Interesting Probiotic Bacteria Other Than the More Widely Used Lactic Acid Bacteria and Bacilli in Finfish

Growing demands stimulate the intensification of production and create the need for practices that are both economically viable and environmentally sustainable. As European Union banned the use of antibiotics in production in 2003, several alternative treatments have been suggested, including probiotics. The first probiotic study in aquaculture was published in 1986, and since then probiotics have been considered as a beneficial tool in this industry. Today current evidence suggests that administration of certain probiotic strains might be able to enhance growth rate, improve the welfare of different fish species by modulating gut microbiota, improve physiological functions, such as metabolism, digestion, immunity, stress tolerance, intestinal histology, and disease resistance. Even though lactic acid bacteria and Bacillus spp. are the most frequently used probiotics in aquaculture, numerous studies have been published on other interesting probiotics. Therefore, the purpose of this paper is to summarize, comment, and discuss the current knowledge related to the effects of Aeromonas, Aliivibrio, Alteromonas, Arthrobacter, Bifidobacterium, Brochothrix, Clostridium, Enterovibrio, Kocuria, Microbacterium, Micrococcus, Paenibacillus, Phaeobacter, Pseudoalteromonas, Pseudomonas, Rhodococcus, Rhodopseudomonas, Rhodosporidium, Roseobacter, Shewanella and Vibrio as probiotics in finfish aquaculture, and present general information on their presence in the gastrointestinal tract of finfish. Moreover, some considerations for future studies are also indicated

Beneficial roles of nutrients as immunostimulants in aquaculture: A review

Protein deficiency is a major difficulty for human needs in the past few decades, while different types of aquatic species are rich in high quality protein. Therefore, aquaculture is considered as the main developing food production sector globally. Bacterial infections are the main problem for aquaculture, and their outbreaks have a great impact on productivity, and previously indiscriminate use of antibiotics to control them. However, the emergence of multidrug-resistant pathogens might lead to sudden infectious disease outbreaks resulting in serious economic loss. Immunostimulants application is an effective technique to protect and enhance the immune system of aquatic animals and therefore improve aquaculture production. Nutrient immunostimulants such as essential fatty acids, amino acids, vitamins, and minerals are the most important responsibility to improve aquaculture production, as well as the cost of this method, which is effective, non-toxic, and environment friendly. These nutrient immunostimulants are supportive to increase the immune system, antioxidant, antiinflammatory, and infection resistance of aquatic animals. In addition, nutritional feed additives improved feed palatability and the excellence of aquatic products and also enhance gut functions. Some information is available on nutrient immunostimulants in aquaculture applications, and this review provides information on different kinds of nutritional administration used in aquaculture to enhance positive impacts on aquatic animals’ health as well as feed quality development. This review will provide theoretical references for the application of nutrient immunostimulants in aquatic feeds

Global attractivity of positive periodic solution of a delayed Nicholson model with nonlinear density-dependent mortality term

This paper is concerned with the existence, uniqueness and global attractivity of positive periodic solution of a delayed Nicholson’s blowflies model with nonlinear density-dependent mortality rate. By some comparison techniques via differential inequalities, we first establish sufficient conditions for the global uniform permanence and dissipativity of the model. We then utilize an extended version of the Lyapunov functional method to show the existence and global attractivity of a unique positive periodic solution of the underlying model. An application to the model with constant coefficients is also presented. Two numerical examples with simulations are given to illustrate the efficacy of the obtained results

Streptococcosis a Re-Emerging Disease in Aquaculture: Significance and Phytotherapy

Streptococcosis, particularly that caused by S. iniae and S. agalactiae, is a major re-emerging bacterial disease seriously affecting the global sustainability of aquaculture development. Despite a wide spread of the disease in aquaculture, few studies have been directed at assessing the in vitro antagonistic activity and in vivo efficacy of medicinal herbs and other plants against streptococcal agents. Most in vitro studies of plant extractives against S. iniae and S. agalactiae have found antibacterial activity, but essential oils, especially those containing eugenol, carvacrol or thymol, are more effective. Although essential oils have shown better anti-streptococcal activity in in vitro assays, in vivo bioassays require more attention. The extracts examined under in vivo conditions show moderate efficacy, increasing the survival rate of infected fish, probably through the enhancement of immunity before challenge bioassays. The available data, however, lack dosage optimization, toxicity and bioavailability assays of a specific plant or its bioactive compound in fish organs; hence, it is difficult to judge the validation of clinical efficacy for the prevention or treatment of fish streptococcosis. Despite the known bioactive compounds of many tested plants, few data are available on their mode of action towards streptococcal agents. This review addresses the efficacy of medicinal plants to fish streptococcosis and discusses the current gaps

Effects of dietary arginine supplementation on cytokine‐ and antioxidant‐related gene expressions in common carp (Cyprinus carpio) fingerling during ammonia toxicity

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Universality in odd-even harmonic generation and application in terahertz waveform sampling

Odd-even harmonics emitted from a laser-target system imprint rich, subtle information characterizing the system's dynamical asymmetry, which is desirable to decipher. In this Letter, we discover a simple universal relation between the odd-even harmonics and the asymmetry of the THz-assisted laser-atomic system -- atoms in a fundamental mid-IR laser pulse combined with a THz laser. First, we demonstrate numerically and then analytically formulize the harmonic even-to-odd ratio as a function of the THz electric field, the source of the system's asymmetry. Notably, we suggest a scaling that makes the obtained rule universal, independent of the parameters of both the fundamental pulse and atomic target. This universality facilitates us to propose a general pump-probe scheme for THz waveform sampling from the even-to-odd ratio, measurable within a conventional compact setup

Synthesis of gelatin stabilized gold nanoparticles with seed particles enlargement by gamma Co-60 irradiation

Gold nanoparticles (AuNPs) with size from 13 to ~36 nm were synthesized by γ-irradiation method using gelatin as stabilizer. The AuNPs with controllable size were prepared using various concentration of Au3+ from 0.5 to 2 mM and seed particle enlargement with different ratios of [Au3+]/[Auo] up to 50. Maximum absorption wavelength (λmax) was measured by UV-Vis spectroscopy, and particle size was determined from TEM images. Results showed that the size of AuNPs increased with the Au3+ concentration. The seed enlargement approach is efficient to control the size of AuNPs. The value of λmax shifted from 527.5 nm (seed particles) to 537.5 nm, and the size of AuNPs increased from 13 nm (seed particles) to ~36 nm for concentration ratio of [Au3+]/[Auo] up to 40. Thus, γ-irradiation method is favorable for production of AuNPs with controllable size and high purity. The AuNPs/gelatin synthesized by γ-irradiation with the advantages of environmental friendly and mass production process may be potentially promising for applications in medicines, cosmetics and in other fields as well. Keywords. Gold, Nanoparticles, Gelatin, γ-irradiation

Sustainable Ornamental Fish Aquaculture: The Implication of Microbial Feed Additives

Ornamental fish trade represents an important economic sector with an export turnover that reached approximately 5 billion US dollars in 2018. Despite its high economic importance, this sector does not receive much attention. Ornamental fish husbandry still faces many challenges and losses caused by transport stress and handling and outbreak of diseases are still to be improved. This review will provide insights on ornamental fish diseases along with the measures used to avoid or limit their onset. Moreover, this review will discuss the role of different natural and sustainable microbial feed additives, particularly probiotics, prebiotics, and synbiotics on the health, reduction in transport stress, growth, and reproduction of farmed ornamental fish. Most importantly, this review aims to fill the informational gaps existing in advanced and sustainable practices in the ornamental fish production

Bacillus sp. as potential probiotics for use in tilapia fish farming aquaculture - A review

peer reviewedAquaculture is a crucial and rapidly expanding industry in global food production. Fisheries are, also an essential socio-economic activity, providing abundant resources and remarkable prospects. However, due to the deteriorating ecological environment, aquatic animals are often exposed to traumatic conditions and are susceptible to bacterial infections that pose significant challenges for aquaculture production. The indiscriminate use of antibiotics in the past has led to the emergence of multidrug-resistant pathogens and sudden outbreaks of infectious diseases, resulting in serious economic losses. Moreover, the use of expensive chemotherapeutic drugs and antibiotics has negative impacts on aquatic environments. Therefore, it is increasingly important to adopt alternative natural agents, such as probiotics and their metabolites, to enhance healthy fish production. Probiotics are microorganisms that have numerous beneficial effects on their hosts. They are environmentally friendly, nontoxic, and cost-effective. This review specifically focuses on the use of Bacillus sp. as probiotics to promote healthy tilapia production in the aquatic sector, while also examining their interactions with the immune system and gut microbiota. The information presented in this review can guide future research and promote effective and healthy tilapia culture production

Association of genetic markers with sex determination in Thai red tilapia

The objectives of this study were to verify the polymorphism on sex-linked marker loci and to assess their associations with phenotypic sex characteristics in red tilapia. Four sex-linked genetic markers of Amh, SCAR4, SCAR5, and Oni3161 were genotyped in the Thai red tilapia population. The Amh marker was significantly associated with the phenotypic sex of red tilapia with an accuracy of 46.2%. No significant association of SCAR4, SCAR5, and Oni3161 marker polymorphisms with phenotypic sex characteristics was observed in this study. However, the combinations of these two, three, and four markers were increasingly associated with phenotypic sex characteristics for red tilapia with an accuracy of 62.8, 68.4, and 72.4%, respectively. These results indicate that these combined genetic markers were associated with the phenotypic sex of red tilapias. These findings confirmed the importance of these genetic markers as candidate markers for sex determination in the Thai red tilapia population