Supplementation with Rare Earth–Chitosan Chelate Improves Tibia Quality, Disease Resistance Capacity, and Performance in Nursery Pigs

The aim of this study was to investigate the effects on the tibia, liver, and gut, and on performance, when supplementing nursery pigs with different levels of rare earth-chitosan chelate (RECC). A total of 80 piglets, weaned at 7.67 ± 0.09 kg, were randomly assigned to groups RECC0 (RECC, 0 mg/kg diet), RECC200 (RECC, 200 mg/kg diet), RECC400 (RECC, 400 mg/kg diet), and RECC600 (RECC, 600 mg/kg diet), with four replicates in each group and five pigs per replicate during a 28 d experiment. Samples of the left hind tibia, serum, and feces were collected for analysis. The results indicated that, compared to pigs from group RECC0, pigs from group RECC200 presented with the following: a longer trabecular perimeter (<i>p</i> < 0.05), a larger trabecular area (<i>p</i> < 0.01), a higher trabecular number (<i>p</i> < 0.05), a smaller degree of trabecular separation (<i>p</i> < 0.01), and a lower number of osteoclasts (<i>p</i> < 0.01) in the tibia; higher abundances of beneficial fecal bacteria such as <i>g_Prevotellaceae_NK3B31_group</i>, <i>g_UCG_005</i>, <i>g_Rikenellaceae_RC9_gut_group</i>, <i>g_Acetitomaculum</i>, <i>g_Glutamicibacter</i>, <i>g_Frisingicoccus</i>, and <i>g_Alistipes</i>; higher (<i>p</i> < 0.01) serum levels of IgM, IgA, IgG, and IL-10; a lower (<i>p</i> < 0.01) serum concentration of TNF-α; a higher (<i>p</i> < 0.05) average daily gain and feed conversion ratio; and a lower (<i>p</i> < 0.01) incidence of diarrhea. The dietary addition of RECC contributes to improvements in tibia quality, gut health, and performance in nursery pigs.