Growth Performance, Dietary Energetics, Blood Metabolites, Carcass Traits, Meat Quality, and Gene Expression of Lambs Supplemented with a Polyherbal Phytogenic Additive

This study aimed to evaluate the effects of supplementation with a polyherbal phytogenic additive (PPA) on the productive performance, dietary energetics, blood metabolites, carcass traits, meat quality, and gene expression of finishing lambs. Thirty-six male Pelibuey lambs (23.61 ± 0.57 kg body weight (BW)) were housed in individual pens and assigned to four treatments (<i>n</i> = 9) with different doses of PPA: 0 (CON), 2.5 (PPAL), 5 (PPAM), and 7.5 (PPAH) g of PPA/kg of DM for 56 days. Average daily gain, dry matter intake, and observed dietary net energy for maintenance and weight gain increased linearly (<i>p</i> < 0.05) in lambs supplemented with PPAH. A linear reduction (<i>p</i> = 0.02) in FCR was detected in lambs fed PPAM and PPAH. The PPAH supplementation linearly increased (<i>p</i> < 0.001) <i>Longissimus dorsi</i> muscle area, but other carcass traits were not affected (<i>p</i> > 0.05) by PPA doses. The physicochemical characteristics of the meat and the hematological parameters of the lambs were not affected (<i>p</i> > 0.05) by the PPA doses. The glucose, uric acid, creatinine, and bilirubin serum concentrations decreased linearly (<i>p</i> < 0.05) in lambs supplemented with PPAM and PPAH. Gene ontology analyses showed that nine biological processes were modified (<i>p</i> < 0.05), including DNA replication, drug metabolism-cytochrome P450, oxidative phosphorylation, and chemical carcinogenesis-reactive oxygen species. In conclusion, high doses (7.5 g/kg DM) of PPA can improve growth performance and dietary energy utilization efficiency in finishing lambs. Likewise, gene expression analysis indicates that supplementation with high doses of PPA could improve energy production and antioxidant status in finishing lambs.