Draft genome sequence of Pseudoalteromonas piscicida strain 36Y_RITHPW, a hypersaline seawater isolate from the south coast of Sonora, Mexico

Safety evaluation and effects of dietary phlorotannins on the growth, health, and intestinal microbiota of Litopenaeus vannamei

Phlorotannins are phenolic compounds with diverse biological activities, yet their efficacy in aquatic animals currently remains unclear. This investigation scrutinized the influence of phlorotannins on the growth, immunity, antioxidant capacity, and intestinal microbiota in Litopenaeus vannamei, concurrently evaluating the potential adverse effects of phlorotannins on L. vannamei. A base diet without phlorotannins supplementation was used as a control, and 4 groups of diets with different concentrations (0, 0.5, 1.0, 2.0 g kg-1) of phlorotannins were formulated and fed to juvenile shrimp (0.25 ± 0.01 g) for 60 days followed by a 24-hour challenge with Vibrio parahaemolyticus with triplicate in each group. Compared with the control, dietary 2.0 g kg-1 phlorotannins significantly improved the growth of the shrimp. The activities of enzymes related to cellular immunity, humoral immunity, and antioxidants, along with a notable upregulation in the expression of related genes, significantly increased. After V. parahaemolyticus challenge, the cumulative survival rates of the shrimp demonstrated a positive correlation with elevated concentrations of phlorotannins. In addition, the abundance of Bacteroidetes and functional genes associated with metabolism increased in phlorotannins supplementation groups. Phlorotannins did not elicit any detrimental effects on the biological macromolecules or histological integrity of the hepatopancreas or intestines. Simultaneously, it led to a significant reduction in malondialdehyde content. All results indicated that phlorotannins at concentrations of 2.0 g kg-1 can be used as safe feed additives to promote the growth, stimulate the immune response, improve the antioxidant capacity and intestinal health of L. vannamei, and an protect shrimp from damage caused by oxidative stress.

Therapeutic Potential of Marine Probiotics: A Survey on the Anticancer and Antibacterial Effects of Pseudoalteromonas spp

Due to the increasing limitations and negative impacts of the current options for preventing and managing diseases, including chemotherapeutic drugs and radiation, alternative therapies are needed, especially ones utilizing and maximizing natural products (NPs). NPs abound with diverse bioactive primary and secondary metabolites and compounds with therapeutic properties. Marine probiotics are beneficial microorganisms that inhabit marine environments and can benefit their hosts by improving health, growth, and disease resistance. Several studies have shown they possess potential bioactive and therapeutic actions against diverse disease conditions, thus opening the way for possible exploitation of their benefits through their application. Pseudoalteromonas spp. are a widely distributed heterotrophic, flagellated, non-spore-forming, rod-shaped, and gram-negative marine probiotic bacteria species with reported therapeutic capabilities, including anti-cancer and -bacterial effects. This review discusses the basic concepts of marine probiotics and their therapeutic effects. Additionally, a survey of the anticancer and antibacterial effects of Pseudoalteromonas spp. is presented. Finally, marine probiotic production, advances, prospects, and future perspectives is presented.

Dietary supplementation of Pseudoalteromonas piscicida 1UB and fructooligosaccharide enhance growth performance and protect the whiteleg shrimp (Litopenaeus vannamei) against WSSV and Vibrio harveyi coinfection

P. piscicida 1Ub and FOS were evaluated for their potential synbiotic effects on growth, immunological responses, and disease resistance against white spot syndrome virus and V. harveyi coinfection, the major pathogen in whiteleg shrimp aquaculture. Four different supplemented diets were used to feed the experimental shrimp for 40 days: control (control, no probiotic, and prebiotic), probiotic (PRO, P. piscisida 1UB 10⁸ CFU mL^-1), prebiotic (PRE, FOS 0.5% w/w), and the synbiotic (SYN, PRO + PRE). Shrimp's body weight, weight gain, specific growth rate, feed conversion ratio, survival, digestive enzyme activity, and metabolism-related gene expression were all evaluated on day 40. After 40 days, shrimp were infected with WSSV as the primary infection and V. harveyi as the secondary infection 24 h later. Shrimp were then grown for seven days and fed with a control diet. Survival, total hemocyte count (THC), differential hemocyte, phenol-oxidase (PO), respiratory burst activity (RB), and immune-gene expression were all analyzed at 0, 3, and 7 days after infection. The results showed that the PRO, PRE, and SYN supplementation improves whiteleg shrimp growth performance, immune responses, and protection against WSSV and V. harveyi coinfection. The increased activity of digestive enzymes and metabolism-related genes correlates with higher growth performance. The increase in THC, PO, RB, and immune-related gene expression after coinfection was associated with a significant reduction in shrimp mortality. Our findings also suggest that supplementing with synbiotics improves the overall performance of whiteleg shrimp significantly more than probiotics or prebiotics only.

Draft Genome Sequence of Pseudoalteromonas sp. Strain JC3

We report the draft genome sequence for Pseudoalteromonas sp. strain JC3, an isolate obtained from an aquaculture facility for whiteleg shrimp (Litopenaeus vannamei). The JC3 genome suggests multiple mechanisms for microbial interactions, including a type VI secretion system and potential for antibiotic production.

Effects of dietary yeast culture on shrimp growth, immune response, intestinal health and disease resistance against Vibrio harveyi

The current study was conducted to evaluate the effects of different levels of yeast culture (YC) supplementation at 0% (YC 0%), 1% (YC 1%), and 2% (YC 2%) on growth, feed conversion ratio, body composition, intestinal morphology, microflora, immune response, and resistance to Vibrio harveyi infection in Litopenaeus vannamei. After 8-weeks feeding trial, the results showed significant improvement (p < .05) in the final weight, weight gain rate, specific growth rate, survival rate and low feed conversion ratio in YC groups than the control. Serum total protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme, and phenol oxidase in shrimps fed diet YC (2%) were significantly higher (p < .05), whereas significantly decreased trend in serum cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase (p < .05) were observed in YC (2%) diet. Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes were the core phylum bacteria found in the shrimp intestines. At the genus level, opportunistic pathogenic bacteria, Vibrio was significantly decreased (p < .05) while beneficial bacteria Pseudoalteromonas was increased in YC (2%) group. Intestinal villus height and width in shrimps fed YC diets were significantly improved than the control diet (p < .05). YC groups challenged test significantly showed (p < .05) improved shrimps immune response against V. harveyi infections with YC (2%) recording the highest percentage survival rate (70%). The present study demonstrated that supplementing YC (2%) can improve growth, intestinal microbiota, intestinal morphology, and immune response against V. harveyi infections in L. vannamei.