A 2 £ 2 factorial experiment was conducted to investigate the interactions between laminarin (LAM; 0 and 300 parts per million (ppm)) and fucoidan (FUC; 0 and 240 ppm) levels on intestinal morphology, selected microbiota and inflammatory cytokine gene expression in the weaned pig. There was an interaction between LAM and FUC supplementation on the Enterobacteriaceae population (P,0·05) and the abundance of attaching and effacing Escherichia coli (AEEC) strains (P, 0·05) in the colon. Pigs offered the FUC diet had a reduced Enterobacteriaceae population compared with pigs offered the basal diet. However, the effect of FUC on the Enterobacteriaceae population was not observed when combined with LAM. Pigs offered the LAM diet had reduced abundance of AEEC strains compared with pigs offered the basal diet. However, there was no effect of LAM on the abundance of AEEC strains when combined with FUC. There was an interaction between LAM and FUC supplementation on villous height (P,0·01) and the villous height:crypt depth ratio (P,0·01) in the duodenum. Pigs offered the LAM or FUC diet had an increased villous height and villous height:crypt depth ratio compared with pigs offered the basal diet. However, there was no effect of the LAM and FUC combination diet on intestinal morphology. Pigs offered the LAM-supplemented diets had a lower IL-6 (P, 0·05), IL-17A (P, 0·01) and IL-1b (P,0·01) mRNA expression in the colon compared with pigs offered the diets without LAM. In conclusion, supplementation with either LAM or FUC alone modified intestinal morphology and selected intestinal microbiota, but these effects were lost when offered in combination.

In the present study, two experiments were conducted to (1) evaluate the effect of laminarin and/or fucoidan on ileal morphology, nutrient transporter gene expression and coefficient of total tract apparent digestibility (CTTAD) of nutrients and (2) determine whether laminarin inclusion could be used as an alternative to ZnO supplementation in weaned pig diets. Expt 1 was designed as a 2 £ 2 factorial arrangement, comprising four dietary treatments (n 7 replicates, weaning age 24 d, live weight 6·9 kg). The dietary treatments were as follows: (1) basal diet; (2) basal diet þ 300 ppm laminarin; (3) basal diet þ 240 ppm fucoidan; (4) basal diet þ 300 ppm laminarin and 240 ppm fucoidan. There was an interaction between laminarin and fucoidan on the CTTAD of gross energy (GE) (P,0·05) and the expression of sodium -glucose-linked transporter 1 (SGLT1/SLC5A1) and GLUT1/SLC2A1 and GLUT2/SLC2A2 (P,0·05) in the ileum. The laminarin diet increased the CTTAD of GE and increased the expression of SGLT1, GLUT1 and GLUT2 compared with the basal diet. However, there was no effect of laminarin supplementation on these variables when combined with fucoidan. Expt 2 was designed as a complete randomised design (n 8 replicates/ treatment, weaning age 24 d, live weight 7·0 kg), and the treatments were (1) basal diet, (2) basal diet and laminarin (300 ppm), and (3) basal diet and ZnO (3100 ppm, 0-14 d, and 2600 ppm, 15-32 d post-weaning). The laminarin diet increased average daily gain and gain: feed ratio compared with the basal diet during days 0 -32 post-weaning (P,0·01) and had an effect similar to the ZnO diet. These results demonstrate that laminarin provides a dietary means to improve gut health and growth performance post-weaning.

The relationship between the endocrine system and immune monokines, such as interleukin-1 (IL-1), is of increasing interest. IL-1, a protein secreted by peripheral monocytes and tissue macrophages, mediates a wide variety of immune responses, and its production appears to be inversely related to the level of gonadal steroids. In this report, we have investigated the relationship between estradiol and progesterone concentrations and the level of IL-1 beta mRNA in cultured human peripheral monocytes and pelvic macrophages. Human peripheral monocytes, isolated during the luteal phase of the menstrual cycle, were activated with lipopolysaccharide (10 micrograms/mL). Cellular RNA was isolated and analyzed by Northern analysis using an 800-basepair IL-1 beta cDNA probe. Hybridization with 32P-labeled probe showed maximal levels of IL-1 beta mRNA occurring between 3 and 7 h of culture. Cultures of lipopolysaccharide-activated human peripheral monocytes incubated for 3-6 h with increasing amounts of progesterone or estradiol (0-10(-5) M) in the presence of either 5% fetal calf serum or 0.1% BSA demonstrated an inverse relationship between IL-1 beta mRNA levels and steroid concentration. In both cases, IL-1 beta mRNA levels decreased by 80-90% as the progesterone concentration increased to 10(-5) M and by 70-90% as the estradiol concentration increased similarly. A similar 80% decrease in IL-1 beta mRNA was observed with peritoneal macrophages incubated with increasing amounts of progesterone. This reciprocal relationship between IL-1 beta mRNA and gonadal steroids may have important ramifications in reproductive biology for both embryonic implantation and fetal survival as well as for clinically relevant changes in bone mass.

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