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L Kung

Publications and source records attributed to L Kung.

53 records · Page 3Linked to original sources
PubMed1995

Additives containing bacteria and enzymes for alfalfa silage.

First-cutting alfalfa was wilted, harvested from alternate rows, left untreated or treated with additives containing lactic acid bacteria and enzymes (cellulase, amylase, and pectinase), and ensiled in bag silos. Inoculation increased lactic acid bacteria from 5 x 10(4) to 1 x 10(6) cfu/g of forage. Because treatments were bagged consecutively, the DM of treated silages was higher than that of untreated silage. However, after 4 d of ensiling, the pH of treated silage, about 4.3, was lower than that of untreated silage, 4.7, and remained lower throughout the ensiling period. After 177 d of ensiling, total lactate was about 25% higher, and ammonia N was about 40% lower, in treated silage. In addition, NDF and ADF contents were lower in treated than in untreated silage. Between 51 and 177 d of storage, glucose content increased in treated silage, but not in untreated silage, suggesting that some plant cell-wall hydrolysis occurred during prolonged storage. In vitro digestion of NDF did not differ among treatments during early incubation, but the extent of digestion after 36 and 48 h was lower in treated than in untreated silage. The microbial and enzyme silage additives used in this study improved fermentation characteristics and reduced fiber content of silage but decreased the in vitro digestibility of fiber.

Amylases↗
PubMed1993

In vitro effects of a thiopeptide and monensin on ruminal fermentation of soluble carbohydrates.

Using a purified diet and a mixed culture of ruminal microorganisms, we studied the in vitro effects of a sulfur-containing peptide (A10255) and monensin on ruminal VFA and lactic acid concentrations. After 22 h of fermentation, total VFA concentration was greater in cultures with A10255 and monensin (2.5 ppm each) than in untreated controls (84.1, 91.9, and 65.2 mM for cultures with A10255, monensin, and control, respectively). The molar proportions of propionate were more than 40% greater, and the molar proportions of acetate were about 15% less, in treated than in untreated cultures. The molar proportions of the remaining VFA were lowest in monensin-treated cultures, intermediate in A10255-treated cultures, and greatest in untreated cultures. Addition of A10255 or monensin also prevented the accumulation of lactate and maintained higher pH than in untreated cultures. In pure culture, growth of Streptococcus bovis was slowed by A10255 at pH 5.5 and 6.5. Growth of S. bovis was reduced markedly with addition of monensin at pH 6.5 and inhibited at pH 5.5. Growth of Lactobacillus acidophilus was inhibited more at pH 5.5 than 6.5 with monensin but was unaffected by A10255. The thiopeptide A10255 and monensin inhibited ruminal lactate production, but sensitivities of lactate-producing bacteria differed between compounds.

Animals↗
PubMed1993

Effect of microbial inoculants on the nutritive value of corn silage for lactating dairy cows.

Two experiments were conducted to evaluate the effect of microbial inoculation on the composition and nutritive value of corn silage for lactating cows. In Experiment 1, forage was untreated or treated at ensiling with Pioneer 1174 or Ecosyl silage inoculants. Forage was offered for free choice consumption, and concentrate was fed by a computerized feeder. Treatment with 1174 inoculant had little effect on silage composition and no effect on cow performance. Silage treated with Ecosyl inoculant had greater lactic acid content, but also greater acetic acid and ammonia N contents. Production of 3.5% FCM was greatest from cows fed silage treated with Ecosyl. In Experiment 2, silage was untreated or treated with Ecosyl and fed in a TMR. Inoculation had no effect on silage composition but increased 3.5% FCM production and DMI as length of time on treatment increased. Microbial inoculation can improve the nutritive value of corn silage for lactating cows even if changes in fermentation end products are minimal.

Animals↗
PubMed1992

Comparison of the galactopoietic response to pituitary-derived and recombinant-derived variants of bovine growth hormone.

Two studies were designed to examine the differences in galactopoietic potency of molecular variants of pituitary- and recombinant-derived bovine GH (bGH). The recombinant bGH molecules included amino-terminal and position-127 amino acid substitutions which are representative of two of the four natural pituitary variants or of partially degraded bGH molecules. Amino-terminal variants of bGH included methionine (Met1), alanine (Ala1), serine (Ser1) or deletion of four amino acids (delta 1-4). The delta 1-4 variants were representative of degradation products previously isolated in pituitary bGH preparations. In the first study, 54 lactating Holstein cows received i.m. injections of a buffer solution (control), pituitary-derived bGH, or recombinant-derived [Met1,Leu127]-bGH, [Met1,Val127]-bGH, [Ala1,Leu127]-bGH, or [Ala1,Val127]-bGH. Cows received 25 mg bGH/day for 21 days. Substitution of the amino-terminal alanyl residue with methionine did not affect milk response. GH variants with Val127 elicited a greater milk response (8.5 kg/day) than Leu127 bGH variants (6.5 kg/day). The average milk response to the four recombinant bGH variants was 7.5 kg/day greater than controls compared with 4.4 kg/day for pituitary-derived bGH. In contrast, blood bGH concentrations were equivalent for pituitary and recombinant bGH treatments, approximately 20 micrograms/l more than control levels at 3 h after injection. Blood free fatty acid concentrations were increased, but insulin and glucose levels were unaffected by bGH treatment. In the second study, 54 lactating Holstein cows received i.m. injections of a buffer control solution or recombinant-derived [Met1,Leu127]-bGH, [Ser1,Leu127]-bGH, [Ser1,Val127]-bGH, [delta 1-4,Leu127]-bGH or [delta 1-4,Val127]-bGH. Cows received 25 mg bGH/day for 28 days. The milk response to full-length bGH variants was 6.6 kg/day greater than the response to the amino-terminal deletion variants (P less than 0.05). Substitution of valine for leucine did not affect milk response to either the deletion (delta 1-4) or full-length (Met1 or Ser1) bGH molecules. In conclusion, the lowered galactopoietic potency of pituitary bGH preparations was demonstrated, at least in part, to be due to the presence of amino-terminal amino acid deletions rather than differences in amino acid sequences of recombinant bGH. Ala1 bGH variants with valine at position 127 elicited a greater milk response than Leu127 variants.

Amino Acid Sequence↗
PubMed1992

In vitro effects of the ionophore lysocellin on ruminal fermentation and microbial populations.

Batch and continuous culture techniques were used to evaluate the effect of the ionophore lysocellin on ruminal fermentation and microbial populations. In batch culture, .5 and 1 ppm (of the fluid) lysocellin markedly decreased (P less than .01) the acetate:propionate ratio without affecting fiber digestion, ammonia concentration, or culture pH. Greater concentrations of lysocellin had negative effects (P less than .05) on fiber digestion and increased (P less than .05) culture pH. In continuous culture, a low level of lysocellin (33 ppm of the diet DM or about .7 ppm of the fluid) decreased pH (P less than .05) and methane (P less than .05) production but had no effect on fiber digestion. Lysocellin tended to increase (P less than .05) OM digestion in corn-based diets but decreased OM digestion in barley-based diets (starch source x lysocellin interaction, P less than .05). In addition, the molar proportion of propionate was increased more in barley- than in corn-based diets. Total anaerobes and amylolytic and lactate-utilizing microorganisms were not affected by the ionophore. In continuous culture, cellulolytic and lactate-producing organisms were insensitive to lysocellin, but, in lysocellin-treated media, cellulolytic organisms were resistant, whereas lactic acid producers were sensitive to lysocellin at 4 ppm. In summary, the ionophore lysocellin alters ruminal fermentation by decreasing ruminal methane production and increasing the molar proportion of propionate; however, effects varied depending on whether corn or barley served as the primary starch source.

Ammonia↗
PubMed1992

Factors affecting response of cows to biweekly injections of sometribove.

Seventy-eight lactating Holstein cows (18 primiparous and 60 multiparous) were used to study certain factors affecting response in milk yields to biweekly injections of bST. Cows were intramuscularly injected with placebo or with 500 mg of bST every 14 d for 36 wk beginning 60 d postpartum. Primiparous cows responded less to bST than did multiparous cows. Cows were separated into three yield groups within each treatment based on pretreatment yield: low (27.0 kg/d), medium (32.0 kg/d), and high (39.0 kg/d). Response of low yielding cows to bST was numerically greater than that of medium or high yielding cows, but there was no significant interaction between treatment and pretreatment milk yield. Individual cow index for milk yield was used as a measure of genetic potential of cows, which were divided into two index groups: high cow index (greater than -23 kg) and low cow index (less than -23 kg). Cows in the high index group showed significantly higher milk yields than the low index group during treatment, but treatment by cow index interaction was not significant, suggesting that cows of widely ranging genetic potential respond similarly to bST. Response of cows to bST in mid to late lactation was slightly greater than in early lactation (15.9 and 10.6% vs. 17.8%, respectively), but no significant interaction of treatment by days postpartum was noted. Finally, even though cows treated with bST exhibited slightly higher rectal temperatures during the hot summer months, no significant difference in milk yield response to bST was noted during periods of moderate versus high ambient temperatures.

Animal Feed↗
PubMed1992

In vitro effects of the thiopeptide A10255 on ruminal fermentation and microbial populations.

Experiments used unadapted mixed cultures of ruminal microorganisms in batch or continuous culture fermentation to investigate the effect of a thiopeptide, A10255, on ruminal fermentation and microbial populations. After 24 h of fermentation in batch culture, addition of A10255 (.5 to 20 ppm of the culture fluid) to 0, 45, 60, and 75% concentrate diets had no effect on total VFA but increased molar proportion of propionate and decreased butyrate. The molar proportion of acetate was decreased by treatment only in the 0 and 75% concentrate diets. The increase in molar proportion of propionate by 20 ppm of A10255 was less than the increase caused by a similar concentration of monensin. The same concentration of A10255 (20 ppm) decreased ADF digestion less than 20 ppm of monensin. In continuous culture, A10255 (33 mg/kg of dietary DM) did not affect total VFA concentration, culture pH, OM digestion, or ADF digestion. Ruminal bacterial populations of total anaerobes and lactate-producing, lactate-utilizing, cellulolytic and amylolytic bacteria were unaffected by treatment. However, molar proportions of acetate, butyrate, and isovalerate were decreased, and propionate was increased, by addition of A10255.

Acetates↗
PubMed1991

Lupin as a protein supplement for growing lambs.

Whole lupins (Lupinus albus) were roasted with exit temperatures ranging from approximately 130 (moderate heat) to 175 degrees C (high heat). In situ N disappearance after 12 h of incubation in the rumen was 83% for raw lupins, 45% for lupins roasted at moderate temperatures, and 39% for lupins roasted at high temperatures. Lambs fed lupins roasted at moderate temperatures retained more N (P less than .01) than those fed soybean meal (SBM). However, growth rate and feed efficiency were similar among lambs fed diets containing SBM, raw lupins, or roasted lupins. Dehulled lupins commercially roasted at low, moderate, and high temperatures resulted in ruminal in situ N disappearances of 59, 47, and 43% for the respective temperatures. Dehulled lupins (Lupinus albus) were also roasted in a laboratory oven for 2, 4, and 6 h at 120, 140, and 160 degrees C. Simulation of roasting for 2 h had no effect (P greater than .10) on ruminal in situ N disappearance at any of the temperatures. In situ N disappearance was reduced (P less than .05) after roasting for 4 h at 160 degrees C, but acid detergent insoluble N was only moderately increased. Nitrogen retention in lambs fed raw, dehulled lupins was equal (P greater than .10) to that of lambs fed SBM. Whole lupins or dehulled lupins can replace SBM as the sole protein supplement for growing lambs. Although roasting lupins decreased ruminal in situ N disappearance, it had no effect on growth of lambs.

Animal Feed↗
PubMed1989

Ammonia-treated alfalfa silage for lactating dairy cows.

Alfalfa was treated (3.3% of forage wet weight) with an aqua-NH3 (14% N) mix prior to ensiling in 2 consecutive yr. In the 1st yr, NH3-treated silage containing 30.5% DM was higher in pH, N, NH3N, acetic acid and butyric acid contents, and lower in amino acids, soluble carbohydrates, and lactic acid than two untreated silages having 32.8 and 47.5% DM. Milk composition and DM intake did not differ among treatments when these silages constituted 50% of the dietary DM and were fed to lactating cows. In situ and in vitro, but not in vivo, digestion of NDF was greater for NH3 silage. Dry matter content of NH3-treated silage in the 2nd yr was 36.1% and that of the two untreated silages was 37.8 and 54.9%. Silage N, NH3N, and acetic acid content were greater in treated silage. However, pH and butyric acid content were similar among treatments and lactic acid was greater for treated silage. Similar to findings in the 1st yr, milk production and DM intake were not different among treatments. Adding NH3 to alfalfa decreased proteolysis; however, when DM was low (30.5%), the buffering effect of NH3 apparently resulted in increased clostridial fermentation. This did not occur when silage DM was increased to 36.1%, presumably due to higher osmotic pressure. Ammonia addition enhanced fiber digestibility but had no effect on milk production.

Ammonia↗
PubMed1988

Metabolism of DL-methionine and methionine analogs by rumen microorganisms.

Rates of degradation of DL-methionine and a number of methionine derivatives by rumen microorganisms were studied in vitro. Methionine hydroxy analog, the ammonium salt, and the amide derivative of methionine hydroxy analog were degraded more slowly than was methionine. Methyl and ethyl esters of methionine hydroxy analog were rapidly converted to methionine hydroxy analog, which was then degraded. Whole rumen contents were separated into protozoal and bacterial fractions, and rates of disappearance of [14C]carboxyl-labeled methionine and methionine hydroxy analog were determined. Disappearance of the label tended to be slower in the bacterial fraction; however, incorporation into cellular material tended to be higher for the bacterial than for the protozoal fraction. Disappearance of labeled methionine hydroxy analog was slower than labeled methionine in all fractions. Addition of unlabeled methionine inhibited disappearance of labeled methionine hydroxy analog, but unlabeled methionine hydroxy analog did not affect disappearance of labeled methionine. The effect of either Na2SO4, methionine, or methionine hydroxy analog on neutral detergent fiber digestion was related to amount of sulfur in the medium and not source of sulfur.

Animals↗
PubMed1987

Rat gene encoding the 78-kDa glucose-regulated protein GRP78: its regulatory sequences and the effect of protein glycosylation on its expression.

The 78-kDa glucose-regulated protein GRP78 is a stress-inducible protein ubiquitously expressed in animal cells. In this paper we show that the first exon of this endoplasmic reticulum-localized protein consists of an 18 amino acid leader sequence rich in hydrophobic residues, followed by a highly acidic mature N-terminus and an 11 amino acid domain that is shared by members of the 70-kDa heat shock protein family. The end of this shared domain also marks the beginning of the first intron of this gene. A DNA region upstream of the promoter element important for induction by calcium ionophore and by a temperature-sensitive mutation was identified by deletion analysis. Our results indicate that a region spanning from 85 to 480 nucleotides upstream of the major transcription initiation site is important for both induction conditions. With evidence suggesting that perturbations in protein glycosylation may be one of the common stimuli involved in transcription activation of the GRPs, we measured the rate of glycosylation during A23187, glucose starvation, and temperature-shift induced conditions. The inverse correlation observed between the rate of glycosylation and the steady-state level of the GRP78 transcripts lends support to this hypothesis.

Amino Acid Sequence↗
PubMed1984

Amino acids in plasma and duodenal digesta and plasma growth hormone in cows fed varying amounts of protein of differing degradability.

Eighty-four Holstein cows in early lactation fed diets varying in protein percent (11, 14, and 17% crude protein) and degradability in the rumen (normal and heated soybean meal) were sampled for effects on amino acids and growth hormone in blood plasma, and amino acid profiles in the duodenal digesta. Essential and branched chain amino acids in plasma increased as protein and amount of protected protein in the diet increased. These changes were accompanied by decreased concentrations of nonessential amino acids. Plasma growth hormone was highest at low protein (11.3%) probably because of decreased intakes on this diet. Molar percentages of amino acids in duodenal contents were not affected by diet suggesting that our heat-treated soybean meal influenced quantity more than quality of amino acids available for absorption in the small intestines.

Amino Acids↗
PubMed1984

Influences of methionine hydroxy analog on milk and milk fat production, blood serum lipids, and plasma amino acids.

Feeding for 150 days of 25 g per day of methionine hydroxy analog was tested on 100 cows (52 treated and 48 controls) in the Brigham Young University herd. Effect of days after parturition of initiating methionine hydroxy analog feeding also was observed. Milk yields were not affected by methionine hydroxy analog, but fat percent and fat yields were increased 21 and 17% by the additive. Abnormally low milk fat by control cows (2.84%) magnified the response to methionine hydroxy analog feeding. Feeding methionine hydroxy analog beginning 0 to 12 days postpartum elicited much larger increases of milk fat than started later (17 to 102 days). Blood from the coccygeal vein of 20 cows from each treatment had 10% more triglycerides from cows fed methionine hydroxy analog than from control cows. Increases of arterio-venous differences across the mammary gland of triglycerides and lipoproteins of blood serum suggested that increases of milk fat could have resulted from greater uptake of performed fat by the udder. Feeding methionine hydroxy analog increased methionine, isoleucine, and leucine in serum of coccygeal vein, but methionine was the only amino acid with significantly higher arteriovenous differences across the mammary gland.

Amino Acids↗
PubMed1983

Performance of high producing cows in early lactation fed protein of varying amounts, sources, and degradability.

Eighty-four multiparous Holstein cows were fed a standard ration from 0 to 21 days postpartum and treatment rations from 22 to 91 days. Treatments varied in amount and source of protein, and only cows averaging at least 26 kg milk daily from 8 to 21 days postpartum were used. Experimental variables included protein percent (11.3, 14.5, 17.5), ammoniated versus untreated corn silage, and heated (2.5 h at 140 degrees C in forced draft oven) versus normal soybean meal. Treatments by protein percent and supplement types were: 1) 11%, untreated silage, normal soy; 2) 14%, ammonia silage, heated soy; 3) 14%, untreated silage, heated soy; 4) 14%, untreated silage, normal soy; 5) 17%, ammonia silage, heated soy; 6) 17%, untreated silage, heated soy; and 7) 17%, untreated silage, normal soy. Milk production and dry matter intakes increased with increased protein. Differences were greater between 11 and 14% than between 14 and 17%. At 14 and 17% protein, cows fed normal soy produced less than those fed heated soy, but silage treatments were not different. The 17% ration containing ammonia silage and heated soy resulted in greatest milk production and highest income over feed costs. A combination of heated soybean meal to limit rumen degradability and ammonia in corn silage to furnish nonprotein nitrogen was the most productive and profitable of several rations compared for cows early in lactation.

Ammonia↗
PubMed1983

Influence of nonprotein nitrogen and protein of low rumen degradability on nitrogen flow and utilization in lactating dairy cows.

Four lactating cows, each fitted with a rumen cannula and duodenal and ileal t-cannulae, were used to measure flow and digestion of nitrogenous compounds in the digestive tract. Dietary dry matter contained 17% crude protein and 50:50 forage:concentrate. Treatments were: 1) corn silage-soybean meal; 2) corn silage-heated soybean meal; 3) ammonia-treated corn silage-soybean meal; and 4) ammonia-treated corn silage-heated soybean meal. Flow of organic matter to the duodenum was overestimated when lanthanum or chromium ethylene-diaminetetraacetate was used as an indigestible marker. This resulted in low estimates of ruminal digestion of organic matter and high estimates of nitrogen flow to the duodenum. However, calculations using lanthanum or lignin as markers yielded similar organic matter flow to ileum and feces. With acid-detergent lignin as a marker, estimates of dietary nitrogen degraded in the rumen were: corn silage-heated soybean meal, 55.0% ammonia-treated corn silage-heated soybean meal, 58.8%; ammonia-treated corn silage-soybean meal, 63.3%; and corn silage-soybean meal, 66.0%. Digestion in the small intestine of nonammonia nitrogen was equal for all treatments suggesting that availability of heated soybean meal in the intestine was not different, although ruminal degradability tended to be lower. Feeding diets containing nonprotein nitrogen did not decrease available nitrogen at the duodenum.

Animals↗
PubMed1980

Supplemental niacin for lactating cows fed diets of natural protein or nonprotein nitrogen.

Thirty-two Holstein cows, 16 in early and 16 in midlactation, were assigned to four treatments: 1) soybean meal protein plus niacin; 2) soybean meal without niacin; 3) nonprotein nitrogen plus niacin; and 4) nonprotein nitrogen without niacin. Niacin dose was 6 g per day, and nonprotein nitrogen supplied 20% of total nitrogen for those treatments. Differences between treatments in milk yields were not significant, but milk persistencies tended to be highest for cows in early lactation fed niacin during wk 9 and 10 of treatment. Intakes of dry matter did not differ significantly, but cows fed nonprotein nitrogen without niacin had lowest intakes per 100 kg bodyweight. Differences between treatments in feed utilization, milk composition, bodyweight changes, plasma ammonia, rumen pH, rumen volatile fatty acids, dry matter digestibilities, nitrogen digestibilities, and retained nitrogen were not significant.

Animal Feed↗