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Sea urchins, ecologically important marine species, host a complex gut microbiota that plays a significant role in their digestion, nutrient acquisition, and overall health. The gut microbes, along with endogenous enzymes, facilitate the breakdown of macroalgae and other food sources. Environmental factors, including temperature, salinity, and habitat type, can greatly influence the microbial communities within sea urchins. Dietary variations can also lead to shifts in the abundance and composition of intestinal bacteria, highlighting the strong connection between diet and gut microbiota. The sea urchin's unique anatomy and digestive system adaptations contribute to their ability to process and absorb nutrients efficiently, supporting their varied diets. Gut microbes not only participate in the decomposition of complex carbohydrates, but also in detoxifying compounds and mitigating the impacts of inhospitable environments. Further research is needed to fully understand the intricate relationships between sea urchin species, their habitats, diets, and gut microbiota composition. A deeper understanding of these interactions may inform sustainable management and aquaculture strategies, ensure the long‐term viability of economically valuable sea urchin species, and provide insights into their ecological roles and adaptability to changing environments. [ABSTRACT FROM AUTHOR]

ABSTRACT Diseases are major constraints to developing large‐scale aquaculture practices in many countries. For decades, synthetic chemotherapeutic agents have been widely applied both as prophylactics and therapeutics to inhibit and control aquatic disease outbreaks. However, their use has become more restricted due to the negative impacts they have on the environment, the host and humans, as well as their limitations in preventing the emergence of antimicrobial‐resistant bacteria. Therefore, there is a growing interest in the use of medicinal plants and seaweeds as potential alternatives to antibiotics and other synthetic chemotherapeutics. Medicinal plants and seaweeds can enhance the immune systems of animals, thereby providing protection against numerous diseases while minimizing the adverse effects associated with synthetic chemotherapeutics. Furthermore, the advantages of medicinal plants and seaweeds, such as their effectiveness, easy availability and ability to be applied on a large scale, make them appealing for use in the aquaculture industry. The main goal of this study was to review the existing knowledge of the effects of medicinal plants and seaweeds, as well as their extracts, on shrimp growth, immune response and disease resistance against bacterial and viral agents. Moreover, this paper discusses the application of seaweeds in shrimp culture. We also conducted a literature review to identify gaps in the research and provide recommendations for further advancement in this field of study. Further studies should focus on evaluating other physiological aspects, such as feed and mineral utilization, enzyme activities and histological examination. [ABSTRACT FROM AUTHOR]

Inorganic phosphates have been used in shrimp feeds to meet phosphorus (P) needs, which may be quantitatively affected by the dietary content of P and other minerals and digestibility. In the present study, performance and digestibility were determined simultaneously in juvenile shrimp (Litopenaeus vannamei) during the grow‐out period (4–23 g ind wt). Shrimps were fed plant‐based diets supplemented with different phosphate ingredients: monosodium phosphate (MSP), monoammonium phosphate (MAP), magnesium phosphate (MgP), and monocalcium phosphate (MCP). The total P level in test diets was 0.79%. MSP supplementation was tested at two dietary calcium:phosphorus ratios to check for possible effects upon shrimp performance and digestibility. A negative control diet was tested with a similar formulation without inorganic phosphate supplementation (0.47% total P). Shrimp was reared in a recirculated clear water tank system (35 ppt salinity, 30°C, 100 individuals/m3) with continuous feeding provided by automatic pellet delivery. Feces were sampled 4–5 times daily throughout the trial. A negative control diet produced P limitation and significantly reduced shrimp performances compared to P‐supplemented diets (P < 0.05). Performance of shrimp‐fed diets containing inorganic phosphates varied for feed conversion rate: 1.24–1.34, survival: 87%–94%, growth: 2.50–2.59 g/week, and no significant difference was found among dietary treatments (P > 0.05). Inorganic P supplementation resulted in significantly higher dry matter, crude protein, ash, and P apparent digestibility coefficient (ADC) compared to P limited negative control diet (P < 0.05). In addition, reduced P ADC (P < 0.05) was checked with higher dietary Ca:P ratio. Phosphorus digestibility in test diets showed significant differences: MSP > MCP, MgP, and MSP + CaCO3; MAP > MSP + CaCO3 (P < 0.05). Digestible P (%) could then be calculated in test diets: MgP (4.77 g Pdig/kg of feed), MSP + CaCO3 (4.81 g Pdig/kg of feed), MCP (5.0 g Pdig/kg of feed), MAP (5.13 g Pdig/kg of feed), and MSP (5.30 g Pdig/kg of feed). Digestible P in phosphate sources (%) could then be calculated: 88.2% MSP, 84.2% MAP, 79% MCP, 72.2% MgP, and 71.8% MSP + CaCO3. Shrimp whole body and exoskeleton phosphorus content also showed significantly higher values in P‐supplemented diets compared to control, regardless of the source tested (P < 0.05). It is concluded that tested phosphates were suitable for feeding juvenile shrimp with MSP, MAP, and MgP diets showing high feed efficiency, while MSP and MAP diets resulted in numerically increased growth, coinciding with numerically higher P digestibility in these phosphates. The elevated P digestibility in the phosphates seems related to their water solubility, though MgP, less soluble and digestible in comparison to MSP and MAP, could also produce good performance. [ABSTRACT FROM AUTHOR]

The Malaysian Straits, a region of significant ecological and economic importance, face growing challenges due to climate change and human activities. This study aimed to assess fish diversity in the Pulai River, situated within the Malaysian Straits, and examine the impact of urbanization and climate change on these fish populations. Rapid industrialization, urbanization, and agricultural runoff have contributed to habitat degradation and water pollution, exacerbating stressors on marine ecosystems. The objective of this study was to evaluate the current status of fish diversity and understand how environmental changes affect fish diversity. Field surveys were conducted to identify fish species in the Pulai River, with specimens collected and categorized into families. The study identified representatives from families such as Latidae, Serranidae, Lutjanidae, Polynemidae, Sciaenidae, Scombridae, and Carangidae, with Carangidae emerging as the dominant family, accounting for 163 individuals out of a total of 380 fish observed. Diversity indices for the marine fish community were calculated, yielding a diversity index (H′) of 2.02143, a species richness index (R′) of 2.474168, and an evenness index (E′) of 0.877896. The analysis revealed a positive allometric growth pattern (b = 1.73), indicating that as fish length increases, their weight decreases disproportionately. These findings highlight the complex responses of fish populations to environmental stressors such as water quality deterioration and habitat alteration. This study provides valuable insights into the fish ecology of the Malaysian Straits, particularly regarding the impacts of urbanization and climate change on fish diversity. The research supports informed conservation efforts aimed at preserving biodiversity in this ecologically significant region. Recommendations for future studies include ongoing monitoring of fish populations, assessment of specific pollutants and habitat changes, and the implementation of targeted conservation strategies to mitigate the impacts of urbanization and climate change on marine ecosystems in the Malaysian Straits. [ABSTRACT FROM AUTHOR]

In recent years, financial losses due to salinity changes threat bivalve industry. In natural habitat, marine bivalves should be adapted to a series of environmental stressors, including biotic (virus, bacteria and protozoan) and abiotic (salinity, temperature and heavy metal) factors. It is known that salinity fluctuations able to change distribution and vital parameters of bivalves. Suboptimal salinity conditions resulted in changes in defense mechanism, growth, free amino acid, heart rate, oxygen consumption and filtration rate. However, it is necessary to determine the optimal salinity level of cultured bivalves to avoid the risk of mortality and improve growth rate. Therefore, this study aimed to review the findings from various reports in vitro and in vivo conditions which evaluated physiological and immunological responses of different bivalve species submitted to different salinity concentrations. The information of present study is very important in understanding the physiological responses of bivalves, which are living in highly changeable environment such as estuarine. [ABSTRACT FROM AUTHOR]