Dietary supplementation of rumen-protected methionine decreases the nitrous oxide emissions of urine of beef cattle through decreasing urinary excretions of nitrogen and urea

Effects of Dietary Protein Level and Rumen-Protected Methionine and Lysine on Growth Performance, Rumen Fermentation and Serum Indexes for Yaks

This study investigated the effects of the dietary protein level and rumen-protected methionine and lysine (RPML) on the growth performance, rumen fermentation, and serum indexes of yaks. Thirty-six male yaks were randomly assigned to a two by three factorial experiment with two protein levels, 15.05% and 16.51%, and three RPML levels: 0% RPML; 0.05% RPMet and 0.15% RPLys; and 0.1% RPMet and 0.3% RPLys. The trial lasted for sixty days. The results showed that the low-protein diet increased the DMI and feed conversion ratio of yaks. The diet supplemented with RPML increased the activities of IGF1 and INS and nutrient digestibility. The high-protein diet decreased the rumen butyrate concentration and increased the rumen isovalerate concentration. The low-protein diet supplemented with RPML increased the rumen pH and the concentrations of total volatile fatty acids, butyrate and NH3-N; the high-protein diet supplemented with a high level of RPML decreased the rumen pH and the concentrations of isobutyrate, isovalerate, propionate and NH3-N. The low-protein diet supplemented with RPML increased the total antioxidant capacity and glutathione peroxidase activity, along with the concentrations of malondialdehyde and amino acids such as aspartic acid, lysine, cysteine, etc. In conclusion, a low-protein diet supplemented with RPML is beneficial for rumen and body health, physiological response, and metabolic status in yaks.

Recent advances in feed and nutrition of beef cattle in China - A review

The beef cattle industry in China has advanced remarkably since its reform and opening up; consequently, China has become the world's third-largest beef cattle producer. China is also one of the countries with the most substantial research input and output in the field of beef cattle feed and nutrition. The progress and innovation by China in the research field of beef cattle feed and nutrition have undoubtedly promoted the development of the domestic beef cattle industry. This review summarizes recent advances in feed resource development, nutrient requirements, and nutritional regulation of beef cattle in China. Limitations in current research and perspectives on future work are also discussed.

Ruminal Degradation of Taurine and Its Effects on Rumen Fermentation In Vitro

Taurine accounts for approximately 0.1% of an animal’s body. It cannot be used for protein synthesis but plays a wide range of important roles in the animal body. Taurine does not exist in plants, while mammals can only synthesize 30–40% of the taurine they need. Supplementing taurine to beef cattle may be necessary to improve their nutrient utilization and health status. However, no data are available regarding the metabolism of taurine in the rumen. Two in vitro trials were conducted to investigate the ruminal degradability of taurine and its effects on rumen fermentation. In Trial 1, Tilley and Terry’s in vitro rumen fermentation technique was used for incubation. As treatments, two levels of taurine, i.e., 0 and 10 mg, were added into plastic tubes containing 0.4000 g of feed mixture with a calibrated volume of 50 mL. Three adult cattle fitted with rumen cannulas were used as the donors for rumen fluid. The incubation was carried out at 39 °C for 48 h. The results showed that the taurine degradability increased with incubation time (p < 0.001) while its 2 h-degradability reached 99%. Taurine decreased the 48 h-dry matter degradability (DMD) (p = 0.008) and increased the 24 h- and 48 h-pH (p = 0.005; p = 0.018), respectively. In Trial 2, the Hohenheim gas test was used for incubation. Four levels of taurine, i.e., 0, 5, 10 and 20 mg, were added into glass syringes containing 0.2000 g feed mixture with a calibrated volume of 100 mL as treatments. The rumen fluid donors were the same as in Trial 1. The incubation was carried out at 39 °C for 48 h. The results showed that taurine increased the 48 h-pH (p < 0.001) linearly, decreased the cumulative gas production (p < 0.001) and the total volatile fatty acids (VFA) concentration (p = 0.014), and quadratically affected the ammonia–nitrogen (p < 0.001) and microbial crude protein (MCP) concentrations (p < 0.001). It was concluded that taurine was highly degradable in rumen fermentation. Taurine inhibits ruminal fermentation by decreasing DMD, VFA and gas production while improving MCP synthesis on a dose-dependent basis.

Effects of rumen-protected methionine supplementation on production performance, apparent digestibility, blood parameters, and ruminal fermentation of lactating Holstein dairy cows

This study aimed to evaluate the effects of reducing dietary CP and supplementing rumen protected-methionine (RPM) on production performance, blood parameters, digestibility of nutrients or ruminal fermentation in lactating Holstein dairy cows. A total of 96 lactating cows were randomly assigned to 1 of 2 treatments: a diet containing 17.3% CP without RPM (control group; CON; n = 49) or a diet containing 16.4% CP and supplemented with 15.0 g/d of RPM (treatment group; RPM; n = 47). No effect was observed in the RPM group on milk yield, milk composition and digestibility of nutrients. The results of blood parameters showed that cows in the RPM group exhibited lower blood urea nitrogen concentration than in CON group. Rumen microbial crude protein (MCP) was higher in the RPM group compared to the CON group. Ruminal volatile fatty acid (VFA) concentrations were not different between treatments except for butyrate and isovalerate, which were higher in the RPM group than the CON group 2 h after feeding. In conclusion, reducing dietary CP with RPM supplementation did not limit milk yield, milk composition or digestibility of nutrients, but could improve nitrogen utilization, synthesis of MCP and partially increase VFA production 2 h after feeding cows.

Effects of dietary inclusion with rapeseed cake containing high glucosinolates on nitrogen metabolism and urine nitrous oxide emissions in steers

Two consecutive trials were conducted to investigate the effects of glucosinolates (GLS) in rapeseed cake (RSC) on nitrogen (N) metabolism and urine nitrous oxide (N₂O) emissions in steers. In trial 1, 8 steers and 4 levels of RSC, i.e. 0, 2.7%, 5.4% and 8.0% dry matter (DM) (0, 6.0, 12.1, 18.1 μmol GLS/g DM) were allocated in a replicated 4 × 4 Latin square. In trial 2, the static incubation technique was used for measuring the N₂O emissions of the urine samples collected from trial 1. The results of trial 1 indicated that dietary inclusion of RSC decreased the digested N and increased the fecal N excretion (P < 0.01), whereas it did not affect the urinary N excretion, total N excretion and N retention (P > 0.10). Dietary inclusion of RSC decreased the urinary excretion of urea while it increased allantoin, total purine derivatives, the predicted rumen microbial N flow and thiocyanate (SCN) (P < 0.05). Dietary inclusion of RSC did not affect the plasma triiodothyronine and thyroxine while it down-regulated the plasma relative concentrations of 4-aminohippuric acid, 3α,7α-dihydroxycoprostanic acid, phosphatidylserine (14:0/16:0), 6β-hydroxyprogesterone, pyrrhoxanthinol, tatridin B, mandelonitrile rutinoside, taraxacoside (P < 0.05), and up-regulated hypoglycin B, neuromedin N (1-4), dhurrin, 5-deoxykievitone (P < 0.01). The results of trial 2 indicated that dietary RSC increased the steer urine N₂O-N fluxes, the ratio of N₂O-N to N application and the estimated steer urine N₂O-N emissions (P < 0.01). A close correlation was found between the estimated steer urine N₂O-N emissions and the output of urinary SCN (P < 0.001). In conclusion, dietary RSC increased the fecal N excretion, whereas it did not affect the urinary N excretion and the N retention rate in steers. Dietary RSC increased rather than decreased the urine N₂O-N emissions even though it decreased the urinary excretion of urea. The SCN excreted in urine could be the major factor in increasing the urine N₂O-N emissions. Whether other metabolites excreted into urine from RSC have an impact on the urine N₂O-N emissions in steers needs to be investigated in the future.

Effect of Supplementary Levels of Rumen-Protected Lysine and Methionine on Growth Performance, Carcass Traits, and Meat Quality in Feedlot Yaks (Bos grunniens)

Simple Summary

Yak is an indigenous ruminant on the Qinghai-Tibetan Plateau and its meat is known as the “beef crown”. Traditionally, yak graze on the rangeland all year round and without any supplementation, and weight loss would occur in the cold season, which leads to rather low productive performance. In recent years, the strategy of intensive feedlot fattening was introduced to the yak raising industry. However, the results were not as encouraging as in the cattle steers, a fact that can be attributed to yak malnutrition due to differences in feed varieties supply and nutrients requirement between yaks and cattle. Consequently, this study was conducted to examine the effect of the first two limiting amino acids on growth performance, carcass traits, and meat quality in feedlot yaks. The animals were offered total mixed ration with supplementary four levels of rumen-protected lysine and methionine throughout the whole experiment. The results showed that the average daily gain, feed to gain ratio, meat color, drip loss, and shear force were improved when yaks were supplemented with rumen-protected amino acid while the medium level was most promising. These results indicated that supplementary rumen-protected amino acid improved the growth performance and meat quality characteristics of fattening yaks in feedlot.

Abstract

Yak, a unique bovine species on the Qinghai-Tibetan Plateau, has provided pastoralists with the basic materials of production and life for thousands of years. Existing literature showed that yak meat is of high nutritional value for humans whereas the growth performance is relatively low. As it has been demonstrated, lysine and methionine are the two key limiting amino acids in ruminants. Therefore, this study was conducted to investigate the effect of supplementary levels of rumen-protected lysine (RPL) and methionine (RPM) on growth performance, carcass traits, and meat quality in feedlot yaks. Thirty-two male yaks, with initial body weight (IBW) of 237.5 ± 13.99 kg were randomly assigned to four dietary treatments (n = 8), including control group (CON; basal diet without adding rumen-protected amino acid (RPAA)), low RPAA supplementation group (Group Low; basal diet supplemented with RPL (30.0 g/animal/day) and RPM (7.5 g/animal/day)), medium RPAA supplementation group (Group Medium; basal diet supplemented with RPL (50.0 g/animal/day) and RPM (12.5 g/animal/day)), and high RPAA supplementation group (Group High; basal diet supplemented with RPL (70.0 g/animal/day) and RPM (17.5 g/animal/day)). The average daily gain was increased linearly (p < 0.001) and quadratically (p < 0.01) while feed to gain ratio was decreased linearly (p < 0.001) and quadratically (p < 0.001) with the increasing RPAA supplementation, and the average daily gain was higher while feed to gain ratio was lower in RPAA than CON (p < 0.001). Meat color L* values and b* were decreased linearly (p < 0.01) with the increase of RPAA supplementation, and b* was lower in RPAA than CON (p < 0.05). Meat color a* value was increased linearly (p < 0.05) with the increasing RPAA supplementation, and a* was higher in RPAA than CON (p < 0.05). The 24 h drip loss and shear force were decreased quadratically (p < 0.01) with the increasing RPAA supplementation, and drip loss and shear force values were lower in RPAA than CON (p < 0.05). The glycine concentration in longissimus dorsi (LD) increased linearly (p < 0.05) with the increasing RPAA supplementation. These results demonstrated that both the growth performance and meat quality characteristics were improved in feedlot yaks as an effect of the dietary supplementation with RPL and RPM, and the medium supplementary level is recommended, since it showed the most promising results.