文献
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《Journal Of Applied Aquaculture》2013,25(3):37-45
ABSTRACT Two generations of selection for increased body weight in Kansas (AU-KS-2) and Marion (AU-MS-2) lines of channel catfish, Ictaluruspunctatus, resulted in a 12% and 11% increase in body weight at market size, respectively. The second generation of selection produced no improvement in growth, and there was a slight negative response to selection for body weights during the second generation. Cumulative realized h2 was 0.17 ±0.03 and 0.15 ±0.03 for AU-KS-2 and AU-MS-2, respectively, based on growth performance measured against a randomly bred, Kansas control for the two generations. Relative size differences were established by the time the fish reached 80 g, and these relative size differences were maintained the remainder of the experiment. Growth rate of the channel catfish ♀ × blue catfish 6, I. furcatus, hybrid was 35% faster than the Kansas control, and better than all three groups of channel catfish. The growth improvement through interspecific hybridization was three times better than through mass selection. 相似文献
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《Journal Of Applied Aquaculture》2013,25(1-2):45-52
Abstract The authors examined the use of culture and polymerase chain reaction (PCR) to detect Flavobacterium columnare in experimentally-infected channel catfish, Ictalurus punctatus. Five treatments were utilized which included immersion exposure to 106, 107, 108 colony forming units (CFU)/mL for 30 minutes, intramuscular injection of 108 CFU/fish and a negative control (i.e., immersion in Cytophaga broth). Flavobacterium columnare was isolated and detected in mucus 30 minutes following exposure by microbiological culture and PCR in all treatments except the negative controls. Gills were positive by culture and by PCR in all treatments at 30 minutes post treatment except the 106 CFU/mL immersion treatment which did not yield positive culture and PCR results until 1 hour. Culture positive samples were observed in the internal organs (anterior and posterior kidney) and blood of the 1078 CFU/mL treatments although at low numbers (≤10 CFU). Results of PCR paralleled that of culture for the mucus and gill samples when analyzing all treatments together over time suggesting either method is useful in determination of the presence ofF. columnare. Polymerase chain reaction was significantly (P < 0.001) better at detection ofF. columnare from skin/muscle than was the use of microbiological culture. These results suggest that PCR may be useful for rapid detection of F. columnare in the mucus. 相似文献
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The purpose of this study was to determine the feasibility of growing marketable channel catfish, Ictalurus punctatus, from pond-run fingerlings (15.9 g/fish) using low stocking densities (7,413 or 14,826 fish/ha) and electrified bug lights to enhance natural forage available to fish. Even at low stocking densities, fish only averaged 0.2 kg at the end of the growing season. Because marketable sizes of fish were not reached over the growing season, stocking small fingerlings at these rates would not be practical under most commercial production scenarios. Nutritionally, captured insects from electrified bug lights were near a complete diet for catfish, but bug lights did not capture sufficient quantities of insects to affect fish production in either stocking density. Stocking small fingerlings at low stocking rates does not produce market‐sized catfish during one growing season; commercially available bug lights did not provide adequate amounts of natural forage to affect production variables. 相似文献
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Nagaraj Chatakondi Brian C. Peterson Terrence E. Greenway Todd S. Byars David J. Wise 《Journal of the World Aquaculture Society》2018,49(4):686-691
This study evaluated the efficacy of an oral live‐attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish (ESC) in channel and hybrid catfish. The vaccine was delivered one time orally by feeding fish a diet coated with an attenuated E. ictaluri isolate at four doses to deliver between 4 × 106 to 3.2 × 107 viable vaccine cells/g wet feed. Thirty‐five days postvaccination, control and vaccinated fish were challenged with virulent E. ictaluri and mortality was examined for 30 d postchallenge. Mortality of nonvaccinated hybrids (85%) and nonvaccinated channel catfish (73%) was similar but significantly greater than all groups of vaccinated fish. In channel catfish, a trend toward increasing mortality with decreasing dose was observed. Mortality of channel catfish vaccinated with the lowest dose (26.6%) was significantly higher than fish vaccinated with the highest dose (14.1%) but similar to fish vaccinated at the intermediate doses (17.5 and 19.4%). In contrast, mortality of four doses of vaccinated hybrid catfish was similar and ranged between 10.4 and 14.0%. The data demonstrate that the attenuated E. ictaluri vaccine at all four doses tested is effective at reducing ESC‐related mortalities in hybrid and channel catfish. 相似文献
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Carole Engle Ganesh Kumar Rebecca Lochmann Brian Bosworth Miles Thompson 《Journal Of Applied Aquaculture》2013,25(2):102-112
Three 28% protein feeds (premium, standard, or a low-cost diet) were fed to channel catfish in a pond study to compare growth, production, and costs as a follow up to similar work with 32% protein feeds. Twelve 0.1-ha earthen ponds at the University of Arkansas at Pine Bluff (UAPB) Aquaculture Research Station were stocked with carryover fish (0.39 kg mean weight) at 5,860 fish/ha and fingerling catfish (mean individual weight of 15.4 g) at 12,500 fish/ha. Total yield (gross and net) did not differ between fish fed the premium as compared to the standard diet, but that of the premium diet was significantly higher than that of fish fed the low-cost diet. The feed conversion ratio (FCR) did not differ between fish fed the premium and standard diets, but was lower than the FCR of fish fed the low-cost diet. There were no differences found in processing yields among treatments. Given the lower cost of the 28% standard diet and yields equivalent to those of the 28% premium diet, the 28% standard diet was economically preferable to the other diets tested. 相似文献
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《Journal Of Applied Aquaculture》2013,25(1-2):43-52
ABSTRACT The humoral antibody response of channel catfish, Ictalurus punctatus, to experimental Flavobacterium columnare infection was measured in control (non-infected) and infected (intraperitoneal- and intramuscular-injected) fish by an indirect enzyme-linked immunoassay (ELISA). The antibody response of the experimentally infected fish was significantly higher (P<0.0001) than that of the non-infected channel catfish by both indirect ELISA and agglutination. The indirect ELISA utilized goat anti-channel catfish IgM and a commercially available rabbit anti-goat IgG enzyme conjugate. The antibody response was directed against a cell-free sonicated antigen preparation derived from live whole F. columnare cells. Indirect ELISA and agglutination results correlated (r2 = 0.60) for anti-F. columnare antibody response in experimentally and non-infected fish. We were also able to correlate ELISA and agglutination results of 60 fish naturally infected with F. columnare(r2 = 0.76). Indirect ELISA will allow for rapid monitoring of humoral antibody, following natural exposure or vaccination against F. columnare, with a small sample of serum. 相似文献
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在面积为6667m2 的池塘混养、鲂鱼种,搭配鲢、鳙及银鲫。、鲂及银鲫投喂配合颗粒饲料,鲢、鳙不投饵。设置2台3kW增氧机,饲养209d,结果共产鱼6960kg,团头鲂6889 6kg,异育银鲫345kg,鲢、鳙共2137 4kg,平均产量为2 45kg m2,平均成本为11 45元 m2,平均利润为6 48元 m2,投入产出比为1∶1 56。 相似文献