Biomedical subjects

L M Potter

Publications and source records attributed to L M Potter.

At least 37 records · Page 2Linked to original sources

PubMed1983

Effects of dietary carbohydrate and of intestinal microflora on excretion of endogenous amino acids by poultry.

The effects of dietary carbohydrate and of intestinal microflora on excretion of endogenous amino acids by poultry were investigated. Excretion of endogenous amino acids was compared among fasted roosters, intact roosters fed low- or high-fiber, N-free diets, and surgically-modified (SM) roosters fed a low-fiber, N-free diet. The low-fiber diet contained 50% corn starch, 45% glucose, and 5% cellulose, whereas the high-fiber diet contained 25% each of corn starch, glucose, and raw potato starch, 17.5% cellulose, and 7.5% pectin. Digesta were obtained from the terminal ileum of SM roosters to eliminate effects of the microflora in the large intestine and ceca. The roosters were force-fed 60 g of the appropriate diet (30 g at the initiation of the trial followed by an additional 30 g 6 hours later). Excreta or digesta and urine were collected quantitatively for 48 hr after the first force-feeding. Roosters fed the high-fiber diet excreted substantially more (P less than .05) amino acids than did fasted roosters or roosters fed a low-fiber diet. Excreta from roosters fed the high-fiber diet contained higher (P less than .05) levels of alanine and aspartic acid than excreta from fasted or digesta from SM roosters, indicating substantial microbial synthesis of amino acids in the gut. In contrast, amino acid composition of excreta from fasted and intact roosters fed the low-fiber diet was similar to that of digesta from SM roosters, suggesting less microbial influence. Excretion of glucosamine plus galactosamine by SM roosters was approximately twice that of intact roosters fed the same diet. Glycine was the most abundant amino acid in digesta of SM roosters. Results of this study indicate that dietary carbohydrate substantially affects excretion of endogenous amino acids by poultry and that fasted birds may not provide an accurate estimate of endogenous amino acid excretion for birds fed high-fiber feedstuffs in amino acid digestibility trials.

Amino Acids↗

PubMed1983

Relative deficiencies of amino acids and nitrogen per se in low protein diets for young turkeys.

Three experiments were conducted to determine the relative deficiencies of lysine, threonine, valine, and nitrogen per se in a low protein diet composed primarily of corn, soybean meal, and .3% added DL-methionine fed to young turkeys. Diets containing 22, 26, and 30% protein served as controls. A mixture of amino acids (AA) was added to the 22% protein diet. Additional diets were formulated by individually removing lysine, threonine, or valine from the AA mixture and by adding 4% glutamic acid to each to form a 5 X 2 design exclusive of 26 and 30% protein diets. In each experiment, each diet was fed ad libitum to two pens of nine male poults and two pens of nine female poults of a medium body-size variety from 8 to 19 or 20 days of age. Body weight gains and feed consumptions were increased (P less than .001) by supplementing the 22% protein diet with the AA mixture or by increasing the protein level to 26 or 30%. Removal of either lysine, threonine, or valine from the AA mixture produced body weight gains and feed efficiencies smaller (P less than .001) than from the fully supplemented diets but greater (P less than .05) than from the unsupplemented diets. The addition of 4% glutamic acid to the diets failed to improve performance, indicating that nitrogen per se is not the limiting factor for growth. From these results, it is postulated that sulfur AA appear more deficient than either lysine, threonine, or valine in the 22% protein corn-soybean meal diet containing .3% added methionine.

Amino Acids↗

PubMed1983

Supplementary inorganic sulfate and methionine for young turkeys.

Two replicated experiments utilizing a total of 864 Large White Turkeys were conducted to determine the effects and possible interactions of supplementary inorganic sulfate and DL-methionine on body weight gain and feed consumption. Experimental diets, in which a corn-soybean meal basal diet was supplemented with inorganic sulfate either in the form of sodium sulfate (0, .0952, and .1904%) or potassium sulfate (0, .1180, and .2360%), and with methionine (0, .05, .10 and .15%) in the place of glucose monohydrate, were fed in a 3 X 2 X 4 experimental design. Each diet was fed to 9 males and 9 females from 1 day to 7 weeks of age. For 0, .05, .10, and .15% added methionine, 7-week body weights were 2020, 2162, 2238, and 2243 g, and feed consumptions were 3346, 3478, 3587, and 3571 g, respectively, producing significant (P less than .001) increases. For 0, .0215, and .0430% added sulfur from sulfates, body weights were 2163, 2167, and 2167 g, and feed consumptions were 3483, 3510, and 3494 g, respectively, but none were significantly different. Interactions were not significant; thus, sulfates did not replace or alter the requirement for added methionine in diets of young turkeys in this study.

Animals↗

PubMed1981

Utilization of amino acid analogues in diets of young turkeys.

1. The relative potencies of three lysine, one tryptophan and six methionine analogues to their corresponding l-amino acids were determined. 2. Male poults, 9 d of age, were used in five 14 d experiments. Experimental diets were formed by adding increasing levels of an amino acid (L-isomer) or its analogues to a basal diet deficient in the test amino acid. Multiple-regression analyses of body-weight gain v. level of added or amount of consumed amino acid supplement were computed. Relative potencies of the analogues were calculated using the slope-ratio technique. 3. Type of independent variable used in the regression analyses did not significantly affect relative potency values. 4. From regression analyses with level of added amino acid supplement as the independent variable, relative potencies (with 95% confidence intervals) on a molar basis of each analogue as a percentage of the respective amino acid were: hydroxymethyl-L-tryptophan monohydrate 9(-12, 22), DL-methionine sulphone 3 (-68, 36), DL-methionine hydantoin - 10 (-63, 29), L-cystine 8 (-31, 40), DL-methionine sulphoxide 59 (24, 95) and 46 (18, 74), oleoyl-DL-methionine 77 (37,138), methionine hydroxy analogue calcium 93 (65, 128), dicocoyl-L-lysine 23 (5,41), bis-hydroxymethyl-L-lysine-calcium 69 (54, 84 and 41 (-1,80), mono-hydroxymethyl-L-lysine-calcium 89 (77, 101) and 99 (65, 134). 5. The first four analogues appeared to have little or no amino acid activity. DL-methionine sulphoxide, dicocoyl-L-lysine, and bis-hydroxymethyl-L-lysine -calcium were partially active. Relative potencies of oleoyl-DL-methionine, methionine hydroxy analogue calcium, and mono-hydroxymethyl-L-lysine- calcium were not significantly different from those of their corresponding amino acids.

Amino Acids↗

PubMed1981

Lysine and protein requirements of growing turkeys.

A study was conducted with 1,751 Large White turkeys divided into 36 pens of males and 36 pens of females between 8 and 24 or 20 weeks of age, respectively, to determine the requirements of protein and lysine for turkeys. Diets were composed of ground yellow corn, dehulled soybean meal, 6% stabilized fat, 4% meat and bone meal, .4% methionine, minerals, and vitamins. A 3 X 3 factorial design of nine diets varying in protein (18, 21, and 24%) and added lysine (0, .1, and .2%) was used between 8 and 12 weeks of age. Birds were reassigned to new balanced pens at the end of each 4-week period, and protein levels were reduced by 3.0%. The addition of 3 and 6% protein, which provides .22 and .44% lysine, to diets of turkeys between 8 and 20 weeks of age increased body weight gains 18.3 and 24.7%, respectively, in contrast to an increase of only 2.2 and 3.6% from .1 and .2% added L-lysine per se. the minimum protein requirements of large White male turkeys at 10, 14, and 18 weeks of age are 21.3, 19.5, and 17.6% and for female turkeys 21.7, 18.4, and 15.0%, respectively. The minimum lysine requirements of large White turkeys to 12, 16, and 20 weeks of age are about 1.4, 1.2, and.9%, respectively, or 4.5, 3.7, and 3.0 g/kcal metabolizable energy. Another amino acid appears to be equally or more deficient than lysine in diets used in this study.

Aging↗

PubMed1980

Influence of dietary protein during the pre-breeder period on subsequent reproductive performance of large white turkeys. 1. Growth, feed consumption, and female-sex-limited reproductive traits.

Large White female turkeys of a commercial variety were used to determine the effects of low dietary protein during the pre-breeder period (12 to 32 weeks of age) on subsequent reproductive performance. Diets containing 10, 12, 14, and 17% protein were fed from 12 weeks or 20 weeks to 32 weeks of age. At 32 weeks of age, all females were fed a 17% protein breeder diet. Reproductive performance was measured for a 24-week production period. Pre-breeder feed consumption and body weight gain from 12 to 32 weeks of age increased with increased dietary protein until diets contained 14% protein. Similar results were obtained when females were fed varying protein levels from 20 to 32 weeks of age. Egg production also showed an increase with increased pre-breeder dietary protein level until diets contained 14% protein. Ten fewer eggs per hen were obtained from females previously fed the 10% protein diet than those fed the 14% (20 to 32 weeks) and 17% protein diets. Pre-breeder dietary protein level did not affect age at sexual maturity, egg weight, specific gravity or shell thickness of eggs, mortality or growth, and feed consumption of progeny. Based upon the results of this study, female breeder turkeys require at least 14% protein to 20 weeks of age and 14% from 20 to 32 weeks of age for optimum egg production.

Animals↗

PubMed1980

Influence of dietary protein during the pre-breeder period on subsequent reproductive performance of large white turkeys. 2. Growth, feed consumption, and male sex-limited reproductive traits.

the effect of low dietary protein during the rearing and breeding periods on the reproductive performance of Large White turkey males was examined. At 12 weeks of age 251 males were randomly divided into two groups and fed either 12 or 17% protein through 56 weeks of age. Body weight gains from 12 to 20 weeks and 20 to 28 weeks of age were significantly reduced for the males receiving the 12% dietary protein. However, after 28 weeks of age, weight differences decreased and by 56 weeks of age body weights of both groups were approximately the same. In addition, a significant reduction in feed consumption was noted for the males fed 12% protein. Males on the high protein diet experienced a higher mortality than those on the low protein diet. Low dietary protein reduced semen volume and spermatozoa concentration at 33 weeks of age, but there were no significant differences thereafter. The percentages of normal, abnormal, or dead spermatozoa were unaffected by dietary protein levels. Feeding 12% protein from 12 to 56 weeks of age to Large White turkey breeder males was adequate for high quality semen production.

Animals↗

PubMed1980

Influence of dietary protein during the pre-breeder period on subsequent reproductive performance of large white turkeys. 3. The effects of semen volume and frequency of insemination on fertility and hatchability.

Large White turkey breeders of a commercial variety were used to determine the effects of pre-breeder dietary protein, frequency of insemination, and semen volume on subsequent reproductive performance. Treatments included female dietary protein levels of 10, 12, 14, and 17% fed from 12 to 32 weeks of age and 10, 12, an 14% protein from 20 to 32 weeks of age; male dietary protein levels of 12 and 17% fed from 12 to 56 weeks of age; and artificial insemination (AI) treatments of a) .025 ml of semen at weekly intervals, b) .025 ml of semen at biweekly intervals, and c) .05 ml of semen at biweekly intervals in a factorial arrangement of treatments. Male dietary treatment had no significant effect on fertility or hatchability of fertile eggs. Female pre-breeder protein levels also had no significant effect on fertility but resulted in lower hatchability of fertile eggs during the latter part of the production period when females were fed either the 10 or 12% protein pre-breeder diets. Weekly inseminations with .025 ml of semen resulted in the highest average level of fertility during the production year (90%), followed by biweekly insemination with .05 ml (87%) and .025 ml (85%) of semen, respectively. Hatchability of fertile eggs was significantly higher for hens receiving .05 ml of semen biweekly than for the other two AI treatments during the latter half of the production year only. However, weekly inseminations caused a significant decline (6.7 eggs/hen) in egg production when compared to hens inseminated at biweekly intervals. The average number of fertile eggs was greatest for females inseminated with .05 ml semen biweekly (54.3) compared to those inseminated with .025 ml of semen biweekly (53.0) or .025 ml of semen weekly (50.2).

Animal Nutritional Physiological Phenomena↗

PubMed1980

Amino acid digestibility of dehulled soybean meal by adult turkeys.

Nine adult Large White male turkeys were fed dehulled soybean meal (DSBM) as the sole dietary component to determine the apparent digestibilities of its dry matter and amino acids. Apparent digestibility was determined by the total excreta collection method. Average apparent dry matter digestibility of DSBM was 53.3%. Amino acid contents of the DSBM and excreta for all except the sulfur amino acids were determined after acid hydrolysis. The sulfur amino acid levels were determined after performic acid oxidation and acid hydrolysis. Apparent amino acid digestibility averaged 87%. Glycine and arginine were the least and most efficiently digested amino acids with values of 80% and 93%, respectively.

Amino Acids↗

PubMed1980

Methionine and protein requirements of turkeys 8 to 16 weeks of age.

Turkeys of medium size strains were fed nine diets varying in protein and added methionine content from 8 to 12 and from 12 to 16 weeks of age. Four experiments with a 3 X 3 factorial design were conducted for each age period. Changing the protein content from 18 to 21% and from 21 to 24% during the 8- to 12-week period increased body weight gain by 11.2 and 5.1%, respectively. Changing the protein content from 15 to 18% and from 18 to 21% during the 12- to 16-week period increased body weight gains by 16.7 and 5.4%, respectively. Added methionine at the .2 and .4% levels increased body weight gains by 10.3 and 11.7% from 8 to 12 weeks and 3.5 to 2.3% from 12 to 16 weeks, respectively. The total sulfur amino acid requirements of Medium White turkeys during the 8- to 12- and 12- to 16-week periods were about .93 and .75%, respectively. Using data from the current and previous studies (Potter and Shelton, 1979), we calculated multiple regression analyses of percentage increase in body weight gains (Y1 of males or females during 2-week periods from increasing the dietary protein content by 3% on percent protein(X1) in the diet and average age (X2) of the turkeys. From these regressions, the protein requirement of Medium White turkeys is about 30.3% at one day of age and decreases .61 and .78 percentage units per week for males and females, respectively.

Animal Nutritional Physiological Phenomena↗

PubMed1980

Relative lysine potencies of eight analogues in diets of young turkeys.

Three experiments were conducted to determine the biological potencies of eight lysine analogues in diets of young turkeys. Diets containing increasing levels of added L-lysine or a lysine analogue were fed to 9-day-old male poults for periods of 12 or 14 days. Multiple regression analyses of body weight gains on levels of supplemental L-lysine or analogue were computed. Relative potencies of the lysine analogues were calculated using the slope-ratio technique. Relative potencies of 6-N-N-dimethylamino-2-hydroxyhexan-N,N-dimethylamide, 6-N-acetylamino-2-hydroxyhexanamide, 6-N-propionylamino-2-hydroxyhexanamide. 6-N-butyrylamino-2-hydroxyhexanamide, 6-N-methylamino-2-hydroxyhexan-N-methylamide and alpha-keto-epsilon-acetylamino-caproic acid were not significantly different from 0%. Mono-hydroxymethyl-L-lysine-calcium and bis-hydroxymethyl-L-lysine-calcium had relative potencies of 62 +/- 6 and 52 +/- 7%, respectively, on a molar basis.

Animals↗

PubMed1979

Methionine and protein requirements of young turkeys.

Nine experiments involving a total of 3697 turkeys divided into 48 pens per experiment were conducted to determine the methionine or total sulfur amino acid and the protein requirements of Medium White turkeys between 0 and 4 weeks and between 4 and 8 weeks of age. In each experiment, 24 diets varying in protein and methionine content in a 4 X 6 factorial design were fed. Body weight gains were found to be more closely related to the total sulfur amino acid content than to the methionine content of practical type corn-soybean meal diets. For the respective age periods between 0 to 4 and 4 to 8 weeks, the total sulfur amino acid requirements of Medium White turkeys were approximately 1.10 and 1.00% or 3.8 and 3.4 mg per kcal metabolizable energy, and the minimum protein requirements were at least 27% and 24% when diets contained sufficient total amino acids.

Amino Acids, Sulfur↗

PubMed1979

Response from menhaden fish meal in diets of young turkeys.

Diets involving three or five fish meal treatments and two zinc bacitracin treatments were fed to 5410 poults. The poults were divided into 552 pens and raised to two, three or four weeks of age in five series of 3 X 2 or 5 X 2 factorial experiments. Body weights increased 9.0 to 31.3% from the addition of 5% menhaden fish meal and 5.4 to 11.9% from the addition of 44 ppm bacitracin. No interaction existed between fish meal and bacitracin. Residues derived from either water or petroleum ether extraction of fish meal, when added to diets at levels equivalent to those in 5% fish meal, produced body weight gains nearly equal to those obtained from 5% fish meal. Body weights were not increased by the addition of either water or petroleum soluble extracts or by charred or ashed fish meal. The addition of a mixture of crystalline amino acids, defluorinated phosphate, and fat equivalent to 5% fish meal produced only a 4.4% increase in body weight. An unidentified growth factor which is non-lipid, non-mineral, and non-water soluble appears to be present in menhaden fish meal when added to well foritified po

Amino Acids↗

PubMed1976

Protein, methionine, lysine and a fermentation residue as variables in diets of young turkeys.

A study was conducted to determine the effects of adding methionine, lysine and a fermentation residue to practical-type diets containing 24, 27, and 30% protein for young turkeys. A 2 X 2 X 2 X 3 factorial design of variables was used in each of two seven-week experiments. A total of 864 poults were divided into groups such that the 24 diets were each fed to 9 males and 9 females in each experiment. Seven-week body weights were increased 11.4% from 0.1% added DL-methionine and decreased 13.7% from 1.5% added fermentation residue, L-Lysine added at 0.157% failed to increase significantly body weights. Increasing the protein from 24 to 27 and 30% increased seven-week body weights 16.7 and 28.9%, respectively. As dietary protein increased, the increases in body weight from added methionine became smaller, i.e., 16.9, 14.4 and 4.8% in diets containing 24, 27, and 30% protein, respectively. Plots of body weight on (1) amount of methionine and on (2) amount of total sulfur amino acids in the diet show a closer relationship with the latter. The sulfur amino acid requirement of poults to seven weeks of age appears to be at least 1.03%, the highest quantity used in this study. The fermentation residue, a product not currently marketed, remains after the isolation of spectinomycin from controlled fermentation of Streptomyces flavopersicus and contains 14% dry matter. The cause of the depressed growth from the added fermentation residue has been discussed.

Animal Feed↗

PubMed1974