Effects of an essential oil blend rich in cinnamaldehyde and carvacrol on rumen biohydrogenation and fatty acid profile in the longissimus lumborum of growing lambs.

BACKGROUND: Essential oils extracted from cinnamon bark and oregano are rich in cinnamaldehyde and carvacrol and show potential for promoting animal performance. However, their impact on rumen biohydrogenation and the fatty acid composition of meat has not been reported. The hypothesis of this study was that a blend of essential oils rich in cinnamaldehyde and carvacrol would inhibit rumen biohydrogenation and promote the accumulation of polyunsaturated fatty acids (PUFAs) in lamb meat. The present study evaluated the effect of a blend essential oil (EO) rich in cinnamaldehyde and carvacrol on the nutrient digestibility, rumen biohydrogenation, growth performance, and fatty acid profile of the longissimus lumborum of lambs. RESULTS: Sixty male lambs with an average age of 84 ± 0.98 days and initial body mass of 25.4 ± 0.29 kg (mean ± standard deviation) were assigned randomly to four diets, and supplemented with 0 (EO0), 30 (EO30), 60 (EO60), and 120 (EO120) mg kg-1 dry matter of EO for 60 days. Although dry matter and neutral detergent fiber digestibility all showed a linear decrease (P ≤ 0.02) with increasing quantities of EO, final body mass and average daily gain increased linearly (P = 0.04), and average daily weight gain (ADG)/dry matter intake (DMI) tended to increase linearly (P = 0.07). Increasing EO supplementation resulted in a linear decrease in total volatile fatty acid concentration, acetate molar percentage, and acetate-to-propionate ratio (P ≤ 0.03), with the EO120 treatment being lower than the other EO treatments (P ≤ 0.05). Seven lambs from the EO120 treatment and seven lambs from the EO0 treatment were randomly slaughtered. It was observed that the proportions of C18:2n6c and PUFA in longissimus lumborum were higher in the EO120 treatment than the EO0 treatment (P ≤ 0.05). The relative abundance of Firmicutes in the rumen was decreased by the EO120 treatment in comparison with the EO0 treatment (P ≤ 0.05). Furthermore, the predicted relative abundances of genes encoding for conjugated linoleic acid reductase tended to decrease with the EO120 treatment (P = 0.06). CONCLUSIONS: We demonstrated that supplementation of the EO blend rich in cinnamaldehyde and carvacrol can enhance lamb growth performance and promote the deposition of desirable PUFAs in meat. © 2024 Society of Chemical Industry.

Does supplemental 18:0 alleviate fish oil-induced milk fat depression in dairy ewes?

Supplementation of dairy ewe diet with marine lipids may be an effective strategy for modulating milk fatty acid composition but induces milk fat depression (MFD). This syndrome has been associated with a shortage of 18:0 for uptake and Δ(9)-desaturation that may impair the capacity of the mammary gland to achieve an adequate fluidity for milk fat secretion. On this basis, it was suggested that supplemental 18:0 may contribute to alleviate marine lipid-induced MFD in sheep. To test this hypothesis, 12 lactating ewes were allocated to 1 of 3 lots and used in a 3×3 Latin square design with 3 periods of 28 d each and 3 experimental treatments: a total mixed ration without lipid supplementation (control) or supplemented with 20 g/kg of DM of fish oil alone (FO) or in combination with 20 g/kg of DM of 18:0 (FOSA). Diets were offered ad libitum, and animal performance and rumen and milk fatty acid composition were studied at the end of each period. After completing the Latin square trial and following a change-over design, the in vivo digestibility of supplemental 18:0 was estimated using 6 lactating sheep. As expected, diet supplementation with fish oil increased the milk content of some potentially health-promoting fatty acids (e.g., cis-9,trans-11 18:2, trans-11 18:1, 20:5n-3, 22:5n-3, and 22:6n-3), but reduced milk fat concentration and yield (-20% in both FO and FOSA treatments). Thus, although reductions in milk 18:0 and cis-9 18:1 output caused by FO (-81 and -51%, respectively) were partially reversed with FOSA diet (-49 and -27%, respectively), the addition of 18:0 to the diet did not prove useful to alleviate MFD. This response, which could not be fully accounted for by the low digestibility coefficient of supplemental 18:0, may challenge the theory of a shortage of this fatty acid as a mechanism to explain fish oil-induced MFD in sheep. Effects of FO and FOSA on rumen and milk fatty acid composition would support that increases in the concentration of some candidate milk fat inhibitors (e.g., cis-9 16:1 or 10-oxo-18:0) might play a relevant role in this type of MFD.

Effect of chemical form, heating, and oxidation products of linoleic acid on rumen bacterial population and activities of biohydrogenating enzymes.

Heating polyunsaturated fatty acids (PUFA) produces oxidation products, such as hydroperoxides, aldehydes, and oxypolymers, which could be responsible at least in part for modification of PUFA rumen biohydrogenation (BH). Three in vitro experiments were conducted to investigate the effects of linoleic acid (cis-9,cis-12-C18:2) oxidation products on BH. In the first experiment, we studied the effects of free linoleic acid (FLA), heated FLA (HFLA, at 150 °C for 6h), triacylglycerols of linoleic acid (TGLA), heated TGLA (HTGLA, at 150 °C for 6h), 13-hydroperoxide (13HPOD), trans-2-decenal (T2D), and hexanal (HEX) on BH in vitro after 6 and 24h of incubation. In the second experiment, aldehydes differing in chain length and degree of unsaturation [pentanal, HEX, heptanal, nonanal, T2D, trans-2,trans-4-decadienal (T2T4D)] were incubated in vitro for 5h in rumen fluid. In the third experiment, 9-hydroperoxide (9HPOD), 13HPOD, HEX, or T2T4D were incubated for 1h in rumen fluid inactivated with chloramphenicol to investigate their effects on enzyme activity. In experiment 1, heat treatment of TGLA generated TGLA oxypolymers, did not affect cis-9,cis-12-C18:2 disappearance, but did decrease BH intermediates, especially trans-11 isomers. Heating FLA decreased cis-9,cis-12-C18:2 disappearance and cis-9,trans-11-CLA and trans-11-C18:1 production. Treatment with HEX and T2D did not affect cis-9,cis-12-C18:2 disappearance and barely affected production of BH intermediates. The bacterial community was affected by 13HPOD compared with FLA and HFLA, in parallel with an increase in trans-10 isomer production after a 6-h incubation. After 24h of incubation, 13HPOD decreased trans-11 isomer production, but to a lesser extent than HFLA. In experiment 2, some weak but significant effects were observed on BH, unrelated to chain length or degree of unsaturation of aldehydes; the bacterial community was not affected. In experiment 3, 9HPOD inhibited Δ(9)-isomerization, and both 9HPOD and 13HPOD inhibited Δ(12)-isomerization. We concluded that oxypolymers did not affect cis-9,cis-12-C18:2 disappearance. Heating both esterified and free cis-9,cis-12-C18:2 greatly altered Δ(12)-isomerization. Aldehydes had few effects. Hydroperoxides are responsible, at least in part, for the effects of fat heating: 13HPOD increased trans-10 isomer production (probably by affecting the bacterial community) and decreased trans-11 isomer production by inhibiting Δ(12)-isomerase activity, whereas 9HPOD inhibited both isomerases.

Inclusion of Sainfoin in the Concentrate of Finishing Lambs: Fatty Acid Profiles of Rumen, Plasma, and Muscle.

The effects of sainfoin inclusion (Onobrychis viciifolia) in the finishing concentrate for light lambs on the fatty acid (FA) composition of the ruminal digesta, plasma, and meat were evaluated. Twenty-six weaned male lambs were divided into three groups and fed individually ad libitum for 40 days with one of three concentrates differing in the level of sainfoin inclusion: 0% (0SF), 20% (20SF), and 40% (40SF). The rumen digesta showed an increase in C18:3 n-3 concentration and a decrease in C18:1 t10 concentration when sainfoin was included in the concentrate regardless of the level of inclusion. However, the highest C18:1 t11 and the lowest C18:2 n-6 proportions were obtained only in the 40SF rumen, showing a stronger t11 biohydrogenation pathway. In plasma, most effects were associated with changes in the levels of polyunsaturated FA (PUFA) n-3. The meat FA profile of 40SF lambs presented higher percentages of PUFA n-3 and CLA c9,t11 and a lower PUFA n-6/PUFA n-3 ratio compared with those from 0SF and 20SF diets because of the potentiation of the ruminal t11 pathway. Inclusions of 20 and 40% sainfoin both showed beneficial effects on meat quality; furthermore, these effects were most marked in the 40% sainfoin diet.

Biohydrogenation Pathway of α-Linolenic Acid in Rumen of Dairy Cow In Vitro.

The t9,c12,c15-C18:3 as an isomer of α-linolenic acid (c9,c12,c15-C18:3; ALA), has been recently detected in milk, but has not been found in the rumen. This study hypothesized that it may be a biohydrogenation product of ALA in rumen and aimed to explore whether it was present in the rumen and help to understand the rumen biohydrogenation mechanisms of ALA. The in vitro experiment included two treatments, a control check (CK group) with 50 µL ethanol added, and ALA group with 50 µL ethanol and 2.6 mg ALA (ALA addition calculated by 1.30% of dry matter base of diet); each sample of fermentation fluid had the composition of C18 fatty acids analyzed at 0, 0.5, 1, 2, 3, 4, 5, and 6 h. The results showed that no t9,c12,c15-C18:3 was detected in the CK group, but ALA addition increased the concentration of t9,c12,c15-C18:3 in fermentation fluid. The content of t9,c12,c15-C18:3 peaked 1 h after fermentation, then declined gradually. At 1 h, no t9c12c15-C18:3 was detected in the fermentation fluid of the CK treatment. The results suggested that ALA converted to the isomer t9,c12,c15-C18:3 through biohydrogenation in the rumen. The addition of ALA can also increase the concentration of t9,c12-C18:2, c9,t11-C18:2, c12-C18:1, t11-C18:1, t9-C18:1, and c6-C18:1 in fermentation fluid. It was concluded using an in vitro experiment that t9,c12,c15-C18:3 was a product of rumen biohydrogenation of ALA.

Inclusion of cocoa by-product in the diet of dairy sheep: Effect on the fatty acid profile of ruminal content and on the composition of milk and cheese.

In this study, we hypothesized that dietary cocoa bean shell (CBS) as a partial replacer of human edible cereal grains in the diet of lactating ewes may affect performance and milk and cheese composition. Twenty Comisana lactating ewes allotted into control (CTRL; n = 10) or cocoa (CBS; n = 10) group received alfalfa hay ad libitum and 800 g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Milk yield and composition did not differ between groups, and only urea concentration was lower in CBS milk. Dietary CBS increased cheese fat and reduced protein percentage in CBS group. Fatty acid composition of rumen content partially reflected that of the ingested diet, with total saturated fatty acids (SFA), total monounsaturated fatty acids (MUFA), 16:0, 18:0 and 18:1c9 greater in the CBS group. Moreover, all the identified trans- and cis-18:1 isomers were greater in CBS rumen content. Milk and cheese showed a similar fatty acid composition. Total MUFAs were greater in milk and cheese of CBS, mainly due to the proportion of 18:1c9, and conversely, total polyunsaturated fatty acids (PUFA), PUFAn-6 and PUFAn-6-to-PUFAn-3 ratio was greater in CTRL group. Concluding, the inclusion of CBS in the diet of lactating ewes within the limit imposed by the current legislation did not cause detrimental effects on animal performance and milk composition. Interestingly, dietary CBS reduced milk urea concentration probably due to the phenols contained in CBS concentrate. However, our results support that biohydrogenation was weakly impaired by dietary CBS. Finally, CBS negatively affected cheese nutritional characteristics due to lower protein and greater fat content, but improved fat health indexes in milk and cheese.

Effect of calcium lignosulfonate supplementation on metabolic profiles of confined lambs.

This study aimed to evaluate the effect of calcium lignosulfonate associated with whole cottonseed in high-concentrate diets for sheep. Eight Dorper crossbred sheep with an average live weight of 42.5 ± 1.70 kg were assigned to two 4 × 4 Latin squares. The following experimental diets were evaluated: control diet (without calcium lignosulfonate) and diets with inclusion of 50, 100, and 150 g of calcium lignosulfonate/kg fresh matter. Diets were composed of soybean meal, ground corn, and whole cottonseed. Feed intake, digestibility, metabolic characteristics, and feeding behavior were evaluated. The intake of nutritional components did not show significant differences as a function of the lignosulfonate levels in the diet; however, the increase in calcium lignosulfonate levels linearly decreased the dry matter digestibility. Rumen ammonia nitrogen concentrations decreased linearly as the lignosulfonate levels in the diets were increased. There was no effect of lignosulfonate levels on blood parameters or feeding behavior of the animals. The use of lignosulfonate associated with cottonseed decreases the digestibility of dry matter and the concentration of rumen ammonia nitrogen, but does not change the intake of nutritional components, the blood parameters, or the feeding behavior of sheep.

Evidence for the Initial Steps of DHA Biohydrogenation by Mixed Ruminal Microorganisms from Sheep Involves Formation of Conjugated Fatty Acids.

Incubation of DHA with sheep rumen fluid resulted in 80% disappearance in 6 h. The products were analyzed as their fatty acid (FA) methyl esters by GC-FID on SP-2560 and SLB-IL111 columns. The GC-online reduction × GC and GC-MS techniques demonstrated that all DHA metabolites retained the C22 structure (no evidence of chain-shortening). Two new transient DHA products were identified: mono-trans methylene interrupted-DHA and monoconjugated DHA (MC-DHA) isomers. Identification of MC-DHA was confirmed by their predicted elution using equivalent chain length differences from C18 FA, their molecular ions, and the 22:5 products formed which were the most abundant at 6 h. The 22:5 structures were established by fragmentation of their 4,4-dimethyloxazoline derivatives, and all 22:5 products contained an isolated double bond, suggesting formation via MC-DHA. The most abundant c4,c7,c10,t14,c19-22:5 appeared to be formed by unknown isomerases. Results suggest that the initial biohydrogenation of DHA was analogous to that of C18 FA.

Rumen Biohydrogenation and Microbial Community Changes Upon Early Life Supplementation of 22:6n-3 Enriched Microalgae to Goats.

Dietary supplementation of docosahexaenoic acid (DHA)-enriched products inhibits the final step of biohydrogenation in the adult rumen, resulting in the accumulation of 18:1 isomers, particularly of trans(t)-11 18:1. Occasionally, a shift toward the formation of t10 intermediates at the expense of t11 intermediates can be triggered. However, whether similar impact would occur when supplementing DHA-enriched products during pregnancy or early life remains unknown. Therefore, the current in vivo study aimed to investigate the effect of a nutritional intervention with DHA in the early life of goat kids on rumen biohydrogenation and microbial community. Delivery of DHA was achieved by supplementing DHA-enriched microalgae (DHA Gold) either to the maternal diet during pregnancy (prenatal) or to the diet of the young offspring (postnatal). At the age of 12 weeks, rumen fluid was sampled for analysis of long-chain fatty acids and microbial community based on bacterial 16S rRNA amplicon sequencing. Postnatal supplementation with DHA-enriched microalgae inhibited the final biohydrogenation step, as observed in adult animals. This resulted particularly in increased ruminal proportions of t11 18:1 rather than a shift to t10 intermediates, suggesting that both young and adult goats might be less prone to dietary induced shifts toward the formation of t10 intermediates, in comparison with cows. Although Butyrivibrio species have been identified as the most important biohydrogenating bacteria, this genus was more abundant when complete biohydrogenation, i.e. 18:0 formation, was inhibited. Blautia abundance was positively correlated with 18:0 accumulation, whereas Lactobacillus spp. Dialister spp. and Bifidobacterium spp. were more abundant in situations with greater t10 accumulation. Extensive comparisons made between current results and literature data indicate that current associations between biohydrogenation intermediates and rumen bacteria in young goats align with former observations in adult ruminants.

Microbial Production of Conjugated Linoleic Acid and Conjugated Linolenic Acid Relies on a Multienzymatic System.

Conjugated linoleic acids (CLAs) and conjugated linolenic acids (CLNAs) have gained significant attention due to their anticarcinogenic and lipid/energy metabolism-modulatory effects. However, their concentration in foodstuffs is insufficient for any therapeutic application to be implemented. From a biotechnological standpoint, microbial production of these conjugated fatty acids (CFAs) has been explored as an alternative, and strains of the genera Propionibacterium, Lactobacillus, and Bifidobacterium have shown promising producing capacities. Current screening research works are generally based on direct analytical determination of production capacity (e.g., trial and error), representing an important bottleneck in these studies. This review aims to summarize the available information regarding identified genes and proteins involved in CLA/CLNA production by these groups of bacteria and, consequently, the possible enzymatic reactions behind such metabolic processes. Linoleate isomerase (LAI) was the first enzyme to be described to be involved in the microbiological transformation of linoleic acids (LAs) and linolenic acids (LNAs) into CFA isomers. Thus, the availability of lai gene sequences has allowed the development of genetic screening tools. Nevertheless, several studies have reported that LAIs have significant homology with myosin-cross-reactive antigen (MCRA) proteins, which are involved in the synthesis of hydroxy fatty acids, as shown by hydratase activity. Furthermore, it has been suggested that CLA and/or CLNA production results from a stress response performed by the activation of more than one gene in a multiple-step reaction. Studies on CFA biochemical pathways are essential to understand and characterize the metabolic mechanism behind this process, unraveling all the gene products that may be involved. As some of these bacteria have shown modulation of lipid metabolism in vivo, further research to be focused on this topic may help us to understand the role of the gut microbiota in human health.

Ruminal Biohydrogenation Kinetics of Defatted Flaxseed and Sunflower Is Affected by Heat Treatment.

The effect of heat treatment on biohydrogenation of linoleic acid (LA) and linolenic acid (LNA) and formation of stearic acid (SA), cis-9, trans-11 conjugated LA (CLA), trans-10, cis-12 CLA and trans-vaccenic acid (VA) was studied in in vitro incubations with diluted rumen fluid as inoculum and partly defatted flaxseed (DF) and partly defatted sunflower (DS) as test feeds. Feeds were heated in a laboratory oven at 110 °C for 0 (unheated), 45, or 90 min. Michaelis-Menten kinetics was applied for quantifying biohydrogenation rate. The DF heated for 90 min showed the lowest biohydrogenation rate of LNA and LA, indicated by the lowest Vmax value (P < 0.04 and P < 0.03, respectively). The DS heated for 45 min had the lowest biohydrogenation rate of LNA, indicated by the lowest Vmax value (P < 0.04). In conclusion, heat treatment decreased biohydrogenation of LA and LNA in DF and LNA in DS.