Background and Aim: Oxygen concentration is an essential water quality parameter for aquaculture systems. Recently, supersaturated dissolved oxygen (DO) has been widely used in aquaculture systems to prevent oxygen depletion; however, the long-term effects of supersaturated oxygen exposure on aquatic animals have not been studied. In this study, we examined the effects of supersaturated DO on the growth, survival, and gene expression of Pacific white shrimp (Litopenaeus vannamei). Materials and Methods: Specific pathogen-free shrimp with a body weight of 8.22 ± 0.03 g were randomly assigned to two groups with four replicates at a density of 15 shrimps per tank. Shrimp were cultivated in recirculating tanks containing 50 L of 15 ppt seawater in each replicate. Oxygen was supplied at 5 mg/L to the control tanks using an air microbubble generator and at 15 mg/L to the treatment tanks using a pure oxygen microbubble generator. Shrimp were fed commercial feed pellets containing 39% protein at 4% of their body weight per day for 30 days. Average daily growth (ADG) and feed conversion ratio (FCR) were determined on days 15 and 30. Shrimp molting was measured every day. Individual hemolymph samples were obtained and analyzed for total hemocyte count, differential hemocyte count, and expression of growth- and immune-related genes at the end of the experiment. Results: Long-term exposure to supersaturated DO significantly affected shrimp growth. After 30 days of supersaturated DO treatment, the final weight and ADG were 14.73 ± 0.16 g and 0.22 ± 0.04, respectively. Shrimp treated with normal aeration showed significantly lower weight (12.13 ± 0.13 g) and ADG (0.13 ± 0.00) compared with the control group. FCR was 1.55 ± 0.04 in the treatment group and 2.51 ± 0.09 in the control group. Notably, the shrimp molting count was 1.55- fold higher in the supersaturated DO treatment than in the supersaturated DO treatment. The expression of growth-related genes, such as alpha-amylase, cathepsin L, and chitotriosidase, was 1.40-, 1.48-, and 1.35-fold higher, respectively, after supersaturated DO treatment. Moreover, the treatment increased the expression of anti-lipopolysaccharide factor, crustin, penaeidin3, and heat shock protein 70 genes by 1.23-, 2.07-, 4.20-, and 679.04-fold, respectively, compared to the controls. Conclusion: Supersaturated DO increased growth and ADG production and decreased FCR. Furthermore, enhanced immune-related gene expression by supersaturated DO may improve shrimp health and reduce disease risk during cultivation. Keywords: gene expression, growth performance, molting, pacific white shrimp, supersaturated dissolved oxygen.

The main pathogen in the Nile tilapia (Oreochromis niloticus) culture, Streptococcus agalactiae, causes economic harm. Infected fish’s immune systems worked to eliminate of the infection. This study demonstrated the effect of different bacterial concentrations on tilapia immunity and optimal vaccine concentration to induce immunity in Nile tilapia. The experiment was performed at 10², 10⁴, 10⁶, 10⁸, and 10¹⁰ CFU/fish of S. agalactiae compared with the control (PBS) through intraperitoneal injection for 72 h. Fish that survived employed to gather blood, and immune responses were assessed through measures of the survival rate include blood smears, antibody titers, and immunoglobulin gene expression. The vaccine experiment investigated formalin-inactivated S. agalactiae vaccination and administered S. agalactiae injections for 14 days. The statistic revealed a significant difference (p < 0.05) in the 10⁸ and 10¹⁰ CFU/fish injections with high survival rates (62.22% and 53.33%, respectively). Immunoglobulin gene expression was highly represented in the 10¹⁰ CFU/fish injection; antibody titers were significantly improved from the control group, and antibody levels were high in the 10¹⁰ CFU/fish injection. The analysis of blood cell types using the blood smear method revealed a progressive increase in leucocytes, particularly lymphocytes, neutrophils, and monocytes, in the treatment group compared to the control group. Moreover, the erythrocyte/leucocyte ratio decreased significantly in response to the high bacterial injection, indicating an increase in leucocytes. Conversely, the erythrocyte level stayed ed within at the 7.03–9.70 × 10² cell/ml and shown no significant difference (p > 0.05). The lymphocytes were almost two-fold in 10¹⁰ CFU/fish compared to 10⁸ CFU/fish. As depicted in the lowest concentration of 10⁶ CFU/fish, the vaccine performance had a high relative percent survival (RPS) at 86.67%. This research suggested that the tilapia infected with high S. agalactiae concentrations did not affect the mortality of the tilapia, and vaccine concentration was effective in 10⁶ CFU/fish.

Background and Aim: Pacific white shrimp (Penaeus vannamei) is a principal species in global aquaculture. However, outbreaks of Vibrio parahaemolyticus, the etiological agent of acute hepatopancreatic necrosis disease (AHPND), cause substantial economic losses. β-glucans derived from marine diatoms, Chaetoceros muelleri (CH) and Thalassiosira weissflogii (TH), have shown potential as immunostimulants to enhance shrimp resistance to pathogenic infections. This study aimed to evaluate the effects of β-glucans derived from CH, TH, and their combination on growth performance, immune responses, and survival of P. vannamei and to elucidate the underlying molecular mechanisms through transcriptomic and gene silencing approaches. Materials and Methods: Juvenile shrimp were assigned to four dietary groups for 30 days: Control (β-glucan-free), β-glucan from CH, TH, and a mixture of both (CH and TH) (CHTH). Growth performance, total hemocyte count (THC), and survival rate were evaluated. RNA-seq was performed on hepatopancreas samples after 14 days to identify differentially expressed genes (DEGs). Key immune-related DEGs were validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Functional analysis of the lysozyme (Lyz) gene was conducted through RNA interference (RNAi), followed by V. parahaemolyticus challenge. Results: The CHTH diet group exhibited significantly enhanced growth metrics and the highest survival rate. Transcriptomic analysis revealed 1,902 DEGs in the CHTH group compared to control, with 915 upregulated and 987 downregulated genes. qRT-PCR validated the expression trends of selected immune-related genes, notably Lyz, which showed robust upregulation. RNAi-mediated Lyz knockdown reduced survival upon bacterial challenge, confirming its role in β-glucan-induced immunity. Conclusion: β-glucans derived from CH and TH, particularly in combination, significantly enhance growth performance and immunocompetence in P. vannamei. These findings underscore the potential of marine diatom-derived β-glucans as viable immunostimulants to mitigate AHPND in shrimp aquaculture, offering a sustainable alternative to antibiotic use. Keywords: immune enhancement, lysozyme, marine diatoms, Penaeus vannamei, RNA interference, transcriptomics, Vibrio parahaemolyticus, β-glucan.

Dog and cat faeces are a globally neglected issue that demands proper management. The poor handling of pet waste not only impacts environmental health but also contributes to community conflicts due to insufficient waste management practices. The objectives were to investigate the properties of pet wastes compared to livestock wastes (pigs, hens, and cattle) with the intention of formulating an efficient compost product suitable for agricultural applications. Faeces from dogs and cats were collected from the community, while faeces from livestock (pigs, cattle, and hens) were collected from farms. Faeces were mixed with probiotics, rice bran, and rice husk to make compost and used to grow sweet corn plants. The nutrient content was compared between fresh and composted faeces. Composted manure from different animal sources was compared for its effectiveness in promoting sweet corn growth. The results showed that fresh and composted dog and cat manures contained higher levels of nutrients (p < 0.05) compared to livestock manures. Additionally, composted pet manure accelerated (p < 0.05) the growth of the plants compared to composted livestock manures and control groups. This is the first study to conclude that composted pet faeces surpass livestock manure in their higher nutrients and enhance plant growth. The findings could help reduce pet waste and transform it into a valuable recycled resource. However, the safety of composted manure, especially concerning toxoplasmosis from cat faeces, remains a significant concern and requires further investigation.