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

The aim of this research was to evaluate the changes in intestinal tract microbiota, hematological parameters and zootechnical indexes of yellowtail lambaris (Astyanax bimaculatus) fed with different probiotic supply frequencies (Lactobacillus spp.). Lambaris (1,200) were distributed in twelve boxes, divided in three treatments, 100% supply; 25% and 0% (control) of feeds supplemented with probiotic. After 87 days, fish fed with supplemented diet, regardless of frequency (100% and 25%), showed an increase in the total lactic acid bacteria count of 7.99±0.15 log CFU mL-1 and 7.04±1, 29 log UFC mL-¹ respectively, in the intestinal tract and decrease of Pseudomonas spp. in both 100% and 25% (4.09±0.84log UFC mL-1 and 4.00±1.12log UFC mL-1, respectively) in relation to the control treatment (6.74±1.04log UFC mL-1). Fish fed with 100% of diets supplemented with probiotics had a higher leukocyte count (47.7±6.7x103μL-1), lymphocytes (36.0±2.6x103μL1), monocytes (12.0±4.2x103μl-1), as well as higher mean final weight (10.60±0.89g) and weekly growth rate (0.80±0.08g.week-1) than the other treatments (25% of probiotic offered and control). Probiotic (Lactobacillus spp.) offered in 25% of feeds (or more) alters the yellowtail lambari microbiota (A. bimaculatus); however, must be offer in 100% of feeds to improve the hematology profile and productive performance.

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.