Effects of Alkaline Mineral Complex Supplementation on Growth Performance, Meat Quality, Serum Biochemical Parameters, and Digestive Function of Fattening Lambs

Serving as a mineral-derived dietary buffer, the alkaline mineral complex (AMC) has the potential to influence the physiological functions of animals. Nonetheless, there is a notable scarcity of research in the field of ruminant science regarding its effects on fattening lambs. Therefore, the purpose of the present study was to investigate the effects of AMC supplementation on the growth performance, meat quality, serum biochemical parameters, and digestive function of fattening lambs. A total of 96 six-month-old male Small-Tailed Han lambs with an average body weight of 48 ± 3.85 kg were randomly assigned to four groups: the control group (CON, 0 g/d per lamb of AMC), test group 1 (LAMC, 2 g/d per lamb of AMC), test group 2 (MAMC, 3 g/d per lamb of AMC), and test group 3 (HAMC, 4 g/d per lamb of AMC). Each group contained 24 lambs, with 3 pens per group and 8 lambs per pen. The trial lasted for 45 days, and the results showed that, compared with the CON group, the MAMC group demonstrated a significantly enhanced average daily gain (ADG) with a reduced feed conversion ratio (FCR) (<i>p</i> < 0.05). The redness (a*) of the meat in the AMC-treated groups was significantly greater than that of the CON group (<i>p</i> < 0.05). The intramuscular fat (IMF) content in the longissimus dorsi (LD) of the MAMC group was significantly increased compared to the CON group (<i>p</i> < 0.05). The low-density lipoprotein (LDL) and total cholesterol (TC) levels in the HAMC group were greater than those of other groups (<i>p</i> < 0.01), and the superoxide dismutase (SOD) content was higher in the AMC-treated groups compared to the CON group (<i>p</i> < 0.05). In addition, the duodenum lipase content in the HAMC group was significantly lower than that in the CON group (<i>p</i> < 0.05), and the amylase content in the MAMC group was significantly higher than that of the CON group (<i>p</i> < 0.05). The HAMC group had a significantly lower jejunum lipase content than those in the other groups (<i>p</i> < 0.05). The LEfSe analysis showed that the MAMC group possessed significantly increased <i>g_Prevotellaceae_Ga6A1_group</i> levels. Furthermore, SOD and catalase (CAT) were both positively correlated with meat redness (a*) but were not significantly associated with ADG. In contrast, malondialdehyde (MDA) was negatively correlated with ADG, while no significant relationship was observed for meat redness (a*). In conclusion, an appropriate supplementation of AMC (3 g/d per lamb) can improve growth performance and meat quality by enhancing the antioxidant capacity and modulating the composition of beneficial rumen bacteria.