Sulfadiazine (SD), sulfamerazine (SM1), and sulfamethazine (SM2) are widely used and disorderly discharged into surface water, causing contamination of lakes and rivers. However, microalgae are regard as a potential resource to alleviate and degrade antibiotic pollution. The physiological changes of Chlorella vulgaris in the presence of three sulfonamides (SAs) with varying numbers of –CH₃ groups and its SA-removal efficiency were investigated following a 7-day exposure experiment. Our results showed that the growth inhibitory effect of SD (7.9–22.6%), SM1 (7.2–45.9%), and SM2 (10.3–44%) resulted in increased proteins and decreased soluble sugars. Oxidative stress caused an increase in superoxide dismutase and glutathione reductase levels but decreased catalase level. The antioxidant responses were insufficient to cope-up with reactive oxygen species (hydrogen peroxide and superoxide anion) levels and prevent oxidative damage (malondialdehyde level). The ultrastructure and DNA of SA-treated algal cells were affected, as evident from the considerable changes in the cell wall, chloroplast, and mitochondrion, and DNA migration. C. vulgaris-mediated was able to remove up to 29% of SD, 16% of SM1, and 15% of SM2. Our results suggest that certain concentrations of specific antibiotics may induce algal growth, and algal-mediated biodegradation process can accelerate the removal of antibiotic contamination.

Farmed fish face persistent challenges arising from diverse environmental factors and human activities, which induce both acute and chronic stress responses, thereby increasing their susceptibility to diseases and mortality. Therefore, it is essential to comprehend the stressors and corresponding stress responses in fish to recognize and mitigate harmful stress during aquaculture practices. In this review, we provide an overview of the various stressors present in aquaculture, along with the resultant alterations in neuroendocrine responses, including the brain–sympathetic–chromaffin cell (BSC) axis, hypothalamus–pituitary–interrenal (HPI) axis, and caudal neurosecretory system (CNSS), as well as neurotransmitter levels within the nervous system, experienced by fish under different types of stress. Fish possess well-developed nervous and endocrine systems that respond to stress, with complex communication networks among these systems demonstrating distributed collaboration. An understanding of the neuroendocrine and neurotransmitter responses to stress may enhance our comprehension of fish stress mechanisms and facilitate the development of an integrated dietary supplementation strategy and improve their resilience against the diverse stresses encountered in aquaculture.

Consistency of individual differences of animal behavior and personality in reactions to various environmental stresses among their life stages could reflect basic divergences in coping style which may affect survival, social rank, and reproductive success in the wild. However, the physiological mechanisms determining personality remain poorly understood. In order to study whether behavior, metabolism and physiological stress responses relate to the personality, we employed post-stress recovery assays to separate zebrafish into two behavioral types (proactive and reactive). The results demonstrated consistent difference among personality, behavior and metabolism in which proactive individuals were more aggressive, had higher standard metabolic rates and showed lower shuttled frequencies between dark and light compartments than the reactive ones. The behavioral variations were also linked to divergent acute salinity stress responses: proactive individuals adopted a swift locomotion behavior in response to acute salinity challenge while reactive individuals remain unchanged. Our results provide useful insight into how personality acts on correlated traits and the importance of a holistic approach to understanding the mechanisms driving persistent inter-individual differences.