Replacement of fish meal (FM) with rice protein concentrate (RPC) as a practical diet for the Pacific white shrimp, Litopenaeus vannamei, was evaluated. Five isonitrogenous (36.6% protein) diets, formulated by replacing 0, 25, 50, 75, and 100% of FM by RPC, were fed to shrimp (initial weight of 6.99 ± 0.08 g) five times daily to satiation for 60 days. Relatively high final weight (FW 17.64-18.25 g) and weight gain (WG 10.81-11.39 g) were obtained in treatments up to 50% of the plant protein inclusion. Above this inclusion level, FW (14.93-14.35 g) and WG (7.68-7.23 g) were reduced. Survival was high (C95%) and similar for all diets. There were no significant differences (P [ 0.05) in tail-muscle composition (moisture, protein, lipid, and ash) among different dietary treatments. Dispensable and indispensable amino acids of the tail muscle of shrimp fed with 25, 50, and 75% RPC were significantly higher than the FM (0%) and 100% RPC diets. A decreasing trend in apparent digestibility coefficient (excluding dry matter) for crude protein (90.52-52.41), ether extract (94.11-80.03), organic matter (87.25-50.16), and gross energy (89.41-55.24) was observed at higher RPC inclusion rates. The results suggest that RPC meal can be a potential candidate for FM replacement up to 50% of the protein in shrimp diets.
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 m 2 /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.
The effects of different dietary nucleotide mixture (NT) levels (0, 2, 4 and 6 g/kg) were investigated on the reproductive performance, fatty acid profile and biochemical parameters in Litopenaeus vannamei female that were co-fed with fresh food (two times daily) and experimental diets (two times daily) for 30 days. Sampling was carried out at the first day of the trial, before eyestalk ablation (ESA) (day 21) and after ESA (day 30).Reproductive performance parameters including the hepatopancreatic index, absolute fecundity, egg diameter and latency period were higher in the NT-supplemented groups than the control group (p < .05). Total n-3 polyunsaturated fatty acids in the ovaries, especially eicosapentaenoic acid, were higher in the NT-supplemented groups than in the control (222.6 ± 7.3 versus 204.7 ± 3.0 mg/g extracted lipid) (p < .05).Total hemocyte count, granular cells, plasma glucose (Glu), total protein (TP), calcium (Ca 2+ ), total cholesterol (Chol), triglyceride (Tg) and high-density lipoprotein (HDL) levels were significantly increased in the NT-supplemented groups in comparison with the control group (p < .05). After ESA, the concentration of plasma Glu, TP, Chol and Tg significantly decreased, but HDL levels increased in all groups (p < .05). These results suggested that the application of dietary NT may present a novel strategy for increasing reproductive performance and health status in L. vannamei.
K E Y W O R D Sfatty acid profile, hemocyte, Litopenaeus vannamei, nucleotide, plasma biochemical indices, reproductive performance
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