Effects of supplementation of limit-fed growing diets with either soybean meal or nonenzymatically browned soybean meal on steer performance

Seventy two individually fed Angus × Hereford steers (642 lb) were used to evaluate the effects of supplementing limit-fed, growing diets with either soybean meal (SBM) or nonenzymatically browned soybean meal (NSBM). Eight steers were allotted to a control diet composed of 39.1% high-moisture corn, 42% cottonseed hulls, 10.4% ground corn, 5% cane molasses 2.25% urea, and 1.5% vitamins and minerals (dry basis). The remaining steers were allotted to diets that derived 100, 80, 60, or 40% of their supplemental protein from SBM or 60, 45, 30, or 15% of their supplemental protein from NSBN. The balance of supplemental protein came from urea. All diets were formulated to contain 13.0% crude protein (dry basis). Steers were fed once daily for 80 days at 2.25% of BW. Average daily gain and efficiency did not differ (P>.05) between sources (ADG=1.932 + .103 × (% CP from SBM) + .097 × (% CP from NSBM); gain:feed=.140 + .0058 × (% CP from SBM) + .0051 × (% CP from NSBM)). The lack of response to NBSBM supplementation above that for SBM suggests that either degradable intake protein was limiting in the basal diet or a large proportion of the amino acids in the NSBM were unavailable due to overprocessing

Effects of green tea or Sasa quelpaertensis bamboo leaves on plasma and liver lipids, erythrocyte Na efflux, and platelet aggregation in ovariectomized rats

This study was conducted to investigate the effects of Sasa quelpaertensis bamboo and green tea on plasma and liver lipids, platelet aggregation, and erythrocyte membrane Na channels in ovariectomized (OVX) rats. Thirty female rats were OVX, and ten female rats were sham-operated at the age of 6 weeks. The rats were divided into four groups at the age of 10 weeks and fed the experiment diets: sham-control, OVX-control, OVX-bamboo leaves (10%), or OVX-green tea leaves (10%) for four weeks. Final body weight increased significantly in the OVX groups compared with that in the sham-control, whereas body weight in the OVX-green tea group decreased significantly compared with that in the OVX-control (P < 0.01). High density lipoprotein (HDL)-cholesterol level decreased in all OVX groups compared with that in the sham-control rats (P < 0.05) but without a difference in plasma total cholesterol. Plasma triglycerides in the OVX-green tea group were significantly lower than those in the sham-control or OVX-control group (P < 0.05). Liver triglycerides increased significantly in the OVX-control compared with those in the sham-control (P < 0.01) but decreased significantly in the OVX-green tea group compared with those in the OVX-control or OVX-bamboo group (P < 0.01). Platelet aggregation in both maximum and initial slope tended to be lower in all OVX rats compared with that in the sham-control rats but was not significantly different. Na-K ATPase tended to increase and Na-K cotransport tended to decrease following ovariectomy. Na-K ATPase decreased significantly in the OVX-green tea group compared with that in the OVX-control group (P < 0.01), and Na-K cotransport increased significantly in the OVX-bamboo and OVX-green tea groups compared with that in the OVX-control (P < 0.05). Femoral bone mineral density tended to be lower in OVX rats than that in the sham-control, whereas the green tea and bamboo leaves groups recovered bone density to some extent. The results show that ovariectomy caused an increase in body weight and liver triglycerides, and that green tea was effective for lowering body weight and triglycerides in OVX rats. Ovariectomy induced an increase in Na efflux via Na-K ATPase and a decrease in Na efflux via Na-K cotransport. Furthermore, consumption of green tea and bamboo leaves affected Na efflux channels, controlling electrolyte and body water balance

Limiting amino acids for growing cattle fed diets based on soybean hulls

Ruminally cannulated Holstein steers were used in three nitrogen balance experiments to determine the sequence of limiting amino acids for growing steers fed soybean hull-based diets. The steers in all experiments were fed the same basal diet (73% soybean hulls, 19% alfalfa, DM basis; formulated to minimize rumen undegradable intake protein and thus maximize microbial protein postruminally) and were given the same intraruminal infusions (400 grams per day acetate; to increase energy supply without increasing microbial protein supply). In experiment 1, treatments consisted of abomasal infusions of: water (control, no amino acids); Lmethionine; and a mixture of 10 essential amino acids. Nitrogen retention (a measure of protein deposition) was greatest for steers receiving the mixture, and steers receiving methionine alone had greater nitrogen retention than control steers. In experiment 2, treatments consisted of abomasal infusions of the mixture of 10 essential amino acids or the same mixture without lysine. Nitrogen retention tended to be greater for the 10 amino acid mixture than for the mixture without lysine. In experiment 3, threonine, rather than lysine, was removed from the amino acid mixture. Nitrogen retention was not affected by removal of threonine. We conclude that methionine was the first limiting amino acid, threonine was not limiting, lysine appeared to be a limiting amino acid, and one or more untested amino acids in the mixture appeared to be second most limiting. Therefore, our data do not support the generally accepted concept that the sequence of limiting amino acids for steers is methionine, lysine, and threonine when microbial protein is the primary contributor to metabolizable (postruminal) protein

In vitro degradation of betaine by ruminal microbes

An in vitro study was conducted to evaluate the degradation of betaine sources by rumen microbes. Five sources of betaine (anhydrous betaine, betaine-HCl, feed-grade betaine, lipidcoated betaine, and concentrated separator byproduct) were incubated in rumen fluid collected from steers fed grain- or forage-based diets. In vitro degradation of betaine was slower with the high roughage diet than the grain diet. Betaine from concentrated separator by-product was degraded most rapidly, but no large differences occurred among the other four sources. The disappearance of betaine from lipid-coated product indicates that it did not resist ruminal degradation. Although betaine from all sources was degraded, some still remained after 24 hours of incubation, suggesting that some betaine may bypass the rumen

Effect of glycine supplementation on sulfur amino acid use in growing cattle

Previous research has suggested the possibility that the supply of glycine, a nonessential amino acid, might affect how efficiently cattle use methionine. This study was conducted to determine the role of glycine on methionine utilization in growing steers as well as how glycine might impact utilization of cysteine, an amino acid produced in the body from methionine. In Exp. 1, treatments were abomasal infusion of 2 or 5 g/day L-methionine and 0 or 50 g/day glycine in a factorial arrangement. Efficiency of methionine use was 27% in the absence of supplemental glycine, but 66% in its presence. Glycine supplementation by itself had little effect on protein deposition. In Exp. 2, treatments were abomasal infusions of 0 or 2.4 g/day L-cysteine and 0 or 40 g/day glycine in a factorial arrangement. Supplementation with cysteine in the absence of supplemental glycine did not change nitrogen balance. In fact, when glycine was supplemented alone, nitrogen retention decreased. However, when glycine and cysteine were supplemented together, nitrogen retention was increased. Thus, in the presence of supplemental glycine, it appears that cysteine can improve protein deposition, presumably by sparing methionine. Comparison of this and earlier studies suggests that B-vitamin status may play an important role in this response

Role of methionine as a methyl group donor in cattle

Holstein steers were used in two 5 × 5 Latin square experiments to evaluate the sparing of methionine by alternative sources of methyl groups (betaine or choline). Steers were housed in metabolism crates and limit fed a diet high in rumen degradable protein. To increase energy supply, volatile fatty acids were infused into the rumens, and glucose was infused into the abomasum. An amino acid mixture, limiting in methionine, was infused abomasally to ensure that non-sulfur amino acids did not limit protein synthesis. Treatments for Exp. 1 were abomasal infusion of 1) water (control), 2) 2 g/day additional L-methionine, 3) 1.7 g/day Lcysteine, 4) 1.6 g/day betaine, and 5) 1.7 g/day L-cysteine + 1.6 g/day betaine. Treatments for Exp. 2 were abomasal infusion of 1) water (control), 2) 2 g/day additional L-methionine, 3) 8 g/day betaine, 4) 16 g/day betaine, and 5) 8 g/day choline. In both experiments, nitrogen retention increased (P<.05) in response to methionine, demonstrating a deficiency of sulfur amino acids. Responses to cysteine, betaine and choline were small. The low response to cysteine indicates that either the response to methionine is not due to transsulfuration to cysteine, or that cysteine supply does not alter the flux of methionine through transsulfuration. The small responses to betaine and choline suggest that they do not substitute for methionine. Thus, under our experimental conditions, responses to methionine likely were due to a correction of a deficiency of methionine per se rather than of methyl group donors

Effect of methionine supplementation on methionine metabolism in growing cattle

Methionine is often the first limiting amino acid for growing cattle. This study was conducted to determine how methionine metabolism is regulated in the liver of growing steers. Six ruminally cannulated steers were used in a replicated 3 × 3 Latin square experiment. Either 0, 5, or 10 g/day L-methionine was infused into the abomasum. These treatments were designed to be deficient, adequate, and in excess of the steers’ requirements for methionine. Methionine supplementation linearly increased protein deposition and decreased the activity of methionine synthase (a methionine conserving enzyme). However, it had little effect on activity of cystathionine synthase (an enzyme that produces cysteine from methionine). Our results suggest that methionine metabolism and regulation in cattle may vary from that in monogastrics

Response of Holstein steers fed a soybean hull-based diet to amino acid supplementation when the methionine requirement was met

A study was conducted to determine the response to amino acid supplementation when the first limiting amino acid (methionine) was provided in excess. Three ruminally cannulated Holstein steer calves (281 lb) were fed 4.8 lb of a soybean hullbased diet (87% soyhulls and 8% wheat straw) daily. Methionine is the first limiting amino acid on diets of this type, and all steers were abomasally infused with 10 g/day of methionine to ensure that this requirement was met. Treatments consisted of increasing amounts (100, 250, or 400 g/day) of an amino acid mixture supplied abomasally. Calves received decreasing amounts of supplemental energy in the form of volatile fatty acids and dextrose as amino acid infusion increased in order for treatments to remain isoenergetic. Nitrogen balance increased as amino acid supply increased, indicating that amino acids other than methionine limited protein deposition. The nitrogen balance change between the 100 and 250 g/day amino acid treatments was greater than that from 250 to 400 g/d, suggesting that 250 g/day supplied amounts of amino acids near the requirement