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Tan X.-Y.,Huazhong Agricultural University | Luo Z.,Huazhong Agricultural University | Liu X.,Panjin Guanghe Fishery Co. | Xie C.-X.,Huazhong Agricultural University
Aquaculture Nutrition | Year: 2011

The present experiment was conducted to quantify dietary copper (Cu) requirement for juvenile yellow catfish Pelteobagrus fulvidraco. The six experimental diets were formulated to contain the graded levels of CuSO4·5H2O (0, 0.005, 0.01, 0.02, 0.04 and 0.08gkg-1 diet respectively) providing the actual dietary copper values of 2.14 (control), 3.24, 4.57, 7.06, 12.22 and 22.25mg Cukg-1 diet respectively. Each diet was fed to triplicate groups of yellow catfish (initial body weight: 3.13±0.09g, means±SD) in an indoor static rearing system for 7weeks. Fish fed the diet containing 3.24mgCukg-1 diet had the highest weight gain and specific growth rate, but they were not significantly different from that of fish fed the 4.57 and 7.06mgCukg-1 diets (P>0.05). The poorest feed conversion rate, the lowest protein efficiency ratio, the lowest hepatosomatic index and viscerosomatic index were observed in fish fed the diet containing the highest Cu content diet (P<0.05). Condition factor showed no significant differences among the treatments (P>0.05). Proximate composition of fish body was significantly affected by dietary copper level (P<0.05). Cu contents of whole body and liver increased with dietary Cu levels (P<0.05), but muscle Cu content remained relatively stable (P>0.05). Analysis by the second-order regression of SGR and linear regression of whole-body Cu retention of the fish indicated that dietary Cu requirements in juvenile yellow catfish were 3.13-4.24mg Cukg-1 diet. © 2009 Blackwell Publishing Ltd. Source


Song Y.-F.,Huazhong Agricultural University | Luo Z.,Huazhong Agricultural University | Chen Q.-L.,Huazhong Agricultural University | Liu X.,Panjin Guanghe Fishery Co. | And 2 more authors.
Archives of Environmental Contamination and Toxicology | Year: 2013

The present study was performed to evaluate the effects of calcium (Ca) pre-exposure and then waterborne cadmium (Cd) exposure on metal element accumulation, enzymatic activities, histology, and ultrastructure in Synechogobius hasta and test the hypothesis that Ca could protect against Cd-induced toxicity in the fish species. Three hundred sixty fish [initial mean weight 25.5 ± 0.1 g (mean ± SEM)] were stocked in 18 circular fiberglass tanks (water volume: 300 l), 9 of which were pre-exposed to Ca at a rate of 400 mg Ca/l for 9 days and then exposed to concentrations of 0, 79.3, and 158.6 μg Cd/l for 9 days. Another 9 tanks were cultured in natural seawater (no extra Ca addition) for 9 days and then exposed to concentrations of 0, 79.3, and 158.6 μg Cd/l for 9 days. Both Ca pre-exposure and then waterborne Cd exposure influenced the accumulation of metal elements [cadmium (Cd), copper, zinc, and iron] in several tissues (muscle, gill, liver, spleen, and intestine), changed hepatic intermediary metabolism, and induced histological and ultrastructural alterations in tissues. In general, Ca pre-exposure seemed to mitigate the severity of Cd-induced mortality and histopathological injuries indicating that Ca pre-exposure had the capacity to decrease Cd toxicity in S. hasta. © 2013 Springer Science+Business Media New York. Source


Luo Z.,Huazhong Agricultural University | Tan X.-Y.,Huazhong Agricultural University | Liu X.,Panjin Guanghe Fishery Co. | Wang W.-M.,Huazhong Agricultural University
Aquaculture International | Year: 2010

The present experiment was conducted to determine the dietary total phosphorus requirement of juvenile yellow catfish Pelteobagrus fulvidraco. Six diets with increasing dietary phosphorus concentration (0.43, 0.55, 0.78, 0.90, 1.05 and 1.18% of dry matter, respectively) were fed to triplicate groups of 20 fish each (mean initial body weight, 2.68 ± 0.08 g, mean ± SD) to apparent satiation for 7 weeks. Weight gain and specific growth rate (SGR) increased with increasing dietary phosphorus level from 0.43 to 0.90% and then declined over dietary phosphorus level of 0.90% (P < 0.05). Phosphorus retention increased with increasing dietary phosphorus level from 0.43 to 0.55% and then declined over dietary phosphorus level of 0.55% (P < 0.05). Dietary phosphorus levels significantly influenced whole body crude protein and ash contents (P < 0.05), but not whole body lipid content (P > 0.05). Vertebrae phosphorus content increased with dietary phosphorus level from 0.43 to 0.78% (P < 0.05) and then plateau over the level of 0.78% (P > 0.05). Dietary phosphorus level significantly influenced condition factor, viscerosomatic index and hepatosomatic index (P < 0.05). The relationship between SGR and whole body ash content against dietary phosphorus levels could be expressed as a second-order polynomial equation and the points of 0.89 and 0.85% were considered to be the optimal dietary total phosphorus level, respectively. Based on broken-line analysis of vertebrae phosphorus content, the minimal dietary total phosphorus requirements for maintaining maximum phosphorus storages were estimated to be 0.76% phosphorus. © 2009 Springer Science+Business Media B.V. Source


Luo Z.,Chinese Academy of Fishery Sciences | Luo Z.,Huazhong Agricultural University | Tan X.-Y.,Huazhong Agricultural University | Li X.-D.,Panjin Guanghe Fishery Co. | Yin G.-J.,Chinese Academy of Fishery Sciences
Aquaculture Nutrition | Year: 2012

An 8-week feeding experiment was conducted to determine the effect of dietary arachidonic acid (ARA) levels on growth performance, hepatic intermediary metabolism and antioxidant responses for juvenile Synechogobius hasta. Five isonitrogenous and isolipidic diets were formulated with arachidonic oil (containing 400gARAkg -1) at inclusion levels of 0, 2, 4, 8 and 16gkg -1 to replace corn oil. Dietary ARA levels were 0.6, 8.6, 16.7, 32.7 and 64.8gkg -1 total fatty acids (FAs), respectively. Fish fed the 8.6-32.7g ARAkg -1 total FAs showed the highest weight gain, specific growth rate (SGR) and feed intake. By contrast, feed conversion ratio was the lowest for fish fed the 8.6-32.7gARAkg -1 total FAs. Increasing ARA and total n-6 fatty acid contents and declining linoleic acid content in liver were observed in fish fed the diet containing increasing dietary ARA levels. As a consequence, ∑n-6/∑n-3 ratios increased with increasing dietary ARA levels. Dietary ARA levels significantly influenced several enzymatic activities involved in hepatic intermediary metabolism, such as succinate dehydrogenase, lactate dehydrogenase, lipoprotein lipase and hepatic lipase. Superoxide dismutase activity increased with increasing dietary ARA levels. Glutathione peroxidase and catalase activities and malondialdehyde levels in liver tended to increase with increasing dietary ARA levels from 0.6 to 32.7gARAkg -1 total FAs then declined when dietary ARA levels further increased to 64.8gARAkg -1 total FAs. Broken-line regression analysis of SGR against dietary ARA level indicated that optimal dietary ARA requirement for juvenile S. hasta was 10.74gkg -1 total FAs. © 2011 Blackwell Publishing Ltd. Source


Tan X.-Y.,Huazhong Agricultural University | Luo Z.,Huazhong Agricultural University | Luo Z.,University of St. Andrews | Zeng Q.,Panjin Guanghe Fishery Co. | And 2 more authors.
Lipids | Year: 2013

trans-10,cis-12 (t10c12) Conjugated linoleic acid (CLA) reduced body lipid deposition in various experimental animals, but the mechanisms involved were still emerging. Carnitine palmitoyltransferase I (CPT I) catalyzes an important regulatory step in lipid metabolism. At present, no studies, to our knowledge, have evaluated the kinetic constants influenced by dietary CLA in fish. In the present study, we tested the hypothesis that changes in body lipid content in fish as a response to dietary t10c12 CLA was related to the change of CPT I kinetic constants [Michaelis constant (K m), maximal velocity and catalytic efficiency for carnitine and palmitoyl-CoA]. Juvenile Synechogobius hasta were fed three experimental diets with fish oil replaced with 0 (control), 1, or 2 % t10c12 CLA for 8 weeks. Weight gain, specific growth rate and protein efficiency rate increased with dietary t10c12 CLA level. Dietary t10c12 CLA addition significantly reduced lipid contents both in liver and muscle. Dietary CLA addition also improved CPT I activities in muscle but did not significantly influence hepatic CPT I activity. CPT I kinetic parameters (K m, V max and catalytic efficiency) were significantly influenced by t10c12 CLA. CPT I catalytic efficiencies with carnitine and palmitoyl-CoA as substrates were higher in muscle and liver of fish fed increasing t10c12 CLA. For the first time, the findings demonstrated effect of dietary CLA addition on CPT I kinetics in fish and supported our starting hypothesis that dietary t10c12 CLA addition induced alterations in CPT I kinetic constants of muscle and liver. Increased CPT I catalytic efficiency might be the main reason for reduced lipid deposition in these tissues by dietary t10c12 CLA supplementation. © 2013 AOCS. Source

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