Table 1.

Literature summary of effect of REE supplementation in pigs

Dose	Results and conclusions	Reference
100 mg/kg DM La for 30 days	Significant increase in ADG and feed intake (13.3% and 5.4%, respectively) Significantly improved in feed conversion ratio (8.5%) Significant increase in levels of serum thyroid hormones (T3 and T4)	Xu et al [45]
Cerium (Ce) at 0.5 to 10 μmol/L and >10 μmol/L	Enhanced the activity of α-amylase from porcine pancreas at lower concentration (0.5 to 10 μmol/L) Inhibited the activity of α-amylase at higher concentration of Ce3+ (>10 μmol/L)	Wang et al [46]
REE at 100, 200, 400, and 800 mg/kg of DM as citrate-bound REE (having lanthanum 30, cerium 55, praseodymium 5, and neodymium 10%)	REE supplementation did not disturb the health of animals Low concentrations (100 mg/kg DM) of REE increased weight gain Higher concentrations (200 mg/kg DM) of REE adversely affected animal growth performance	Förster et al [47]
0.1% peptide-bound REE mineral-yeast (mixture contained 35.3 lanthanum, 25.2 cerium, 10.2 praseodymium, and 29.3 of several minerals which were present in trace amounts)	Significantly increased in total tract digestibility of DM, CP, and GE	Han and Thacker [48]

REE, rare earth elements; DM, dry matter; ADG, average daily gain; CP, crude protein; GE, gross energy.