Tariq Hujaz, Sharma Amit, Sarkar Srobana, Ojha Lamella, Pal Ravi Prakash, Mani Veena
Animal Nutrition Division, ICAR-National Dairy Research Institute (Deemed University), Karnal, Haryana 132001, India.
Department of Animal Nutrition, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, 141004, India.
Asian-Australas J Anim Sci. 2020 Mar;33(3):373-381. doi: 10.5713/ajas.19.0242. Epub 2019 Aug 3.
There is a need for newer feed additives due to legal prohibition on inclusion of growth promoting antibiotics in livestock diets in several countries due to antimicrobial resistance. In this context, rare earth elements (REE) have gained attention among animal nutritionists as potential growth promoters. Currently, several studies have reported better weight gain, milk production, egg laying capacity and feed conversion efficiency among different breeds of farm animals following supplementation with REE, with however largely inconsistent results. Furthermore, REE supplementation has also shown to improve ruminal fibrolytic and proteolytic activities as well as flavor of meat with negligible residues in edible tissue, however the mechanism behind this action is still unclear. According to existing research, due to their poor absorption and similarity with calcium REE might exert their action locally on gut microbial populations within the gastrointestinal tract (GIT). Moreover, REE have also shown anti-inflammatory, anti-oxidative as well as immune stimulating effects. The present review aims to broaden the knowledge about use of REE as feed additives for livestock and sum up efficacy of REE supplementation on performance and health of animals by comparing the findings. Till date, researches with REE have shown properties that make them a promising, new and safe alternative feed additive but further exploration is recommended to optimize effects and clarify discrepancy of various results before practical proposals can be drafted.
由于几个国家因抗微生物药物耐药性而在法律上禁止在牲畜日粮中添加促生长抗生素，因此需要更新型的饲料添加剂。在这种背景下，稀土元素（REE）作为潜在的生长促进剂已引起动物营养学家的关注。目前，多项研究报告称，在不同品种的农场动物中补充REE后，体重增加、产奶量、产蛋能力和饲料转化效率都有所提高，但结果在很大程度上并不一致。此外，补充REE还显示出能提高瘤胃纤维分解和蛋白水解活性以及改善肉的风味，且可食组织中的残留量可忽略不计，然而这一作用背后的机制仍不清楚。根据现有研究，由于REE吸收不良且与钙相似，它们可能在胃肠道（GIT）内对肠道微生物群产生局部作用。此外，REE还显示出抗炎、抗氧化以及免疫刺激作用。本综述旨在拓宽关于将REE用作牲畜饲料添加剂的知识，并通过比较研究结果总结补充REE对动物性能和健康的功效。迄今为止，对REE的研究已显示出其特性，使其成为一种有前景的新型安全替代饲料添加剂，但建议进一步探索，以优化效果并澄清各种结果的差异，然后才能起草实际建议。
