Partially substituting alfalfa hay with hemp forage in the diet of goats improved feed efficiency, ruminal fermentation pattern and microbial profiles

Tao Ran; Zhipeng Xu; Wenzhu Yang; Dalin Liu; Duanqin Wu

doi:10.1016/j.aninu.2024.01.003

Partially substituting alfalfa hay with hemp forage in the diet of goats improved feed efficiency, ruminal fermentation pattern and microbial profiles

Anim Nutr. 2024 Jan 29:17:49-60. doi: 10.1016/j.aninu.2024.01.003. eCollection 2024 Jun.

Authors

Tao Ran^{1

2}, Zhipeng Xu³, Wenzhu Yang⁴, Dalin Liu⁵, Duanqin Wu⁶

Affiliations

¹ College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, Gansu, China.
² State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou, 730020, Gansu, China.
³ Changshu Center for Animal Disease Prevention and Control, Changshu, 215500, Jiangsu, China.
⁴ Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
⁵ College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
⁶ Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha, 410205, Hunan, China.

Abstract

The use of hemp as a forage source in livestock diets has been less studied because bioactive residues in animal tissues may pose a risk to consumers. This study investigated the effects of partial substitution of alfalfa hay (AH) with hemp forage (HF) in growing goat diets on growth performance, carcass traits, ruminal fermentation characteristics, rumen microbial communities, blood biochemistry, and antioxidant indices. Forty Xiangdong black goats with body weight (BW) 7.82 ± 0.57 kg (mean ± SD) were grouped by BW and randomly assigned into one of the four treatment diets (n = 10/treatment) in a completely randomized design. The goats were fed ad libitum total mixed rations containing 60% forage and 40% concentrate (DM basis). The diets included control (CON; 60% AH and 40% concentrate), 55% AH and 5% HF (HF5), 50% AH and 10% HF (HF10), and 40% AH and 20% HF (HF20). Increasing the substitution of HF for AH linearly decreased (P < 0.01) DM intake and improved feed conversion efficiency. However, final BW, average daily gain, carcass traits, meat quality, and most blood biochemistry indices did not differ among treatments. The ruminal NH₃-N concentration and blood urine nitrogen linearly increased (P < 0.01) with increasing substitution rate of HF, whereas the total volatile fatty acids concentration quadratically changed (P < 0.01). Substitution of AH with HF had no effect on the diversity and richness of ruminal microbes, though it linearly decreased (P = 0.040) Prevotella_1 and linearly increased (P = 0.017) Rikenellaceae_RC9_gut_group. The cannabinoids and/or their metabolites were detected in both ruminal filtrates (8) and plasma (4), however, no detectable cannabinoid-related residues were observed in meat. These results indicate that the HF could be used to partially substitute AH in goat diets, whereas the effects vary between substitution rates of HF for AH. Although no cannabinoid-related residues were detected in meat, the presence of cannabinoids residues in blood warrants further study of HF feeding to confirm the cannabinoids residues are not present in the animal products.

Keywords: Alfalfa hay; Cannabinoid metabolism; Goat; Growth performance; Hemp forage; Ruminal microbiota.