Nutriphysiological and cytological responses of juvenile channel catfish (Ictalurus punctatus) to dietary oxidized fish oil

An 86‐day growth trial was conducted to investigate the effect of dietary oxidized fish oil on the growth and cytopathology of juvenile channel catfish (Ictalurus punctatus). Four diets containing 0 g kg^?1 (control: fresh fish oil), 30 g kg^?1 (low‐oxidized oil group), 60 g kg^?1 (medium‐oxidized oil group) and 90 g kg^?1 (high‐oxidized oil group) graded oxidized oil levels with the same dietary lipid level (90 g kg^?1 diet) were evaluated. The results show that the specific growth rate decreased with increasing dietary oxidized oil level (P < 0.05). All examined liver and kidney tissues in all dose groups exhibited what appeared as dose‐dependent cellular modifications. In addition, lipid droplet accumulation in the hepatocytes of fish in all dose groups was increased, and their localizations were distinctly different between all dose groups. The ultrastructural changes suggest the progression of mitochondrial vacuolation, especially in the renal tubules, in all dose groups. These results reveal a previously underappreciated effect of dietary oxidized fish oil on channel catfish kidneys. Overall, a series of nutriphysiological responses were adversely affected by exposure to dietary oxidized fish oil, and the corresponding interference patterns on the metabolism and transport of nutrients within cells were observed.     

The evaluation of practical diets on a basis of digestible crude protein,lysine and methionine for Litopenaeus vannamei

A feeding trial was conducted to evaluate the efficacy of replacing fish meal (FM) with blood meal (BM), poultry by‐product meal (PBM), meat and bone meal (MBM) and shrimp head meal (SHM), rapeseed meal (RM) and peanut meal (PM) on a digestible basis of crude protein and lysine and methionine in five practical diets for the Pacific white shrimp at the FM levels of 300, 250, 200, 150 and 100 g kg^?1 under laboratory conditions. Each of the five experimental diets was hand‐fed to four replicate tanks of shrimp with an average weight of 0.33 ± 0.03 g to satiation at each meal. The shrimp were fed three times a day over a six‐week period. The per cent weight gain of initial body weight (WG%) was significantly lower in shrimp fed 100 g kg^?1 FM diet, but the value for hepatosomatic index (HSI) and the level of blood urea nitrogen (BUN) tended to be higher in shrimp fed 100 g kg^?1 FM diet than those in shrimp fed other diets. The lowest value for feeding rate (FR) occurred for shrimp fed the basal diet and was significantly lower than that in shrimp fed the FM diets at 100–150 g kg^?1. Shrimp fed diets containing 200 g kg^?1 or lower FM had significantly lower feed utilization than those fed the 250 g kg^?1 FM diet and the basal diet. The protein efficiency ratio (PER) in the shrimp fed the basal diet was significantly higher than in the other FM diets. Decreasing the FM replacement level significantly reduced nutrient digestibility except in the cases of ash and gross energy, but it did not affect the survival, condition factor (CF), body composition, digestive enzyme activity or plasma transaminase activity. The results of the study indicate that feeding a diet formulated on a digestible basis and involving FM replacement with other protein sources at a greater replacement proportion will not produce a level of shrimp growth equal to that achieved by feeding the basal diet.     

Effect of dietary protein reduction with lysine and methionnine supplementation on growth performance,body composition and total ammonia nitrogen excretion of juvenile grass carp,Ctenopharyngodon idella

A 63‐day growth trial was undertaken to estimate the effects of supplemented lysine and methionine with different dietary protein levels on growth performance and feed utilization in Grass Carp (Ctenopharyngodon idella). Six plant‐based practical diets were prepared, and 32CP, 30CP and 28CP diets were formulated to contain 320 g kg^?1, 300 g kg^?1 and 280 g kg^?1 crude protein without lysine and methionine supplementation. In the supplementary group, lysine and methionine were added to formulate 32AA, 30AA and 28AA diets with 320 g kg^?1, 300 g kg^?1 and 280 g kg^?1 dietary crude protein, respectively, according to the whole body amino acid composition of Grass Carp. In the groups without lysine and methionine supplementation, weight gain (WG, %) and specific growth rate (SGR, % day^?1) of the fish fed 32CP diet were significantly higher than that of fish fed 30CP and 28CP diets, but no significant differences were found between 30CP‐ and 28CP‐diet treatments. WG and SGR of the fish fed 32AA and 30AA diets were significantly higher than that of fish fed 28AA diets, and the performance of grass carp was also significantly improved when fed diets with lysine and methionine supplementation (P < 0.05), and the interaction between dietary protein level and amino acid supplementation was noted between WG and SGR (P < 0.05). Feed intake (FI) was significantly increased with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05), but feed conversion ratio (FCR) showed a significant decreasing trend (P < 0.05). Two days after total ammonia nitrogen (TAN) concentration test, the values of TAN discharged by the fish 8 h after feeding were 207.1, 187.5, 170.6, 157.3, 141.3 and 128.9 mg kg^?1 body weight for fish fed 32CP, 32AA, 30CP, 30AA, 28CP and 28AA diets, respectively. TAN excretion by grass carp was reduced in plant‐based practical diets with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05). The results indicated that lysine and methionine supplementation to the plant protein sources‐based practical diets can improve growth performance and feed utilization of grass carp, and the dietary crude protein can be reduced from 320 g kg^?1 to 300 g kg^?1 through balancing amino acids profile. The positive effect was not observed at 280 g kg^?1 crude protein level.     

Identification of immunogenic proteins of Flavobacterium columnare by two‐dimensional electrophoresis immunoblotting with antibacterial sera from grass carp,Ctenopharyngodon idella (Valenciennes)

Flavobacterium columnare is a Gram‐negative bacterium causing columnaris disease of freshwater fish worldwide, and development of efficacious vaccines has been a continuous challenge in aquaculture. In this study, 14 proteins were identified from cellular components of F. columnare using an immunoblotting approach in two‐dimensional electrophoresis map gels with antibacterial sera from grass carp, Ctenopharyngodon idella (Valenciennes), and then anti‐grass carp‐recombinant Ig (rIg) polyclonal antibodies. These proteins were characterized conclusively by matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF/TOF MS). The 14 proteins are immunogenic molecules of F. columnare, including chaperonins DnaK, GroEL and trigger factor, and translation elongation factor G, translation elongation factor Tu, 30S ribosomal subunit protein S1, dihydrolipoamide succinyltransferase, succinyl‐CoA synthetase, SpoOJ regulator protein, alcohol dehydrogenase, fructose‐bisphosphate aldolase, 3‐hydroxybutyryl‐CoA dehydrogenase and two conserved hypothetical proteins. These identified immunogenic proteins may provide candidate molecules for the development of vaccines against columnaris disease.     

Molecular cloning of gonadotropin cDNA in sevenband grouper, Epinephelus septemfasciatus

The cDNA for glycoprotein hormone (GPH) α-subunit, β-subunits of the FSH (GtH I) and LH (GtH II) were isolated, cloned, and sequenced from sevenband grouper pituitary using RACE PCR. These results show that sevenband grouper has two different types of gonadotropins FSH (GtH I) and LH (GtH II), as other teleosts.     

The Yangtze River dolphin or baiji (Lipotes vexillifer): population status and conservation issues in the Yangtze River,China

• 1. Baiji were sighted 17 times during three recent simultaneous multi‐vessel surveys in the Yangtze River, China (November 4–10, 1997; December 4–9, 1998; October 31–November 5, 1999). There were 11 sightings in 1997 (consisting of 17 animals), five in 1998 (seven animals), and two in 1999 (four animals). It was concluded that 13 individuals could be considered as a minimum number of the baiji currently in the Yangtze River.
• 2. An annual rate of population decrease was roughly estimated as 10%. From the body sizes observed, the proportions of old, adult and immature individuals were approximately estimated at 57, 26, and 17% respectively.
• 3. Baiji showed a significant attraction to confluences and sand bars with large eddies. The present distribution range of the baiji is less than 1400 km in length in the Yangtze main river. Distances between the two nearest groups of baiji appear to be increasing.
• 4. Two typical sightings are described, in which surfacing and movements of baiji were recorded. Baiji were often found swimming together with finless porpoise. In the surveys they occurred in the same group in 63% of occurrences. Interactions between baiji and finless porpoise are described and discussed.
• 5. Human activities are the main threats to the baiji. Illegal electrical fishing accounted for 40% of known mortalities during the 1990s. Engineering explosions for maintaining navigation channels have become another main cause of baiji deaths. The last hope of saving the species may be to translocate the remaining baiji into a semi‐captive reserve, known as the ‘Baiji Semi‐natural Reserve’.

Copyright © 2003 John Wiley & Sons, Ltd.     

Study of the near-infrared transmission of woven fabrics based on statistical analysis

47 kinds of woven fabrics were prepared with different fibers, thicknesses, weights per square meter and percentage covers. Statistical analysis method was employed to study the influence of the material and structure parameters on near-infrared transmission of these fabrics. Firstly, the effect of materials on near-infrared transmittance was determined through the contingency table analysis. Then the parameters significantly influencing near-infrared transmittance were found out and correlations among them were discussed by direct correlation and partial correlation analysis. Finally, regression equation of the near-infrared transmittance was established using factor analysis and principal component extraction. Results show that materials have little influence on near-infrared transmittance of woven fabrics. However, thickness, weight per square meter and percentage cover of the fabrics are closely related to near-infrared transmittance. Because there are correlations among thickness, weight per square meter and percentage cover, two new factors are extracted to establish the regression equation. The equation has an error rate of less than 5 % and thus can predict near-infrared transmittance precisely.     

大豆中主要致敏蛋白及其去除方法

大豆因其丰富的营养和功能特性被作为一种重要的蛋白源应用在食品加工和饲料领域。但是,大豆蛋白中含有的多种致敏性蛋白,严重阻碍了他的应用。文中对大豆致敏蛋白的分类、结构特点、去除方法进行了综述,并就存在的问题及今后的研究发展方向进行了探讨。     

基于倍四元数和Groebner基的6R机械手的位置反解

提出了一般6R机械手的位置反解的新算法,该算法是把齐次变换矩阵转以倍四元数形式表示,建立了倍四元数形式的串联6R机械手运动学方程,再通过线性消元和两次应用分次字典序Groebner基消去5个变元,得到一个一元16次方程.此方法没有增根,是一种对空间任意尺寸6R机械手进行建模和求解的新算法.其中求解Groebner基采用了计算机代数系统进行有理数运算,目前的求解速度尚不是很高,需进一步改进.     

Usefulness of rNcGRA7- and rNcSAG4-based ELISA tests for distinguishing primo-infection, recrudescence, and chronic bovine neosporosis

Bovine reproductive failure caused by the parasite Neospora caninum is a major problem and is responsible for severe economic losses worldwide. Currently, appropriate control measures depend on the predominant transmission route in a particular herd. Therefore, the development of diagnostic tools capable of discriminating between primo-infection, recrudescence, re-infection, and chronic infection is a major challenge in the serodiagnosis of bovine neosporosis. Here, two recombinant protein-based ELISAs utilizing the immunodominant NcGRA7 dense granule protein and the NcSAG4 bradyzoite stage-specific protein were developed and showed good diagnostic performances. Their usefulness for discerning between primo-infection, recrudescence, re-infection, and chronic infection was also studied by analyzing an appropriate panel of serum samples belonging to different groups of experimentally and naturally infected bovines. Our results suggest that anti-rNcGRA7 antibody levels may be indicative of acute infection (primo-infection, re-infection, and recrudescence), whereas the presence of anti-rNcSAG4 antibodies may be associated with chronic infection and could be a good indicator of infection establishment (tachyzoite-bradyzoite conversion). Moreover, primo-infection associated with a Neospora-associated epidemic abortion pattern is characterized by the detection of anti-rNcGRA7 antibodies together with the absence or detection of anti-rNcSAG4 antibody levels around the cut-off point. In contrast, the detection of antibody levels directed against both recombinant proteins may be quite indicative of recrudescence or re-infection associated with abortion and/or vertical transmission in herds with a Neospora-associated endemic abortion pattern. In conclusion, both serological tests developed in the present study offer additional information to conventional avidity tests and, consequently, improve the diagnosis of bovine neosporosis with perspectives for control measures.