Association between dietary components and muscle fatty acid
depositioninlongissimus dorsi: Results from a metabarcoding diet analysis of
grazing Tan sheep
Running title:
Metabarcoding
in sheep diet and PUFAs
Yanping Guo1, Xingang Zhao1, Ming
Liu1, Can Zhang1, Yingjun
Zhang2, Qing Ma3, Bing
Wang1, and Hailing Luo1*
1 State Key Laboratory of Animal Nutrition,
College of Animal Science and
Technology, China Agricultural University, Beijing 100193, China;
2 Key Laboratory of Grasslands Management and
Utilization, College of Grassland Science and Technology, China
Agricultural University, Beijing 100193, China
3 Research Center of Grass and Livestock, Ningxia
Academy of Agriculture and Forestry Sciences, Yinchuan 750002, Ningxia,
China;
*Corresponding author:
Hailing Luo, State Key Laboratory
of Animal Nutrition, College of Animal Science and Technology, China
Agricultural University, Beijing 100193, China. Email:
luohailing@cau.edu.cn
YPG:
guoyp@cau.edu.cn
XGZ: 1404010216@cau.edu.cn
ML: liu-ming@cau.edu.cn
CZ: zhang_can@cau.edu.cn
YJZ: zhangyj@cau.edu.cn
QM: maqing1973@126.com
BW: wangb@cau.edu.cn
HLL: luohailing@cau.edu.cn
Abstract
Understanding
the natural diets of grazing herbivores can help fulfill their
nutritional requirements and develop management strategies.
Emerging metabarcoding techniques
can provide more accurate estimates
for dietary composition of grazing
animals. Thirty-nine Tan sheep with weights of 25.10 ± 1.88 kg were
randomized into three groups: the grazing group, the time-limited
grazing group, and the stall-fed group. Effects of grazing on meat fatty
acid composition in lambs were compared to concentrate-based
systems.
Simultaneously, we investigated sheep diets using DNA metabarcoding of
feces to assess the prevalence of
medicinal herbage plants consumed by grazing sheep. Metabarcoding data
determined that Lespedeza sp. , Artemisia sp. ,Chenopodium sp. , Corispermus sp. , and Phellodendron
amurense were predominant with
different proportions (P < 0.05). Our results
demonstrated that grazing systems could transform the muscle fatty acid
composition and promote n-3 PUFAs, including C18:3n3 (ALA), C20:5n3
(EPA), and C22:6n3 (DHA) deposition. To establish the association of
PUFAs with the herbage taxa, we conducted multivariate and correlation
analyses. Some highlighted herbage species (e.g., Bassia
scoparia , Euphorbia humifusa , and Arnebia euchroma ) were
significantly correlated with omega-3 PUFAs. The dominant groupLespedeza sp. showed a positive correlation with C18:2n6.
Overall, these results demonstrated the utility of metabarcoding diet
analysis and how diversification in dietary composition was associated
with muscle fatty acid deposition. This research examined the
correlation between herbage taxa and omega-3 fatty acids, and the
results provide an initial view of the effects of herbage on PUFAs of
lambs. The study provides experimental evidence for future feeding
research.
Keywords: Herbivore, sheep, diet, feces, muscle PUFAs, meat
flavor