Does Dietary Sodium Alginate with Low Molecular Weight Affect Growth, Antioxidant System, and Haemolymph Parameters and Alleviate Cadmium Stress in Whiteleg Shrimp (Litopenaeus vannamei)?

Decreasing low molecular weight can improve the digestibility and availability of ingredients such as sodium alginate. This study aimed to test the four dosages of low molecular weight sodium alginate (LMWSA) (0%: Control, 0.05%: 0.5 LMWSA, 0.10%: 1.0 LMWSA, and 0.2%: 2.0 LMWSA) in whiteleg shrimp (Litopenaeus vannamei) (3.88 ± 0.25 g) for eight weeks. After finishing the trial, shrimp were exposed to cadmium (1 mg/L) for 48 h. While feed conversion ratio (FCR) improved in shrimp fed dietary 2.0 LMWSA (p < 0.05), there was no significant difference in growth among treatments. The results showed a linear relation between LMWSA level and FCR, and glutathione S-transferase (GST) before; and malondialdehyde (MDA), glutathione (GSH), GST, and alanine transaminase (ALT) after cadmium stress (p < 0.05). The GST, MDA, ALT, and aspartate transaminase (AST) contents were changed after stress but not the 2.0 LMWSA group. The survival rate after stress in 1.0 LMWSA (85.23%) and 2.0 LMWSA (80.20%) treatments was significantly higher than the Control (62.05%). The survival rate after stress negatively correlated with GST and ALT, introducing them as potential biomarkers for cadmium exposure in whiteleg shrimp. Accordingly, the 2.0 LMWSA treatment had the best performance in the abovementioned parameters. As the linear relation was observed, supplementing more levels of LMWSA to reach a plateau is recommended.

Reproductive performance and vitellogenin mRNA transcript abundance in the hepatopancreas of female Litopenaeus vannamei fed diets with different soy lecithin content.

A 30-day nutritional study was conducted for determining the effects of supplementing soy lecithin (SL) in the diet of female Litopenaeus vannamei. Four isonitrogenous and isoenergetic diets were supplemented with graded amounts of SL including 0 (control), 20, 40 and 60 g Kg-1. The brooding specimens fed the 40 g SL/kg diet had the greatest gonadosomatic index (3.4 ±â€¯0.2 %) and the shortest latency period from eyestalk ablation to the first spawning (5 days). In addition, there was a larger content of long chain polyunsaturated fatty acids (LC-PUFA) in the hepatopancreas of brooding specimens fed with the 20 and 40 SL/kg diets compared to the other treatments. Furthermore, brooding specimens fed with the 40 g SL/kg diet had the greatest hemolymph cholesterol and high density lipoprotein concentrations. The abundance of vitellogenin mRNA transcript was greater in the hepatopancreas of brooding specimens fed with the 40 and 60 g SL/kg diets compared with the other groups. Results indicate that supplementing diets with 40 g SL/kg can improve growth and reproductive performance in L. vannamei female brooding specimens probably by enhancing LC-PUFA deposition and enhancing vitellogenin gene expression, as indicated by a greater abundance of mRNA transcript for vitellogenin, in the hepatopancreas.

Calcined Umbonium vestiarium snail shell as an efficient adsorbent for treatment of wastewater containing Co (II).

In the present study, the Umbonium vestiarium snail shell (UVS) was used as an abundant and low-cost resource for the removal of Co (II) from aqueous solution. The characteristics of calcined Umbonium vestiarium snail shell (CUVS) were analyzed using FTIR, SEM, MAP, EDAX, and BET analyses. The results showed that the specific surface area of the CUVS was obtained 17.02 m2/g which was an acceptable amount. The presence of Co (II) in the adsorbent structure was confirmed by EDAX, and Map analyses after Co (II) adsorption showed that the adsorbent successfully adsorbed Co (II) from aqueous solution. The effect of different parameters such as, contact time, initial concentration of cobalt ion, the adsorbent dose, and pH value was also investigated. The maximum efficiency of cobalt ion adsorption was measured 93.87% at a pH value of 6, contact time of 80 min, the adsorbent dose of 3 g/L, and initial ion concentration of 10 mg/L. Also, Langmuir, Freundlich, and D-R isotherm models were used to determine the most appropriate isotherm model for cobalt ion adsorption. The adsorption equilibrium data were better fitted with the Langmuir model with a maximum adsorption capacity of 93.46 mg/g. Additionally, the average free energy of adsorption was evaluated in the amount of 1.4085 KJ/mol, revealing a physical adsorption. Moreover, the kinetic behavior study showed that the experimental data follow the pseudo second order kinetic model to the value of correlation coefficient.

Effect of gamma radiation on the growth, survival, hematology and histological parameters of rainbow trout (Oncorhynchus mykiss) larvae.

Effects of low (1, 2.5 and 5Gy) and high doses (10, 20 and 40Gy) of gamma radiation were examined on the growth, survival, blood parameters and morphological changes of the intestines of rainbow trout (Oncorhynchus mykiss) larvae (103±20mg) after 12 weeks of exposure. Negative effects of gamma radiation on growth and survival were observed as radiation level and time increased. Changes were well documented at 10 and 20Gy. All the fish were dead at the dose of 40Gy. In all the treatments, levels of red blood cells (RBC), hematocrit (HCT) and hemoglobin (HB) were significantly (P<0.05) declined as the irradiation levels increased, whereas the amount of mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) did not change. No significant differences (P>0.05) were found in the levels of white blood cells (WBC), lymphocytes and monocytes. Destruction of the intestinal epithelium cells was indicated as the irradiation levels increased to 1Gy and above. The highest levels of growth, survival, specific growth rate (SGR), condition factor (CF) and protein efficiency rate (PER) were obtained in the control treatment. The results showed that gamma rays can be a potential means for damaging rainbow trout cells.