In vitro rumen biohydrogenation of unsaturated fatty acids in tropical grass-legume rations

Effects of herbal plant supplementation on rumen fermentation profiles and protozoan population in vitro

Background and Aim

In the livestock sector, particularly ruminants, an approach to minimize methane emissions can be carried out through a feeding strategy involving herbal plants containing bioactive compounds that can reduce protozoa and decrease methane gas emissions. The aim of this in vitro study was to analyze the effects of herbal plant supplementation on rumen fermentation, total gas, and methane production, in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), and protozoa populations within the rumen.

Materials and Methods

Two experiments were conducted in this study. Experiment 1 was conducted to determine the most promising herbal plants capable of increasing total gas production and reducing protozoan populations. Three potential herbals selected in Experiment 1 were continued in Experiment 2 as supplements in the palm kernel meal (PKM)-based ration (70% PKM + 30% herbal plants).

Results

Experiment 1 revealed that Eurycoma longifolia (EL), Cola acuminata (CLA), and Cassia alata (CSA) were potential herbal candidates for enhancing total gas production and the percentages of IVDMD and IVOMD. In Experiment 2, supplementation with EL, CLA, and CSA significantly increased IVDMD from 62.84% to 70.15%, IVOMD from 61.61% to 53.18%, and NH3 from 13 mM to 17 mM, as well as reduced partial volatile fatty acids and total gas production. In addition, the methane gas and protozoan populations were reduced.

Conclusion

The utilization of EL, CLA, and CSA effectively increased the production of total gas, IVDMD, and IVOMD while reducing methane gas protozoa populations in rumen fermentation compared with the control.

Supplementation of Water Spinach (Ipomoea aquatica) on the utilization of Mimosa pigra and Leucaena leucocephala leaf for in vitro fermentation

Background and Aim

Ipomoea aquatica (Water Spinach) is the most potential for livestock growth performance, including chickens, pigs, cattle, and goats, especially in a tropical country like Cambodia. It is not only an alternative feed source but also one kind of supplemented feed for goat raising. Supplementation with Water Spinach in the utilization of low-quality tree foliage results in an increase in dry matter intake in goat production. This study aimed to identify the effectiveness of supplementation of Water Spinach in the utilization of Mimosa pigra and Leucaena leucocephala leaf in in vitro fermentation.

Materials and Methods

The study was designed according to a 2 × 2 factorial arrangement in randomized design of seven treatments with different ratios consisted of different three types of dietary treatments, including M. pigra, L. leucocephala, and Water Spinach. The treatments were arranged according to a completely randomized design and were as follow: T1 = M. pigra leaf (100%); T2 = L. leucocephala leaf (100%); T3 = M. pigra leaf and L. leucocephala leaf (50% and 50%); T4 = M. pigra leaf and Water Spinach (99.5% and 0.5%); T5 = L. leucocephala leaf and Water Spinach (99.5% and 0.5%); T6 = M. pigra leaf and Water Spinach (99% and 1%); and T7 = L. leucocephala leaf and Water Spinach (99% and 1%). A total of 200 mg (dry matter) of dietary treatments were prepared in a 60 mL syringe. Each treatment was replicated 3 time. Gas recording of each treatment lasted for 3 days. In vitro was performed for 72 h, was followed by Makkar method. Gas production was recorded at 2, 4, 8, 12, 24, 36, 48, and 72 h of incubation by using strict anaerobic technique. A mixture of rumen fluid and dietary treatments were carried out under continuous flushing with CO₂ in sharking incubator at 39°C. After incubating for 72 h, the ammonia concentration (NH₃-N) was measured and recorded to identify pH, nutrient digestibility, and ammonia concentration (NH₃-N).

Results

Nutrient digestibility of the treatment with Water Spinach supplement in the utilization of L. leucocephala was obtained at a higher digestibility than treatment with M. pigra (p < 0.05). Gas production was different between groups (p < 0.05). Treatment with only M. pigra leaf had the highest gas production (A), while treatment with Water Spinach supplementation had the lowest gas production (A). At 0-24 h, the treatment with L. leucocephala leaf and Water Spinach 0.5% had the highest gas production, but after 24 h, M. pigra leaf and Water Spinach 1% and L. leucocephala leaf and Water Spinach 0.5% produced more gas compared to the other treatments (p < 0.05).

Conclusion

The supplementation of Water Spinach 1% in treatment with M. pigra and L. leucocephala leaf resulted in increased degradability, gas production, and NH₃-N concentration without a change in the pH value rumen condition. Based on these results, it is recommended that the level of Water Spinach supplementation should be 1% of dietary intake. Future studies should consider investigating the rumen ecology associated with Water Spinach supplementation. Feeding with Water Spinach remains a good supplement for ruminant performance; therefore, further studies should be conducted using Water Spinach in ruminant feeding in both metabolic and feeding trials.

Using canonical correlation analysis to understand the rumen biohydrogenation patterns of linoleic and alpha-linolenic acids in the rumen fluid of bovines

The objective of this study was to determine the multivariate relationship among linoleic acid, alpha-linolenic acid, and their main rumen biohydrogenation (BH) intermediates and products in bovine rumen fluid using canonical correlation analysis (CCA). A dataset consisting of 1177 observations generated by 107 in vitro rumen incubation systems of pure and mixed linoleic acid (18:2-c9, c12) and alpha-linolenic acid (18:3-c9, c12, c15) was gathered. Two canonical variates were defined: A: composed of the nine main BH intermediates and products (18:2-c9, t11; 18:2-t11, c15; 18:1-t11; 18:1-t9; 18:1-t6; 18:1-c11; 18:1-c6; 18:1-c9; 18:0) of 18:2-c9, c12 and 18:3-c9, c12, c15 and B: composed of 18:2-c9, c12 and 18:3-c9, c12, c15. Two canonical functions between A and B with significant canonical correlations (R1=0.990 and R2=0.738; p <0.01) were obtained. However, only the first function was selected for CCA. Exploration of canonical loadings for first function, revealed the following quantitative significance (absolute value) order for fatty acids (FA) within their respective canonical variates: A: 18:0(0.958)>18:1-t9(0.837)>18:1-c11(0.835)>18:1-c6(0.824)>18:1-t11(0.747)>18:1-c9(0.738)>18:1-t6(0.415)>18:2-t11, c15(0.387)> 18:2-c9, t11(0.239); B: 18:2-c9, c12(0.667)>18:3-c9, c12, c15(0.488). The CCA showed that 18:2-c9, c12 has a greater contribution than that of 18:3-c9, c12, c15 on the production of the aforementioned BH intermediates, in which 18:0, as well as the groups of 18:1 cis and trans-FA were mainly affected.

Tropical grass and legume pastures may alter lamb meat physical and chemical characteristics

The present study assessed the influence of the type of the tropical pastures on lamb body weight (BW) gain and meat quality. Fifty-four lambs were allocated to three grazing pastures: (1) AG - Aruana grass (Panicum maximum cv. IZ-5); (2) PP - pigeon pea legume (Cajanus cajan cv. Anão); and (3) CS - contiguous swards, half of the paddock with AG and half with PP. After 92 days of grazing, the lambs were slaughtered. Carcasses were evaluated and the longissimus muscle was collected to determine color, lipid profile, tocopherol concentrations, and lipid oxidation. Although the pastures present differences in the characteristics of nutritional quality, the animals did not show difference in BW gain. The results show that all forage presented similar concentration of alpha-tocopherol (137 ± 14.37 mg kg^-1 of fresh matter), whereas total and condensed tannin contents were greater in PP, intermediate in CS, and the lowest in AG treatment (P = 0.0001). Meat α-tocopherol content was similar among treatments (P = 0.1392), with an average concentration close to the optimal level to reduce the meat oxidation. Meat from AG treatment had 45 and 25% lower n-6/n-3 ratio than meat from PP and CS treatments, respectively. The legume increases the unsaturated fatty acids and the grass can reduce the n6/n3 ratio. The level of condensed tannin concentration did show to have important effect on meat characteristics. Both tropical pastures studied can provide a high amount of alpha-tocopherol, generating a great potential to increase the concentration of this antioxidant in lamb's meat.

Effects of rumen-degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis

BACKGROUND AND AIM

Feeding ruminants must notice the degradability of feed, especially protein. Microbial rumen requires ammonia from rumen degradable protein (RDP) beside that ruminant require bypass protein or rumen undegradable protein (RUP) and microbial crude protein. The aim of the study was to discover the best RDP:RUP ratio in beef cattle diets commonly used by Indonesian farmers using an in vitro methodology.

MATERIALS AND METHODS

Samples of Pennisetum purpureum, Leucaena leucocephala, Indigofera zollingeriana, cassava, maize, palm kernel cake, rice bran, and tofu waste were formulated into dietary treatments (dry matter [DM] basis). All experiments were carried out using a 3×3×2 factorial, randomized block design with three replications. Treatments consisted of three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels (55:45, 60:40, and 65:35). The experimental diets were incubated in vitro using buffered rumen fluid for 48 h at 39°C. After incubation, the supernatants were analyzed to determine pH, ammonia concentration, total volatile fatty acid (VFA), and microbial protein synthesis. The residues were analyzed to determine DM, organic matter, protein, and RUP digestibility.

RESULTS

Increased protein, energy, and RDP levels increased digestibility, ammonia concentrations, total VFAs, and microbial protein synthesis (p<0.05), while rations with 16% protein lowered these parameters (p<0.05).

CONCLUSION

Increased dietary protein (from 12% to 14% DM), energy (from 65% to 70% DM), and RDP (from 55% to 65% crude protein [CP]) levels increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. The diet containing 14% DM dietary protein and 70% DM energy, which contained 55%, 60%, or 65% CP RDP optimally increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. Thus, feed based on these RDP:RUP ratios can optimize ruminant productivity.