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Water quality parameters determines the success or the failure of a fish culture operation, so any proper-prepared plan for aquaculture must describe the quality and quantity of water available for this purpose. The aim of this study was to evaluate the physical and chemical water parameters in Rainbow trout culture, in the summer season from three salmonid farms, due to the environmental changes that are nowadays happening and affect the fish culture operation. The water samples were collected from Bistria-Năsăud County, from three trout farms: Strâmba, oimul de Jos and Fiad, in the summer of 2018, between May and August. For the determination of water parameters (dissolved oxygen, total dissolved solids, electrical conductivity and resistivity, pH, temperature, salinity) was used the Hanna HI 9828/4- 01 Multi-Parameter and for the chemical parameters (total ammonia, nitrates, nitrites) samples were transferred to the USAMV laboratories. The samples collection was made in each farm from three different places: catchment, basins and evacuation water areas. The results of the study showed that the parameters observed from the three farms were different, with major differences in month of July and August. The environment of fish aquaculture is a complex system with critical parameters as are the temperature, suspended solids, dissolved oxygen, nitrite and ammonia. However, the temperature and the dissolved oxygen are the most important parameter, requiring continuous monitoring in aquaculture production systems, due to the fish aerobic metabolism which requires an elevated level of dissolved oxygen at optimum temperatures. [ABSTRACT FROM AUTHOR]

Anesthetics are widely used in fish farming. Their purpose is to reduce the mobility and stress of fishes due to manipulation. In the present study we tested the efficiency of clove oil (Eugenia caryophyllata) in different doses [4.70 mL anesthetic/50 liter of water (0.094 mL/Lwater); 2.36 mL anesthetic/50 liter of water (0.0472 mL/Lwater); 1.82 mL anesthetic/50 liter of water (0.0364 mL/Lwater)] in carp (Cyprinus carpio) and in Prussian carp (Carassius gibelio) with different body mass. Anesthesia induction times were monitored. At each of these stages the respiratory rate was monitored by recording the opercular movements. The results show a direct correlation between the fish size and the induction times of anesthesia. Regardless of species, larger and heavier specimens require longer periods for anesthesia. Instead, recovery times in larger-body specimens were shorter. Different doses have influenced the duration of anesthesia induction and recovery times, the most effective dose being 4.70 mL/50 liter of water followed by 2.36 mL/50 liter of water. The dose of 1.82 mL/50 liter of water did not induce anesthesia. [ABSTRACT FROM AUTHOR]

Simple Summary: Rainbow trout is one of the main freshwater fish species farmed in Romania, in a temperate continental climate. Blood biochemistry parameter values are well known for humans and other higher vertebrates, including some species of fish, and are fundamental for the assessment of physiological status. In this study, we examined the physicochemical parameters of water quality and the blood profile (hematological and hormonal profiles, antioxidant enzyme activities) of rainbow trout females reared in three farms, during the summer season, to monitor stress. These findings permit the progress of knowledge of blood parameters in fish and will encourage efforts to expand hematological and biochemical studies to assess the health of salmonids, which is essential for the sustainable development of aquaculture. Blood biochemistry parameters are valuable tools for monitoring fish health. Their baseline values are still undefined for a multitude of farmed fish species. In this study, changes in the blood profile of rainbow trout females (Oncorhynchus mykiss) from three farms were investigated using different biomarkers during the summer season. In the given context, the main water physicochemical parameters were investigated and twelve biochemical parameters were measured from blood samples of rainbow trout reared in the Fiad, Șoimul de Jos, and Strâmba farms. We selected these farms because the genetic background of the rainbow trout is the same, with all studied specimens coming from the Fiad farm, which has an incubation station. Forty-five samples were collected monthly (May to August) throughout summer to observe the changes in the blood profile of rainbow trout. Principal component analysis showed a clear separation both among the studied farms and months. Furthermore, significant correlations (p < 0.05) between the majority of the biochemical parameters were found, indicating that the environmental parameters can influence several blood parameters at the same time. The present study provides several useful norms for assessing the welfare of rainbow trout, indicating that the relationships among different parameters are important factors in interpreting the blood biochemical profiles. [ABSTRACT FROM AUTHOR]

Because recirculating systems for breeding fish (in general) and trout (in particular), are more and more used in fish production and aquaculture, we investigated the influence of two different growth systems (classic system vs. recirculating system) on the fish health. Physiological status of trout was evaluated by histological investigations made at the liver level. At trout reared in the classical system, histological changes have not been major. At trout reared in a recirculating system, where environmental conditions are maintained at optimum parameters, voluntary feed intake (much enhanced by optimal environmental conditions), led to the appearance of massive lipid inclusion, such as the liver appears to be a hypertrophic fat mass. This may lead to the occurrence of the diseases and could endanger fish production. [ABSTRACT FROM AUTHOR]

Reproduction is one of the most important function of organisms, after which arise descendants that inherit the parental characteristics. At fish, the reproduction is materialized following the occurrence a large number of gametes (Miclea and Zăhan, 2006). At the majority salmonids species, the breeders are procured from the natural environment, during the breeding. In rainbow trout (Oncorhynchus mykiss) case, the breeding stock is reared in special ponds from the trout farms. In this case, the breeding stock is the results of a strict selection (Gjedrem, 2005), and the growth requires optimal environmental conditions. As the literature shows differences regarding the production performances of rainbow trout female according to their age (Fornshell, 2002), in the present study we aimed to determine the fertility and eggs quality in four age categories. [ABSTRACT FROM AUTHOR]