Dietary zinc requirement of Siberian sturgeon (Acipenser baerii,Brandt 1869) juveniles,based on the growth performance and blood parameters

International Aquatic Research - This study investigated the effect of dietary Zn levels on growth performance, feed utilization, and hematological parameters of juvenile Siberian sturgeon...     

Effects of Dietary Ascorbic Acid on Growth Performance,Body Composition,and Some Immunological Parameters of Caspian Brown Trout,Salmo trutta caspius

A 9‐wk feeding experiment was conducted to investigate the effect of dietary ascorbic acid (AA) on growth performance and tissue compositions of Caspian brown trout. The fish (9.64 ± 0.62 g) were held in tanks at a density of 40 fish per tank. Five experimental diets were prepared by providing of 9.8, 43.8, 89.4, 188.5, and 384.2 mg AA equivalent/kg diet, respectively. At the end of the trial, an increasing trend was found on growth performance with the increase of AA supplementation. Fish fed diet supplemented with more than 188.5 mg/kg AA also had significantly higher bone collagen than fish fed diets containing 9.8 mg/kg AA (P < 0.05). According to the broken line, the dietary AA requirement of Caspian brown trout fingerlings was 177.24 mg AA/kg diet based on the weight gain, 186.97 mg AA/kg diet based on the protein tissue, and 163.95 mg AA/kg diet based on the bone collagen. Serum lysozyme and alternative complement pathway activities were also influenced by graded level of AA supplementation to the diet. The present research clearly indicated that AA is required for normal growth and enhancement of immune response in Caspian brown trout fingerlings.     

Growth performance,blood biochemical parameters,immune response,and antioxidant defense of Asian seabass (Lates calcarifer) fingerlings exposed to monovalent and bivalent vaccines against Streptococcus iniae and Vibrio harveyi

The present study investigated the effects of monovalent and bivalent vaccines against Streptococcus iniae and Vibrio harveyi on growth performance, blood biochemical parameters, immune system, and antioxidant defense of Asian seabass (Lates calcarifer) fingerlings. Fish were exposed to seven experimental groups containing phosphate buffer saline (control), S. iniae vaccine by injection, S. iniae vaccine by immersion method, V. harveyi vaccine by injection, V. harveyi vaccine by immersion method, S. iniae/V. harveyi vaccines by immersion method, and S. iniae/V. harveyi vaccines by injection in triplicate for 60 days. Vaccination resulted in a significant alteration of the final weight (FW), feed conversion ratio (FCR), daily weight gain (DWG), relative growth rate (RGR), glucose, lysozyme, and complement levels at 60 days post-vaccination. Also, serum glutathione activity significantly increased in group SVIM (S. iniae/V. harveyi vaccines by immersion method) compared to the control group at 60 days post-vaccination. The level of MDA in serum was significantly decreased in SIN (S. iniae vaccine by injection) and SVIM groups compared to the control group 60 days post-vaccination where the value of this parameter was significantly higher in VIM (V. harveyi vaccine by immersion method) and SVIN (S. iniae/V. harveyi vaccines by injection) groups. The results of this study suggest that exposure to monovalent and bivalent vaccines against S. iniae and V. harveyi could alter the growth performance, nonspecific immune response, and antioxidant defense of Asian seabass fingerlings.

     

钾磷缺乏对辽杨中多胺含量的影响

钾磷水平变化对辽杨中多胺含量有显著的影响。随着钾水平的降低,叶和根中腐胺含量大幅度增加,尤其是根中更为显著。它们的最高含量分别是同一时期对照的23倍和85倍。然而,磷水平的变化对叶和根中腐胺含量没有明显的影响。研究表明,钾对腐胺代谢有着灵敏的调节作用,腐胺含量可作为辽杨需钾的生化指标。缺钾和缺磷都使叶和根中精胺含量明显下降,叶中更为显著。在所有处理中,精胺含量与其相应部位的生物量积累有一定的相关性,表明精胺与生长之间可能存在着密切联系。     

Species and space: a combined gap analysis to guide management planning of conservation areas

Landscape Ecology - With accelerating global declines in biodiversity, establishment and expansion of conservation areas (CAs) have increasingly been advocated in recent decades. Gap analysis has...     

Quantitative dietary copper requirement of juvenile Siberian sturgeon,Acipenser baerii,and effects on muscle composition and some enzymatic activities

An 8‐week feeding trial was conducted to quantify dietary copper (Cu) requirement of juvenile Siberian sturgeon, Acipenser baerii. Five isonitrogenous diets were formulated to provide actual dietary copper values of 1.8, 5.7, 10.1, 15.9 and 28.3 mg Cu per kg diet. Experimental diets were fed to the Siberian sturgeon (27.57 ± 0.24 g) in triplicate to apparent satiation for 8 weeks. At the end of experiment, weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) were significantly increased with increasing dietary Cu level up to 10.1 mg/kg and then decreased with further increases in dietary Cu level (p < .05). The Cu concentration in the liver and cartilage was positively correlated with the respective concentrations in the diet (p < .05), while muscle and serum Cu concentrations remained significantly unchanged (p > .05). Superoxide dismutase and glutathione peroxidase had the highest activities in serum of fish fed with 15.9 and 28.3 mg Cu per kg diet, respectively. Analysis by the broken‐line regression of SGR, crude protein content and superoxide activity demonstrated that the optimum dietary Cu requirements in juvenile Siberian sturgeon were 9.51, 9.58 and 16.10 mg/kg diet, respectively.