Vannamei shrimp (Litopenaeus vannamei) is an important food commodity of economic benefit due to its high price, low susceptibility to disease, and popularity for consumption. These advantages have led many farmers to cultivate vannamei shrimp. Efforts are underway to improve the aquaculture performance of this species, including the use of probiotics, which are non-pathogenic bacteria that aid in digestion and help fight disease. Probiotics are usually obtained from the intestines of vannamei shrimp or the culture environment. They are low-cost, non-pathogenic, and largely non-toxic source of antibiotics and are able to synthesize various metabolites that have antibacterial functions and applications. Research on probiotic use has primarily been focused on increasing vannamei shrimp aquaculture production. Bacterial species, such as Lactobacillus or Nitrobacter, can be administered orally, by injection, or as a supplement in aquaculture water. Probiotics help to improve survival rate, water quality, immunity, and disease resistance through space competition with disease-causing bacteria, such as Vibrio spp. An increased number of probiotic bacteria suppresses the growth and presence of pathogenic bacteria, which lowers disease susceptibility. In addition, probiotic bacteria also aid digestion by breaking down complex compounds into simpler substances that the body can absorb more easily. This mechanism improves growth performance in terms of weight, length, and feed conversion ratio. This review aimed to provide information regarding contribution of probiotic to improve vannamei shrimp production in aquaculture. Keywords: application, bacteria, farm, microbiome, shrimp.

Microplastics (MPs) are tiny particles derived from plastic, and their high fragmentation poses a significant threat to the marine environment. MPs can originate from various sources, such as primary or secondary sources as well as internal or external sources. However, in marine environments, MPs mainly enter from external sources, such as plastic waste, debris from land-based activities, tourism, shipping, and atmospheric deposition. MP accumulation in marine ecosystems is also influenced by the use of plastic equipment, aquaculture feed, health products, and particular environmental conditions. Understanding the ecotoxicological effects of environmentally relevant concentrations of MPs on the health of marine organisms is crucial. The effects of MPs on the health of marine organisms are well reported by different studies, highlighting their interactions with a wide range of marine life, including plankton, invertebrates, crustaceans, corals, seagrass, fish, and even humans. Thus, MPs have been reported as a notorious pollutant because of their deleterious impacts on the morphology, physiology, immunology, behavior, reproduction, and heredity of marine organisms. Moreover, most MPs are slowly degradable, and degradation is dependent on various biotic and abiotic factors, resulting in continuous accumulation in the marine environment. This review provides an in-depth explanation of the sources of MPs, along with their impacts on marine organisms, ecosystems, aquaculture, and human health. In addition, it will discuss the degradation of MPs in the marine environment to explore the potential strategies for reducing the harmful impacts of MPs.

Fish represent an excellent source of animal protein as well as a biomedical research model as a result of their evolutionary relatedness and similarity with the human genome. Commercial and ornamental fish culture has achieved popularity, but reproductive dysfunctions act as a limiting factor for quality fry production, interfering with the sustainability of the aquaculture industry. Fish reproduction is crucial for any species’ existence, and reproductive performance can potentially be improved through applications of epigenetics and probiotics. Epigenetics is a highly sensitive molecular approach that includes chromatin structure and function alteration, DNA methylation, and modification of non-coding RNA molecules for the transfer of desired information from parents to offspring. DNA methyltransferase improves reproductive cyp11a1, esr2b, and figla gene expression and feminizes zebrafish (Danio rerio). Moreover, epigenetics also contributes to genome stability, environmental plasticity, and embryonic development. However, methylation of specific genes can negatively affect sperm quality, resulting in poor fertilization. Probiotic administration is able to induce responsiveness of incompetent follicles to maturation-inducing hormones and can change oocyte chemical composition during vitellogenic development. The positive role of probiotics on testicular cells is validated by upregulating the transcription levels of leptin, bdnf, and dmrt1 genes facilitating the spermatogenesis. This review not only discusses the effects and mechanism of epigenetics and probiotics for improving fish reproduction, but also presents an overview of the causal factors and current techniques used to eradicate dysfunction. Moreover, key genes and hormones related to fish reproduction along with research gaps and future prospects are also considered. This review provides an overview of necessary information for students, scientists, researchers, and breeders to resolve fish reproduction-related problems to ensure profitable and sustainable aquaculture.

This study investigates the potential of pure chitosan powder as an effective, sustainable, and low-cost adsorbent for the removal of synthetic dyes from aqueous media. The work demonstrates the potential of pristine chitosan for practical wastewater treatment applications by adsorbing two commonly used textile dyes, methyl orange (MO) and methylene blue (MB). To elucidate the adsorption mechanism, chitosan was comprehensively characterized using zeta potential analysis, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM–EDX), Thermogravimetric Analysis (TGA), Brunauer–Emmett–Teller (BET) surface area analysis, and point of zero charge (pHpzc) determination. FTIR analysis revealed notable shifts in –NH₂ and –OH functional groups after dye adsorption, confirming their involvement in electrostatic interactions and hydrogen bonding with MO and MB. SEM images demonstrated significant surface morphological changes following adsorption, while EDX spectra confirmed successful dye uptake through the appearance of sulfur and nitrogen signals characteristic of MO and MB, respectively. Zeta potential and pHpzc results explained the strong pH-dependent adsorption behavior, highlighting favorable electrostatic attraction between chitosan and the ionic dyes. The optimum adsorption conditions were achieved at adsorbent dosages of 0.5 g for MO and 1.0 g for MB, a contact time of 30 min, initial dye concentrations of 20 and 100 mg/L, and solution pH values of 3 for MO and 9 for MB at room temperature. The adsorption data fit the Langmuir isotherm model, indicating monolayer adsorption on a homogeneous chitosan surface, with maximum adsorption capacities of 7.843 mg/g for MO and 7.605 mg/g for MB. Kinetic studies showed that adsorption followed the pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Thermodynamic analysis indicated that the adsorption process was endothermic and non-spontaneous under the investigated conditions. In conclusion, these findings demonstrate that unmodified chitosan is a practical, eco-friendly adsorbent for dye removal, achieving removal efficiencies comparable to many modified chitosan composites, and represents a promising candidate for sustainable wastewater treatment.

The present study was conducted to reveal specific bacterial consortium belong to same genus capable of mineralizing petroleum hydrocarbons and also act as a valid indicator to locate the oil reservoir in Red Sea, Saudi Arabia. The study focused on area consist of hydrocarbons in briny water and sediment. The sites included Port Sudan Deep, Suakin Deep, Hatiba Deep, and Brian salt in the Red Sea, Saudi Arabia. The concept of the study is to identify crude oil reservoir using the presence of hydrocarbon degrading bacterial strains. The Marinobacter strains isolated were grown in different media such as marine broth with crude oil, tryptic soy agar and mineral salt medium with phenanthrene as sole carbon source at 40 g/L of NaCl concentration. The strains present in hydrocarbon reservoirs of different deeps were isolated and identified as Marinobacter hydrocarbonoclasticus strain MAM1 (MF716467), Marinobacter sp. strain MAM2 (MF716468) and Marinobacter hydrocarbonoclasticus strain MAM3 (MF716469). Marinobacter consortium was pertained by the mixture of the above strains (MAM1, MAM2 and MAM3) from different deep samples. The consortium potentially utilized PAHs (polycyclic aromatic hydrocarbons) such as phenanthrene (PHN) and pyrene (PY). The consortium degraded 72 ± 1.5% of PHN at 1500 mg/L concentration in 16 days under saline condition (4%). The degradation of PY (300 mg/L) by the consortium was 86 ± 1.1% in 12 days under saline condition (4%). Also the presence of Marinobacter strains in the deep water samples and crude oil drilling rig (core) samples, confirmed the relationship between the bacterial strains and oil reservoir. Thus the study confirmed Marinobacter can be used as a potential indicator strain in different deeps at Red Sea to identify the crude oil reservoir.