Different rumen biohydrogenation extents in lambs: Assessing fatty acid composition, growth performance, carcass characteristics, and digestibility

Abstract

Rumen microbial biohydrogenation is a crucial process in the ruminant digestive system. Variability in fatty acid composition of longissimus lumborum, rumen fermentation, and bacterial communities was examined between lambs categorized into low (LB) and high (HB) rumen biohydrogenation extent groups. Lambs in HB group demonstrated enhanced apparent digestibility of feed nutrients compared to LB lambs (P ≤ 0.05). Furthermore, the HB lambs displayed higher rumen tissue weight, and rumen/carcass ratio. Higher concentrations of ammonia and total VFA, but lower acetate/n-butyrate ratio in rumen of HB lambs than in the rumen of LB lambs were observed (P ≤ 0.05). Distinct rumen bacterial communities were observed between the HB and LB lambs, with the former exhibiting higher abundance of WCHB1–41_ge but lower abundance of Fibrobacter (P ≤ 0.05). No gene directly involved in biohydrogenation was detected according to the PICURSt functional prediction. Moreover, HB lambs displayed elevated relative abundance of C18:0 in their muscles (P ≤ 0.05). In conclusion, individual biohydrogenation extent in rumen is connected with rumen fermentation, fiber degradation, and meat FA profile. Rumen fermentation parameters and amplicon results confirmed a shift in fermentation mode from acetate to n-butyrate, potentially facilitated by fiber-degrading bacterium WCHB1–41_ge. The findings suggest that enhancing biohydrogenation extent could improve feed nutrient utilization and rumen function, potentially leading to better growth performance and carcass characteristics in lambs. The observed differences in rumen fermentation patterns and bacterial communities inform dietary strategies aimed at optimizing meat fatty acid profiles, which are important for both meat industry stakeholders and consumers seeking healthier meat products.