PURPOSE: In the present study, phyllanthin isolated from Phyllanthus amarus was investigated for its immunosuppressive effects on various cellular and humoral immune responses in Balb/C mice.
METHODS: Male mice were treated daily at 20, 40 and 100mg/kg of phyllanthin for 14 days by oral gavage. The effects of phyllanthin on cellular immune responses in treated /non treated mice were determined by measuring CD 11b/CD 18 integrin expression, phagocytosis, nitric oxide (NO) production, myeloperoxidase activity (MPO), T and B cells proliferation, lymphocyte phenotyping, serum cytokines production by activated T-cells and delayed type hypersensitivity (DTH). Its effects on humoral immune responses were evaluated by determining the serum levels of lysozyme and ceruloplasmin, and immunoglobulins (IgG and IgM).
RESULTS: Phyllanthin dose-dependently inhibited CD11b/CD18 adhesion, the engulfment of E. coli by peritoneal macrophages molecules, NO and MPO release in treated mice. Phyllanthin caused significant and dose-dependent inhibition of T and B lymphocytes proliferation and down-regulation of the Th1 (IL-2 and IFN-γ) and Th2 (IL-4) cytokines. Phyllanthin at 100mg/kg caused a significant reduction in the percentage expression of CD4(+) and CD8(+) in splenocytes and the inhibition was comparable to that of cyclosporin A at 50mg/kg. At 100mg/kg, phyllanthin also dose-dependently exhibited strong inhibition on the sheep red blood cell (sRBC)-induced swelling rate of mice paw in DTH. Significant inhibition of serum levels of ceruloplasmin and lysozyme were observed in mice fed with higher doses (40 and 100mg/kg) of phyllanthin. Anti-sRBC immunoglobulins (IgM and IgG) antibody titer was down-regulated in immunized and phyllanthin-treated mice in a dose-dependent manner with maximum inhibition being observed at 100mg/kg.
CONCLUSION: The strong inhibitory effects of phyllanthin on the cellular and humoral immune responses suggest that phyllanthin may be a good candidate for development into an effective immunosuppressive agent.
METHODS: Twelve 3 to 4 months old male goats and sheep were randomly allocated into two dietary treatment groups in a 2 (species)×2 (oil levels) factorial experiment. The treatments were: i) goats fed basal diet, ii) goats fed oil-supplemented diet, iii) sheep fed basal diet, and iv) sheep fed oil-supplemented diet. Each treatment group consisted of six animals. Animals in the basal diet group were fed with 30% alfalfa hay and 70% concentrates at a rate equivalent to 4% of their body weight. For the oil treatment group, linseed oil was added at 4% level (w:w) to the concentrate portion of the basal diet. Growth performance of the animals was determined fortnightly. Digestibility study was conducted during the final week of the feeding trial before the animals were slaughtered to obtain rumen fluid for rumen fermentation characteristics study.
RESULTS: Sheep had higher (p<0.01) average daily weight gain (ADG) and better feed conversion ratio (FCR) than goats. Oil supplementation did not affect rumen fermentation in both species and improved ADG by about 29% and FCR by about 18% in both goats and sheep. The above enhancement is consistent with the higher dry matter and energy digestibility (p<0.05), as well as organic matter and neutral detergent fiber digestibility (p<0.01) in animals fed oil- supplemented diet. Sheep had higher total volatile fatty acid production and acetic acid proportion compared to goat.
CONCLUSION: The findings of this study suggested that sheep performed better than goats when fed a fattening diet and oil supplementation at the inclusion rate of 4% provides a viable option to significantly enhance growth performance and FCR in fattening sheep and goats.