The influence of acid,alkali or enzyme pretreatments on the co-production of hydrogen and methane during the typha anaerobic process was studied based on anaerobic fermentation kinetics and the evolution of reduced sugar and other metabolites combination with aquatic plant microstructures. The results showed that,after the acid,alkali or enzyme pretreatment,the content of hydrogen and methane significantly increased in anaerobic fermentation process,and the optimum pretreatments were 1. 0 molL HCl,1. 0 molL NaOH and 10 mgg( TVS) cellulose enzyme R-10,respectively. The best pretreatment of typha was 1. 0 molL NaOH. The hydrogen content was up to 30. 09%,the cumulative hydrogen production 11. 39 mLg( TVS),the methane content up to 67. 48%,the cumulative methane yield 41. 87 mLg( TVS),the reduced sugar utilization rate 50. 87%,and the sCOD removal rate 66. 17% after the best pretreatment. In addition,the methane production ability was significantly improved after enzyme pretreatment as well. For instance,the methane content was up to 71. 39% at the methanogenic phase,the accumulated methane production 46. 32 mLg( TVS),and the reducing sugar utilization rate up to 72. 10%. The results of SEM showed that the cellulose structure of aquatic plants was severely damaged,and the superficial area of plants and microbes increased effectively after alkali pretreatments,which was beneficial to the rapid start-up and stable operation of the co-production process in anaerobic fermentation.
Quinolone antibiotics are widely utilized in aquaculture, but little is known about the health effects of their residues. This study used UPLC-MS/MS to analyze the distribution of 11 quinolone antibiotics in cultured fish sold in a coastal city in southeast China - Fujian Province and to assess their health risks. The study found 35.77% of 260 cultured fish samples detected quinolones, with three exceeding the MRL and one containing the banned drug ofloxacin. Of the 11 quinolones tested, three were found in cultured fish, with enrofloxacin at up to 246.0 μg kg
Taking chicken liver as main material,based on the single factor experiment,three factors were studied through the L9(34)orthogonal experiment to find the overall quality of products and the best dosage,which were the ratio of chicken liver and fat of pork,the amount of corn starch added and the amount of garlic added.The experimental results indicated that the ratio of chicken liver and fat of pork had the greatest impact on product quality,the corn starch addition and the garlic addition on product quality was decrease successively;the best formula of the sausage with chicken liver and garlic was as follows:the ratio of chicken liver and pork fat 1:3,the amount of corn starch added 27%,the amount of garlic added 5%,the amount of white pepper added 0.6%.The product is characterized by the intestinal surface smooth,organization compact,full of flexibility;slice smooth,cut surface pink;delicate taste,moderate salinity,and a strong chicken liver flavor and garlic aroma.
A fast method for determination of polycyclic aromatic hydrocarbons (PAHs) in water samples was established. The samples from the Dianchi Lake and Panlong River were analyzed directly using stir bar sorptive extraction-thermal desorption system-gas chromatography/ mass spectrometry (SBSE-TDS-GC/MS). Polydimethylsiloxane (PDMS) was used as the extraction phase. The samples were extracted with stir bars at 1100 r/min for 60 min at ambient temperature (25 degrees C). Desorption was carried out at 300 degrees C for 5 min under a helium flow of 50 mL/min in the splitless mode while maintaining a cryofocusing temperature of 0 degrees C in the programmed-temperature vaporization (PTV) injector of the GC/MS system. The limits of detection of PAHs ranged from 1.0 pg to 468.8 pg. The theoretical recoveries of PAHs were greater than 90% (except that naphthalene was 64.90%), and the recoveries of 16 PAHs from water samples ranged from 83.1% to 109.4%, and the relative standard deviations (RSDs) ranged from 1.2% to 9.3% (n = 6). PAHs in Dianchi Lake and Panlong River samples were quantified rapidly by this method. The results show that, the total content of these 16 PAHs is 89.16 ng/L in Dianchi Lake, 65.41 ng/L in the up-stream of Panlong River, 339.22 ng/L in the middle-stream of Panlong River and 62.25 ng/L in the down-stream of Panlong River. It is demonstrated that the Dianchi Lake and Panlong River were polluted by PAHs to some degree.
The effect of replacing fish meal (FM) with meat and bone meal (MBM) in diets for juvenile Pseudobagrus ussuriensis was evaluated in a 90-day feeding trial. Six isonitrogenous (crude protein, 430 g/kg) and isolipidic (crude lipid, 74 g/kg) diets were formulated to contain MBM to replace FM at 0 (S0), 200 (S20), 400 (S40), 600 (S60), 800 (S80) and 1000 g/kg (S100), respectively. The results showed that there was no significant difference in weight gain (WG) among fish fed S0, S20 and S40 diets. However, a significant reduction in WG occurred when 600, 800 and 1000 g/kg FM protein was replaced by MBM (p < .05). Similar trends were observed in specific growth rate and protein efficiency ratio. Apparent digestibility coefficients (ADC) of protein and dry matter of the diets S80 and S100 were significantly lower than those of the other diets. The ADC of phosphorus significantly reduced with the increase in dietary MBM level. Nitrogen and phosphorus excretion increased with the increasing dietary MBM level. Protease, lipase and amylase activities of the diets S80 and S100 were significantly lower than those of the other diets (p < .05). The results of this study showed that the optimum dietary MBM replacement level was 34.3% according to broken-line model based on WG against dietary MBM replacement level.
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