Supplementation with rumen-inert fat in the growing phase altered adipogenic gene expression and the size and number of adipocytes in Hanwoo steers.

We hypothesized that the provision of rumen-inert fat (RIF) to growing cattle (9 to 13 mo of age) would affect the expression of genes involved in lipid metabolism and thereby affect the size and number of adipocytes of steers slaughtered at 30 mo of age. Thirty steers with an average initial body weight (BW) of 239 ±â€…25 kg were allocated to six pens, balanced for BW and genetic merit for marbling, and assigned to one of two treatment groups: control (only basal diet) or test diet (basal diet with 200 g of RIF per day, on an as-fed basis) for 5 mo. Biopsy samples of longissimus lumborum (LM) muscle were then collected for analysis of fatty acid composition and gene expression. Both groups were then fed the same basal diets during the early and late fattening phases, without RIF, until slaughter (average shrunk BW = 759 kg). Supplementation with RIF increased the longissimus thoracis (LT) intramuscular fatty acid concentration at slaughter (P = 0.087) and numerically increased the quality grade score (P = 0.106). The LM intramuscular relative mRNA expression of genes such as PPARα, ZFP423 and SREBP1, FASN, SCD, FABP4, GPAT1, and DGAT2 were downregulated (P < 0.1) following RIF supplementation. Supplementation of RIF decreased (P < 0.1) diameter and concomitantly increased intramuscular adipocytes per viewing section at slaughter. This likely was caused by promotion of triacylglycerol hydrolysis during the growing phase. Another possible explanation is that the relative mRNA expression of gene ATGL was upregulated by RIF supplementation during the growing (P < 0.1) and the fattening phases (P < 0.05), while the genes associated with fatty acid uptake (FABP4) and esterification (DGAT2) were downregulated during the growing phase and upregulated (P < 0.1) during the fattening phase. This implies that the lipid turnover rate was higher for steers during the growing than fattening phase. This study demonstrated that RIF supplementation during the growing phase induced a carryover effect on the lipogenic transcriptional regulation involved in adipocyte lipid content of intramuscular adipose tissue; increased triacylglycerol hydrolysis during the growing phase subsequently was followed by increased lipid accumulation during the fattening phases.

Rumen inert fat (RIF) is a type of fat supplement that is used in the diets of beef cattle as early as 6 mo of age in calves and continues through the finishing period to improve the dietary energy density which can be used by the animal to deposit more lipid in the muscle tissue. However, for Hanwoo beef cattle, the precise time of RIF supplementation has not yet been determined. This study hypothesized that supplementing RIF at the growing phase (9 to 13 mo of age) would have a positive influence on the marbling characteristics of meat at slaughter. The growth rate and performance of steers were not improved by RIF supplementation, however, an increase in intramuscular fatty acid content was noted that was accompanied by the increased number of intramuscular adipocytes and decreased intramuscular adipocyte diameter. Supportively, upregulation of the genes associated with fatty acid uptake and esterification during the fattening phase of RIF-fed animals was noted. Overall, supplementing RIF at the growing stage could improve the lipid content of the meat which is supported by the increased lipid hydrolysis during the growing phase and followed by increased lipid accumulation during the fattening phases.

In Vitro Screening of East Asian Plant Extracts for Potential Use in Reducing Ruminal Methane Production.

Indiscriminate use of antibiotics can result in antibiotic residues in animal products; thus, plant compounds may be better alternative sources for mitigating methane (CH4) production. An in vitro screening experiment was conducted to evaluate the potential application of 152 dry methanolic or ethanolic extracts from 137 plant species distributed in East Asian countries as anti-methanogenic additives in ruminant feed. The experimental material consisted of 200 mg total mixed ration, 20 mg plant extract, and 30 mL diluted ruminal fluid-buffer mixture in 60 mL serum bottles that were sealed with rubber stoppers and incubated at 39 °C for 24 h. Among the tested extracts, eight extracts decreased CH4 production by >20%, compared to the corresponding controls: stems of Vitex negundo var. incisa, stems of Amelanchier asiatica, fruit of Reynoutria sachalinensis, seeds of Tribulus terrestris, seeds of Pharbitis nil, leaves of Alnus japonica, stem and bark of Carpinus tschonoskii, and stems of Acer truncatum. A confirmation assay of the eight plant extracts at a dosage of 10 mg with four replications repeated on 3 different days revealed that the extracts decreased CH4 concentration in the total gas (7-15%) and total CH4 production (17-37%), compared to the control. This is the first report to identify the anti-methanogenic activities of eight potential plant extracts. All extracts decreased ammonia (NH3-N) concentrations. Negative effects on total gas and volatile fatty acid (VFA) production were also noted for all extracts that were rich in hydrolysable tannins and total saponins or fatty acids. The underlying modes of action differed among plants: extracts from P. nil, V. negundo var. incisa, A. asiatica, and R. sachalinensis resulted in a decrease in total methanogen or the protozoan population (p < 0.05) but extracts from other plants did not. Furthermore, extracts from P. nil decreased the population of total protozoa and increased the proportion of propionate among VFAs (p < 0.05). Identifying bioactive compounds in seeds of P. nil by gas chromatography-mass spectrometry analysis revealed enrichment of linoleic acid (18:2). Overall, seeds of P. nil could be a possible alternative to ionophores or oil seeds to mitigate ruminal CH4 production.

Characterization of ambrette seed oil and its mode of action in bacteria.

In the present study, chemical composition and the antibacterial mechanism of ambrette seed oil are investigated. Chemical composition of the oil was analysed by gas chromatography-mass spectrometry (GC-MS). Thirty-five compounds were identified and the major compounds were found to be farnesol acetate (51.45%) and ambrettolide (12.96%). The antibacterial activity was performed by well diffusion assay and the mechanisms were studied by measuring the alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and protein leakage assays. The antibacterial effect of the ambrette seed oil showed inhibitory effect against Bacillus subtilis, Staphylococcus aureus and Enterococcus faecalis. The LDH activity was high in all tested bacteria compared with control, whereas the ALP and protein concentrations were also increased in E. faecalis. Molecular docking revealed the ligands farnesol acetate and ambrettolide had satisfactory binding energy towards the beta lactamase TEM-72 and dihydrofolate reductase (DHFR) protein. Due to its better antibacterial properties, the ambrette seed oil could be used as a source of antibacterial agents.