The use of biochemical,sensorial and chromaticity attributes as indicators of postmortem changes in commercial‐size,cultured red porgy Pagrus pagrus,stored on ice

The freshness of red porgy slaughtered in ice slurry and stored in melting ice was evaluated instrumentally, biochemically and sensorialy. Additionally, postmortem skin colour changes were monitored, in an attempt to demonstrate the use of chromaticity parameters as a reliable and convenient approach to quality assessment. Dielectric properties showed a statistically significant decrease (P<0.05) from 12±0 on day 0 to 7.85±0.31 on day 7; there was also a significant decrease in muscle polyamines with more than two amino groups (spermidine and spermine) and an increase in the di‐amine putrescine. The sensorial score was significantly decreased from 30±0 to 4.33±0.21 on day 7. Minimal lightness (L^*) and hue (H°ab) at the dorsal skin area were observed on days 1 and 3 following harvesting. Finally, there was a marked decrease in the entire colour index (ECI – a combination of skin hue and chroma) of both the dorsal and the ventral area in day 3 onwards to day 7, as well as a statistically significant correlation between all the estimated freshness indices and ECI. Based on all these, we inferred that the total polyamines (or putrescine to spermidine and spermine ratio) and ECI could be reliable estimators of freshness, at least under the experimental conditions applied.     

Fatty acids in muscle of wild and farmed red porgy, Pagrus pagrus

The total fat content and the fatty acids of total lipids (TL), phospholipids (PL) and triacylglycerols (TAG) were analysed in white muscle from wild and reared red porgy, Pagrus pagrus (L.). The fat percentage was higher in reared (3.03 ± 0.57%) (mean ± SE) than wild (0.65 ± 0.03%) fish. The fatty acid pattern of reared porgy TL reflected the diet's lipid. Wild red porgy showed higher levels of ω3 and ω6 polyunsaturated fatty acids (PUFA) than reared, but both the atherogenic index and the index of thrombogenicity were very low for both wild and reared red porgy. The lipid fractions showed that the PL were composed of very high levels of PUFA, especially 22:6ω3, and their composition seemed to be better regulated than the composition of TAG. TAG showed greater differences between wild and reared fish, presumably because they reflected the dietary content of lipids. PUFA were the principal component of wild red porgy TAG.     

不同水温下虹鳟血液红细胞数及血清中血糖与矿质元素含量测定

采用显微记数法和使用日立7170A全自动生化分析仪与贝克曼CX-3电解质分析仪,测定水温14℃、19℃、23℃时虹鳟(Salmoirideus Gibbons)血液中红细胞数量和血清中血糖与矿质元素含量。结果表明:水温从14℃升至23℃,虹鳟血液红细胞数量显著减少;血清中血糖含量在水温19℃时表现为增加、在23℃时又表现为减少;铜元素含量在水温23℃时较14℃时增加84.06%,钾、磷、钙、镁、钠、氯、铁元素含量在水温23℃时较14℃时增幅为1.65%～33.66%。     

Diel pattern of haematocrit, serum metabolites, osmotic pressure, electrolytes and thyroid hormones in sea bass and sea bream

The diel pattern of haematocrit, serum metabolites, electrolytes and thyroid hormones are described in sea bass, Dicentrarchus labrax, and sea bream, Sparus auratus, held under 12L:12D light cycle (0600–1800 h light). No diel rhythmicity in haematocrit, total proteins, potassium and chloride was observed. Maximum values of glucose, osmotic pressure and sodium were recorded at dusk (1800 h) in both species, irrespective of differences in the size of fish and feeding regime used. Maximum and minimum triiodothyronine values were found during the scotophase in bass and during the photophase in bream. Maximum thyroxine levels occurred at 1400 h (bass) and 1800 h (bream) and minimum during the scotophase, in both species. The light/dark alternation seems to be an important synchronizer of the observed diel changes. Results are discussed in relation to the timing of feeding and the general activity of the fish.     

QuEChERS-液相色谱-串联质谱法测定鲤肝脏中氟虫腈及其代谢物残留

以QuEChERS作为样品前处理方法,结合高效液相色谱-串联质谱(HPLC-MS/MS)检测技术,建立了鲤(Cyprinus carpio)肝脏中氟虫腈(fipronil)及代谢物氟甲腈(fipronil desulfinyl)、氟虫腈亚砜(fipronil sulfide)和氟虫腈砜(fipronil sulfone...