Comparison of rumen bacterial communities between yaks (Bos grunniens) and Qaidam cattle (Bos taurus) fed a low protein diet with different energy levels

Abstract

The yak (Bos grunniens), an indigenous bovine on the Qinghai-Tibetan plateau (QTP), is reported to digest low quality forage to a greater extent and to require less protein and energy for maintenance than the introduced Qaidam cattle (Bos taurus). Ruminal bacteria play a major role in feed degradation, and therefore, we hypothesized that ruminal bacteria composition would differ between yaks and cattle, and confer an advantage to yaks for poor quality diets. To test our hypothesis, we determined the ruminal bacteria profiles, rumen fermentation parameters, and enzyme activities in these bovine species consuming a low-protein diet differing in energy level. Six castrated yaks (155 ± 5.8 kg) and 6 castrated Qaidam cattle (154 ± 8.0 kg) were used in two concurrent 4 × 4 Latin square designs with 2 additional animals of each species in each period. The animals were offered a low-protein diet of 70.4 g/kg dry matter (DM) and one of four metabolizable energy levels, namely 6.62, 8.02, 9.42, and 10.80 MJ/kg. Ruminal pH, concentrations of ammonia-N and total volatile fatty acids (VFAs), the molar proportion of acetate, and the ratio of acetate to propionate (A:P) were greater (P < 0.05), whereas the molar proportion of propionate was lesser (P = 0.043) in yaks than in cattle. With increasing dietary energy level, ruminal pH, the molar proportion of acetate and the ratio of A:P decreased linearly (P < 0.05), whereas, the concentration of total VFAs, molar proportions of propionate, butyrate, iso-butyrate, and iso-valerate and concentration of ammonia-N increased linearly (P < 0.05). The relative abundance (RA) of Firmicutes increased linearly (P < 0.01), whereas, the RA of Bacteroidetes decreased linearly (P < 0.001) with increasing energy level in both bovine species. The RAs of Prevotella and Rikenellaceae_RC9_gut_group decreased linearly (P < 0.05) with increasing energy level in both yaks and cattle. The RAs of fibrolytic (e.g., Rikenellaceae_RC9_gut_group), and H2-incorporating (e.g., Quinella) bacteria were greater (P < 0.05) in yaks than in cattle. We concluded that the two bovines differ in ruminal bacterial profiles and rumen fermentation parameters, and confer an advantage to yaks over cattle in consuming a low protein diet with differing energy level.

Effects of dietary N-carbamylglutamate on rumen fermentation parameters, and bacterial community diversity of Holstein dairy cows in Tibet

“…This might be the reason for the greater acetic acid production in cows fed NCG. Moreover, greater milk fat contents were determined in Jersey cows offered same dose of NCG like the current study ( Liu H. et al, 2022 ; Liu Z. et al, 2022 ), suggesting that enhanced acetic acid are beneficial for milk fat syntheses. Dietary supplementation of NCG did not affect the molar proportion of propionate acid, thus lead to greater acetate to propionate ratio.…”

“…Therefore, it is widely used as a viable and cost-effective alternative to Arg. Our parallel study indicated that dietary supplementation of NCG by 20 g/d/head prevented hypoxic stress and tended to improve milk quality of Jersey dairy cows in Tibet ( Liu H. et al, 2022 ; Liu Z. et al, 2022 ). This suggests that NCG also has beneficial effects on the physiological regulation of introduced animals at high altitude plateau.…”

“…Due to the special geographical and environmental conditions, the Qinghai-Tibet Plateau has a long cold climate, strong ultraviolet radiation, strong wind and low oxygen content in the air ( Liu H. et al, 2022 ; Liu Z. et al, 2022 ), leading to an extremely harsh living environment for livestock. As the hinterland of plateau, the living environment is even worse in Tibet, making it a major restricting factor for the development of Tibet’s animal husbandry.…”

Exploring the temporal dynamics of rumen bacterial and fungal communities in yaks (Bos grunniens) from 5 days after birth to adulthood by full-length 16S and 18S rRNA sequencing

“…DNA was quantified using the Qubit dsDNA BR Assay kit (Invitrogen, USA) and quality was assessed by running an aliquot on a 1% agarose gel. To amplify variable regions V1-V9 of the bacterial 16S rRNA gene, degenerate PCR primers 27F (5′-AGRGTTYGATYMTGGCTCAG-3′) and 1492R (5′-RGYTACCTTGTTACGACTT-3′) were used ( 14 ). Additionally, degenerate PCR primers ITS3 (5′-GCATCGATGAAGAACGCAGC-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) were used to amplify the ITS2 of the internal transcribed spacer (ITS) region ( 15 ).…”

Exploring the growing forest musk deer (Moschus berezovskii) dietary protein requirement based on gut microbiome

“…As the diet of FMD changes from consuming milk to eating plants, the richness and diversity of intestinal microbiota of young FMD increased significantly ( Li et al, 2021 ). What’s more, previous found that dietary protein levels not only affect the growth performance of ruminants, but also play an important role in regulating the microbial structure of the digestive tract ( Liu et al, 2022 ; Zhang et al, 2022 ).…”