Ran Li

This experiment was conducted to investigate the impacts of dietary incorporation of a combination of broccoli by‐product and citrus peel by‐product (CBC) as a functional additive on the growth and resistance of the Japanese abalone ( Haliotis discus ) under various stressor conditions. A total of 2520 abalone juveniles (initial weight of 3.33 g) were assigned to 21 net cages, with 120 individuals per cage and three cages per feed. Six formulated feeds, supplemented with 0%, 0.5%, 1%, 2%, 3%, and 5% CBC, were prepared and labeled as the control (Con), CBC0.5, CBC1, CBC2, CBC3, and CBC5 feeds, respectively. Additionally, dry Saccharina japonica was prepared to compare the performance of abalone fed with the formulated feeds. All abalone were fed once daily for 16 weeks. Following the 16‐week feeding experiment, 60 abalone from each cage were randomly chosen and evenly divided into 3 groups. These groups were then exposed to stressors: 20 h air exposure, 20 h high temperature exposure (30°C), and 12 h low salinity exposure (25 psu). The survival of abalone was checked for 5 days following these stress tests. The specific growth rate (SGR) of abalone fed all artificial feeds was statistically ( p < 0.05) greater than that of abalone fed the S. japonica , but no statistical differences were observed among abalone fed the different formulated feeds. The shell length, width, and height, and soft body weight of abalone fed with all artificial feeds were statistically superior ( p < 0.05 for all) compared to those fed with S. japonica . After the 5‐day observation period following 20 h air exposure or high temperature exposure at 30°C, the survival rates of abalone fed with CBC2, CBC3, and CBC5 feeds were statistically ( p < 0.05) greater than those fed with S. japonica . Increasing the CBC inclusion level (0–5%) in feeds linearly enhanced the abalone survival under 20 h air and high temperature exposures. Therefore, CBC exhibited great potential as a stress reducer in abalone feed, and the inclusion of at least 2% CBC in formulated feeds is recommended to enhance abalone’s resistance to air and high‐temperature stressors.

The black-spotted frog (Pelophylax nigromaculatus) is a common economic species in the rice–frog ecological cropping mode. The present study investigated microbial community structures in paddy water and black-spotted frog’s guts across rice monoculture and low-/high-density rice–frog co-cropping systems at four rice growth stages. Proteobacteria dominate in paddy water, while frog guts are enriched in Firmicutes and Actinobacteriota. The frog density shows no impact on the α-diversity, but rice growth stages significantly alter the Shannon, Simpson, and Pielou_e indices (p < 0.01). Co-cropping may promote amino acid synthesis, elemental cycling, and stress tolerance in paddy water microbiota, which are more diverse than gut microbiota. Strong correlations exist between paddy water and gut microbiotas, with Limnohabitans being linked to gut diversity (p < 0.05). Low-density co-cropping enhances Xenorhabdus, which is beneficial for pest control and stabilizes gut microbiota. The results of this study offer insights for managing rice–frog systems based on rice growth stages.

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.

This study was conducted to elucidate the impact on the growth and feed availability of rockfish (Sebastes schlegeli) from including jack mackerel meal (JMM) in feeds which otherwise substitute 20% fish meal (FM) with chicken by-product meal (CBM). Six formulated feeds were designed to be isonitrogenous and isolipidic. Specifically, 55% FM was included in the control (Con) diet. In the Con diet, 20% FM was substituted by CBM, and then the graded levels (0, 20, 40, 60, and 80%) of JMM were included instead of FM, named as the C20J0, C20J20, C20J40, C20J60, and C20J80 diets, respectively. Five hundred and forty juvenile rockfish (initial weight of 11.2 g) were assigned to 18 tanks. All experimental feeds were fed to triplicate groups of rockfish twice daily for 8 weeks. Superior weight gain, specific growth rate (SGR), and feed intake of rockfish fed the C20J60 and C20J80 diets compared to rockfish fed the Con and C20J0 diets were observed. However, the feed utilization, biological indices, proximate composition, amino acid profiles, and blood chemistry of the rockfish were not affected by the dietary treatments. The slightly but not significantly higher economic profit index and growth performance were obtained in the C20J60 diet compared to the C20J80 diet. In conclusion, the C20J60 diet was the most recommendable treatment based on the improvement in growth performance (weight gain and SGR) and feed intake of rockfish, and the highest economic return to farmers.

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.

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.

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.