Mitochondria are considered the ‘powerhouses’ of cells, generating the essential energy in the form of adenosine triphosphate that they need for their energy demands. Nevertheless, their function is easily adaptable as regards the energy demands and the availability of chemical substrates. This allows cells to buffer sudden changes and reassure cellular metabolism, growth or survival. Currently, humans have different dietary habits, which provide several stimuli to the cell. According to the energy substrate availability due to the diet quality and diet temporality, mitochondrial physiology is greatly affected. The present review article aimed to collect all the available information that has been published to date concerning the impact of five different popular diets (high‑fat diet, ketogenic diet, fasting, caloric restriction diet and the Mediterranean diet) on specific mitochondrial physiological aspects, such as function, biogenesis, mitophagy and mitochondrial fission/fusion.

The impact of climate change on both terrestrial and aquatic ecosystems tends to become more progressively pronounced and devastating over the years. The sector of aquaculture is severely affected by natural abiotic factors, on account of climate change, that lead to various undesirable phenomena, including aquatic species mortalities and decreased productivity owing to oxidative and thermal stress of the reared organisms. Novel innovative technologies, such as aquaponics that are based on the co-cultivation of freshwater fish with plants in a sustainable manner under the context of controlled abiotic factors, represent a promising tool for mitigating the effect of climate change on reared fish. The rainbow trout (Oncorhynchus mykiss) constitutes one of the major freshwater-reared fish species, contributing to the national economies of numerous countries, and more specifically, to regional development, supporting mountainous areas of low productivity. However, it is highly vulnerable to climate change effects, mainly due to the concrete raceways, in which it is reared, that are constructed on the flow-through of rivers and are, therefore, dependent on water’s physical properties. The current review study evaluates the suitability, progress, and challenges of developing innovative and sustainable aquaponic systems to rear rainbow trout in combination with the cultivation of plants. Although not commercially developed to a great extent yet, research has shown that the rainbow trout is a valuable experimental model for aquaponics that may be also commercially exploited in the future. In particular, abiotic factors required in rainbow trout farming along, with the high protein proportion required in the ratios due to the strict carnivorous feeding behavior, result in high nitrate production that can be utilized by plants as a source of nitrogen in an aquaponic system. Intensive farming of rainbow trout in aquaponic systems can be controlled using digital monitoring of the system parameters, mitigating the obstacles originating from extreme temperature fluctuations.

Aquaculture is affected by numerous factors that may cause various health threats that have to be controlled by the most environmentally friendly approaches. In this context, prebiotics, probiotics, and synbiotics are frequently incorporated into organisms’ feeding rations to ameliorate the health status of the host’s intestine, enhancing its functionality and physiological performance, and to confront increasing antimicrobial resistance. The first step in this direction is the understanding of the complex microbiome system of the organism in order to administer the optimal supplement, in the best concentration, and in the correct way. In the present review, pre-, pro-, and synbiotics as aquaculture additives, together with the factors affecting gut microbiome in crayfish, are discussed, combined with their future prospective outcomes. Probiotics constitute non-pathogenic bacteria, mainly focused on organisms’ energy production and efficient immune response; prebiotics constitute fiber indigestible by the host organism, which promote the preferred gastrointestinal tract microorganisms’ growth and activity towards the optimum balance between the gastrointestinal and immune system’s microbiota; whereas synbiotics constitute their combination as a blend. Among pro-, pre-, and synbiotics’ multiple benefits are boosted immunity, increased resistance towards pathogens, and overall welfare promotion. Furthermore, we reviewed the intestinal microbiota abundance and composition, which are found to be influenced by a plethora of factors, including the organism’s developmental stage, infection by pathogens, diet, environmental conditions, culture methods, and exposure to toxins. Intestinal microbial communities in crayfish exhibit high plasticity, with infections leading to reduced diversity and abundance. The addition of synbiotic supplementation seems to provide better results than probiotics and prebiotics separately; however, there are still conflicting results regarding the optimal concentration.

Taking into consideration the essential contribution of Mytilus galloprovincialis farming, it is of rising importance to add knowledge regarding bacterial species occurrence in water samples from aquaculture zones from the point of view of both the organism and public health. In the present study, we investigated the bacterial community existing in water samples from six Mytilus galloprovincialis aquaculture areas in the Thermaikos gulf, northern Greece, that may provoke toxicity in aquatic organisms and humans and may indicate environmental pollution in mussel production as well as algal blooms. Bacterial species were identified molecularly by sequencing of a partial 16s rRNA segment and were analyzed phylogenetically for the confirmation of the bacterial taxonomy. The results obtained revealed the presence of four bacterial genera (Halomonas sp., Planococcus sp., Sulfitobacter sp., and Synechocystis sp.). Members of the Halomonas and Sulfitobacter genera have been isolated from highly polluted sites, Planococcus bacteria have been identified in samples derived directly from plastic debris, and Synechocystis bacteria are in line with microcystin detection. In this context, the monitoring of the bacteria community in mussel aquaculture water samples from the Thermaikos gulf, the largest mussel cultivation area in Greece, represents an indicator of water pollution, microplastics presence, algal blooms, and toxin presence.

The use of antimicrobials is beneficial for livestock health; however, their overuse and misuse may increase resistance to these compounds. Thus, the aim of the present study was the phenotypic and molecular examination of the presence of Escherichia coli antibiotic-resistant strains in broiler and laying hen farms. The resistance of E. coli strains was examined against various antibiotics, including several families of compounds such as penicillin class medications (ampicillin), cephalosporins (cefotaxime, cefoxitin, cefpodoxime and ceftazidime), sulfonamides (co-trimoxazole), quinolones (enrofloxacin and nalidixic acid), aminoglycosides (gentamicin), β-lactams (imipenem), aminoglycoside (streptomycin), and polymyxin (colistin). In total, 106 strains were investigated, sampled during the years 2016–2019 from 91 poultry farms, including 75 broiler farms and 16 laying hen farms, originating from three Regional Units in Greece. The examined isolates revealed the highest resistance rates to sulfamethoxazole (81.1%), nalidixic acid (73.6%), tetracyclin (70.8%), and streptomycin (70.8%). On the other hand, the resistance of the isolates to third generation cephalosporins was found to be at lower levels for ceftazidime (2.8%), ceftriaxone (3.7%) cefoxitin (4.7%), and cefotaxime (4.7%). Phenotypic tests showed that 13.6% and 10.2% of the isolates produced ESBL, while 2.7% and 1% produced AmpC b-lactamase, for broiler and laying hens, respectively. The prevalence of the mcr-1 gene was found to be 22.7%, detected only in broiler isolates. Based on our results, E. coli antibiotic resistance represents a critical control point in poultry production that, apart from farm animals, may affect public health as well.