Sylimarin as hepatic protector and immunomodulator in Nile tilapia during Streptococcus agalactiae infection.

This study investigated the use of silymarin, an extract obtained from the milk thistle (Silybum marianum) and its effects as a possible hepatoprotector in Nile tilapia (Oreochromis niloticus). Silymarin was used as feed additive to the diet at a concentration of 0.1% (1 kg per ton of dry ration) with the commercial product named Di-Heptarine S® (16% silymarin phosphatide). A total of 90 juvenile tilapia with approximately 45 days old and mean weight of 0.72 ±â€¯0.04 g were distributed in two groups, one fed with a diet with the hepatoprotector and the other without the additive. At the end of the assay (55 days after feeding), samples of blood were collected for hematological, immunological, histological (liver, spleen and intestine) and enzymatic analysis such as superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST). After 55 days all fish were challenged with Streptococcus agalactiae serotype Ib to verify the sylimarin effects on the immunological parameters and its protection effect while challenged. During the challenge period another biological material sample was collected for hematological, immunological and histopathological analysis (liver, spleen and intestine). Before the challenge, an increase on the count of thrombocyte was found in the supplemented fish. In the liver, dilation of the sinusoids was observed in unsupplemented fish while supplemented fish the alteration was less severe. No significant alteration was found in SOD, CAT and GST between the groups. Histological changes after the challenge were provoked by bacterial toxins as a result of inflammatory processes. Periacinar degeneration was less intense in unsupplemented fish when compared to supplemented fish. On the other hand, eosinophilic and lymphocytic infiltrate did occur in unsupplemented fish differently from supplemented fish which did not show the alteration. The survival was 28% higher in silymarin supplemented fish when compared to unsupplemented fish that presented no survival. Silymarin supplementation in the diet provided a hepatoprotective and immunomodulatory effect on Nile tilapia.

Blood biochemical parameters and melanomacrophage centers in Nile tilapia fed essential oils of clove basil and ginger.

Nile tilapia (Oreochromis niloticus) is the most farmed freshwater fish in the world, however, disease outbreaks are the main cause of losses in production. Due to this, there is an increasing interest in natural products for enhancing disease resistance, without causing physiological impairment. The aim of this study was to verify the effect of the essential oils of clove basil (Ocimum gratissimum) and ginger (Zingiber officinale) on physiological and immunological parameters of nile tilapia. After 35 and 55 days of supplementation (0.5%, 1.0% and 1.5%), blood collection was performed for determination of metabolites (glucose, cholesterol, triglycerides, serum total protein and immunoglobulins) and lysozyme activity. Spleen tissue was also collected at 55 days for analyzing melanomacrophages centers. At 35 days, cholesterol showed significant reduction in the treatments 0.5% and 1.5 ginger and 1.5% clove basil. The serum triglycerides showed significant reduction in these same treatments, in addition to 1.0% clove basil. At 55 days all the supplemented groups showed significant reduction for both parameters. The lysozyme activity at 35 days was significantly higher in fish supplemented with 1.0% ginger and showed no difference among the treatments at 55 days. Regarding the melanomacrophage centers, at 35 days increased number in fish supplemented with 0.5% clove basil was observed but with no significant difference in the total percent area of spleen occupied by centers. The levels of glucose, total serum protein and immunoglobulins did not show significant differences in both sampling times. The addition of essential oils showed to be useful for improving physiological status of the fish, without excessive activation of defense mechanisms.

Effect of dietary supplementation with propolis and Aloe barbadensis extracts on hematological parameters and parasitism in Nile tilapia.

This study evaluated the influence of diet supplementation with propolis and Aloe barbadensis on hematological parameters and parasitism in tilapia. One hundred and eighty fish were distributed among 12 water tanks forming four treatments: fish supplemented with a 1:1 mixture of 0%, 0.5%, 1% and 2% propolis and aloe extracts. After the fish had been fed on the experimental diets for 15 and 21 days, blood samples were taken and parasites collected. The monogeneans Cichlidogyrus sclerosus, C. halli, C. thurstonae and Scutogyrus longicornis were identified in the gills. Between the sampling times, there were increases in the numbers of erythrocytes, leukocytes, thrombocytes and lymphocytes, as observed after 21 days, possibly due to the stress level over the course of the assay and/or accumulation of substances in the organism. Supplementation with the mixture of propolis and aloe for 15 days showed the highest efficacy against the parasites. This was possibly due to the association between the two compounds. The results demonstrated that supplementation with mixtures of extracts did not produce hematological alterations and also favored a significant reduction in the number of gill parasites. The best results were achieved after 15 days of feeding with a diet with 0.5% and 1% supplementation with the extract mixture, which increased efficiency by 83 and 85% respectively.

Effect of dietary supplementation with propolis and Aloe barbadensis extracts on hematological parameters and parasitism in Nile tilapia / Efeito da suplementação dietária com extratos de própolis e Aloe barbadensis sobre parâmetros hematológicos e parasitismo em tilápia do Nilo

This study evaluated the influence of diet supplementation with propolis and Aloe barbadensis on hematological parameters and parasitism in tilapia. One hundred and eighty fish were distributed among 12 water tanks forming four treatments: fish supplemented with a 1:1 mixture of 0%, 0.5%, 1% and 2% propolis and aloe extracts. After the fish had been fed on the experimental diets for 15 and 21 days, blood samples were taken and parasites collected. The monogeneans Cichlidogyrus sclerosus, C. halli, C. thurstonae and Scutogyrus longicornis were identified in the gills. Between the sampling times, there were increases in the numbers of erythrocytes, leukocytes, thrombocytes and lymphocytes, as observed after 21 days, possibly due to the stress level over the course of the assay and/or accumulation of substances in the organism. Supplementation with the mixture of propolis and aloe for 15 days showed the highest efficacy against the parasites. This was possibly due to the association between the two compounds. The results demonstrated that supplementation with mixtures of extracts did not produce hematological alterations and also favored a significant reduction in the number of gill parasites. The best results were achieved after 15 days of feeding with a diet with 0.5% and 1% supplementation with the extract mixture, which increased efficiency by 83 and 85% respectively.

Este estudo avaliou a influência da alimentação de tilápias com dieta suplementada com extratos de própolis e Aloe barbadensis sobre os parâmetros hematológicos e parasitismo. Setenta e dois peixes foram distribuídos em 12 tanques, formando 4 tratamentos: peixes suplementados na dieta com extrato de própolis e aloe (0%, 0,5%, 1% e 2%). Após 15 e 21 dias de alimentação com dietas experimentais foram realizadas coletas de sangue e parasitos. Os monogeneas Cichlidogyrus sclerosus, C. halli, C. thurstonae e Scutogyrus longicornis foram identificados nas brânquias. Entre os períodos de coleta, observou-se aumento nos valores de eritrócitos, leucócitos, trombócitos e linfócitos, após 21 dias de alimentação, o que pode significar estresse ao longo do período experimental e/ou acúmulo dos produtos no organismo.A suplementação com a mistura de própolis e aloe, por 15 dias, apresentou melhor eficácia frente parasitos, possivelmente, devido à associação dos compostos. Os resultados demonstram que a suplementação com a mistura dos extratos não alterou os parâmetros hematológicos, além de favorecer redução significativa no número de parasitos branquiais. Os melhores resultados foram obtidos em 15 dias de alimentação com a dieta suplementada com 0,5% e 1% da mistura dos extratos, respectivamente por 83% e 85% de eficiência.

Leukocyte phagocytosis and lysozyme activity in Nile tilapia fed supplemented diet with natural extracts of propolis and Aloe barbadensis.

Although there is evidence on the benefits in the use of immunostimulants in aquaculture, there are few commercial products being used. This study evaluated the use of natural substances as potential sources for the production of immunostimulants. Propolis and Aloe barbadensis have been widely studied and its extracts have different chemical constituents responsible for antimicrobial, anti-inflammatory and immunostimulant. Tilapia juveniles were fed for two weeks with diets supplemented mix of propolis extracts and aloe (1:1) in different concentrations: 0.5, 1 e 2%. After the experimental period, fish blood was collected for hematoimmunological as follows : hematocrit, total plasma protein, erythrocytes (RBC), leukocytes (WBC), differential leukocyte count, phagocytic activity, serum lysozyme activity, and serum antimicrobial activity, serum antimicrobial activity (evaluated against Aeromonas hydrophila, Enterococcus durans and Escherichia coli). Except for higher number of thrombocytes in 1%-supplemented fish, the rest did not show significant difference.