Twenty male Saanen goats were randomly assigned to four levels of lovastatin supplementation and used to determine the optimal dosage and sustainability of naturally produced lovastatin from fermentation of palm kernel cake (PKC) with Aspergillus terreus on enteric methane (CH4) mitigation. The effects on ruminal microbiota, rumen fermentation, feed digestibility and health of animal were determined over three measuring periods (4-, 8- and 12-weeks) and the accumulation of lovastatin in tissues was determined at the end of the experiment. The diets contained 50% rice straw, 22.8% concentrates and 27.2% of various proportions of untreated or treated PKC to achieve the target daily intake level of 0 (Control), 2, 4 or 6 mg lovastatin/kg body weight (BW). Enteric CH4 emissions per dry matter intake (DMI), decreased significantly (P<0.05) and equivalent to 11% and 20.4%, respectively, for the 2 and 4 mg/kg BW groups as compared to the Control. No further decrease in CH4 emission thereafter with higher lovastatin supplementation. Lovastatin had no effect on feed digestibility and minor effect on rumen microbiota, and specifically did not reduce the populations of total methanogens and Methanobacteriales (responsible for CH4 production). Similarly, lovastatin had little effect on rumen fermentation characteristics except that the proportion of propionate increased, which led to a decreasing trend (P<0.08) in acetic: propionate ratio with increasing dosage of lovastatin. This suggests a shift in rumen fermentation pathway to favor propionate production which serves as H+ sink, partly explaining the observed CH4 reduction. No adverse physiological effects were noted in the animals except that treated PKC (containing lovastatin) was less palatable at the highest inclusion level. Lovastatin residues were detected in tissues of goats fed 6 mg lovastatin/kg BW at between 0.01 to 0.03 μg/g, which are very low.
We investigate the effects of postbiotic Lactobacillus plantarum RG14 on gastrointestinal histology, haematology, mucosal IgA concentration, microbial population and mRNA expression related to intestinal mucosal immunity and barrier function. Twelve newly weaned lambs were randomly allocated to two treatment groups; the control group without postbiotic supplementation and postbiotic group with supplementation of 0.9% postbiotic in the diet over a 60-day trial. The improvement of rumen papillae height and width were observed in lambs fed with postbiotics. In contrast, no difference was shown in villi height of duodenum, jejunum and ileum between the two groups. Lambs received postbiotics had a lower concentration of IgA in jejunum but no difference in IgA concentration in serum and mucosal of the rumen, duodenum and ileum. In respect of haematology, postbiotics lowered leukocyte, lymphocyte, basophil, neutrophil and platelets, no significant differences in eosinophil. The increase in of IL-6 mRNA and decrease of IL-1β, IL-10, TNF mRNA were observed in the jejunum of lambs receiving postbiotics. Postbiotics also improved the integrity of the intestinal barrier by the upregulation of TJP-1, CLDN-1 and CLDN-4 mRNA. Postbiotic supplementation derived from L. plantarum RG14 in post-weaning lambs enhance the ruminal papillae growth, immune status and gastrointestinal health.