The Requirement and Protective Effects of Dietary Protein against Chronic Ammonia Exposure in Juvenile Genetically Improved Farmed Tilapia (Oreochromis niloticus).

Ammonia is a key risk factor in intensive aquaculture systems. This experiment is aimed at investigating the influence of dietary protein levels on genetically improved farmed tilapia (GIFT, Oreochromis niloticus) under chronic ammonia stress. GIFT juveniles of 4.00 ± 0.55 g were exposed to high ammonia level at 0.88 mg/L and fed with six diets comprising graded protein levels at 22.64%, 27.26%, 31.04%, 35.63%, 38.47%, and 42.66% for 8 weeks. The fish in negative control was fed the diet with 31.04% protein in normal water (0.02 mg ammonia/L water). Our results showed that high ammonia exposure (0.88 mg/L) caused significant decrease in fish growth performance, hematological parameters, liver antioxidant enzymes (catalase and glutathione peroxidase), and gill Na+- and K+-dependent adenosine triphosphatase (Na+/K+-ATP) activity. When fish were under high ammonia exposure, the weight gain rate, special growth rate, feed efficiency, and survival rate elevated significantly with dietary protein supplementation increase to 35.63%, whereas protein efficiency ratio, hepatosomatic index, and viscerosomatic index showed a decreased tendency. Dietary protein administration significantly enhanced crude protein but reduced crude lipid contents in the whole fish. Fish fed diets with 35.63%-42.66% protein had higher red blood cell counts and hematocrit percentage than fish fed 22.64% protein diet. The values of serum biochemical indices (lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase), hepatic antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase), and gill Na+/K+-ATP activity were all elevated with the increment of dietary protein. Moreover, histological analysis indicated that dietary protein administration could prevent the ammonia-induced damages in fish gill, kidney, and liver tissues. Based on weight gain rate as a response criterion, the optimal dietary protein requirement for GIFT juveniles under chronic ammonia stress was 37.9%.

The copper(II) complex of dantron showed therapeutic effect on bacterial gill-rot disease in tilapia infected by Flavobacterium columnar.

Dantron (DA), a kind of polyhydric anthraquinone and one of the bio-active ingredient in Rheum officinale was chosen as the ligand to coordinate with the bio-active copper(II) ion to achieve its antibacterial copper(II) complex, DA-Cu. The coordination structure of DA-Cu, both in the crystal state and solution state, was studied by spectroscopy and X-ray single-crystal diffraction analysis. The inhibition zone, MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) values regarding the in vitro antibacterial activity of DA-Cu towards Flavobacterium columnar, which causes the bacterial gill-rot disease on fish, were significant and specific. DA-Cu in vivo acute toxicity on zebrafish and tilapia was evaluated, suggesting that the higher dose of DA-Cu than 0.1 mg/mL might give potential toxicity. The further therapeutic effect of DA-Cu on the tested tilapia challenged by Flavobacterium columnar was also studied, which showed its clear advantage (including the survival rate, relative weight gain rate, and feed conversion ratio) over DA and the positive control, Sanhuang San, at a much lower dosage of 0.025 mg/mL.

Occurrence and distribution of phthalate esters in freshwater aquaculture fish ponds in Pearl River Delta, China.

The concentrations, congener profiles and spatial distribution of 13 phthalate esters (PAEs) in the freshwater fish ponds in the Pearl River Delta (PRD) region were investigated in water and sediment samples collect from 22 sites during Jul. 2016-Sept. 2017. The di-2-ethylhexyl phthalate (DEHP) was the predominant compounds in both water and sediment samples, accounting for 70.1% and 66.1% of ∑PAEs, respectively. The DEHP concentrations in the water samples collected from the sites of Zhongshan (35.7 µg/L), Jingmen (17.3 µg/L) and Nanhai (14.2 µg/L) were higher than that collected from other sampling sites (p <0.05), and exceed the Chinese environmental quality standards for surface water (DEHP, 8.00 µg/L). The concentrations of ΣPAEs (mean and median were 11.8 mg/kg dw and 7.95 mg/kg dw) in sediment was higher than that in sediment of river and estuary in the PRD region (p <0.05). The median concentrations of DEHP and di-n-butyl phthalate (DBP) exceeded recommend environmental risk limit (ERL) that posed a potential risk to the aquaculture fish pond environment in the PRD.

[Combined effects of fluoxetine and triclosan on Pseudorasbora parva.] / 氟西汀与三氯生复合暴露对麦穗鱼的毒性效应.

We examined the effects of binary mixture of two different pharmaceutical and personal care products (PPCPs) on aquatic organisms. The topmouth gudgeon Pseudorasbora parva, native to northeast China, was used to study the combined effects of fluoxetine (FLX) and triclosan (TCS) on its different organs. After acute (4 h) and chronic (42 d) treatments, the combined effects of FLX/TCS on phase I and phase II detoxification enzymes, nervous system, digestive system and antioxidant system were evaluated. The results showed that the AChE activity in the brain of P. parva was transiently inhibited, whereas the activity of EROD in the liver was continuously inhi-bited. The activity of α-Glu in the intestine was induced after acute exposure but was inhibited after chronic exposure. Meanwhile, the level of lipid peroxidation in the liver was elevated after chronic exposure. In conclusion, the mixture of fluoxetine and triclosan produced toxic effects on multiple organs of P. parva, which could be alleviated after prolonged exposure, indicating an acclimation. However, the mechanisms of this acclimation needed further study.

Pollution characteristics and risk assessment of human exposure to oral bioaccessibility of heavy metals via urban street dusts from different functional areas in Chengdu, China.

Urban street dusts were collected in commercial area (CA), traffic area (TA), educational area (EA), residential area (RA) and parks area (PA) of Chengdu, China, to investigate the concentrations of heavy metals (Pb, Zn, Cu, Ni, Cd and Cr), and analyzed to evaluated possible sources and health risk assessment. The average concentrations (mg/kg) of Pb (82.3), Zn (296), Cu (100), Cd (1.66) and Cr (84.3) in urban street dusts were all higher than the local soil background values. The concentrations of heavy metals in each functional area could be classified as follows: CA>TA>RA>EA>PA. Principal component analysis and Cluster analysis showed mainly derived from the mixed sources of nature and traffic (51.7%). The results of health risk assessment showed no non-carcinogenic and carcinogenic risks of the metals for inhabitants. However, higher concentrations and oral bioaccessibility of the heavy metals in the dusts from CA and TA, indicating there was more health risks to the inhabitants in than that in other functional areas.

[Determination of multi-element contents in gypsum by ICP-AES].

The content of multi-element in gypsum was determined by ICP-AES. The sample was pretreated by acid-soluble method or alkali-fusion method. Acid-soluble method is suitable for the determination of CaO, SOs, Al2O3, Fe2O3, MgO, K2O, Na2O, TiO2, P2O5, MnO, SrO and BaO. Alkali-fusion method is suitable for the determination of CaO, SO3, SiO2, Al2O3, Fe2O3, MgO, TiO2, P2O5, MnO, SrO, BaO and B2O3. Different series standard solutions were prepared considering the properties and content of elements and solution matrix. The limit of detection and quantification were confirmed for each element under their best analysis spectral lines. The recoveries of the two pretreatment methods were from 93% to 110%, besides that for TiO2 was 81%-87% as pretreated by acid-soluble method. All RSDs (n=6) of tests were from 0.70%-3.42%. The accuracies of CaO and SO3 with ICP-AES method were less than the chemical analysis method. The determination of CaO and SO3 with ICP-AES method is only suitable for the case of low accuracy requirement. The results showed that the method can be used for the determination of multi-element contents in gypsum, with simple operation, fast analysis and reliable results. Total elements can be analysed with both acid-soluble method and alkali-fusion method.