This work aimed to evaluate the probiotic Lactobacillus spp. in the microbiota of Astyanax bimaculatus reared in a water recirculation system. The experiment was randomized, using 800 postlarvae distributed into eight polyethylene containers, separated into two treatments, in quadruplicate: supplementation with Lactobacillus spp. (Probiotic) and no supplementation (Control). After 90 days of culture, 13 fish per container were anaesthetized. Three of these underwent microbiological evaluation, and haematological analyses were carried out on five. Immunological assessment was performed on another five fish. Zootechnical parameters were evaluated for all animals. In the microbiological evaluation, the probiotic group presented higher counts of lactic acid bacteria, but lower counts of Vibrio spp., Pseudomonas spp., and Staphylococcus spp., when compared with control. After haematological analysis, the supplemented group presented low haematimetric indices of Mean Corpuscular Haemoglobin Concentration and Mean Corpuscular Haemoglobin (MCHC and MCH, respectively) and higher amounts of total leucocytes, thrombocytes and circulating monocytes when compared with control. The immunological profile did not differ between treatments. In the zootechnical performance, probiotic group presented higher productivity, survival and apparent food efficiency when compared with control. Therefore, when Lactobacillus spp. was supplemented in the diet of A. bimaculatus, immunocompetence and the zootechnical performance of animals increased. K E Y W O R D Shaematology, immunology, Lactobacillus spp., microbiology, yellow tail lambari

Pseudocapillaria tomentosa is a common pathogen of zebrafish (Danio rerio) in research facilities. We developed a method to collect and concentrate the nematode eggs using a modified sugar centrifugation method, and documented their normal development. Embryonating stages with blastomere formation followed by elongation of the embryo prior to larva formation cumulated in developed larvae inside the eggs and hatching after 5–10 d. We then evaluated the efficacy of heat and chlorine to kill them based on a larva development assay. Eggs were exposed to 40, 50, 60°C for 30 min and 1 h. Chlorine treatment was performed at 100, 250, 500, 1000, 3000 and 6000 ppm for 10 min. Samples exposed to 40°C for 30 min or 1 h showed incidences of larvated eggs similar to controls. In contrast, no larvation occurred with eggs exposed to either 50 or 60°C for 30 min or 1 h. Remarkably, in repeated assays, samples exposed to low doses of chlorine (100, 250, 500 and 1000 ppm for 10 min) showed significantly higher incidence of larvation than controls. Eggs treated with 3,000 ppm for 10 min did not develop larvae and no eggs were found after 6,000 ppm treatment.

This study evaluated the dietary supplementation with essential oil of Lippia alba on the hemato-immunological parameters of Nile tilapia (Oreochromis niloticus) submitted to acute inflammation induced by carrageenin injection in the swim bladder. For a period of 45 days, 96 fish were divided into four treatments in triplicate, as follows: (a) fish fed supplemented diet with essential oil of L. alba (4 mL kg -1 dry ration) injected with carrageenin; (b) fish fed supplemented diet with cereal alcohol injected with carrageenin; (c) fish fed unsupplemented diet with essential oil injected with carrageenin; (d) fish fed unsupplemented diet and noninjected. Cortisol levels, erythrogram, leukogram and the inflammatory infiltrate were analyzed 6 hours after an inflammatory stimulus. Carrageenin-injected fish showed an acute inflammatory reaction in the swim bladder characterized by higher infiltrate of neutrophils and monocytes. The circulating neutrophils number was significantly higher in fish fed L. alba when compared to other treatments. No difference in cortisol levels was found. For the dose, time and administration form tested, supplementation with essential oil of L. alba did not present anti-inflammatory activity. On the other hand, an influence of dietary supplementation was observed on the neutrophils number after induced aerocystitis highlighting its immunomodulatory characteristic. Keywords: Oreochromis niloticus. Stress. Phytotherapics. Hematology. Acute inflammation. ResumoEste estudo avaliou a suplementação dietária com óleo essencial de Lippia alba sobre os parâmetros hematoimunológicos em tilápias do Nilo (Oreochromis niloticus) submetidas à inflamação aguda induzida por carragenina na bexiga natatória. Pelo período de 45 dias, 96 peixes foram divididos em quatro tratamentos em triplicata: (a) peixes suplementados com óleo essencial de L. alba (4 mL kg -1 de ração seca) injetados com carragenina; (b) peixes suplementados com álcool de cereais injetados com carragenina; (c) peixes não suplementados com óleo essencial injetados com carragenina; (d) peixes não suplementados e não injetados. Os níveis de cortisol, o eritrograma, o leucograma e o infiltrado inflamatório foram analisados seis horas após o estímulo inflamatório. Peixes injetados com carragenina apresentaram reação inflamatória aguda na bexiga natatória caracterizada pela maior concentração de infiltrado de neutrófilos e monócitos. O número de neutrófilos circulantes foi significativamente maior nos peixes suplementados com L. alba, numa comparação com os outros tratamentos. Não houve diferença nos níveis de cortisol. Para a dose, o tempo e a forma de administração testada, a suplementação com óleo essencial de L. alba não apresentou atividade anti-inflamatória. Por outro lado, foi constatada influência da suplementação dietária no número de neutrófilos após a aerocistite, enfatizando a sua característica imunomoduladora. Palavras-chave: Oreochromis niloticus. Estresse. Fitoterápicos. Hematologia. Inflamação aguda.

This study aimed to evaluate the viability of supplementing two diets for the shrimp Litopenaeus vannamei with Lactobacillus plantarum. One using fish meal as a protein source and another using soy protein concentrate, as well as the effect of these formulations on shrimp intestinal microbiota. To assay probiotic viability in the formulated diets, the number of CFU g-1 was observed weekly over the course of four weeks. The viability of Lactobacillus plantarum in relation to the physical parameters of the diets, including stability, buoyancy, and expansion, was quantified. The effect of the diets on microbiota and intestinal tract morphology was determined by performing a 2x2 factorial experiment (two diets, with or without supplementation) in triplicate, totaling 12 experimental units, with five animals per unit, fed with 3.5% of biomass for 17 days. The concentration of lactic acid bacteria decreased over time, irrespective of protein source. The diet with fishmeal as a protein source, independent of probiotic supplementation, presented good stability and did not disintegrate after four hours. In contrast, the diet with soy protein concentrate, supplemented or not, disintegrated between 2.5 and 3 hours, presenting low stability. All diets presented 0% buoyancy. The expansion rate was higher in diets with soy protein concentrate, but without the influence probiotic supplementation or interaction between the factors. In the in vivo assay, both supplemented diets showed greater total heterotrophic bacteria count than without probiotic; however, no difference in count was noted in diets with different protein source. Lactic acid bacteria were only observed in the shrimp fed diets supplemented with probiotic. Histology of the intestinal tract showed that all intestines had intact, well-developed and well-organized cells, irrespective of diet. Thus, L. plantarum, when combined with different protein sources, produced similar effects on the structure and microbiota of the marine shrimp Litopenaeus vannamei.