Effects of Rumen-Protected Methionine on Dairy Performance and Amino Acid Metabolism in Lactating Cows

Effects of Supplementing Rumen-Protected Methionine and Lysine on Milk Performance and Oxidative Status of Dairy Ewes

There is limited information on the impact of dietary supplementation with separate rumen-protected (RP) amino acids (AA), or with their combination, on ewes' oxidative status. Sixty ewes were divided into five groups; C: basal diet (control); M: basal diet + 6 g/ewe RP methionine; L: basal diet + 5 g/ewe RP lysine; LML: basal diet + 6 g methionine and 5 g lysine/ewe; and HML: basal diet + 12 g methionine + 5 g lysine/ewe. Milk's fat content increased in RP-AA fed ewes, while that of protein in M and L only. In blood plasma, the malondialdehyde (MDA) content was reduced in the M, LML, and HML compared to C-fed ewes. An increase in glutathione transferase activity in the blood plasma of the M and LML compared to the C and HML-fed ewes were found. In milk, lower values of the ferric reducing ability of plasma (FRAP) in the LML and HML-fed ewes and of 2,2'-Azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) in LML only, were found. Lysine increased milk's FRAP values and MDA content. Both L and HML diets increased milk's protein carbonyls content. Methionine improves the organism's oxidative status, without adversely affecting milk's oxidative stability. Lysine dietary inclusion affects negatively the oxidative stability of milk.

Use of encapsulated L-lysine-HCl and DL-methionine improves postprandial amino acid balance in laying hens

The supplementation of dietary limiting amino acids (AA) with crystalline AA makes the use of low-protein diets an option in poultry production. The differing absorption rates of crystalline and protein-bound AA may lead to temporally imbalanced AA in the postabsorptive period. In this study, two experiments were conducted to evaluate the effect of encapsulated L-lysine-HCl (L-Lys-HCl) and DL-methionine (DL-Met) on the laying performance of hens. In exp. 1, a total of 135 forty-seven-wk-old Hy-Line Brown hens were subjected to three dietary treatments for 8 wk: basal diet supplemented with 0.14% L-Lys-HCl and 0.17% DL-Met to satisfy the NRC (1994) total Lys and Met recommendation (control) and basal diet supplemented with encapsulated L-Lys-HCl and DL-Met at the levels of 60% (60CLM, 0.084% L-Lys-HCl and 0.102% DL-Met) or 80% of control (80CLM, 0.112% L-Lys-HCl and 0.136% DL-Met), respectively. In exp. 2, 24 fifty-five-wk-old Hy-Line Brown hens were individually reared in cages and subjected to the same treatments as in exp. 1. The plasma concentrations of free AA and nitrogen metabolites were measured 2, 4, and 6 h after fed. The results showed that dietary AA treatment had no significant influence on body weight (BW), feed intake, laying rate, egg weight, egg mass, or feed efficiency. The expression levels of AA transporters CAT-1, y+LAT1, b0,+AT, B0AT, rBAT, EAAT3, and PepT1 in the duodenum, jejunum, and ileum were not influenced (P > 0.05) by dietary treatment. There was an interaction of dietary AA treatment and time (P < 0.05) and the 80CLM hens exhibited higher concentrations of Lys (P < 0.05) than the controls at 2-h time point. In contrast, plasma Met concentration was not influenced (P > 0.05), while Cys was reduced in the 60CLM hens at every time point. The 80CLM hens had higher taurine concentrations than those receiving the control diet at every postprandial time point. In conclusion, these findings demonstrate that by using encapsulated form, the supplemental levels of synthetic L-Lys-HCl and DL-Met can be effectively reduced by approximately 20% with no negative effect on laying performance. The result suggests that encapsulated Lys and Met may ameliorate the postabsorptive AA balance and contribute to the reduced dietary AA supplemental levels.

Beneficial effects of rumen-protected methionine on nitrogen-use efficiency, histological parameters, productivity and reproductive performance of ruminants

Providing essential amounts of balanced nutrients is one of the most vital aspects of livestock production. Among nutrients, protein has an essential role in many physiological functions of animals. Amino acids in needs for both high and medium yielding ruminant animals are not fully covered by microbial degraded feed sources in the rumen of animals, and they must be met by protecting the proteins from being broken down in the rumen; hence, the dietary supplementation of rumen-protected proteins (RPP), including mainly rumen-protected methionine (RPM), became imperative. Many researchers are interested in studying the role of (RPM) in ruminant animals concerning its effect on milk yield, growth performance, digestibility, dry matter intake and nitrogen utilization efficiency. Unfortunately, results obtained from several investigations regarding RPM indicated great fluctuation between its useful and useless effects in ruminant nutrition particularly during early and late lactation period; therefore, this review article may be helpful for ruminant farm owners when they decide to supplement RPM in animal's diet. Conclusively, supplementation of RPM often has a balanced positive influence, without any reported negative impact on milk yield, growth performance and blood parameters especially in early lactating ruminant animals and when used with the low crude protein diet.

Assessing bioavailability of ruminally protected methionine and lysine prototypes

Met and Lys are essential AA that can limit lactational performance in dairy cattle fed protein-sufficient diets. Thus, there is industry demand for ruminally protected (RP) sources of Met and Lys. One method of providing ruminal protection for Met and Lys is lipid encapsulation. The objective of this work was to assess 3 lipid-encapsulated Met prototypes (P1, P2, and P3) and 1 Lys prototype (P4) to determine ruminal protection, small intestine absorption (experiment 1), and animal production responses (experiment 2). Ruminal protection was estimated from 8-h in situ retention during ruminal incubation and intestinal absorption from plasma appearance after an abomasal bolus of the in situ retentate. Blood samples were collected over time to determine plasma Met and Lys concentration responses compared with unprotected Lys and Met infused abomasally. The prototypes were not exposed to the total diet or subjected to typical feed handling methods before evaluation. The bioavailability of P1, P2, and P3 Met prototypes was found to be 14, 21, and 18% of the initial AA material, respectively. The RP-Lys prototype had a bioavailability of 45%. To evaluate production responses, 20 Holstein cows were randomly assigned to 2 trials (n = 10 each) in a replicated Latin square design with 14-d periods. The base diet was predicted to be deficient in metabolizable Met (-14.8 g/d) and Lys (-16.1 g/d) per the Cornell Net Carbohydrate and Protein System (version 6.55). In the Met trial, the base diet was supplemented with RP-Lys to meet Lys requirements, and treatments were as follows: no added RP-Met (NCM), NCM plus Smartamine M (SM; Adisseo, Alpharetta, GA), and NCM plus P1, P2, or P3 at 148% of the Met content of SM. In the Lys trial, the base diet was supplemented with RP-Met to meet the Met requirement, and treatments were as follows: no added Lys (NCL), NCL plus AjiProL (AL; Ajinomoto Heartland Inc., Chicago, IL), and NCL plus P4 at 55, 78, or 102% of the reported absorbed Lys in AL. All products were top dressed on the diet without prior mixing or extended exposure to the rest of the diet. Milk protein concentration significantly increased when diets were supplemented with P2, P3, or SM (3.12, 3.12, and 3.11%, respectively) compared with NCM (3.02%). Only P1 (3.04%) was significantly lower than SM. Prototype P2 had the greatest numerical milk protein output response among the 3 RP-Met prototypes, suggesting that it may have had the greatest efficacy when supplemented into these rations. There was a numerical milk protein concentration response to AL and a linear increase in milk protein concentration for P4. The P4 and AL treatments resulted in comparable milk protein production regardless of P4 dose.

Varying the ratio of Lys:Met while maintaining the ratios of Thr:Phe, Lys:Thr, Lys:His, and Lys:Val alters mammary cellular metabolites, mammalian target of rapamycin signaling, and gene transcription

Amino acids are not only precursors for but also signaling molecules regulating protein synthesis. Regulation of protein synthesis via AA occurs at least in part by alterations in the phosphorylation status of mammalian target of rapamycin (mTOR) pathway proteins. Although the ideal profile of Lys:Met to promote milk protein synthesis during established lactation in dairy cows has been proposed to be 3:1, aside from being the most-limiting AA for milk protein synthesis, the role of Met in other key biologic pathways such as methylation is not well characterized in the bovine. The objective of this study was to determine the influence of increasing supplemental Met, based on the ideal 3:1 ratio of Lys to Met, on intracellular metabolism related to protein synthesis and mTOR pathway phosphorylation status. MAC-T cells, an immortalized bovine mammary epithelial cell line, were incubated (n = 5 replicates/treatment) for 12 h with 3 incremental doses of Met while holding Lys concentration constant to achieve the following: Lys:Met 2.9:1 (ideal AA ratio; IPAA), Lys:Met 2.5:1 (LM2.5), and Lys:Met 2.0:1 (LM2.0). The ratios of Thr:Phe (1.05:1), Lys:Thr (1.8:1), Lys:His (2.38:1), and Lys:Val (1.23:1) were the same across the 3 treatments. Applying gas chromatography-mass spectrometry metabolomics revealed distinct clusters of differentially concentrated metabolites in response to Lys:Met. Lower Phe, branched-chain AA, and putrescine concentrations were observed with LM2.5 compared with IPAA. Apart from greater intracellular Met concentrations, further elevations in Met level (LM2.0) led to greater intracellular concentrations of nonessential AA (Pro, Glu, Gln, and Gly) compared with IPAA and greater essential AA (EAA; Met, Ile, and Leu) and nonessential AA (Pro, Gly, Ala, Gln, and Glu) compared with LM2.5. However, compared with IPAA, mRNA expression of β-casein and AA transporters (SLC7A5, SLC36A1, SLC38A2, SLC38A9, and SLC43A1) and mTOR phosphorylation were lower in response to LM2.5 and LM2.0. Overall, the results of this study provide evidence that increasing Met while Lys and the ratios of Phe, Thr, His, and Val relative to Lys were held constant could increase the concentration and utilization of intracellular EAA, in particular branched-chain AA, potentially through improving the activity of AA transporters partly controlled by mTOR signaling. Because EAA likely are metabolized by other tissues upon absorption, a question for future in vivo studies is whether formulating diets for optimal ratios of EAA in the metabolizable protein is sufficient to provide the desired levels of these AA to the mammary cells.

Effect of long-term rumen-protected methionine supplementation on performance of Shami goats and growth performance of their kids

An experiment was conducted to study the effect of supplementing the diets of Shami goats with rumen-protected methionine (RPM) in late pregnancy (last 60 days) and early lactation on milk production, composition, fatty acid profile in the first 60 days of lactation, and on growth performance of their kids. Three groups were used (25 goats/group) in a completely randomised design. Groups were a control with no supplements (0RPM) or supplemented with either 2.5 (2.5RPM), or 5.0 g/head.day RPM (5RPM). Birth and weaning weights for kids were recorded and analysed. Milk production was measured and sampled biweekly from each dam and analysed for milk composition. Results showed that RPM had no effect on birth and weaning weights, or average daily gain of Shami kids. However, milk to gain ratio of kids was significantly (P &lt; 0.05) improved. Milk production increased significantly (P &lt; 0.05) in 5RPM group compared with 0RPM and 2.5RPM groups. Milk protein content was the highest (P &lt; 0.05) in the 2.5RPM group, followed by the 5RPM and 0RPM groups, whereas milk fat content was not different among the groups. Meanwhile, yields of both components were significantly (P &lt; 0.05) higher in milk of treated groups. Casein and energy-corrected milk were increased (P &lt; 0.05) with treatment. No effect on dry-matter intake was recorded, while feed to milk ratio was better (P &lt; 0.05) for RPM groups than for 0RPM group. Milk fatty acids composition did not show significant changes after RPM treatment. In conclusion, results showed that supplementing RPM to Shami goats in late pregnancy did not affect birthweight or growth of suckling kids but improved milk production and milk protein, although no clear dose response to RPM was detected.

The effect of dietary supplementation with rumen-protected methionine alone or in combination with rumen-protected choline and betaine on sheep milk and antioxidant capacity

This study investigated the effects of dietary inclusion of rumen-protected methionine alone or in combination with rumen-protected choline and betaine on: (i) milk yield, chemical composition and fatty acids (FA) profile and (ii) blood plasma glutathione transferase (GST) activity of periparturient ewes. Furthermore, the oxidative stress indicators for measuring total antioxidant and free radical scavenging activity [ferric reducing ability of plasma (FRAP) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays] were also determined in plasma and milk of ewes. Thus, 45 ewes were divided into three equal groups. Each animal of the control group fed daily with a basal diet. The same diet was offered also in each animal of the other two groups. However, the concentrate fed to M group was supplemented with 2.5 g/kg rumen-protected methionine, while the concentrate fed to MCB group with 5 g/kg of a commercial product which contained a combination of methionine, choline and betaine, all three in rumen-protected form. The results showed that the M diet, compared with the control, increased significantly the ewe's milk fat and the total solids content. Likewise, a tendency for higher milk fat and total solids content in ewes fed the MCB diet was also observed. Both M and MCB diets had not noticeable impact on ewes milk FA profile. Significantly higher FRAP values in the blood plasma of ewes fed the MCB and in the milk of ewes fed with the M diet compared with the control were found. Additionally, significantly higher GST activity in the blood plasma of ewes fed the M diet, compared with the control, was observed. Moreover, a significant increase (by 20%) and a tendency for increase (by 16.72%) in the growth rate of lambs nursing ewes fed with M and MCB diets, respectively, compared to controls, were found.

Nitrogen supply in cattle coupled with appropriate supply of utilisable crude protein at the duodenum, a precursor to metabolisable protein

The overall objective of this study was to calculate the amount of nitrogen (N) that cattle feed must contain in order to utilise the potential supply of utilisable crude protein at the duodenum provided by their energy intake without incurring a negative N balance, that is, without having to break down body protein. For this purpose, the literature was screened for measurements of net degradation and renal excretion of urea as well as N balances (N intake, faecal N and urinary N) in ruminants (cattle, sheep and goats) fed diets with varying N concentrations. Irreversible loss of N from the body urea pool increased with increasing N intake, but net degradation of urea as a proportion of irreversible loss decreased concurrently. Faecal N appeared not to be influenced by N intake and exceeded 11 g/kg dry matter intake (DMI) only in 7% of the data sets available. Urinary non-urea-N rarely exceeded 4 g/kg DMI and appeared independent of N intake. Urinary urea-N showed a clear dependence of N intake, and it is concluded that 1 g N/kg DMI is sufficient for compensating inevitable N losses in the form of urinary urea. In conclusion, ruminant rations should contain the following N concentrations (per kg DM) to account for obligatory losses: 11 g for compensating losses as faecal N, 4 g for compensating losses as urinary non-urea-N and 1 g for compensating inevitable losses as urinary urea-N. The derived recommendations should be helpful for limiting N excretion where this is desirable for ecological reasons.

Milk yield and quality in Guernsey cows fed cottonseed cake-based diets partially substituted with baobab (Adansonia digitata L.) seed cake

The objective of this study was to determine the effects of partially substituting cottonseed cake with graded levels of baobab (Adansonia digitata L.) seed cake (BSC) on milk yield and quality in Guernsey cows. Sixteen cows in mid-lactation and in their third parity were allocated to diets containing 0% (control), 5%, 10%, and 15% BSC in a completely randomized design. Each cow was given a daily feed ration of 6 kg and a basal diet of soya bean stover ad libitum. There were no differences in daily feed intake (P > 0.05), but basal intake differed among all treatment groups with cows on the control diet having the highest intake (30 ± 0.34 kg/day). Mean daily milk yield differed (P < 0.05) among all treatment groups. However, the control had higher milk yield of 12.1 ± 0.73 kg/day, and the 15% BSC had the least yield of 7.46 ± 0.73 kg/day. Cows on the control diet had higher milk butterfat content (6.12%; P < 0.05) than those on the BSC-based diets. Protein content differed (P < 0.05) across all treatment groups with cows on 15% BSC producing the highest protein content (3.43%) while the control had the least (2.6%). The concentration of milk total solids for cows fed on 15% BSC was higher (P < 0.05) than that from cows on other diets. Lactose content was not affected by the diets (P > 0.05). These results indicate that BSC can substitute soya bean cake in dairy diets, but milk production and butterfat content are compromised.