Aquaculture Fisheries
The concentration of formaldehyde in 1013 fishery product samples, which including 314 samples of 12 species of freshwater fishes, 356 samples of 19 species of marine fishes, 147 samples of 9 species of crustaceans, 137 samples of 5 species of shellfish and 59 samples of 4 species of cephalopods, were determined by acetylacetone spectrophotometric method. The results showed that the median of formaldehyde content in fresh fishery products is 0.25 mg/kg, which was far below the average concerntration (6.31 mg/kg), indicating that most samples have low formaldehyde contentration. In the survey of 49 species, bombay duck（Hacpodon neheceus）, cod（Cadous macrocephalus, Theragra chalcogramma and Miciomesistius poutassou）, squid (Loligo chinensis), squill (Oratosquilla) and swimming crab (Portunus trituberculatus and Portunus pelagicus) had higher levels of formaldehyde in the background. While formaldehyde content in tilapia seemed to be significantly higher than other freshwater fish species (p<0.05). Significant differences on types showed that the formaldehyde conerntration in marine fish samples were great, followed by samples of cephalopods, crustaceans and shellfish, however, samples of freshwater fish was in the lowest formaldehyde content (p<0.05).
This paper provided a measure to estimate the meat yield and to selective breed of Procambarus clarkii and Cherax quadricarinatus. The correlation between meat yield and body measurements in these two kinds of crayfish were studied by statistics analysis. The results showed that, the meat yield value of Cherax quadricarinatus was higher than that of Procambarus clarkii. First abdominal segment width was the main variable to Procambarus clarkii. Body length and carapace length were the main variables to Cherax quadricarinatus, followed by total length. It was concluded that: (1) the correlation to meat yield was more significant than that to body weight; (2) it was possible to predicting meat yield based on ratio of two body measurements or the individual variable in Procambarus clarkii and Cherax quadricarinatus.
It is the research on main nutrient components and chemical protein evaluation of Acipenser schrenckii roe that provide reference for deep processing of Acipenser schrenckii roe and scientific basis for exploitation, and comprehensive utilization of Acipenser schrenckii resources. The nutritive components of Acipenser schrenckii roe were determinated by conventional analytical methods. The results showed that the crude protein content of Acipenser schrenckii roe was 26.00%. The 18 amino acids content of Acipenser schrenckii roe was 25.21%. Among these amino acids, the essential amino acids content was 10.16%, and the fraction of essential amino acids was approximately 40.30%. The ratio of essential amino acids to non-essential amino acids was 67.51%. Tryptophane, the first limiting amino acids, scores 92. The unsaturated fatty acids amount of ASO was 62.8%. The EPA and DHA amount of Acipenser schrenckii roe reached to 10.3%. The content of mineral elements, such as Fe and Zn, were high. Its content was 22.07 mg/kg, 18.00 mg/kg, respectively. Acipenser schrenckii roe had the characteristics of high protein, low carbohydrate, and reasonable proportion of amino acid, abundant minerals and abundant unsaturated fatty acid, which had a bright application future.
AFLP(Amplified Fragment Length Polymorphism) analysis system for Oncorhyrchus masou masou were established in this study, the genomic DNA were digested by two groups of restriction enzymes, with the relative processes being optimized, including the quantity of the restricting enzymes, the time of digested reaction, quantity of the template for pre-amplification and times of pre-amplification products dilution. It was proved that the results were best with 100ng DNA digested for 3h at 37℃ by 3U EcoRI and then 4h at 65℃ by TaqI and Tru9I respectively, then ligated by ligase. Quite clearly results could be achieved by 3μL ligation products as the template for pre-amplification which products were diluted 50 times for selective amplification. The comparison of the two pairs showed that the group of EcoRI-Tru9I obtained more amplification bands but lower ratio of polymorphic loci than EcoRI-TaqI.
To analysis the chromosome number and karyotype of Leptobotia taeniops. The karyotype of Leptobotia taeniops was studied through the chromosome preparations obtained from head kidney by the method of injecting PHA and colchicines and used air drying method to make chromosome samples. The total chromosome number of the fish was 50, the karyotype formula was 2n=6m+10sm+8st+26t, and NF=66. There was no visible evidence of po1yploidy chromosome and sex chromosome. This study provided Leptobotia taeniops with cytogenetics paramete, and offered a theoretical basis for Cross breeding of Leptobotia taeniops.
To discuss the dynamic variation of potassium ferrite (K2FeO4) on oxidation-reduction potential (Oxidation- Reduction Potential, ORP) and its acute toxicology to fish; the experiment measured the dose, time, and pH depended-ORP of K2FeO4, and its acute toxicology to carp (Cyprinus carpio), tilapia (Oreochromis aureus), and zebra fish (Brochydaino rerio). The results showed that, ORP in aquatic environment positively depended on the concentration of K2FeO4 when it was dissolved into aquatic environment. ORP in aquatic environment decreased to the minimum concentration and reached to steady state after 48 h. The effect of pH to ORP was also very evident; the details showed that the decrease rate in alkaline water was higher than that one in acidity and neutral water. Different fish had different toxicology to K2FeO4, the 96 h LC50 to carp, tilapia fish, zebra fish was 156.36, 145.31, 123.74 mg/L respectively, and the toxic effect occurred before 48 hours, and disappeared in 48-96 h. The experiment showed that the toxic effect to fish directly depended on the ORP of K2FeO4 in aquatic environment, the toxic effect of K2FeO4 to fish was caused by the strong oxidizing property.
Aquaculture Fisheries
