Long-term dietary supplementation of organic selenium modulates gene expression profiles in leukocytes of adult pigs.

Seventy-two pigs at 34.4 kg body weight (BW) were allotted to two treatments with six replicates/treatment and six pigs/pen: the CON (negative control, no added selenium (Se)) and the OS (0.36 mg/kg added selenium from selenium-enriched yeast). Pigs were fed until 130 kg BW. The CON diet contained 0.18 mg/kg indigenous Se whereas the OS diet contained 0.54 mg/kg Se. Blood samples were collected at 130 kg BW and further processed for microarray analysis, prepared with 885 genes related to immune function of pigs. Among those, 28 genes related to improved immune status and innate immunity were up-regulated (P < 0.05) in leukocytes from Se-fed pigs and those include major histocompatibility class I (> 1.66), arginase I (> 1.27), integrin beta-1-subunit (> 1.20), toll like receptor 2 (> 1.12) and double-stranded RNA-dependent protein kinase. However, 24 genes including tissue factor (< 4.70), serum amyloid A-2 protein (< 3.11) and p27Kip1 (< 1.42) were down-regulated (P < 0.05) in leukocytes from Se-fed pigs. Expression of four selected genes was validated using quantitative PCR (qPCR) showing significant correlation between mircroarray analysis and qPCR analysis. This study indicates that a long- term dietary supplementation (0.3%) of organic Se improves the expression of genes that are related to enhanced immunity of pigs.

Molecular identification and characterization of ileal and cecal fungus communities in broilers given probiotics, specific essential oil blends, and under mixed Eimeria infection.

Broiler digestive tract fungal communities have gained far less scrutiny than that given corresponding bacterial communities. Attention given poultry-associated fungi have focused primarily on feed-associated toxin-producers, yeast, and yeast products. The current project focused on the use of pyrosequencing and denaturing gradient gel electrophoresis (DGGE) to identify and monitor broiler digestive fungal communities. Eight different treatments were included. Four controls were an Uninfected-Unmedicated Control, an Unmedicated-Infected Control, the antibiotic bacitracin methylene disalicylate plus the ionophore monensin as Positive Control, and the ionophore monensin alone as a Negative Control. Four treatments were two probiotics (BC-30 and Calsporin) and two specific essential oil blends (Crina Poultry Plus and Crina Poultry AF). All chickens except the Unmedicated-Uninfected Control were given, at 15 days of age, a standard oral Eimeria inoculum of sporulated oocysts. Ileal and cecal digesta were collected at pre-Eimeria infection at 14 days of age and at 7 days post-Eimeria infection at 22 days of age. Extracted cecal DNA was analyzed by pyrosequencing to examine the impact of diet supplements and Eimeria infection on individual constituents in the fungal community, while DGGE was used to compare more qualitative changes in ileal and cecal communities. Pyrosequencing identified three phyla, seven classes, eight orders, 13 families, 17 genera, and 23 fungal species. Ileal and cecal DGGE patterns showed fungal communities were clustered mainly into pre- and post-infection patterns. Post-infection Unmedicated-Uninfected patterns were clustered with pre-infection groups demonstrating a strong effect of Eimeria infection on digestive fungal populations. These combined techniques offered added versatility towards unraveling the effects of enteropathogen infection and performance enhancing feed additives on broiler digestive microflora.

Rumen bacterial diversity dynamics associated with changing from bermudagrass hay to grazed winter wheat diets.

Rumen bacterial communities in forage-fed and grazing cattle continually adapt to a wide range of changing dietary composition, nutrient density, and environmental conditions. We hypothesized that very distinct community assemblages would develop between the fiber and liquid fractions of rumen contents in animals transitioned from bermudagrass hay diet to a grazed wheat diet. To address this hypothesis, we designed an experiment utilizing a 16S-based bTEFAP pyrosequencing technique to characterize and elucidate changes in bacterial diversity among the fiber and liquid rumen fractions and whole rumen contents of 14 (Angus x Hereford) ruminally cannulated steers sequentially fed bermudagrass hay (Cynodon dactylon; 34 days) and grazing wheat forage (28 days). Bermudagrass hay was a conserved C4 perennial grass lower in protein and higher in fiber (11% and 67%, respectively) content than grazed winter wheat (Triticum aestivum), a C3 annual grass with higher protein (20%) and a large (66%) soluble fraction.Significant differences in the OTU estimates (Chao1, Ace,and Rarefaction) were detected between fractions of both diets, with bermudagrass hay supporting greater diversity than wheat forage. Sequences were compared with a 16S database using BLASTn and assigned sequences to respective genera and genera-like units based on the similarity value to known sequences in the database. Predominant genera were Prevotella (up to 33%) and Rikenella-like (upto 28%) genera on the bermudagrass diet and Prevotella (upto 56%) genus on the wheat diet irrespective of the fractions. Principle component analyses accounted for over 95% of variation in 16S estimated bacterial community composition in all three fractions and clearly differentiated communities associated with each diet. Overall, bermudagrass hay diets clustered more clearly than wheat diets.These data are the first to explore bacterial diversity dynamics in a common population of animals in response to contrasting grass forage diets.