Chemical and biological assay procedures for lysine in fish meals.
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Biomedical subjects
Publications and source records attributed to E L Miller.
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The effect of supplementing barley diets with urea (U), extracted decorticated groundnut meal (GNM) or Peruvian fish meal (PFM) on plasma free amino acid concentrations in sheep have been examined and the first limiting amino acid has been indicated by measuring the changes in the concentration of the plasma essential amino acids (PEAA) during a rumen infusions of a volatile fatty acid (VFA) mixture. 2. Three wethers fitted rumen and re-entrant duodenal cannulas were given isonitrogenous, isoenergetic diets containing (g/kg dry matter (DM) U 20, GNM 106 and PFM 78, the crude protein (nitrogen x 6.25) contents being 139, 145 and 148 respectively. The sheep were fed hourly, the mean daily DM intake being 0.634 kg. 3. Plasma concentrations of valine, threonine, lysine, isoleucine and leucine were linearly related to their concentrations in duodenal digesta. 4. A VFA mixture was infused into the rumen for 6 h to supply (mmol/min) acetate 1.47, propionate 0.22 and n-butyrate 0.27. Blood samples were taken 6 h before, during and 12 h after the end of the infusion. 5. The concentration of all PEAA decreased relative to the pre-infusion and post-infusion controls but there were no significant differences between diets. 6. The mean decrease in concentration averaged over all three diets showed that the decrease in concentration of methionine (41.5%) was far greater than for any other essential amino acid suggesting that under these conditions methionine was the first limiting amino acid.
1. In a randomized block design, four sheep were given 800 g daily of diets containing: chopped lucerne (L), chopped lucerne-rolled barley (2:1; LB), rolled barley-chopped lucerne (2:1; BL), rolled barley (B); each diet was supplemented with minerals, vitamins and urea as considered necessary. Chronic oxide was included in the diets as a flow marker. 2. Flows of organic matter (OM) and non-ammonia-nitrogen (NAN) to the small intestine (SI) were measured and microbial protein was identified by a 35S-incorporation procedure. 3. OM disappearance in the rumen increased linearly with increasing inclusion of barley in the diet but there was no significant change in microbial NAN flow to the SI so that the yield of microbial NAN (g)/kg fermented OM (FOM) decreased from 29.6 (diet L) to 22.7 (diet B). Changes in the energetic efficiency of microbial protein synthesis appeared to be unrelated to alterations in rumen fluid volatile fatty acid (VFA) proportions or in rumen fluid dilution rate (D). 4. The degradability of dietary protein (non-urea-N), estimated using the 35S procedure, was 0.72, 0.76, 0.86 and 0.86 for diets L, LB, BL and B respectively. Similar values were obtained from concurrent polyester-bag experiments when the fractional outflow rate of undegraded protein from the rumen (k) was assumed to be 0.046.
1. The effect of supplementing barley diets with urea (U), extracted, decorticated groundnut meal (GNM) or Peruvian fish meal (PFM) on rumen bacterial protein synthesis and the proportion of undegraded food protein passing to the duodenum of sheep has been examined. 2. Three wethers were given isonitrogenous, isoenergetic diets containing (g/kg dry matter (DM)): U 20, GNM 106 or PFM 78, the crude protein (nitrogen x 6.25) contents being 139, 145 and 148 respectively. The sheep were fed hourly, the mean daily intake of DM being 0.634 kg. 3. Rumen bacterial protein synthesis was determined using 35S and diaminopimelic acid (DAPA) as bacterial markers and polyethylene glycol (PEG) and chromic oxide as markers of digesta flow. Rumen volatile fatty acid (VFA) production rate was determined by a continuous infusion of [1-14C]acetate. 4. 35S and DAPA gave similar estimates of the proportion of bacterial N in the trichloroacetic acid-precipitable nitrogen of the rumen digesta, the mean value being 0.86. The VFA production rate did not vary significantly between diets, the mean being 5.8 mol/24 h. The flow of bacterial N from the rumen was calculated from the PEG and CR2O3 estimates of flow and the 35S and DAPA estimates of the proportion of bacterial N in the rumen. 35S and DAPA gave similar values (mean 12.5 g/24 h) and Cr2O3 gave a slightly lower value (11.5 g/24 h) than PEG (13.5 g/24 h). Dietary effects, averaged over the four methods, were not significant; the values were 13.0, 13.4 and 11.0 g/24 h for the U, GNM and PFM diets respectively. 5. Duodenal samples were taken from two 12 h continuous collections from re-entrant cannulas and the DM flow adjusted to total recovery of Cr2O3. The mean recovery Cr2O3 at the duodenum was 0.798. The rates of flow of DM were 0.296, 0.311 and 0.334 kg/24 h and of non-ammonia-N (NAN) 13.5, 15.2 and 15.4 g/24 h on the U, GNM and PFM diets respectively. 6. The concentrations of the essential amino acids in duodenal digesta were generally higher with the PFM diet than with either of the other two diets. The flow of most amino acids through the duodenum was generally higher on the PFM and GNM diets than on the U diet. 7. The energetic efficiency of bacterial protein synthesis was calculated to be 2.1 g bacterial N/mol VFA or 28 g bacterial N/kg organic matter fermented in the rumen. 8. From the estimates of bacterial N flow the rumen and NAN flow through the duodenum it was calculated that 0.22 and 0.69 of the supplemental N from GNM and PFM respectively passed through the rumen undegraded.
1. A simple procedure using 35S incorporation for the measurement of microbial protein in absomasal or duodenal digesta of ruminants was developed and tested. 2. Microbial protein synthesized in the rumen was labelled with 35S by intraruminal infusion of 35SO4 and a microbial fraction was isolated by differential centrifugation. 3. 35S not bound by micro-organisms and present as inorganic 35S in whole digesta and in microbial fractions was oxidized to 35SO4 and the samples were brought into solution by acid-hydrolysis. 35SO4 was precipitated as Ba35SO4. 4. The proportion of microbial non-ammonia-nitrogen (NAN) in digesta NAN was determined as 35S: NAN (digesta) divided by 35S: NAN (microbial). 5. In sheep offered grass nuts at maintenance level of feeding, 48% of NAN flowing through the abomasum was of microbial origin. NAN flow to the small intestine was estimated using chronic oxide as a marker and it was calculated that 49% of the grass N was degraded in the rumen.
Methods of determining protein requirements are reviewed and recent proposals of the Agricultural Research Council working party on nutrient requirements of ruminants outlined. Needs of the rumen microorganisms for degradable nitrogen to achieve optimum rumen digestion of feed are predicted. The extent to which milk production and live-weight gain can be sustained by microbial protein alone is estimated. Higher milk yields and rates of growth require dietary protein that escapes degradation in the rumen but is digested in the small intestine. Small changes in degradability of dietary protein are predicted to have a large effect on the dietary crude protein requirement. Although there is still inadequate data for precise prediction, the concepts of the metabolic approach have been valuable in understanding those physiological situations where protein is most likely to be limiting, where use of protected proteins and urea might be most appropriate, in the planning of critical experiments and in the design of new methods of feeding or management of ruminants.
This report presents the results of an original investigation designed to determine (1) the prevalence in the natural dentition of a maxillary midline located in the exact middle of the mouth using the philtrum as the most reliable guide and (2) the percentage of people in whom the maxillary and mandibular midlines precisely coincide with each other. Results indicate that the midline is situated in the exact middle of the mouth in approximately 70% of people and that the maxillary and mandibular midlines fail to coincide in almost three fourths of the population.
A large segment of our society associates cancer with doom and despair. This negative view appears to originate partially from the public's general lack of knowledge of the disease and of current treatment potential. In response to this lack of information and overall pessimistic attitude, a cancer education course was developed for school teachers and school nurses. The unique two-day course provides cognitive and affective learning experiences. Through the multiple teaching strategies employed, students are able to examine their own health practices, increase their knowledge of cancer and cancer treatment, interact with a person who is successfully living with cancer, and learn how to share information related to cancer. At the conclusion of the course, a comparison of the participants' pretest and posttest scores indicate a statistical improvement in both their cognitive and affective domains.
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