No abstract

The objective of this study was to evaluate menthol and eugenol as anesthetics for early juveniles of curimba, Prochilodus lineatus. Juveniles of 4.0±0.5 g and a total length of 8.8±0.1 cm were exposed to the anesthetics menthol (20, 30, 40, 50, 60, 70, and 80 mg L −1 ) and eugenol (20, 30, 40, 50, 60, and 70 mg L −1 ) up to deep anesthesia. The anesthetic effects were evaluated measuring the induction time to deep anesthesia (characterized by loss of equilibrium, absence of swimming, reduction of opercular movements, and responses only to intense tactile stimuli), recovery time, time to appetite return, and mortality rate after 96 h of procedure. The concentrations between 60 to 80 mg of menthol L −1 provided the lowest time of induction. Increased concentrations led to a decrease in recuperation time. The concentrations between 50 to 70 mg of eugenol L −1 provided the lowest induction times; however, recovery time was not affected by eugenol concentrations. The return to appetite was observed 24 h after anesthesia, while the survival after 96 h was >90%. Concentrations of 60 and 50 mg L −1 of menthol and eugenol, respectively, are recommended for effective anesthesia with limited side effects.

Morphological and cytochemical studies of peripheral blood cells of fish have improved the understanding of their functions and cell types. The present study performed the Morphological and cytochemical analysis of the peripheral blood of Prochilodus lineatus, Characiform native to South America, which has been gaining space in local aquaculture and as a species introduced in Asia. Our analysis provided information on the morphological and cytochemical characteristics of the leukocytes, for the formulation of hypothesis about their role in the immune system of the species. It was found that Prochilodus lineatus has morphological and cytochemical features in common with other fish species, mainly of the Characiformes order. However, we detected the presence of heterophils and PAS positive granulocytes simultaneously with neutrophils. We also found that heterophils and PAS positive granulocytes are very similar, both morphologically and cytochemically.

A tilápia é considerada um dos peixes mais difundidos e cultivados no mundo, principalmente pelo seu rápido crescimento, alta prolificidade, rusticidade e excelente aceitação de mercado. Na piscicultura, os animais cultivados de forma intensiva não consomem prontamente toda ração disponível nos tanques de cultivo. Como consequência, a lixiviação dos nutrientes e excretas dos animais vão para o sistema aquático gerando excesso de formas de estruturas químicas, principalmente relacionadas aos elementos N e P, que são prejudiciais ao sistema de cultivo de peixes. Entretanto, tais efluentes gerados representam um aporte rico em nutrientes essências para o crescimento vegetal, e, portanto, ações voltadas para melhorar a produção agrícola podem ser implementadas para produção de alimentos de modo sustentável, como exemplo, a fertirrigação. Nesse sentido, o presente projeto visa avaliar o desempenho da fertirrigação na produção de cenouras irrigada com efluentes da criação de tilápia como integração de práticas e modelos produtivos que possibilitem a diversificação de atividades no meio rural e aprimoramento dos sistemas de produção. Os ensaios experimentais estão em andamento, com 30 dias após semeadura, na Unidade Didática de Piscicultura, Pesquisa e Produção de Peixes de Cordeiro (UDPPPC) da FIPERJ. Os canteiros de cenouras estão sendo irrigados com água da criação de tilápia em sistema de recirculação e água de poço tubular semi-artesiano. Semanalmente, os parâmetros físico-químicos da água são coletados e registrados para análises posteriores. Ao término do ciclo de produção da cenoura, serão avaliadas a biomassa total dos canteiros, o peso, diâmetro e comprimento unitário, e realização da análise bromatológica e de betacaroteno da cenoura dos diferentes grupos experimentais.

This study investigated the depuration time of tilapia in saline and freshwater environments and its influence on animal performance and meat quality. Depuration until the seventh day resulted in significant reductions in average weight, condition factor, viscerosomatic index, hepatosomatic index and fillet yield in both environments. Regarding proximate composition, the saline environment promoted the maintenance of crude protein, moisture and ash percentages. Depuration in the freshwater environment resulted in reduced percentages of crude protein, ash and energy and increased humidity. Total lipids were reduced in both environments, but with a significantly lower in saline. Maximum rigor index occurred in up to three and nine hours for fish depurated in freshwater and saline environments, respectively. During the post-rigor period, the rigor index experienced a sharp drop in the freshwater environment, while in the saline environment it remained similar to that of the pre-depuration group. Depuration in a saline environment for up to seven days was efficient at maintaining of proximate composition and rigor mortis, however, depuration until the fifth day is indicated to maintain performance indices.

Anesthetics have been used frequently in aquaculture to minimize stress during handling. However, several factors can affect the efficiency of anesthetics. For example, temperature is one of the abiotic factors that control animal metabolism and consequently, the effect of anesthetics. This study aimed to evaluate the effectiveness of benzocaine as an anesthetic for early juveniles of curimba Prochilodus lineatus at different water temperatures. Juveniles (4.7 ± 1.6 g and total length of 7.4 ± 0.7 cm) were submitted to anesthesia at concentrations of 30, 40, 50, 60, 70, and 80 mg L-1 of benzocaine and temperatures of 22, 25, 28, and 31 °C. The effects were evaluated by measuring the induction time to deep and surgical anesthesia, recovery time, time to appetite return, and 96-h mortality rate. The higher temperatures (25, 28 and 31°C) provided shorter induction times to reach deep anesthesia and at 50 mg L-1 of benzocaine, the induction time was between 2 and 3 min. Juveniles at temperatures of 28 and 31 °C showed lower surgical anesthesia induction time at concentrations ranging from 60 to 80 mg L-1. Recovery time was longer at 22 °C at all concentrations. The time to appetite return occurred in the first 24 h after anesthesia and the 96-h mortality rate was lower than 10%. Under these conditions, for deep anesthesia, benzocaine concentration of 50 mg L-1 for water temperatures of 25, 28, and 31 °C and 60 mg L-1 for 22 °C are recommended. Surgical anesthesia can be performed with 50 mg L-1 of benzocaine at all four water temperatures. The differences documented in the present study underline the need for adequate concentrations of anesthetics depending on the prevalent water temperature for Neotropical fish species. This should be considered in recommendations for large-scale use.

The objective of the present study was to evaluate the influence of seasonality on the hematological aspects of juvenile farmed Prochilodus lineatus, to highlight the changes caused by seasonal variations and to develop reference intervals appropriate for each season. The study of the hematological parameters of farmed species has showed the mechanisms of adaptation to environmental variations, both in the natural environment and in production systems, allowing discernment of the differences between physiological and pathological reactions. Among the environmental factors, temperature and day length are recognized as a key factor in promoting changes in fish physiology, which can be reflected in hematological parameters. The present study analyzed the hematological parameters of juveniles of farmed streaked prochilod (Prochilodus lineatus) considering seasonal features such as temperature and day length, to highlight the changes caused by seasonality and the mechanisms involved in adaptation, and thus, elaborate reference intervals for each season. We found that seasonality has a significant impact on the hematological parameters of juvenile specimens of farmed streaked prochilod (Prochilodus lineatus), as it promotes changes in hematimetry, hemoglobinometry, white blood cells count and in the prevalence of leukocyte types. These findings demonstrate the importance of establishing reference intervals for farmed species, considering the factors responsible for physiological modifications, especially seasonal features.

The integration of care with food safety and animal welfare is a technological challenge guided by legal demands and the consumer market (Brazil, 2017). The transport of live fish is a common practice in aquaculture (Harmon, 2009;Vanderzwalmen et al., 2019). In addition to ensuring the survival and well-being of animals, transport must be carried out under conditions that minimize contamination by pathogens.Pathogens were found in the Nile tilapia (Oreochromis niloticus) intestine, such as enteropathogenic Escherichia coli, Salmonella spp., Proteus spp., Micrococcus spp. and Providencia sp., the authors recommended care with water containing excreta (Youssef et al., 1992).Although proper cooking deactivates Aeromonas spp., high incidences were found in the intestines of fish with the possibility of cross contamination (González et al., 2001). Olsen et al. (2002) found that acute stress influenced the microbiota and the adhesion of bacteria in the intestine of salmon (Salmo salar). Stress reduced