| dc.description.abstract | The current trends in climate change and global warming are expected to have a profound effect on the cattle industry. Availability of good quality water in sufficient amounts is one aspect in cattle operations that can be adversely affected by such climate phenomenon. Water is an essential nutrient playing a pivotal role in maintaining critical physiological functions in cattle. The gastrointestinal microbial community of ruminants such as cattle are central to the digestion of plant material, production of volatile fatty acids, and the production of microbial crude protein essential in replenishing the nutrient requirement of the animal. Factors such as dietary composition, host genetics, production environment, age, sex etc. have been associated with significant changes in the gut microbiome of cattle. However, the effect of water restriction on the gut microbial dynamics of cattle is yet to be extensively studied. Hence, we used rumen and fecal samples from feedlot cattle collected during ad libitum water intake and at 50% water restriction) to reconstruct rumen and fecal microbial communities using 16S rRNA V4 gene amplicon sequencing and whole metagenome sequencing. The amplicon sequencing data summarized at genus level revealed significant differences (p<0.05) in the overall species composition of rumen and fecal microbiomes during water restriction. Genera such as Methanobrevibacter, Rikenellaceae_RC9_gut_group and Prevotellaceae_UCG_003 showed significant differences in their relative abundance when subjected to water restriction. The fecal microbiome exhibited the most prominent changes due to water restriction where genera such as Turicibacter, Clostridium_sensu_stricto_1, Christensenellaceae_R_7_group, Romboutsia, and Paeniclostridium showed significant differences (p<0.05) in their relative abundance in comparison to ad libitum water intake. Christensenellaceae_R_7_group, Paenoclostridum, Rombutsia, Clostridoides, Akkermansia and Lactobacillus were identified as biomarkers in animals that performed significantly better (p<0.05) under water restricted conditions. Metagenome sequencing data summarized at species level showed a significant decrease (p<0.05) in the abundance Ruminococcaceae bacterium P7, Methanosphaera sp BMS, and Methanobrevibacter millerae in the fecal microbiome during water restriction. A multitude of biologically significant metabolic pathways in the rumen/fecal microbiome, pertaining to amino acid biosynthesis, methanogenesis, pyruvate fermentation etc. differed significantly (p<0.05) in pathway abundance during water restriction. | |
