Low Rumen-undegradable Protein Research Articles

Use of Heating Methods and Xylose to Increase Rumen Undegradable Protein of Alternative Protein Sources: 1) Peanut Meal

Peanut meal has an excellent total protein content but also has low rumen undegradable protein (RUP). High-performance ruminants have high RUP requirements. We aimed to evaluate the effects of processing peanut meal with an autoclave and conventional and microwave ovens, with and without using xylose on its ruminal kinetics degradation parameters and intestinal digestibility (ID). In situ studies were conducted to determine dry matter (DM) and crude protein (CP) rumen degradation kinetics. In vitro studies were conducted to evaluate intestinal digestibility (ID). The control treatment had a greater fraction A for DM and CP than peanut meals processed with an autoclave or conventional oven. The control had greater kd for CP compared with the microwave. The addition of xylose decreased fraction A, the degradation rate of fraction B (kd) and RUP, and increased the protein B fraction of autoclaved peanut meal. We observed a decrease in effective degradability (ED) and increased RUP for processed treatments in all experiments compared with the control. Processing methods did not affect the protein ID of autoclaved peanut meal compared to the control. An interaction between xylose and heating time was observed, where increasing heating time linearly reduced the ID of xylose-untreated treatments. Overall, these results suggest that the tested methods effectively increased the RUP content of peanut meal.

Enhancing Metabolic Efficiency through Optimizing Metabolizable Protein Profile in a Time Progressive Manner with Weaned Goats as a Model: Involvement of Gut Microbiota.

ABSTRACTFeeding a growing global population and lowering environmental pollution are the two biggest challenges facing ruminant livestock. Considering the significance of nitrogen metabolism in these challenges, a dietary intervention regarding metabolizable protein profiles with different rumen-undegradable protein (RUP) ratios (high RUP [HRUP] versus low RUP [LRUP]) was conducted in young ruminants with weaned goats as a model. Fecal samples were collected longitudinally for nine consecutive weeks to dissect the timing and duration of intervention, as well as its mechanism of action involving the gut microbiota. Results showed that at least 6 weeks of intervention were needed to distinguish the beneficial effects of HRUP, and HRUP intervention improved the metabolic efficiency of goats as evidenced by enhanced growth performance and nutrient-apparent digestibility at week 6 and week 8 after weaning. Integrated analysis of bacterial diversity, metabolites, and inferred function indicated that HRUP intervention promoted Eubacterium abundance, several pathways related to bacterial chemotaxis pathway, ABC transporters, and butanoate metabolism and thereafter elicited a shift from acetate production toward butyrate and branched-chain amino acid (BCAA) production. Meanwhile, three distinct phases of microbial progression were noted irrespective of dietary treatments, including the enrichment of fiber-degrading Ruminococcus, the enhancement of microbial cell motility, and the shift of fermentation type as weaned goats aged. The current report provides novel insights into early-life diet-microbiota axis triggered by metabolic protein intervention and puts high emphasis on the time window and duration of dietary intervention in modulating lifelong performance of ruminants.IMPORTANCE Precise dietary intervention in early-life gastrointestinal microbiota has significant implications in the long-life productivity and health of young ruminants, as well as in lowering their environmental footprint. Here, using weaned goats as a model, we report that animals adapted to high rumen-undegradable protein diet in a dynamic manner by enriching fecal community that could effectively move toward and scavenge nutrients such as glucose and amino acids and, thereafter, elicit butyrate and BCAA production. Meanwhile, the three dynamic assembly trajectories in fecal microbiota highlight the importance of taking microbiota dynamics into account. Our findings systematically reported when, which, and how the fecal microbiome responded to metabolizable protein profile intervention in young ruminants and laid a foundation for improving the productivity and health of livestock due to the host-microbiota interplay.

Influence of flaxseed with rumen undegradable protein level on milk yield, milk fatty acids and blood metabolites in transition ewes

An experiment was conducted to determine the effects of two levels of rumen undegradable protein (RUP) without or with whole or extruded flaxseed on milk yield, milk component, milk fatty acids (FAs) profile and plasma metabolites in transition ewes. Three weeks before and after lambing, seventy-two Baluchi ewes were used in a completely randomized design with a 3 × 2 factorial arrangement of treatments. The treatments contained 1) no flaxseed + 20% RUP (no flaxseed, low RUP [NFLR]); 2) no flaxseed + 40% RUP (no flaxseed, high RUP [NFHR]); 3) 10% whole flaxseed + 20% RUP (whole flaxseed, low RUP [WFLR]); 4) 10% whole flaxseed + 40% RUP (whole flaxseed, high RUP [WFHR]); 5) 10% extruded flaxseed + 20% RUP (extruded flaxseed, low RUP [EFLR]), and 6) 10% extruded flaxseed + 40% RUP (extruded flaxseed, high RUP [EFHR]). Ewes fed 10% extruded flaxseed exhibited higher (p < 0.001) dry matter intake (DMI) and colostrum yield (p < 0.1) compared to other treatments. Two types of flaxseed and RUP levels had no significant effect on milk yield, but milk fat and protein contents decreased and increased in diets containing 40% RUP, respectively. Ewes fed extruded flaxseed produced milk with lower concentrations of saturated fatty acids (SFA) and higher α-linolenic and linoleic acids and also polyunsaturated fatty acids (PUFA) compared to other groups (p < 0.05). During post-lambing, the ewes fed diets containing flaxseed exhibited higher concentration of serum non-esterified FAs (NEFA) compared to diets without flaxseed (p < 0.01). The concentration of serum β-hydroxybutyric acid (BHBA) decreased in the diets containing flaxseed types at pre-lambing, but increased in diets containing extruded flaxseed at post-lambing (p < 0.01). The serum glucose concentration of ewes (pre and post-lambing) which consumed diets containing extruded flaxseed or 40% RUP increased, but blood urea concentration was elevated following supplementation of diet with whole flaxseed or 40% RUP (p < 0.001). In conclusion, utilization of 10% extruded flaxseed in the diets of transition ewes had positive effects on animal performance with favorable changes in milk FAs profile. However, there is no considerable advantage to supply more than 20% RUP level in the diet of transition dairy sheep.

Effects of replacing soybean meal with canola meal differing in rumen-undegradable protein content on ruminal fermentation and gas production kinetics using 2 in vitro systems

Previous research indicated that there were significant differences in rumen-undegradable protein (RUP) among canola meals (CM), which could influence the nutritional value of CM. The objectives of this study were to (1) evaluate the effects of feeding CM with different RUP contents on ruminal fermentation, nutrient digestion, and microbial growth using a dual-flow continuous culture system (experiment 1) and (2) evaluate ruminal gas production kinetics, in vitro organic matter (OM) digestibility, and methane (CH4) production of soybean meal (SBM) and CM with low or high RUP in the diet or as a sole ingredient using a gas production system (experiments 2 and 3). In experiment 1, diets were randomly assigned to 6 fermentors in a replicated 3 × 3 Latin square. The only ingredient that differed among diets was the protein supplement. The treatments were (1) solvent-extracted SBM, (2) low-RUP solvent-extracted CM (38% RUP as a percentage of crude protein), and (3) high-RUP solvent-extracted CM (50% RUP). Diets were prepared as 3 concentrate mixtures that were combined with 25% orchardgrass hay and 15% wheat straw (dry matter basis). Experiments 2 and 3 had the same design with 24 bottles incubated 3 times for 48 h each. During the 48-h incubation, the cumulative pressure was recorded to determine gas production kinetics, in vitro OM digestibility, and CH4 production. In experiment 1, N flow (g/d), efficiency of N use, efficiency of bacterial N synthesis, total volatile fatty acids (mM), and molar proportion of acetate, propionate, and isobutyrate were not affected by treatments. There were tendencies for a decrease in ruminal NH3-N and an increase in molar proportion of butyrate for the SBM diet compared with both CM diets. The molar proportion of valerate was greater in both CM diets, whereas the molar proportion of isovalerate and total branched-chain volatile fatty acids was lower for the CM diets compared with the SBM diet. In experiments 2 and 3, the SBM diet had a greater gas pool size than both CM diets. The SBM diet increased in vitro OM digestibility; however, it also tended to increase CH4 production (mM and g/kg of DM) compared with both CM diets. Based on the results of this study, CM with RUP varying from 38 to 50% of crude protein does not affect ruminal fermentation, nutrient digestion, and microbial growth when CM is included at up to 34% of the diet.

Effects of excess metabolizable protein on ovarian function and circulating amino acids of beef cows: 1. Excessive supply from corn gluten meal or soybean meal

In the dairy industry, excess dietary CP is consistently correlated with decreased conception rates. However, the source from which excess CP is derived and how it affects reproductive function in beef cattle is largely undefined. The objective of this experiment was to determine the effects of feeding excess metabolizable protein (MP) from feedstuffs differing in rumen degradability on ovulatory follicular dynamics, subsequent corpus luteum (CL) development, steroid hormone production and circulating amino acids (AA) in beef cows. Non-pregnant, non-lactating mature beef cows (n=18) were assigned to 1 of 2 isonitrogenous diets (150% of MP requirements) designed to maintain similar BW and body condition score (BCS) between treatments. Diets consisted of ad libitum corn stalks supplemented with corn gluten meal (moderate rumen undegradable protein (RUP); CGM) or soybean meal (low RUP; SBM). After a 20-day supplement adaptation period, cows were synchronized for ovulation. After 10 days of synchronization, gonadotropin releasing hormone (GnRH) was administered to reset ovarian follicular growth. Starting at GnRH administration and daily thereafter until spontaneous ovulation, transrectal ultrasonography was used to diagram ovarian follicular growth, and blood samples were collected for hormone, metabolite and AA analyses. After 7 days of visual detection of estrus, CL size was determined via ultrasound. Data were analyzed using the MIXED procedures of SAS. As designed, cow BW and BCS were not different (P⩾0.33). Ovulatory follicular wavelength, antral follicle count, ovulatory follicle size at dominance and duration of dominance were not different (P>0.13) between treatments. Cows supplemented with CGM had greater post-dominance ovulatory follicle growth, larger dominant follicles at spontaneous luteolysis, shorter proestrus, and larger ovulatory follicles (P⩽0.03) than SBM cows. No differences (P⩾0.44) in peak estradiol, ratio of estradiol to ovulatory follicle volume, or plasma urea nitrogen were observed. While CL volume and the ratio of progesterone to CL volume were not affected by treatment (P⩾0.24), CGM treated cows tended to have decreased (P=0.07) circulating progesterone 7 days post-estrus compared with SBM cows. Although total circulating plasma AA concentration did not differ (P=0.70) between treatments, CGM cows had greater phenylalanine (P=0.03) and tended to have greater leucine concentrations (P=0.07) than SBM cows. In summary, these data illustrate that excess MP when supplemented to cows consuming a low quality forage may differentially impact ovarian function depending on ruminal degradability of the protein source.

Manipulation of Soluble and Rumen-Undegradable Protein in Diets Fed to Postpubertal Dairy Heifers

Eight postpubertal Holstein heifers (455±4.0), fit with rumen cannulas, were used in 2 experiments to investigate the effects of altering dietary protein type on nutrient digestibility, rumen fermentation, and nitrogen utilization. Heifers were fed diets containing low or high levels of soluble (SP) and low or high levels of rumen-undegradable protein (RUP) in a 4×4 Latin square design with a 2×2 factorial arrangement of treatments. The treatment rations in experiment 1 were formulated with corn silage composing the majority of the forage fraction, whereas in experiment 2, grass hay composed the highest proportion of ration DM. Blood and rumen samples were collected over 2 d and total fecal and urine collections were conducted for 4 d. Dry matter, organic matter, and neutral detergent fiber digestibility were not different in either experiment 1 or 2. Increasing the proportion of dietary crude protein that was SP increased mean daily rumen ammonia concentrations in each experiment, although no other rumen parameter differed. Excretion of urinary nitrogen in experiment 1 was highest for diets with low SP and low RUP and with high SP and high RUP, which resulted in these rations being the least efficient in retention of apparently digested nitrogen. The proportion of consumed or absorbed nitrogen retained in experiment 2 was not significantly different between treatments. Responses to alterations in crude protein degradability are observable in postpubertal heifers; however, the level of response may depend on the diet in which protein degradability is altered.

Effects of glutamate on microbial efficiency and metabolism in continuous culture of ruminal contents and on performance of mid-lactation dairy cows

Three experiments were conducted to determine (1) the dose of glutamate needed to alter fermentation and nitrogen (N) partitioning in a continuous culture system, (2) the effect of supplemental glutamate in diets varying in rumen-undegradable protein on fermentation and N partitioning in a continuous culture system, and (3) the effect of dietary supplemental glutamate on the lactational performance of mid-lactation dairy cows, total tract nutrient digestibility, and ruminal microbial N synthesis. In experiment 1, the equivalent of 0, 40, or 80 g of supplemental glutamate per cow per day was added to a basal diet. The dietary treatments were evaluated in a continuous culture system. Glutamate decreased protein digestion and microbial growth while increasing non-ammonia, non-microbial N. Within the doses tested, the equivalent of 80 g glutamate per cow per day most effectively increased non-ammonia, non-microbial N. In experiment 2, dietary treatments consisted of diets formulated to have low rumen-undegradable protein (LRUP; 62 g/kg DM), low rumen-undegradable protein plus the equivalent of 80 g glutamate per cow per day (LRUP + G), and high rumen-undegradable protein [HRUP; 68 g/kg dry matter (DM)]. The dietary treatments were evaluated in a continuous culture system. When added to a diet low in rumen-undegradable protein, glutamate tended to decrease DM and organic matter (OM) digestibility, decreased total volatile fatty acid (VFA) production, increased fermenter pH, increased feed N converted to microbial N, and had no effect on microbial N production. The LRUP + G diet was similar to the HRUP diet and different from the LRUP diet in feed N converted to microbial N and ammonia N concentration. In experiment 3, 40 Holstein cows were utilized in a crossover study to test the effects of two dietary treatments: 0 or 80 g of supplemental glutamate per cow per day. The addition of glutamate to the diet of lactating dairy cows did not improve lactational performance or nutrient digestibility. Based on the results from these in vitro and in vivo experiments, the addition of glutamate to lactating cow diets is not recommended.

Feeding value of peas for backgrounding beef heifers

Four diets in which peas progressively replaced barley [0% (0P), 30% (30P), 50% (50P), and 100% peas (100P)] and one in which canola meal (CM) replaced 10% of the barley, were fed to 90 beef heifers (initial weight 215.8 ± 13.8 kg). The heifers achieved average daily gains (ADGs) of 0.72, 0.80, 0.79, 0.83, and 0.76 kg d-1 on the five diets, respectively, with the difference between the 0P group and the 100P group being significant (P = 0.028). The total feed costs of gain were $0.786, 0.779, 0.799, 0.860, and 0.817 kg-1 for the five groups, respectively, with the cost of gain being significantly greater (P &lt; 0.05) for the 100P group than for the 0P, 30P or 50P groups. The latter three were not significantly different from each other. Three rumen-cannulated steers (575 ± 56.3 kg) were used to estimate the degradability of the dry matter (DM) and N in the barley straw (BS), CM, barley grain (BG) and peas used in the feeding trial. The rumen undegradable protein (RUP) levels supplied by the five diets were 17.5, 19.0, 19.9, 21.5, and 22.5%, respectively, and all of them met the requirements of these cattle. The RUP content of peas ground through a 1-mm screen was lower than that of peas ground through 2- or 4-mm screens (P &lt; 0.01), which were themselves not significantly different from each other (P = 0.67). The low RUP content of peas was not a limiting factor for growth in backgrounding cattle. Key words: Cattle, field peas, dry matter intake, feed conversion efficiency, rumen me

Effects of Genetic Merit and Varying Dietary Protein Degradability on Lactating Dairy Cows

Eighty two multiparous Holstein cows were blocked by genetic merit (high vs. low) and assigned to one of two treatments [high rumen-undegradable protein (RUP): rumen-degradable protein (RDP) vs. low RUP: RDP] from d 21 before to d 150 after calving to study the effects of these treatments on production and reproductive performance. Diets were isonitrogenous (dry cow 10.5% crude protein; lactating cow 19.3%), isoenergetic (dry cow 10.0 MJ of metabolizable energy (ME); lactating cow 10.9 MJ of ME) and fed as total mixed rations. Feeding more RUP significantly increased dry matter intake and milk yield, reduced body tissue mobilization, and lowered concentrations of serum nonesterified fatty acids (NEFA) and plasma urea. Expression of estrus at first ovulation was improved, first service conception rate was higher, and calving to conception interval was shorter for the high RUP group. Cows of high genetic merit produced more milk, mobilized more body tissue, and had higher concentrations of plasma growth hormone. The dry matter intake and concentrations of blood metabolites did not significantly differ with genetic merit. Expression of estrus at first ovulation was significantly lower for cows of high genetic merit. Serum NEFA concentrations were significantly higher, and estrus was not observed at first ovulation for cows of higher genetic merit fed the low RUP diet. The interaction between dietary RUP and genetic merit was not significant for other measures of performance or fertility. Feeding a low RUP: high RDP diet had negative effects on some aspects of production and reproductive performance. The effects of diet on NEFA concentrations and estrus display were greater in cows of high genetic merit, indicating that potential interactions should be evaluated in future reproductive studies involving protein and fertility.

Supplementation of Rumen-Undegradable Protein to the Diets of Early Lactation Holstein Cows on Grass Pasture

The objectives were to evaluate supplements differing in rumen-undegradable protein (RUP) on the performance of early lactation cows on grass pasture. Twenty-four Holstein cows averaging 68 d of lactation and 39.8 kg/d of milk were rotationally grazed on predominantly Dactylis glomerata pasture for 8 wk. Cows were blocked according to parity, milk yield, and days of lactation and were randomly assigned to a grain mixture with a low or high RUP content. Pasture and the low and high RUP grain mixtures averaged 25.6, 14.7, and 13.7% crude protein and 4.0, 7.0, and 8.4% RUP, respectively (dry matter basis). Grain was fed twice daily at 1 kg/4kg of milk, pasture provided all forage in the diet, and grain consumption was similar (8.9 kg/d per cow) for cows on both treatments. Total dry matter intakes estimated using chromic oxide were 19.9 and 20.9 kg/d for cows fed low and high RUP grain mixtures. Milk yields did not differ between treatments; means were 34.2 and 35.5 kg/d for cows fed low and high RUP grain mixtures. Multiparous cows tended to yield more milk (36.2 vs. 34.5 kg/d) and milk protein (1.06 vs. 0.98 kg/d) when fed the high RUP grain mixture. Concentrations of plasma urea N and nonesterified fatty acids were unaffected by treatment and averaged 18.7 mg/dl and 307 μeq/L, respectively. Results indicated that a supplemental grain mixture with a high RUP content did not alter milk yield of high yielding cows when pasture was the sole forage; however, milk protein yield tended to be greater for multiparous cows fed the high RUP grain mixture.

Effect of Rumen-Undegradable Protein and Energy on Growth and Feed Efficiency of Growing Holstein Heifers1,2

Thirty-two Holstein heifers were used to determine the effect of energy and rumen-undegradable protein (RUP) on growth and feed efficiency. Treatment diets were in a 2×2 factorial consisting of two energy concentrations (supporting 0.6 or 0.9kg of average daily gain) and two percentages of RUP (30 or 50% of crude protein). Isonitrogenous diets based on corn silage, alfalfa silage, orchardgrass hay, corn, soybean meal, blood meal, and minerals were fed. Treatment diets were fed until 385 d of age, constituting phase 1 of the trial. During phase 2 (until calving), heifers were housed together and fed a common diet for 0.7kg of average daily gain. Dry matter intake (kilograms per day) during phase 1 was 4.46, 5.42, 7.38, and 5.95 for heifers fed low energy and low RUP, low energy and high RUP, high energy and low RUP, and high energy and high RUP diets, respectively. Average daily gain (kilograms) during phase 1 was 0.62, 0.74, 1.01, and 0.96, respectively. Dry matter intake and gain were higher for heifers receiving high energy diets. Dry matter efficiency was higher for heifers fed high energy and high RUP diets. Apparent total digestible nutrient efficiency was higher for heifers fed high RUP diets. Average daily gain during phase 2 was 0.53, 0.43, 0.33, and 0.50kg, respectively. Overall average daily gain was not affected by energy or RUP levels during phase 1 because the slow growth of heifers during phase 1 was compensated by faster growth during phase 2.

Some factors related to the voluntary intake of silage by individual dairy cows housed as a group during two winter-feeding periods

ABSTRACTThe consumption of grass silage by each individual cow in a group housed during two consecutive winter-feeding periods was continuously recorded. During the first winter, one of two concentrates, containing high starch or high fibre, were offered on a sliding scale and half the cows were injected with bovine somatotropin (bST). During the second winter, one of two concentrates, containing high or low rumen-undegradable protein were offered at a flat rate ivith two-thirds of the cows receiving bST. The cows injected with bST had significantly greater yields of milk but their consumption of silage was similar to that of cows not treated with bST. The type of concentrate offered had no significant effect on silage consumption. Although there were significant variations in the consumption of silage from day to day, there were highly significant variations in consumption attributable to individual cows. This individuality of intake persisted in a consistent manner throughout a feeding period and could not be explained on the basis of milk production, body weight, age or parity. In 24 of the cows which were used in both years, their individual intakes for the two periods were significantly correlated. The possibility that this individuality may be of economic importance is discussed.