Curcumin addition in diet of laying hens under cold stress has antioxidant and antimicrobial effects and improves bird health and egg quality.

Curcumin is an herbal component with several biological properties, and we highlight here the thermal stability, antioxidant and anti-inflammatory activity. We determined whether curcumin supplementation in the diets of laying hens under cold stress and naturally infected with Escherichia coli would control infection, and would have positive effects on overall health, as well as egg production and quality. We allocated 36 chickens that had been naturally infected with E. coli into two groups, with six replicates and three chickens per repetition: control group and curcumin group (200 mg curcumin/kg). The experimental period lasted 42 days, and fecal, blood and egg samples were collected at 1, 21 and 42 days We found that feces and eggs had lower total bacterial counts, E. coli counts and total coliform counts in the curcumin group at 21 and 42 days. In fresh eggs, the brightness and yellow intensity (b+) were significantly higher in the curcumin group. In stored eggs, higher specific gravity, albumen height and lower yolk pH were observed in the curcumin group. Fresh eggs collected and stored on day 42 showed lower levels of lipid peroxidation in the curcumin group, while the total antioxidant capacity in the stored eggs was significantly higher in the curcumin group. The curcumin group showed lower total leukocyte counts as a result of lower numbers of neutrophils and lymphocytes, as well as lower levels of total protein, alkaline phosphatase and alanine aminotransferase. Lower serum lipoperoxidation at 42 days was observed in the curcumin group, probably because of the higher activity of glutathione peroxidase and glutathione transferase in other words, because of antioxidant stimulation. Taken together, our findings suggest that curcumin supplementation in laying hens under cold stress and with colibacillosis has positive effects on infection control because of antioxidant stimulation.

Purinergic signaling creates an anti-inflammatory profile in spleens of grass carp Ctenopharyngodon idella naturally infected by Saprolegnia parasitica: An attempt to prevent ATP pro-inflammatory effects.

Extracellular adenosine triphosphate (ATP) is as key mediator of immune and inflammatory responses. ATP is normally sequestered in the intracellular milieu and released by apoptotic and necrotic cells, where it acts as a pro-inflammatory mediator in the extracellular milieu. A limited number of studies have explored the involvement of purinergic signaling in oomycete infections, including Saprolegnia parasitica; this is a most destructive oomycete pathogen, associated with high mortality and severe economic losses for fish producers. The aim of this study was to determine whether purinergic signaling exerts anti- or pro-inflammatory effects in spleens of grass carp (Ctenopharyngodon idella) naturally infected by S. parasitica. Animals naturally infected with S. parasitica showed typical gross lesions characterized by cotton-wool tufts on the tail and fins, as well as severe histopathological lesions such as necrosis. Spleen ATP and metabolites of nitric oxide (NOx) levels were higher in fish naturally infected by S. parasitica compared to control on day 7 post-infection (PI). Spleen nucleoside triphosphate diphosphohydrolase (NTPDase) activity (ATP as substrate) was greater in fish naturally infected by S. parasitica than in uninfected on day 7 PI, while no significant differences were observed between groups with respect to NTPDase (adenosine diphosphate as substrate) and 5'-nucleotidase activities. Finally, adenosine deaminase (ADA) activity was lower in fish naturally infected by S. parasitica than in uninfected fish on day 7 PI. In summary, spleen tissue necrosis in the context of saprolegniosis provokes an intense release of ATP into the extracellular milieu, where it interacts with the P2X7 purine receptor and leads to a self-sustained pro-inflammatory deleterious cycle, contributing to an intense inflammatory process. In response to excessive ATP levels in the extracellular milieu, ATP and adenosine hydrolysis were modulated in an attempt to restrict the inflammatory process via upregulation of NTPDase and downregulation of ADA activities. We conclude that the purinergic signaling pathway modulates immune and inflammatory responses during natural infection with S. parasitica.

Dietary supplementation with caffeine increases survival rate, reduces microbial load and protects the liver against Aeromonas hydrophila-induced hepatic damage in the grass carp Ctenopharyngodon idella.

The indiscriminate use of antibiotics is a major concern for the aquaculture industry because of the increasing prevalence of bacterial resistance, including the emergence of multi-resistant strains of Aeromonas hydrophila. Therefore, alternative ecofriendly therapeutic or prophylactic approaches such as natural products have been suggested, including caffeine, a methylxanthine with potent bactericidal and antioxidant properties. The aims of this study were to evaluate whether dietary supplementation with caffeine exerted bactericidal effects against A. hydrophila, and to determine whether caffeine protected the liver of grass carp (Ctenopharyngodon idella) against A. hydrophila-induced oxidative damage. Experiment I evaluated the antimicrobial properties of caffeine dietary supplementation linked to longevity and mortality rates during aeromonosis. Fish infected with A. hydrophila that were fed diets containing 5% and 8% caffeine lived significantly longer than those fed with control diets. Experiment II evaluated hepatic oxidative stress-related parameters and microbial loads on day 7 post-infection. Levels of hepatic reactive oxygen species (ROS), lipid peroxidation (LOOH) and protein carbonylation (PC) levels were significantly higher in infected fish fed with control diet than in uninfected fish, and hepatic antioxidant capacity against peroxyl radicals (ACAP) levels, and superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) activities were significantly inhibited. Dietary supplementation with 5% and 8% caffeine prevented the increase on hepatic ROS, LOOH and PC levels (except 5% caffeine) elicited by infection. Caffeine supplementation reduced or prevented the inhibition of hepatic SOD, GPx and GST activities. Finally, both caffeine concentrations reduced the hepatic microbial load compared to fish fed with control diets that were infected with A. hydrophila. Taken together, the data suggest that dietary supplementation with 8% caffeine may be considered a compelling prophylactic approach to aeromonosis caused by A. hydrophila.