Given the economic significance of Procambarus clarkii in freshwater aquaculture and the lack of microbial antioxidants in Procambarus clarkii diet research, this study aimed to investigate the optimal supplementation level and feeding duration of microbial antioxidants in Procambarus clarkii diets. A series of three experiments were conducted to assess the long-term effects of different MA levels on crayfish and evaluate the palatability of the diets by observing feeding behavior and examining the short-term effects of high levels of MA. Our results indicate that long-term feeding using 1.5% MAs markedly increased the activities of antioxidant enzymes (T-AOC, T-SOD, and GSH-PX) and decreased the malondialdehyde (MDA) content in the hepatopancreas and hemolymph, with the crayfish showing significantly higher survival rates due to better antioxidant capacity after 24 h of air exposure stress. Under the condition of long-term feeding, the appropriate level of addition of MAs that can promote the growth of crayfish is 0.62–0.66%. The feeding behavior results indicate that the lower willingness and food intake of the crayfish in the high MA group may be the main reason affecting their growth. Conversely, short-term feeding using MAs alleviated the adverse effects on growth associated with the reduced palatability of the diet. The results indicate that the inclusion of 1.5% MAs in the diet for a period of 21 d optimized crayfish growth, accompanied by an improvement in antioxidant capacity and survival during transportation. This study demonstrates that diets supplemented with microbial antioxidants (MAs) can improve growth performance, antioxidant capacity, and resistance to air exposure stress in Procambarus clarkii. These results provide valuable insights into the potential benefits of MA supplementation in crayfish aquaculture.

Freshwater ecosystems are increasingly degraded by Cladophora blooms, prompting a need to understand its reproductive characteristics for effective control. We combined continuous microscopical monitoring and single-factor and orthogonal experiments, to characterize the life history and reproductive and growth response to different nutrients, pH, temperature, and light conditions of a bloom-forming Cladophora sp. A novel mode was observed, in which mature sporangia and gametangia rupture to extrude a pyknotic cytoplasmic mass, inside which zoospores and gametes complete maturation and release. The peak zoospore production occurred in Aquatic No. 6 medium at pH 5, 35 °C, and 54 µmol m⁻² s⁻¹, whereas maximum gamete release was recorded in Knop medium at pH 4, 30 °C, and the same irradiance, with temperature being the principal driver for zoospores and nutrient regime for gametes. Growth trials further revealed that low-N and -P conditions sustain growth, whereas nutrient-rich conditions favor reproduction. In addition, pH 4–5, 35 °C, and 54 µmol m⁻² s⁻¹ conditions favored propagule formation, while pH 7–8, 25 °C, and 81 µmol m⁻² s⁻¹ maximized biomass. These findings provide a basis for predicting Cladophora bloom dynamics and offer references for sustainable management of Cladophora in freshwater ecosystems.

This study evaluates regional differences in ecosystem service values (ESVs) between the integrated rice–crayfish systems of Huoqiu County (HQ) and Chongming District (CM) in China. The assessment was based on the Common International Classification of Ecosystem Services (CICES) V5.1, which categorizes ecosystem services into provisioning, regulation and maintenance, and cultural services. In this framework, each service category was quantified using region-specific biophysical indicators combined with monetary valuation methods. The results showed that the ESVs in HQ and CM were 346,113.59 CNY/ha and 467,334.89 CNY/ha, respectively, with greenhouse gas (GHG) emissions accounted for as a negative value. Regulation and maintenance services dominated both regions (59% in HQ and 52% in CM), followed by provisioning services (22%) in HQ and cultural services (19%) in CM. Among these, temperature regulation, water storage and flood control, soil nutrient retention, social security functions, and greenhouse gas emissions were higher in HQ than in CM, with the key difference lying in social security value in HQ and greater tourism development value in CM. A SWOT-AHP analysis recommends a pioneering strategy leveraging strengths and opportunities for sustainable development. These findings inform region-specific policies to balance economic growth and environmental sustainability, contributing to global discourse on integrated agriculture–aquaculture (IAA) systems. Future research incorporating primary data and refining model parameters would further enhance the precision and practical application of these assessments.

To meet the growing market demand for high‐quality red swamp crayfish ( Procambarus clarkii ), nutritional strategies are needed to improve both health and visual traits. The microalga Dunaliella salina , renowned for its rich natural β‐carotene content, presents a promising solution. This study investigated the effects of dietary supplementation with D. salina powder at five graded levels (0%, 0.34%, 0.67%, 1.34%, and 2.00%) on juvenile crayfish over a 60‐day feeding trial. Results demonstrated that weight gain rate (WGR) and specific growth rate (SGR) were highest in the 2.00% supplementation group. Notably, a low inclusion level of 0.34% significantly promoted ovarian development, as evidenced by the highest gonadosomatic index (GSI) and digestive enzyme activities. Antioxidant capacity (AOC, total superoxide dismutase [T‐SOD], total AOC [T‐AOC]) and nonspecific immunity (alkaline phosphatase [AKP]) were maximally enhanced at 0.67% inclusion. Most importantly, dietary D. salina was efficiently converted to astaxanthin and deposited in tissues, with carapaces and ovaries coloration parameters showing a strong, dose‐dependent correlation with carotenoid accumulation. Regression analysis identified an optimal inclusion range of 1.23%–1.53% for maximizing carotenoid deposition, immune function, and AOC. Furthermore, the 2.00% supplementation group exhibited the highest tolerance to air exposure stress. Our findings provide definitive, data‐driven insights for the precise application of D. salina in functional crayfish feeds, facilitating the industry’s transition from quantity‐focused production to quality‐ and value‐driven aquaculture.

Cladophora-dominated filamentous algal blooms constitute a growing threat to aquatic ecosystem stability and aquaculture operations. This study systematically evaluated the algicidal efficacy of sodium hypochlorite (NaClO), both individually and in combination with an organosilicone adjuvant, against Cladophora sp., with particular focus on induced oxidative damage mechanisms. Results demonstrated that NaClO exhibited a dose- and time-dependent inhibitory effect, achieving ≥90% inhibition at 1.20 mmol L⁻¹ within 48 h and >99% by 120 h, significantly surpassing the efficacy of lower concentrations (0.40 mmol L⁻¹) (p < 0.05). Physiological assessment revealed that 1.20 mmol L⁻¹ NaClO significantly suppressed total antioxidant capacity (T-AOC) after 96 h (p < 0.05). Notably, synergistic enhancement was observed with adjuvant co-application: at 0.40 mmol L⁻¹ NaClO, superoxide dismutase (SOD) activity reached its minimum with 0.33 ppm organosilicone adjuvant, showing significant reduction compared to higher adjuvant concentrations (p < 0.05). Furthermore, combinations of 0.80 and 1.20 mmol L⁻¹ with organosilicone adjuvant consistently maintained inhibition rates ≥ 94% across all sampling intervals, achieving control efficacy equivalent to 2.00 and 2.40 mmol L⁻¹ NaClO alone within 48 h. These findings demonstrate that NaClO supplemented with low-dose organosilicone adjuvant constitutes a promising and efficient strategy for mitigating Cladophora blooms.