Perspectives for rare earth elements as feed additive in livestock — A review

Abstract

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.

Review of Rare Earth Elements as Fertilizers and Feed Additives: A Knowledge Gap Analysis

“…REE-associated effects in plant models ranged from growth stimulation (hormesis) to inhibitory effects as a function of REE concentration (Poschenrieder 2013;Morkunas et al 2018;Nascarella and Calabrese 2016;Liu et al 2016a, b;Xu et al 2002); 2. Different accumulation gradients were noted in plant and animal organs, with minimal-if any-accumulation in the edible parts (Xu et al 2002;Tariq et al 2020); Liu et al (2008) Ruminally cannulated Simmental steers CeCl 3 80-240 Increased the digestibility of neutral detergent fibre, decreased molar ratio of rumen acetate to propionate Lin et al (2015) 3. REE-based feed additives in poultry failed to result in increased weight gain in broiler chicks, whereas REEsupplemented laying hens improved quantitative and qualitative egg production (Durmuş and Bölükbaşı 2015;Bölükbaşı et al 2016;Cai et al 2016); 4.…”

Veterinary and sanitary characteristics of quail meat by feeding nanocrystalline cerium dioxide

“…Токсичність РЗЕ за введення перорально дуже низька, оскільки лише незначна частина їх всмоктується в шлунково-кишковому тракті. Припускають, [11,12] що пероральне вживання РЗЕ тваринами може становити ризик для їх здоров'я як кухонна сіль.…”

“…Через погане засвоєння і швидке виведення РЗЕ з організму тварин, ризики для здоров'я людей, які споживають їстівні частини цих тварин є незначні [12,13]. Використання кормових добавок із РЗЕ розглядають як безпечний та перспективний напрям у зоотехнічній діяльності.…”

“…Проведена ветеринарно-санітарна експертиза м'яса перепелів дослідної і контрольної груп не виявила відмінностей між ними. Дослідження узгоджуються з повідомленнями інших авторів [12,13], що продукти, отримані від тварин в раціон яких були введені РЗЕ, є безпечними для здоров'я людини. Отже, використання НДЦ з водою перепелам не має негативного впливу на якість м'яса і його ветеринарно-санітарну оцінку.…”

Excessive dietary lead reduces growth performance and increases lead accumulation in pigs

“…Lead, even at a relatively low concentration, can cause various damages to animals such as poisoning and growth retardation [ 3 , 4 ]. In animals fed with a Pb-contaminated diet, Pb is mainly absorbed through the gastrointestinal tract and accumulated in bone, liver, kidneys, and hair [ 5 , 6 ]. The Pb concentration in a complete diet should not exceed 10 mg/kg in the Republic of Korea, 30 mg/kg in the United States [ 7 ] and less than 5 mg/kg in the Europe Union [ 8 ].…”