Computational histomorphometry is an available and easy tool that has been used in the assessment of morphophysiological tissue changes, offering greater scientific reliability to the data, as well as facilitating the automation process. The present work aimed to describe the application of the methodology of the free software ImageJ for morphological evaluation of fish tissues. For this, micrographs of histological sections of the intestinal tract of fish stained with Periodic Acid-Schiff (PAS) were used as a model. The images were analyzed for variables of length, width, and tissue area and, number of cells or molecules. The application of computational histomorphometry demonstrated efficiency in the evaluation of histological structures of the intestine of fish supplemented with probiotics, contributing to the improvement of image analysis techniques in animal tissue models.

Mortalidade em pacus (Piaractus mesopotamicus) ocasionada por Pantoea agglomerans e Pseudomonas aeruginosa em tanque escavadoMortality in Pacus (Piaractus mesopotamicus) caused by Pantoea agglomerans and Pseudomonas aeruginosa in Excavated Tank ABSTRACT Background: Fish production in Brazil is growing strongly. This growth is being mainly driven by mainland aquaculture, which in 2017 produced 691.700 tons of fish. To improve production levels, fish farms have become increasingly intensive, but in these systems, the high fish densities in the ponds, the high feeding rate, and the high organic matter levels in the water can lead the fish becoming stressed. This can cause bacterial proliferation and an increase in mortality. Most species of fish-causing bacteria are saprophytes. They are found naturally in the environment and are usually responsible for secondary or opportunistic infections. This study reports on an outbreak of Pacus (Piaractus mesopotamicus) mortality at an intensive fish farm, in the municipality of Campo Grande, MS, Brazil, that used excavated tanks. Cases: The outbreak occurred at a fish farm in the municipality of Campo Grande, MS, during August, 2015. A total of 200 pacus in two tanks died after they showed the following symptoms: lethargy, anorexia, increased mucus production, and disordered swimming and water surface searching. The temperature and dissolved oxygen were measured using a digital thermometer and an oximeter, respectively, and water transparency was measured with a Secchi disc. The pH was measured using a portable digital potentiometer. The values for the water quality parameters analyzed during the mortality period were temperature, 22.5 o C; transparency, 20 cm; oxygen dissolved in the early morning 3 mg/L and at the end of the afternoon, 4.5 mg/L; pH 8.3; and toxic ammonia, 0.002 ppm. Five fishes were collected from the tank, immediately cooled to 4°C, and sent to the Microbiology and Pathology Laboratories to perform the microbiological and pathological laboratory procedures. After the replication process, the slow glucose fermentation characteristics in MacConkey Agar and other biochemical tests showed that the lactose non-fermenter bacterium was Pseudomonas aeruginosa and the fermenting bacterium was Pantoea agglomerans. A necroscopic examination revealed congestion of viscera in general and thickening of the gills; the histopathological examination showed an intense inflammatory reaction in the gills; and the liver showed congestion and dilation of the central, hepatoportal, and sinusoidal veins, marked cytoplasmic vacuolization, the presence of hemosiderin and leukocytosis, and coagulation necrosis and cholestasis foci. Discussion: The water temperature in the tanks (22.5°C) was lower than what is considered ideal for tropical fish. It ranged from 25 to 32°C. Furthermore, the pH (8.3) was close to the limit of what is considered appropriate. The mean tank flow rate at the time of death was 15 L/min, corresponding to a daily renewal rate of 1.2%, which was lower than the ...

The processes of technological innovation influence the great advances in the world agribusiness sector. These progresses are the result of scientific and technological studies. In this context, fish farming appears as an alternative to diversify agricultural production, being the most responsible system in the world for food security. In addition, the practice of fish farming is a potential strategy for environmental conservation since it contributes to capture fisheries reduction. However, the traditional management commonly adopted in fish farming results in innumerable environmental consequences such as: pollution of water bodies and introduction of exotic species, generation of effluents, emergence of diseases in man and animals. Probiotics as a dietary supplement for captive-bred fish appear as an alternative resource, aiming to improve the zootenic and sanitary performance of fish, healthy conditions and increase production with efficiency. It should be noted that diets are related to ethological aspects, structural integrity, sanity, physiology, reproduction, growth, and sanitary or environmental conditions. The present study aimed to revise assessments on the use of functional food additives in captive-bred fish diet and the results obtained by their administration. A qualitative approach was used with a descriptive and documentary method. The data analysed here contribute to further studies and to glimpse the potentials of nutrition of captive fish, considerating that negative impacts to the environment, production and quality of fish can be mitigated.