Leizhou goats are famous for their delicious meat but have inferior growth performance. There is little information on rumen-protected fat (RPF) from the Leizhou goat. Hence, we observed the effects of RPF on growth, fecal short-chain fatty acids, and bacteria community with respect to Leizhou goats. Twelve goats (13.34 ± 0.024 kg) were selected and assigned randomly to one of two treatments: (1) a control diet (CON) and (2) 2.4% RPF with a control diet (RPF). The final body weight and average daily gain (ADG) were greater (p < 0.05), and the dry matter intake (DMI): ADG was lower (p < 0.05) in the RPF group than in the CON group. There were no differences in DMI between the CON and RPF groups. The concentrations of total short-chain fatty acids, acetate, propionate, and butyrate were lower (p < 0.05) in the RPF group than in the CON group. The relative abundances of Ruminococcus, Rikenellaceae_RC9_gut_group, Treponema, norank_f__norank_o__RF39, Eubacterium_siraeum_group, and Ruminococcus_torques_group were lower (p < 0.05) in the RPF group than in the CON group. The relative abundances of Bacteroides, norank_f__norank_o__Clostridia_UCG-014, norank_f__Eubacterium_coprostanoligenes_group, Eubacterium_ruminantium_group, norank_f__Oscillospirale-UCG-010, Oscillospiraceae_UCG-002, and Family_XIII_AD3011_group were greater (p < 0.05) in the RPF group than in the CON group. It was concluded that RPF could improve the goats’ growth performance by regulating their fecal bacteria communities.

The objective of this study was to evaluate the effect of fecal bacterial community and metabolomics in goats when consuming a lower-protein diet with different energy levels. Eight healthy Leizhou goats, with 11 ± 0.78 kg of body weight, were selected and housed individually in cages. The animals were randomly allocated to a lower-protein diet that varied with four metabolites energy levels (7.01, 8.33, 9.66, and 10.98 MJ/kg DM) in a replicated 4 × 4 Latin square design. Notably, energy-dependent microbial restructuring was observed at both phylum and genus levels. At the phylum level, the relative abundances of Firmicutes and Spirochaetote increased linearly, whereas the Bacteroidota and Patescibacteria decreased linearly with increasing dietary energy levels (p < 0.05). The relative abundances of Verrucomicrobiota increased quadratically, whereas others decreased quadratically with increasing dietary energy levels (p < 0.05). At the genus level, a total of 316 bacteria were identified in the 32 fecal samples. The relative abundances of Christensenellaceae_R-7_group, unclassified_f__Lachnospiraceae, Ruminococcus, norank_o__Clostridia_UCG-014, Treponema, [Eubacterium]_siraeum_group, and [Eubacterium]_ruminantium_group increased linearly, whereas the Oscillospiraceae_UCG-005, norank_f__[Eubacterium]_coprostanoligenes_group, Prevotellaceae_UCG-004, unclassified_c__Clostridia, norank_f__Ruminococcaceae, unclassified_f__ Oscillospiraceae, and others decreased linearly with an increasing dietary energy levels (p < 0.05). In addition, the metabolomic analysis of feces showed that there are many differential metabolites in goats when consuming a lower-protein diet with different energy levels; for example, lipid metabolism and amino acid metabolic pathways were increased in MLE, MHE, and HE groups compared to the LE group. In conclusion, this study provides further information regarding the effects on fecal bacterial community composition and metabolites in goats when consuming a lower-protein diet with different energy levels.

This study examined the effect of dietary supplementation of nano-selenium (nano-Se) on the average daily gain (ADG), fecal bacteria community, and concentrations of fecal minerals and volatile fatty acids in feedlot Hainan black goats. Eighteen goats (18.6 ± 0.69 kg) were divided randomly into three groups, with each group receiving a different level of supplementary nano-Se (n = six goats per treatment) as follows: (1) 0.0 mg (CON); (2) 0.2 mg; and (3) 0.4 mg nano-Se/kg dry matter intake (DMI). The final body weight (p = 0.012) and ADG increased linearly (p < 0.01), whereas the ratio of DMI to ADG decreased linearly (p < 0.01) with increasing dietary nano-Se levels. Fecal concentrations of Se increased linearly (p < 0.001), whereas Cu (p < 0.01), Zn (p = 0.020), and Fe (p = 0.010) decreased linearly with increasing dietary nano-Se levels. The relative abundances of Treponema (p = 0.046), norank_f__norank_o__Clostridia_UCG-014 (p < 0.01), norank_ f_norank_o__RF39 (p < 0.01), Eubacterium_siraeum_group (p < 0.001), and Family_XIII_AD3011_group (p = 0.040) increased linearly, and unclassified_f__Lachnospiraceae (p < 0.001), Rikenellaceae_RC9_gut_group (p < 0.01), Eubacterium_ruminantium_group (p = 0.021), and Prevotella (p < 0.001) decreased linearly with increasing dietary nano-Se levels. It was concluded that supplementary nano-Se could improve ADG and reduce the DMI to ADG ratio and fecal heavy metals by altering the bacterial community in feedlot goats. We recommend a dietary supplementation of approximately 0.4 mg nano-Se/kg DM for feedlot Hainan black goats, but further research is warranted to determine the precise dose and the possible contamination risks of Se.