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 ( = 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 ( < 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 NH-N concentration and blood urine nitrogen linearly increased ( < 0.01) with increasing substitution rate of HF, whereas the total volatile fatty acids concentration quadratically changed ( < 0.01). Substitution of AH with HF had no effect on the diversity and richness of ruminal microbes, though it linearly decreased ( = 0.040) _ and linearly increased ( = 0.017) . 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.

中文翻译：

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在山羊日粮中用大麻饲料部分替代苜蓿干草可改善饲料效率、瘤胃发酵模式和微生物特征

使用大麻作为牲畜饮食中的饲料来源的研究较少，因为动物组织中的生物活性残留物可能对消费者构成风险。本研究调查了生长山羊日粮中用大麻草料 (HF) 部分替代苜蓿干草 (AH) 对生长性能、胴体性状、瘤胃发酵特性、瘤胃微生物群落、血液生化和抗氧化指数的影响。将 40 只体重 (BW) 7.82 ± 0.57 kg（平均值 ± 标准差）的湘东黑山羊按 BW 分组，并以完全随机设计随机分配到四种治疗日粮中的一种（= 10/处理）。山羊随意饲喂含有60%草料和40%精料（DM基础）的总混合日粮。日粮包括对照（CON；60% AH 和 40% 浓缩物）、55% AH 和 5% HF (HF5)、50% AH 和 10% HF (HF10) 以及 40% AH 和 20% HF (HF20)。增加 HF 对 AH 的替代量可线性降低 ( < 0.01) DM 采食量并提高饲料转化效率。然而，最终体重、平均日增重、胴体性状、肉质和大多数血液生化指标在处理之间没有差异。随着HF替代率的增加，瘤胃NH-N浓度和血尿氮浓度呈线性增加（<0.01），而总挥发性脂肪酸浓度则呈二次方变化（<0.01）。用HF替代AH对瘤胃微生物的多样性和丰富度没有影响，尽管它线性下降（= 0.040）并线性增加（= 0.017）。在瘤胃滤液 (8) 和血浆 (4) 中均检测到大麻素和/或其代谢物，但在肉中未观察到可检测到的大麻素相关残留物。这些结果表明，HF 可用于部分替代山羊日粮中的 AH，但不同 HF 替代 AH 的效果不同。尽管肉类中没有检测到大麻素相关残留物，但血液中大麻素残留的存在值得进一步研究高频喂养，以确认动物产品中不存在大麻素残留。