Effects of Management, Dietary Intake, and Genotype on Rumen Morphology, Fermentation, and Microbiota, and on Meat Quality in Yaks and Cattle

Abstract

Traditionally, yaks graze only natural grassland, even in harsh winters. Meat from grazing yaks is considered very healthy; however, feedlot fattening, which includes concentrate, has been introduced. We questioned whether this change in management and diet would have an impact on the rumen and meat quality of yaks. This study examined the morphology, fermentation, and microbiota of the rumen and the quality of meat of three groups of bovines: (1) grazing yaks (GYs, 4-year olds), without dietary supplements; (2) yaks (FYs, 2.5-year olds) feedlot-fattened for 5 months after grazing natural pasture; and (3) feedlot-fattened cattle (FC, Simmental, 2-year olds). This design allowed us to determine the role of diet (with and without concentrate) and genotype (yaks vs. cattle) on variables measured. Ruminal papillae surface area was greater in the FYs than in the GYs (P = 0.02), and ruminal microbial diversity was greater but richness was lesser in the GYs than in the FC and FYs. Concentrations of ruminal volatile fatty acids were greater in the yaks than in the cattle. In addition, both yak groups had higher protein and lower fat contents in meat than the FC. Meat of GY had a lower n6:n3 ratio than FY and FC, and was the only group with a ratio below r, which is recommended for healthy food. Essential amino acids (EAA), as a proportion of total AA and of non-essential AA of yak meat, met WHO criteria for healthy food; whereas FC did not.

Simulated seasonal diets alter yak rumen microbiota structure and metabolic function

“…Rumen microbiota can cooperatively degrade polysaccharides, starch, and fibers in the feed, producing VFAs that provide energy for the host, and play a crucial role in host growth and development. In this study, we found that the Bacteroidetes and Firmicutes were the dominant phyla among the three treatment groups, which is consistent with previous studies (Xue et al, 2016;Hu et al, 2021;Jiang et al, 2021;Liu et al, 2021). Bacteroidetes can degrade soluble polysaccharides and starch in the rumen to produce acetate, propionate and butyrate, which can be utilized by the host (Rosewarne et al, 2014;Ahmad et al, 2020).…”

“…Other than host influence (Henderson et al, 2013;Hu et al, 2021), feed type strongly affects microbial diversity and species richness (Henderson et al, 2015;Cremonesi et al, 2018;Wang et al, 2020). In the present study, bacterial ASV richness was higher in GSG samples than in SG samples, further supporting that a concentrated diet can reduce bacterial diversity (McCann et al, 2014;Ku et al, 2021), while fungal richness and diversity were higher in the NSG and SG rumen.…”

The Preventive Effects of Fermented and Germinated Foxtail Millet Whole Grain on Kidney Damage in a Diabetic Mouse Model

“…The relative abundances of several commensal bacteria that have been reported contributing to inflammation control and disease prevention were significantly higher in the Db-FM group than in the Db-93M group. For example, Ruminococcaceae ( 41 ), Odoribacter ( 42 ), Ileibacterium ( 43 ), Lachnospiraceae NK4A136 ( 44 ), Rikenellaceae RC9 gut group ( 45 ), and Mucispirillum schaedleri ( 46 ). The details of representative taxa are shown in Figure 6C .…”

Transcriptome-metabolome analysis reveals how sires affect meat quality in hybrid sheep populations

“…Studies have shown that fatty acid metabolism levels and composition affect meat quality and its nutritional value; for example, dodecanoic (C12:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0), linoleic (C18:1), alpha-linolenic (C18:2) and linolenic fatty acids (C18:3) can enhance meat flavors ( 38 – 41 ). Dodecanoic acid is reported to enhance intramuscular fat deposition and increase the accumulation of myristic and myristoleic acids (C14:1), which may benefit human health ( 42 ). Myristic acid can increase high-density lipoprotein (“good”) cholesterol more than can any other fatty acid ( 43 ).…”