The dietary supplementation of prebiotics, probiotics and symbiotic in hybrid surubins (a Pseudoplatystoma corruscans and P. fasciatum cross) was evaluated for the effects on their autochthonous intestinal microbiota and on haematological and immunological parameters. A total of 160 fish were divided into four treatment groups with four replicates each. The treatment groups were fed with the following diets for 15 days: control diet without supplementation; 0.5% inulin (prebiotic) supplementation; Weissella cibaria (CPQBA 001-10 DRM 02) (7.87 ± 0.2 log CFU g )1 ) supplementation; or 0.5% inulin and W. cibaria supplementation (symbiotic group). The midgut intestines of the fish with the symbiotic diet supplementation had higher concentrations of lactic acid bacteria (7.07 ± 1.11 log CFU g )1 ) and low levels of Vibrio spp (1.90 ± 0.60 log CFU g )1 ) and Pseudomonas spp (2.23 ± 1.48 log CFU g )1 ). In addition, increased erythrocytes and reduced circulating neutrophils were observed in this group. No differences in blood glucose, serum protein or lysozyme levels were detected between treatment groups. However, a higher concentration of total immunoglobulin was observed in fish fed with the probiotic and symbiotic diets. The addition of 0.5% inulin (prebiotic) thus W. cibaria (probiotic) to the diet of Pseudoplatystoma hybrid surubins reduce the number of pathogenic bacteria and stimulate the beneficial intestinal microbiota and may possibly alter their immune defence system.

Resumo -O objetivo deste trabalho foi isolar bactérias ácido-lácticas do intestino de tilápias-do-nilo, e avaliar seu potencial probiótico. Foram isoladas cepas de bactérias ácido-lácticas, e foi avaliada a inibição aos patógenos in vitro. As cepas com os melhores resultados foram identificadas e utilizadas no experimento de colonização do trato intestinal de tilápias-do-nilo, via suplementação na dieta, em delineamento inteiramente ao acaso, com três tratamentos e quatro repetições. Foram avaliados: o total de bactérias, as bactérias ácido-lácticas, Vibrio ssp. e Pseudomonas ssp. A cepa com melhor resultado foi utilizada na infecção experimental, em delineamento inteiramente ao acaso, em esquema fatorial 2x3: dieta suplementada com a cepa e dietacontrole; e os peixes não submetidos à injeção, peixes submetidos à injeção de solução salina e à injeção de Enterococcus durans, com três repetições. Foram avaliados os parâmetros hematológicos. As duas cepas identificadas foram: Lactobacillus plantarum e Lactobacillus brevis, que colonizaram o trato intestinal de tilápias, contudo L. plantarum teve menor número total de bactérias e de Pseudomonas ssp. Foi observado maior número total de eritrócitos, trombócitos, leucócitos, linfócitos, neutrófilos e monócitos, em peixes alimentados com L. plantarum e submetidos à injeção de E. durans. O L. plantarum tem efeito probiótico e melhora o sistema imune das tilápias.Termos para indexação: Enterococcus durans, Lactobacillus plantarum, Oreochromis niloticus, hematologia, infecção experimental. Lactic-acid bacteria isolated from the intestinal tract of Nile tilapia utilized as probioticAbstract -The objective of this work was to isolate lactic-acid bacteria from the intestines of Nile tilapia, and to assess their potential as probiotic. Strains of lactic-acid bacteria were isolated, and inhibition against pathogens was evaluated in vitro. Strains with best results were identified and used in tilapia intestinal tract colonization experiment through supplementation in the diet, in a completely randomized design, with three treatments and four replicates. Total number bacteria, lactic-acid bacteria, Vibrio ssp. and Pseudomonas ssp. were evaluated. The strain with best result was used for experimental infection, in a completely randomized design, in factorial arrangement 2x3: diet supplemented with strain and control diet; and fish not submitted to injection, fish submitted to injection of saline solution, and fish submitted to injection of Enterococcus durans, with three replicates. Hematological parameters were evaluated. Two strains were identified as Lactobacillus plantarum and Lactobacillus brevis, which colonized fishes' intestinal tract. However, L. plantarum had the lowest number of total bacteria and of Pseudomonas ssp. Greater number of red blood cells, thrombocytes, leukocytes, lymphocytes, neutrophils and monocytes were observed in fish fed with L. plantarum and submitted to injection of E. durans. L. plantarum has probiotic effect on Nile tilapias and improve their imm...

The aim of this work was to evaluate the effects of Haematococcus pluvialis (H. pluvialis) (carotenoid source) and H. pluvialis plus soy lecithin on development, carotenoid content, and pigmentation of shrimp (Litopenaeus vannamei). One hundred and eighty shrimps (7.8 g) were divided in six tanks (n = 30) and fed with control food, H. pluvialis, and H. pluvialis plus soy lecithin for 2 weeks. Carotenoids were extracted with acetone and quantified by UV–vis spectrophotometry, and astaxanthin was determined by high‐performance liquid chromatography. Colour was analysed by colorimetry. Lecithin/H. pluvialis group presented higher survival rate (100%) when compared to control group (93.3%). Haematococcus pluvialis and lecithin/H. pluvialis groups presented higher red‐like colour (a* 16.4 and 19.9) than control (a* 20.6). Lecithin/H. pluvialis group presented higher carotenoids content (8.2 mg kg−1 muscle, 26.8 mg kg−1 exoskeleton) and astaxanthin (8.5 mg kg−1 muscle, 23.3 mg kg−1 exoskeleton) than control (carotenoids: 4.2 mg kg−1 muscle, 12.3 mg kg−1 exoskeleton; astaxanthin: 3.2 mg kg−1 muscle, 8.1 mg kg−1 exoskeleton). Feeding with 60 ppm carotenoids (from H. pluvialis) during 2 weeks was sufficient for favouring red‐like pigmentation in shrimp, and lecithin increased astaxanthin content only in exoskeleton.

Previous studies have shown that the gut microbiota of fish differs depending on host feeding habits and these populations may also be influenced by dietary ingredients. In this study, the bacterial populations of the intestinal tract of the opportunistic omnivore jundiá Rhamdia quelen and the typical omnivore tilapia Oreochromis niloticus were investigated in two experiments. In experiment I, the levels of amylolytic, cellulolytic, lipolytic, proteolytic and total culturable bacteria were compared in the proximal, mid and distal intestine using selective agar. Higher levels of amylolytic, cellulolytic, lipolytic, proteolytic and total culturable bacteria were observed in the tilapia than jundiá, in all intestinal regions. Jundiá contained higher levels of proteolytic bacteria and lipid digesting bacteria in the distal intestinal portion as compared with the mid intestine; both fish species also presented more amylolytic bacteria in the distal intestine. In experiment II, the amylolytic intestinal microbiota between the two species was compared after administration of diets containing different carbohydrate sources. Jundiá fed broken rice presented higher total culturable bacterial levels; however, dietary cassava bagasse and ground corn significantly elevated the population of amylolytic bacteria in tilapia (P > 0.05). PCR‐DGGE was also used to assess the bacterial communities in experiment II. A Cetobacterium spp. was detected in jundiá fed diets containing broken rice, and tilapia fed cassava bagasse, dextrin, broken rice and ground corn. Microbial differentiation was further demonstrated between jundiá and tilapia, because an uncultured bacterium was unique in tilapia and an uncultured spirochete was observed only in jundiá; the presence of these bacterial species was also influenced by dietary carbohydrate sources.

Resumo:O objetivo deste trabalho foi avaliar as alterações na microbiota do trato intestinal e desempenho zootécnico de alevinos de tilápia do Nilo (Oreochromis niloticus) alimentados com dietas suplementadas com Lactobacillus plantarum. Cento e vinte alevinos revertidos sexualmente foram distribuídos em seis caixas, divididos em dois tratamentos, em triplicata: alevinos alimentados com dieta suplementa com L. plantarum e alevinos alimentados com dieta controle. Após 42 dias, as tilápias alimentadas com a dieta suplementada com L. plantarum apresentaram maior número de bactérias ácido-lácticas, 3,5x104 UFC e 1,1x10 2 UFC por g de trato, e menor de bactérias totais, 5,8x106 UFC e 5,2x10 7 UFC por g de trato intestinal, em relação aos alimentados com dieta controle, além de incrementar em 3,9% o ganho em peso semanal, 15,6% a biomassa final e 15,5% eficiência alimentar. O uso de probiótico na alevinagem de tilápia eleva a produtividade. Palavras-chave: cultivo de peixes; probióticos; tilápia. Abstract:The objective of this study was to evaluate alterations in the intestinal tract microbiota and growth performance of Nile tilapia (Orechromis niloticus) fed diets supplemented with Lactobacillus plantarum. One hundred and twenty sexually reversed fingerlings were stocked in six aquaria and divided into two treatments, in triplicate: fingerlings fed diet supplement with L. plantarum and fingerlings fed control diet. After 42 days, tilapia fed the diet supplemented with L. plantarum had higher amount of lactic acid bacteria, 3,5x10 4 CFU and 1,1x10 2 CFU per g tract, and lower total bacteria, 5,8x10 6 CFU and 5,2x10 7 CFU per g tract, than the fish fed the control diet. Furthermore, probiotics increased 3,9% the weekly weight gain, 15,6% final biomass and 15,5% feed efficiency. The use of probiotics in tilapia hatcheries boosts productivity.