This work aims to determine the impact of dietary supplementation of polysaccharide, extracted from brown seaweeds Sargassum dentifolium on growth indices, feed utilization, biochemical compositions, microbial abundance, expressions of growth and immunity-related genes, and stress genes of the Pacific Whiteleg shrimp Litopenaeus vannamei. A total of 360 post-larvae of L. vannamei were randomly distributed into a 12-glass aquarium (40 L of each) at a stocking density of 30 shrimp with an initial weight of (0.0017 ± 0.001 g). During the 90-day experiment trial, all shrimp larvae were fed their respective diets at 10% of total body weight, three times a day. Three experimental diets were prepared with different seaweed polysaccharide (SWP) levels. The basal control diet had no polysaccharide level (SWP₀), while SWP₁, SWP₂, and SWP₃ contained polysaccharides at concentrations of 1, 2, and 3 g kg⁻¹ diet, respectively. Diets supplemented with polysaccharide levels showed significant improvements in weight gain and survival rate, compared to the control diet. Whole-body biochemical composition and the microbial abundance (the total count of heterotrophic bacteria and Vibrio spp.) of L. vannamei showed significant differences among polysaccharide-treated diets compared to the control. At the end of the feeding experiment, the dietary supplementation of polysaccharide levels enhanced the expression of growth-related genes (Insulin-like growth factors (IGF-I, IGF-II), immune-related genes (β -Glucan-binding protein (β-Bgp), Prophenoloxidase (ProPO), Lysozyme (Lys), and Crustin), and stress genes (Superoxide dismutase (SOD) and Glutathione peroxidase (GPx) in the muscle tissue of L. vannamei. However, the current study concluded that the inclusion rate of 2 g kg^–1 of polysaccharide as a dietary additive administration enhanced both weight gain and survival rate of L. vannamei, while the incorporation level of 3 g kg^–1 reduces the abundance of pathogenic microbes and enhances the growth-, immunity- and stress-related gene expressions of L. vannamei.

Solenocera crassicornis is a commercially important shrimp of the Solenoceridae family. The current study investigated the morphology, molecular identification, phylogenetic relationships, and population dynamics of S. crassicornis in Egypt. Samples were collected monthly (total, 1722; male = 40.19%, wet weight, 0.89–10.77 g; female = 59.81%, wet weight, 1.55–19.24 g) from Al-Attaka commercial catch in the Gulf of Suez in the Red Sea. Two barcode markers, 18S rRNA and cytochrome c oxidase subunit I (COI), were used for molecular identification. COI partial sequences were used to construct the phylogenetic relationships among different species of genus Solenocera and to infer the origin of the studied Solenocera crassicornis. The applied molecular markers successfully identified the studied species to the species level. The genetic distances among S. crassicornis sequences from different countries revealed the Indo-West Pacific origin of S. crassicornis. The relationship between total length (TL) and total weight (TW) was TW = 0.035TL^2.275 and r² = 0.805 for males and TW = 0.007TL^3.036 and r² = 0.883 for females, indicating that females were heavier than males. Despite its social and economic relevance in the area, information on the hatching, larval rearing, and farming of S. crassicornis is scarce and requires future studies under Egyptian conditions.

The present study evaluated the influence of different commercial agricultural by-products as a carbon source in a bifloc-based (BFT) culture system on growth performance, whole-body proximate composition, digestive enzyme activities, gut microbial abundance, and hepatopancreas histology of Pacific whiteleg shrimp, Litopenaeus vannamei post larvae (Pls). Three groups were designed, the first group was the control group, where the shrimp was reared in clear water (without carbon source addition and water exchange rate of 100% two times a week) and fed with a commercial diet, in the second and third groups shrimp were reared in BFT systems using two different carbon sources, sugarcane bagasse (SB) and rice bran (RB) without additional feeding or water exchange. The initial stocking density was 16 Pls/liter with an average individual shrimp weight of 0.01 ± 0.002 g and age (PL20). The experiment lasted 90 days. The water quality parameters were maintained at optimum levels during the experiment. The final body weight and specific growth rate of shrimp were significantly (p ≤ 0.01) higher in the control group than those reared in both SB and RB-based BFT. Meanwhile, the survival rate was significantly (p < 0.05) higher in BFT groups than in the control. The protease activity in shrimp stomach did not differ significantly. Meanwhile, protease, lipase, and amylase in the intestine showed a significant increase (p < 0.01) in BFT groups than those obtained in the control group. The total heterotrophic bacteria were significantly (p < 0.05) higher in BFT groups. Furthermore, the hepatopancreas histological status of shrimp reared in the SB-based BFT group showed an increase in the hepatopancreas tubules in the distal and B-cell zones (blister-like cells) by 16.83 and 34.89%, respectively, compared to the control. This study revealed that BFT could be used as a natural feed without artificial diets, which influenced the gut microbiota of shrimp, increased digestive enzyme activities, as well as improved the histological structure of the hepatopancreas of shrimp. However, the success of this conditions under high stocking density still needs more investigation.

In this study, we investigate the effect of the biofloc (BF) system using various carbon sources including sugarcane bagasse (SCB), rice bran (RB) and rice straw (RS) on growth parameters, hepatopancreatic digestive enzymes and the expression of growth‐related genes of white‐leg shrimp, Litopenaeus vannamei . Single‐nucleotide polymorphisms (SNPs) in the haemocyanin gene in small‐ and large‐sized Litopenaeus vannamei for 3 months reared in outdoor concrete ponds were also screened. The results showed that the growth and survival of shrimp in the RB and SCB groups were improved ( p ≤ 0.05) and the same trend was observed for the digestive enzyme activities. The expression of different growth‐related genes including growth hormone, insulin‐like growth factor‐I and II, myosin and paramyosin was significantly increased in all biofloc groups reaching the highest levels in the RB group. The SNPs recorded in the haemocyanin gene between the small‐ and large‐sized L. vannamei revealed an insertion of Adenine at position 554 and a substitution at 1114 in large‐sized RS shrimp. So far, the RB group was attained the best growth, digestive enzyme activity and expression of growth‐related genes between different carbon sources. Furthermore, the haemocyanin gene can be used as a marker for the selection of large‐sized shrimp.

Microorganisms obtained from the marine environment may represent a potential therapeutic value for multiple diseases. This study explored the possible protective role of marine‐derived potential probiotic Enterococcus faecium EA9 (E. faecium) against pulmonary inflammation and oxidative stress using the cecal ligation and puncture (CLP) model of sepsis in Wistar rats. Animals were pretreated with E. faecium for 10 days before either sham or CLP surgeries. Animals were sacrificed 72 hours following the surgical intervention. The histological architecture of lung tissues was evaluated as indicated by the lung injury score. In addition, the extend of pulmonary edema was determined as wet/dry weight ratio. The inflammatory cytokines were estimated in lung tissues, including tumor necrosis factor‐alpha (TNF‐α), interleukin‐6 (IL‐6), and interleukin‐1 beta (IL‐1β) using the enzyme‐linked‐immunosorbent‐assay (ELISA) technique. Moreover, markers for lipid peroxidation such as thiobarbituric acid reaction substances (TBARs), and endogenous antioxidants, including reduced glutathione (GSH) were determined in lung tissues. Finally, the enzymatic activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) were assayed in the lungs. Pretreatment with E. faecium markedly attenuated CLP‐induced lung injury and pulmonary edema. Markers for inflammation, including TNF‐α, IL‐6, and IL‐1β were augmented in the lung tissues of CLP animals, while E. faecium ameliorated their augmented levels. E. faecium pretreatment also restored the elevated TBARS levels and the prohibited CAT, SOD, and GPx enzymatic activities in CLP animals. GSH levels were corrected by E. faecium in CLP animals. The inflammatory and lipid peroxidation mediators were positively correlated, while antioxidant enzymatic activities were negatively correlated with CLP‐induced lung injury and pulmonary edema. Collectively, marine‐derived Enterococcus faecium EA9 might be considered as a prospective therapeutic tool for the management of pulmonary dysfunction associated with sepsis.