Aquaculture, a vital component of global food supply, faces challenges from environmental stressors that compromise aquatic animal health and productivity. Astaxanthin, a potent carotenoid antioxidant, has shown promise in enhancing growth and stress resilience in aquaculture species, yet its effects remain inconsistent across studies. This meta-analysis systematically evaluates the efficacy of dietary astaxanthin supplementation on growth, feed utilization, antioxidant capacity, and immune function in aquaculture animals. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 64 studies (33 species, 964 comparisons) published prior to 2025 were analyzed using a random-effects model. Results demonstrated that astaxanthin significantly improved final body weight, weight gain rate, specific growth rate, survival rate, and protein efficiency ratio, while reducing feed conversion ratio. Additionally, it enhanced digestive enzyme activities, hepatopancreas antioxidant biomarkers, and immune parameters. The subgroup analysis revealed differences related to species, trophic level, and habitat, and estimated the optimal dose for key indicators. Despite heterogeneity and publication bias, adjusted effect sizes remained significant for most outcomes. These findings underscore astaxanthin’s potential as a multifunctional feed additive to promote sustainable aquaculture, though its efficacy depends on species, dosage, and environmental context, warranting further mechanistic and optimization studies.

Cadmium (Cd) exposure can affect metal handling, metabolism and tissue condition in bivalves on different timescales. We examined these responses in the blood clam Anadara kagoshimensis (Tokunaga, 1906) exposed to a nominal Cd concentration of 100 μg/L. Respiration, tissue Cd, redox biomarkers and histology were assessed over 480 h, alongside hepatopancreas RNA profiles at 0 h, 24 h and 21 d. Oxygen consumption reached its lowest exposed mean at 96 h. At 480 h, Cd concentrations were 44.23 ± 8.99 μg/g dry weight in the hepatopancreas and 31.75 ± 1.81 μg/g in the gill. SOD and CAT activities followed tissue-specific trajectories, GSH content declined, and MDA showed non-monotonic changes. Histological observations included epithelial detachment and disruption of digestive tubule structure. Descriptive expression comparisons identified metal handling, redox, cell-death and immune-related candidates, with more twofold expression differences at 21 d than at 24 h. qRT-PCR examined ten selected targets using three tank-derived RNA samples per time. Together, the physiological measurements, tissue observations and exploratory expression profiles describe a tissue- and time-dependent response to Cd exposure and identify candidates for further functional study.

This study evaluated the effects of salinity stress on survival, gill morphology, and immune-, osmoregulatory-, and antioxidant-related enzyme activities in Mercenaria mercenaria. Nine salinities (0–50, practical salinity units, PSU) were tested, with 30 as the control. Survival was monitored for 168 h, and median lethal salinities under hypo- and hypersaline conditions were estimated. Gill histology was examined at 24, 72, and 168 h under salinities 15, 30, and 50, while ACP, AKP, SOD, CAT, and Na+/K+-ATPase activities were measured at five time points. M. mercenaria showed substantial tolerance to salinity stress. After 168 h, cumulative mortality was 20% at salinity 45 and 22% at salinity 20, with median lethal salinities of 52.232 and 15.097, respectively. Both low and high salinity caused gill damage, including filament shrinkage at 24 h and wider inter-filament spaces after 72 h. Enzyme activities generally increased initially, then declined and stabilized, although response timing differed among enzymes. These results indicate strong early phase physiological plasticity (72 h), which could increase mortality risk, may reflect either impaired osmoregulation, antioxidant capacity and immune defense, or the establishment of physiological acclimation. The findings support pond culture management and breeding of salinity-resilient strains.