Effect of Oregano Oil and Cobalt Lactate on Sheep In Vitro Digestibility, Fermentation Characteristics and Rumen Microbial Community

Abstract

The objective of this experiment was to evaluate the effect of different EOC (0.1425% cobalt lactate + 1.13% oregano essential oil + 98.7275% carrier) levels on in vitro rumen fermentation and microbial changes. Six EOC levels (treatments: 0 mg·L−1, CON; 50 mg·L−1, EOC1; 100 mg·L−1, EOC2; 400 mg·L−1, EOC3; 800 mg·L−1, EOC4 and 1500 mg·L−1, EOC5) were selected to be used to in vitro incubation. The in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), in vitro acid detergent fiber digestibility (IVNDFD), pH, ammonia-nitrogen (NH3-N) concentration, total volatile fatty acid (TVFA) concentration and microbial protein (MCP) concentration were measured after 48 h incubation, after which the groups with significant nutrient digestibility and fermentation parameters were subjected to 16S rRNA sequencing. The results showed that the total gas production (GP) of the EOC5 group was higher than that of the other groups after 12 h of in vitro incubation. TVFA, NH3-N and MCP concentrations were also shown to be higher in group EOC5 than those in other groups (p < 0.05), while NH3-N and MCP concentrations in the EOC2 group were lower than those in other groups significantly (p < 0.05). The molar ratio of acetic acid decreased while the molar ratio of propionic acid increased after the addition of EOC. 16S rRNA sequencing revealed that the rumen microbiota was altered in response to adding EOC, especially for the EOC5 treatment, with firmicutes shown to be the most abundant (43.1%). The relative abundance of Rikenellaceae_RC9_gut_group was significantly lower, while the relative abundance of uncultured_bacterium_f_Muribaculaceae and Succiniclasticum was significantly higher in the EOC5 group than those in other groups (p < 0.05). Comprehensive analysis showed that EOC (1500 mg·L−1) could significantly increase gas production, alter sheep rumen fermentation parameters and microbiota composition.

Effect of Oregano (Lippia graveolens) Essential Oil as a Phytogenic Feed Additive on Productive Performance, Ruminal Fermentation, and Antioxidant Activity in Lamb Meat

“…Although no significant differences were observed, adding 0.02 and 0.04% OEO reduced ruminal NH 3 -N concentration by 16 and 22%, respectively. These results can be attributed to the antimicrobial activity of OEO [44] by inhibiting ammonia-producing bacteria [45], produced by thymol, one of the main components of OEO (Lippia graveolens) [46], acting on rumen microorganisms and by affecting protein deamination [47].…”

“…VFAs are the main products of carbohydrate degradation in diets and provide most of the energy precursors for metabolic processes in ruminants, so a variation in the acetate: propionate ratio could affect the productive performance [45,48]. Other studies have reported that the inclusion of different levels of OEO has not affected VFA production [41,49] or the acetate: propionate ratio [13].…”

Short Term Effect of Ivermectin on the Bacterial Microbiota from Fecal Samples in Chinchillas (Chinchilla lanigera)

“…For the genus level, Uncultured_bacterium_f_Muribaculaceae was the most common genus, found in the rumen microbial community of sheep as well [ 24 ], being slightly more predominant on day 14 post ivermectin usage in this study. This bacterial genus could produce succinic acid as an important gluconeogenic intermediate and was helpful with polysaccharides degradation and metabolism [ 25 ].…”

Effect of Methionine Hydroxy Analog on Hu Sheep Digestibility, Rumen Fermentation, and Rumen Microbial Community In Vitro

“…Gas production is an important indicator reflecting the degree of rumen fermentation. The stronger the fermentation of the diet, the higher the microbial activity [ 36 , 37 ]. Previous studies have shown that the addition of rumen-protected methionine to the diet could significantly increase gas production [ 38 , 39 ].…”