This study was conducted to evaluate the effects of replacing inorganic trace minerals (ITM) with compound organic trace minerals (OTM) at lower levels on plasma biochemical parameters, antioxidant capacity, carcass traits, meat quality, and tissue mineral deposition in Chinese yellow-feathered broilers. A total of 960 one-day-old male broilers were randomly allocated to six treatment groups. The birds were fed with either the basal diets (negative control, NC), or diets supplemented with 1,000 mg/kg (positive control, PC), 300 mg/kg, and 500 mg/kg ITM or OTM for 53 d, respectively. The results showed that the alkaline phosphatase (ALP) activity of the OTM300 group was significantly higher than that of the NC, PC, and ITM300 groups (P < 0.05). Dietary OTM supplementation could significantly increase the serum concentrations of Fe and Cu, promote the deposition of Zn and Cu in breast muscle, and increase Zn content in the tibia of Chinese yellow-feathered broilers (P < 0.05). Furthermore, dietary OTM300 treatment could significantly increase plasma CAT and CuZn-SOD activities, as well as the CAT activity in the liver (P < 0.05). The liver GSH-Px activity of the OTM500 group were significantly higher than the other groups (P < 0.05). Moreover, the supplementation of dietary OTM could significantly increase the pH_45min of breast muscle, as well as decrease drip loss_24h and drip loss_48h of Chinese yellow-feathered broilers (P < 0.05). Furthermore, pH_45min was positively correlated with liver T-AOC activity and the concentrations of Zn, Fe, Cu, and Mn in breast muscle, while drip loss_48h was negatively correlated with liver T-AOC activity, plasma CAT and CuZn-SOD, as well as the concentration of Cu and Zn in breast muscle. Trace mineral sources or levels had no significant effect on the carcass traits of Chinese yellow-feathered broilers (P > 0.05). Compared with the ITM groups, OTM300 significantly increased the heart index of Chinese yellow-feathered broilers (P < 0.05). Dietary OTM upregulated the mRNA expression of TGF-β and downregulated the mRNA expression of IL-1β in the spleen (P < 0.05). In conclusion, dietary supplementation with compound OTM at lower levels could promote the deposition of trace minerals in serum and tissues, enhance antioxidant capacity, and improve the meat quality of Chinese yellow-feathered broilers.

This study aimed to investigate the effects of reducing inorganic trace minerals (ITM) by supplementing compound organic trace minerals (OTM) chelates on growth performance, fecal mineral excretion, intestinal health, and cecal microbiota of yellow-feathered broilers. A total of 960 one day old male broilers were randomly assigned to 6 treatments, among which birds were fed with the basal diets (negative control, NC), or supplemented with 1,000 mg/kg (positive control, PC), 300, and 500 mg/kg ITM or OTM, respectively. Dietary supplementation of OTM significantly increased the average daily gain (ADG) during 22-53 d and 1-53 d, and reduced the fecal emissions of Fe, Cu, Zn, and Mn of Chinese yellow-feathered broilers (P < 0.05). Furthermore, the OTM300 group significantly reduced the crypt depth in the duodenum, and increased the ratio of villus height to crypt depth (V/C) in the duodenum and jejunum (P < 0.05). The mRNA expression of TGF-β, Bcl-2, CAT, and GPX4 as well as tight junction proteins (occludin, ZO-1, claudin-1, and claudin-5) in jejunum mucosa were significantly increased by compound OTM when comparing with ITM300 group (P < 0.05). Moreover, dietary compound OTM significantly changed the Chao1 index and β diversity index of cecal microbiota of Chinese yellow-feathered broilers. The abundances of Firmicutes (phylum), Eubacterium_coprostanoligenes_group (family) and Oscillibacter (genus) were increased, while the abundances of Bacteroidetes (phylum) and Rikenellaceae RC9 group (genus) were decreased by OTM treatment. Spearman correlation analysis showed that the mRNA of occludin and jejunal V/C ratio were positively correlated with the abundance of Firmicutes (phylum), but negatively correlated with the abundance of Bacteroidota (phylum). In addition, the abundance of Eubacterium_coprostanoligenes_group (family) was positively correlated with the mRNA of claudin-1, Bcl-2, and TGF-β. PICRUST prediction of microbial function revealed that OTM treatment enriched the pathways related to amino acid metabolism and DNA replication. In conclusion, dietary supplementation at lower levels of compound OTM to replace ITM could improve growth performance and intestinal health, and reduce the fecal excretion of trace elements by modulation of cecal microbiota community and diversity in Chinese yellow-feathered broilers.

The objective of this study is to evaluate the effects of crude protein (CP) levels and antibiotics in feed on the growth performance, body composition, nutrient digestion and absorption, gut health, and microbiota of weaned piglets. A total of 100 piglets (Duroc × Landrace × Yorkshire, weaned at day 21) with an initial weight of 6.39 ± 0.03 kg were randomly assigned to four treatments and fed with 18% CP antibiotic-free diets, 18% CP with antibiotics diets, 24% CP antibiotic-free diets, and 24% CP with antibiotics diets for 0–14 d (S1). Furthermore, the piglets were fed with an identical diet (19% CP and without antibiotics) starting day 15 until they reached 25 kg (S2). Results indicated that the average daily gain (ADG) and gain feed ratio (G:F) during the S1 phase as well as BW at day 14, were significantly decreased (p < 0.05) in the 18% CP group compared with the 24% CP group. Similarly, piglets in the 18% CP group showed a significantly decreased body protein content and body water, protein deposition rates at the S1 phase, and significantly improved the body lipid content and deposition rate but not (p > 0.05) at the S2 phase. The 18% CP group demonstrated significantly increased (p < 0.05) serum concentrations of Threonine, Valine, Isoleucine, and Lysine in weaned piglets during the S1 phase, while Glycine concentration significantly decreased, and no significant (p > 0.05) effects were observed in the S2 phase. Furthermore, dietary antibiotic supplementation had no effect on (p > 0.05) piglet growth performance, body composition, nutrient digestion, and metabolism throughout the entire trial period. In the absence of antibiotics, compared to the 24% CP diet group, the piglets fed with an 18% CP diet significantly increased the relative abundance of Lactobacillus in the colon of weaned piglets upon reaching 25 kg BW (p < 0.05). Compared to the diet without added antibiotics, the addition of antibiotics to the diet significantly decreased the relative abundance of Pseudoramibacter in the colon of weaned piglets on day 14. No significant (p > 0.05) difference was observed in intestinal morphology or gastrointestinal pH among the groups. In conclusion, lower dietary protein levels in the early post-weaning period reduced growth performance and promoted gut microbiota balance, and compensatory growth occurred after returning to higher protein levels two weeks after weaning.