PSX-B-9 Effect of trace mineral sources in the supplement for grazing cattle on ruminal bacteria diversity

The rumen soluble Cu and Zn can affect the rumen microbial populations. This study aimed to evaluate the effect of trace mineral sources (Cu and Zn) in the supplement of grazing steers on ruminal bacteria diversity. Eight rumen cannulated Nellore steers (541 kg ± 18 kg BW) were distributed in a randomized block design in individual paddocks of Urochloa brizantha cv. Marandu. Steers were supplemented during 101 days between dry to rainy season at 5 g/kg BW with commercial supplement (25% CP) containing Cu (40 mg/ kg) and Zn (148 mg/kg) in the inorganic (Control) or hydroxy (HDX; Micronutrients Inc., IN) source. Samples of ruminal content were collected before supplementation at day 97 of experimental period and the total DNA extracted by commercial kit (Quick-DNA Fecal/Soil Microbe Miniprep). The V3/V4 regions of 16SrRNA gene was sequencing using the Illumina MiSeq, using the Quantitative Insights into Microbial Ecology (QIIME v.1.9.1) to filter reads and determine Operational Taxonomic Units (OTUs). Data were compared using an unpaired Wilcoxon test in R. A total of 293 OTUs were identified at genus level. The HDX resulted in a higher ruminal abundance of Corynebacterium 1 (P = 0.01), Prevotella 1 (P = 0.01), Lachnoclostridium 10 (P = 0.02), Lachnospiraceae AC2044 group (P = 0.03), Lachnospiraceae UCG-008 (P = 0.03), Streptococcus (P = 0.02), Ruminococcaceae UCG-010 (P = 0.01), Ruminococcaceae UCG-014 (P = 0.01), Ruminococcus 1 (P = 0.04), Coprococcus 1 (P = 0.04), Mogibacterium (P = 0.02), Selenomonas 1 (P = 0.02), Anaerovibrio (P = 0.03), Methylobacterium (P = 0.02), Treponema 2 (P = 0.02), Rikenellaceae RC9 gut group (P = 0.03), Ruminococcaceae; uncultured rumen bacterium (P = 0.02) and Eubacterium hallii group (P = 0.05), and lower abundance of Fibrobacter (P = 0.04), Butyrivibrio 2 (P = 0.05), Anaerotruncus (P = 0.03), Ruminiclostridium 5 (P = 0.03), Anaerorhabdus furcosa group (P = 0.02) and Erysipelotrichaceae UCG-004 (P = 0.01). The use of HDX in the supplement for grazing cattle between dry to rainy season increase the ruminal abundance of bacteria, mainly into Firmicutes phylum with important structural and non-structural carbohydrates degradation functions.

Gut microbial communities associated with phenotypically divergent populations of the striped stem borer Chilo suppressalis

Chilo suppressalis is a serious stem borer of rice and water-oat, however, little is known about the effect of diet and gut compartments on the gut microbial communities of this species. We analyzed the microbial communities in phenotypically divergent populations of C. suppressalis. In original and cross-rearing populations, the most dominant phyla were Proteobacteria (16.0% to 96.4%) and Firmicutes (2.3% to 78.9%); the most abundant family were Enterobacteriaceae (8.0% to 78%), followed by Enterococcaceae (1.7% to 64.2%) and Halomonadaceae (0.3% to 69.8%). The genera distribution showed great differences due to diet types and gut compartments. The fewest microbial species were shared by original populations, whereas the highest bacteria diversity was found for midgut of rice population feeding on water-oat. The bacterial communities in the midgut were more diverse than those in the hindgut. A comparison among phenotypically divergent populations of C. suppressalis shows that gut microbial communities vary with diet types and gut compartment.