Sustainable Aquaculture and Health Management Journal
Volume:8 Issue: 1, Winter and Spring 2022

In recent years, many studies were carried out for developing new food packaging systems. There is a variety of synthetic and natural antimicrobial compounds used to control the growth of microorganisms. The use of natural antimicrobial agents, due to the low side effects and high antibacterial potential, has captured the attention of scientists. The main aim of this study was to produce polylactic acid-based biodegradable active films containing lemon verbena Essential oil nanoemulsion to control the growth of two common foodborne pathogenic bacteria (Staphylococcus aureus and Escherichia coli) in Rainbow Trout. To aim this, the antibacterial activity (in vitro) of the films were assessed under MIC and MBC assays using the microdilution method. The nanoemulsion was prepared by ultrasonic waves. Based on dynamic light scattering, the mean droplet size was reported at about 22.4 nm. Based on the antibacterial results, the growth of both microorganisms was significantly decreased after 0, 3, and 7 days of storage in comparison with the control group (p <0.05). To sum up, the presence of Lippia citriodora Nanoemulsion in the matrix of the polylactic acid film showed notable antibacterial activity during 7 days of storage at 4˚C (refrigerator). It can be concluded that this film can be a good candidate for food packaging purposes to control the growth of microorganisms.

The anesthetic effect of Datura seed extract was evaluated on 15 pieces of young Cyprinus carpio weighing approximately 25 to 50 g. In order to determine the effectiveness of L. Datura stramonium extract on the importance and severity of Cyprinus carpio  anesthesia in doses between zero mg to 10 mg /L, 10 treatments (zero treatment, control) were devised with the identical conditions (pH 7/2, temperature 22 °C, extract and fish). When fish were placed in different treatments in the drug bath, the onset time of anesthesia, the time of complete anesthesia, deep anesthesia and mortality percentage were measured by a chronometer. The results showed that increasing the concentration of Datura extract reduced the onset time of anesthesia. There was a significant difference between the onset time of anesthesia in the range between 6 mg /L and 8 mg / L (p≤0.05), There was no significant difference between 6 and 7 mg / L and 7 and 8 mg / L (p>0/05). There was also a significant difference between the mean time of complete anesthesia between 6 and 8 mg / L treatments (p≤0.05) but there is no significant difference between 6 and 7 mg / L and 7 and 8 mg / L (p>0/05). With increasing drug concentration, the mean return time from anesthesia in the treatments was different and a significant difference was observed between 6 and 8 mg / L (p ≤0.05).

This study investigated the effect of the water-soluble fraction of diesel (WSFD) on common carp behavioral, biochemical, and growth responses. Fish were divided into four groups, including control group (G1) and three exposures of 4% (G2), 8% (G3), and 16% (G4) WSFD. After 168 hours, weight gain (WG), specific growth rate (SGR), and daily growth rate (DGR) were calculated, and blood samples were taken. The results showed a significant difference between the growth indices of the G1 and the exposure groups (p<0.05). The mean of WG, SGR, and DGR indices (7.00 g, 1.85 %, 0.99, respectively) in the G2 had a significant difference with the G3 (4.44 g, 1.12 %, 0.64, respectively) and the G4 (0.89 g, 0.25 %, 0.12, respectively) (p<0.05). In addition, there was a significant difference between growth indices in the G3 and the G4 (p<0.05). There was a significant difference between the mean cortisol and serum glucose levels of the G1 (3.18 µg/dl, 61.33 mg/dl) and the G4 (10.70 µg/dl /ml, 108.33 mg/dl) (p<0.05). Swimming pattern changes, activity level, food intake, and gill movements occurred due to WSFD exposure. The fish behavior was expected in the G1 and G2. However, with increasing the concentration of the WSFD to 16%, an imbalance was observed with swimming changes, loss of appetite, decreased mobility, and impaired breathing. The present study's findings showed that WSFD exposure causes growth retardation, disturbance of biochemical blood factors, and behavioral changes in fish.

The purpose of this study was to determine the lethal concentration (LC50-96 h) of malachite green on rainbow trout and also the histology effects of this substance on the liver, gills and kidney. With increasing concentrations of malachite green, rainbow trout mortality increased during the period of 24 to 96 hours. Twenty four hour lethal concentration (LC50-24 h) of malachite green on O. mykiss is 32.28 mg L-1. Forty eight hour lethal concentration (LC50-48 h) of malachite green is 16.32 mg L-1, and 72-hour lethal concentration (LC50-72 h) of malachite green is 2.52 mg L-1. All lethal concentrations at 72 hours showed a clear reduction compared to 24 and 48 hours. The median lethal concentration of malachite green (LC50-96 h) of rainbow trout was 0.83 mg L-1 during four consecutive days (96 hours). On the other hand, malachite green showed destructive effects on liver, gills and kidney tissue of rainbow trout, and these changes were more intense with increasing concentration of malachite green. Therefore, due to the grading of toxicity is determined by the amount of LC50-96 h and also observing tissue effects exposed to this substance, the malachite green is considered highly toxic to rainbow trout. For this reason, there are always concerns about the possibility of its transmission to consumers or humans; therefore, regarding to this matter that using this substance in the fish farms has been prohibited by Iran Veterinary Organization, it is necessary to remove malachite green from the list of drugs used in fish breeding and provide the other safe drugs.

The objectives to this research were to determine the haematological changes in Oryctolagus cuniculus as an animal model in response to killed hemorrhagic septicemia virus (VHSV) virulent to Oncorhynchus mykiss. This study composed of 5 groups; Treatment 1 (T1) with 1cc virus, treatment 2 (T2) with 0.5cc virus and 0.5cc adjuvant, treatment 3 (T3) with 0.75cc virus and 0.25cc adjuvant, treatment 4 (T4) with 0.25cc virus and 0.75cc adjuvant, and a control for a period of 4 months, once a month IM injection in 5 group of three New Zealand rabbits with health certification prepared by Razi Vaccine and Serum Research Institute. After 15 days, blood parameters, hematocrit (HCT), hemoglobin (HGB), mean hemoglobin concentration in red blood cells (MCH), red blood cells (RBC), average concentration of red blood cell (MCHC), white blood cells (WBC), neutrophils (SEG), lymphocytes (Lyn), eosinophil (Eos), aspirate transaminase (AST) and alanine transaminase (ALT).The results showed that ALT, AST, HCT, HGB and WBC concentrations of all rabbits significantly were difference (p < 0.05). T2 (0.5cc virus and 0.5cc adjuvant) and T3 (0.75cc virus and 0.25cc adjuvant) showed higher ALT, AST, HCT and WBCs among other treatments in all 4 blood samplings and among these treatments, T2 with lower levels of ALT and AST (indicating less pressure on the liver) and higher levels of WBCs which can lead to greater amount of neutralizing polyclonal antibodies indicated better results.

Nowadays, the Aquaculture industry has played a major role in dealing with a broad range requirements for human protein needs. Though environmental pollution and the incidence of the disease have always been the significant challenges in the use of aquatic products. Increasing the antibiotic resistance rate in fish pathogens has attracted attention to searching for alternatives to antibiotics. In this regard, nanotechnology as a new and innovative strategy has a range of applications in aquaculture and preserving sea animals and can provide a reliable way to protect farmed fish from pathogens. The producers, therefore, try to eliminate barriers in food fields using nano-based tools and cause growth, proliferation, aquaculture, and water purification to increase production in the aquaculture industry. One of the most outstanding issues that researchers point out nano-scale is finding appropriate methodologies for the synthesis of environment-friendly and non-toxic nanoparticles. The specific chemical, physical and biological properties of nanoparticles have increased the incentive to produce them. Today these agents have found their way into many medical applications, including detection, vaccinations, medicine, and gene transfer. Moreover, the use of nanoparticle-based vaccines for many viral pathogens is a developing field in fish disease research. So, Nanoparticles have been widely taken into consideration as a special and sensitive tool to identify bacterial, fungal and viral diseases in aquaculture. This study focuses on the antimicrobial effects of nanoparticles, especially antibiotic-resistant bacteria, and the nanotechnology applications in fisheries.