The biosorption of Pb(II) from aqueous solutions by lactic acid bacterium, Lactobacillus brevis, was studied. The effects of initial pH, contact time, initial Pb(II) concentration, bacterial concentration, rotate speed and temperature of biosorption of Pb(II) from aqueous solutions were investigated. The optimal condition for Pb²⁺ ions adsorption was observed at pH 6, with the rotate speed of 120 rpm.min⁻¹, bacterial concentration of 3 g.L⁻¹, temperature of 40 °C and contact time of 12 h. The correlation regression coefficients showed that the biosorption process can be well fitted with the Redlich-Peterson, Langmuir, Freundlich and Temkin isotherm models. The equilibrium adsorption capacity reached to 53.632 mg.g⁻¹. Binding energy value was 0.264 kJ/mol, it indicated that the adsorption process seemed to involve chemisorption and physisorption. Kinetics of adsorption was found to fit well with pseudo-second-order and Elovich kinetic equation. Thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of adsorption.

This study aims to evaluate the dietary replacement effect of various levels of fish meal (FM) with meat meal (MM) on the growth, feed utilization, chemical composition, hematological parameters, and innate immune responses of olive flounder. A total of 360 juvenile fish (initial weight of 14.7 g) were randomly assigned to 18 flow-through containers. The control (MM0) diet included 65% FM. Then, 10%, 20%, 30%, 40%, and 50% FM in the MM0 diet were replaced with MM, referred to as the MM10, MM20, MM30, MM40, and MM50 diets, respectively. The fish were hand-fed to satiation daily for 56 days. Weight gain, the specific growth rate, the feed efficiency ratio, and the protein efficiency ratio of fish fed the MM0 diet were statistically greater than those of fish fed the MM30, MM40, and MM50 diets, but not statistically different from those of fish fed the MM10 and MM20 diets. To incite the maximum values of weight gain and the specific growth rate (SGR) of the fish, an estimated 7.0% of FM substitution with MM in diets was required according to regression analysis. However, the feed consumption, protein retention, hematological parameters, and innate immune (superoxide dismutase and lysozyme activities) responses of the fish were not statistically impacted by the dietary replacement levels of MM for FM. In conclusion, the feed ingredient grade of MM can substitute FM by up to 20% in the diet without causing any negative impact on the growth, feed consumption, feed utilization, or innate immune responses of olive flounder.

This experiment was performed to assess the substitution impact of fish meal (FM) with tuna by-product meal (TBM) in feeds on growth and feed availability of the early stage of juvenile rockfish (S. schlegeli). Six experimental feeds were prepared to be isonitrogenous and isolipidic. Fifty-five percent of FM was contained in the control (Con) diet. In the Con diet, 20, 40, 60, 80, and 100% FM were replaced by TBM, named the TBM₂₀, TBM₄₀, TBM₆₀, TBM₈₀, and TBM₁₀₀ diets, respectively. A total of 540 early-stage juvenile rockfish averaging 2.4 g was divided into 18 tanks and hand-fed to satiation for 56 days. Weight gain and feed consumption of rockfish fed the TBM₂₀ and TBM₄₀ diets were comparable to rockfish fed the Con diet. The specific growth rate (SGR) of rockfish fed the Con diet was comparable to rockfish fed the TBM₂₀, TBM₄₀, and TBM₆₀ diets. Feed efficiency, biometric indices, hematological parameters, proximate composition, and amino acid profiles of rockfish were not impacted by dietary treatments. The economic profit index (EPI) of the Con, TBM₂₀, and TBM₄₀ diets were higher than that of all other diets. FM up to 40% could be substitutable with TBM in the diets of rockfish without deteriorating weight gain and feed consumption, but producing the highest EPI.

A 56-day feeding experiment was carried out to evaluate the effects of substituting fish meal (FM) with chicken by-product meal (CBM) in diets on the growth and feed utilization of rockfish (Sebastes schlegeli). Six experimental diets were formulated to be isonitrogenous and isolipidic. The control (Con) diet included 55% FM. In the Con diet, 10%, 20%, 30%, 40%, and 50% of FM was replaced with CBM, named as the CBM₁₀, CBM₂₀, CBM₃₀, CBM₄₀, and CBM₅₀ diets, respectively. A total of 540 juvenile fish were distributed into 18 tanks (30 fish per tank and 3 tanks per diet) and fed to apparent satiation two times daily for 56 days. The weight gain and specific growth rate of rockfish fed the CBM₁₀ and CBM₂₀ diets were comparable to rockfish fed the Con diet. The feed consumption of rockfish fed the Con and CBM₁₀ diets was significantly (p < 0.001) higher than that of fish fed all other diets, except for the CBM₂₀ diet. However, protein retention, biometric indices, chemical composition, amino acid profiles, and plasma and serum parameters of rockfish were not significantly influenced by dietary FM substitution with CBM. The Con, CBM₁₀, and CBM₂₀ diets showed superior (p < 0.001) economic profit index (EPI) compared to the CBM₃₀, CBM₄₀, and CBM₅₀ diets. Conclusively, FM up to 20% could be substituted by CBM in diets without impairing growth, feed availability, chemical composition, amino acid profiles, and blood parameters of rockfish grown from 2.5 g to 12.5 g. However, the long-term effects of CBM substitution or the potential use of combined CBM and other alternative protein sources for FM in rockfish diets are needed in future.