Endogenous amino acid flow in the avian ileum: quantification using three techniques.

The aim of the present study was to compare the protein-free diet, guanidinated casein (GuC) and enzyme hydrolysed casein (EHC) methods for the quantification of endogenous amino acid (AA) flow in the avian ileum. Growing broiler chickens (5 weeks old) were used. All three assay diets were based on dextrose, and in the GuC and EHC diets GuC or EHC were the sole source of N. Endogenous AA flows determined with the use of protein-free diet were considerably lower (P<0.05) than those determined by the GuC and EHC methods. The total endogenous AA flows determined by the GuC and EHC methods were almost 3-fold greater (P<0.05) than those determined by the protein-free diet. The endogenous AA values obtained from GuC and EHC methods were similar (P>0.05), except for the flow of arginine, which was lower (P<0.05) in the EHC method. Glutamic acid, aspartic acid, threonine and glycine were the predominant endogenous AA present in digesta from the distal ileum. The contents of methionine, histidine and cystine were lower compared with other AA. The method of determination had no effect on the AA composition of endogenous protein, except for threonine, glutamic acid, lysine, arginine and cystine. The concentrations of threonine and arginine were lower (P<0.05) and that of lysine was higher (P<0.05) with the EHC method compared with the other two methods. The concentration of glutamic acid was greater (P<0.05) and that of cystine was lower (P<0.05) in the EHC and GuC methods compared with the protein-free diet method. The results showed that the ileal endogenous flows of N and AA are markedly enhanced by the presence of protein and peptides, above those determined following feeding of a protein-free diet. It is concluded that the use of EHC and GuC methods enables the measurement of ileal endogenous losses in chickens under normal physiological conditions.

A comparison of ileal digesta and excreta analysis for the determination of amino acid digestibility in food ingredients for poultry.

1. The apparent ileal and excreta digestibilities of amino acids in 15 samples representing 12 food ingredients were determined using 5-week-old male broiler chickens. The ingredients included 3 samples of cereals (wheat, maize and sorghum), 6 samples of plant protein meals (soyabean meal, cottonseed meal, canola meal and sunflower meal) and 6 samples of animal protein meals (meat meal, meat-and-bone meal, feather meal and fish meal). 2. The test ingredients were incorporated as the sole source of dietary protein in assay diets. Each diet was offered ad libitum to 3 pens (4 birds/pen) from d 35 to d 42 post-hatching. Total collection of excreta was carried out during the last 4 d. All birds were killed on d 42 and the contents of the lower half of the ileum were collected. Apparent ileal and excreta amino acid digestibilities were calculated using acid-insoluble ash as the indigestible marker. 3. The influence of site of measurement was found to vary among food ingredients, among samples within an ingredient and among different amino acids within an ingredient. Ileal amino acid digestibility values were similar in some ingredients, but significantly lower or higher in others than the corresponding excreta values. 4. Average ileal and excreta amino acid digestibilities in sorghum and maize were similar, but significant differences were observed for individual amino acids. In contrast, ileal amino acid digestibility values were higher than the corresponding excreta digestibility values in wheat. 5. The average ileal and excreta digestibilites of amino acids in the 3 soyabean meal samples were similar although small, but significant differences were noted for individual amino acids. Site of measurement had no effect on the digestibility of amino acids in canola meal. Digestibilities of valine, isoleucine, phenylalanine, histidine, glutamic acid, alanine and tyrosine in sunflower meal and those of valine, methionine, isoleucine, leucine, lysine, glutamic acid and alanine in cottonseed meal were lower by excreta analysis. 6. Digestibilities in animal protein meals, with the exception of blood meal and fish meal, were consistently higher by excreta analysis. Ileal-excreta differences in individual amino acid digestibilities were more evident in feather meal, meat meal and meat-and-bone meal. 7. Threonine and valine were the indispensable amino acids that were more frequently influenced by the site of measurement. Of the dispensable amino acids, aspartic acid, serine, glutamic acid and alanine were the most affected. 8. Differences determined between ileal and excreta digestibilities in the present study clearly demonstrate that amino acid metabolism by hindgut microflora in chickens may be substantial and that digestibilities measured in the terminal ileum are more accurate measures of amino acid availability than those measured in the excreta.

Influence of guanidination on apparent ileal amino acid digestibility in some protein sources for broilers.

High pH employed during the guanidination process (conversion of lysine residues to homoarginine) and its possible effects on racemization of amino acid residues to D-forms and on amino acid digestibility are concerns often raised with the use of guanidinated proteins to estimate endogenous amino acid losses in monogastric animals. The objective of the present study was to investigate the influence of guanidination on apparent ileal amino acid digestibility of casein, soybean meal, cottonseed meal, and canola meal for broiler chickens. Apparent ileal digestibility of amino acids in guanidinated and unreacted proteins, with few exceptions, were found to be remarkably similar. These results suggest that the guanidination process has no influence on the susceptibility of proteins to proteolysis and that racemization is not a practical problem when the proteins are guanidinated at low temperatures.

Impact of family history of diabetes on the assessment of beta-cell function.

Numerous factors impinge on beta-cell function, and include the genetic background and insulin sensitivity of the individual. The aim of the present study was to evaluate the impact of a family history of non-insulin-dependent diabetes mellitus (NIDDM) on beta-cell function and to determine whether the relationships between beta-cell function and insulin sensitivity and age are influenced by a family history of diabetes. Thirty-three healthy control subjects (CON), 20 normal glucose-tolerant first-degree relatives of known NIDDM patients (REL), and 12 nondiabetic identical twins with an identical twin with known NIDDM were studied. Insulin and C-peptide responses to an acute intravenous glucose (AIRg) and glucagon bolus (at euglycemia [AIR[G.GON]]) were measured, as well as each individual's insulin sensitivity. Fasting insulin and C-peptide levels were similar in all groups. AIRg was significantly reduced by 65% in the nondiabetic twins compared with the CON and REL groups, with the latter group being similar to CON, whereas for the AIR[G.GON], the insulin responses in the twin subjects were reduced only by 35% compared with CON. Following stepwise (default) multiple regression analysis, three independent variables (insulin sensitivity, 23%; family history of NIDDM, 20%; and fasting glucose, 7%) were identified, and these combined to fit a model for prediction of acute beta-cell responses to glucose that yielded an R2 (adjusted) value of 50%. Following analysis of covariance (ANCOVA), a positive family history of NIDDM and insulin sensitivity but not the age of the subject were confirmed as separate factors affecting AIRg. In conclusion, in subjects with normal or mild glucose intolerance, the individual's genetic background and insulin sensitivity are important determinants of insulin secretion.

The Australian Multicenter Trial of Growth Hormone (GH) Treatment in GH-Deficient Adults.

GH treatment in adults with GH deficiency has numerous beneficial effects, but most studies have been small. We report the results of an Australian multicenter, randomized, double-blind, placebo-controlled trial of the effects of recombinant human GH treatment in adults with GH deficiency. GH deficiency was defined as a peak serum GH of < 5 mU/liter in response to insulin-induced hypoglycemia. Patients were randomly assigned to receive either GH (0.125 U/kg per week for 1 month and 0.25 U/kg per week for 5 months) or placebo. After 6 months, all patients received GH. The primary end points were biochemical responses, body composition, quality of life, and safety. One hundred sixty-six patients (72 females and 91 males) with a mean age of 40 +/- 1 yr (+/- SEM; range 17-67 yr) were recruited. Serum insulin-like growth factor-I (IGF-I) increased from a standard deviation score of -2.64 +/- 0.27 (range -8.8 +3.82; n = 78) to +1.08 +/- 2.87 (range -7.21 to +6.42) at 6 months in the GH/GH group; 38% of the whole group were above the age-specific reference range following treatment [17.6% and 68.9% with subnormal (< 2 SD) or normal (+/- 2 SD) pretreatment levels, respectively]. Fasting total cholesterol (P = 0.042) and low-density lipoprotein cholesterol (P = 0.006) decreased over the first 6 months. Fat-free mass increased in the first 6 months whether measured by bioelectrical impedance (P < 0.001) or dual energy x-ray absorptiometry (DEXA; P < 0.001). Total-body water increased in the first 6 months whether measured by bioelectrical impedance (P < 0.001) or deuterium dilution (P = 0.002). Fat mass measured by DEXA (P < 0.001), skinfold thicknesses (P < 0.001), and waist/hip ratio (P = 0.001) decreased in the first 6 months. Most changes in body composition were complete by 3 months of treatment and maintained to 12 months. Whole-body bone mineral density (BMD) (by DEXA) was unaffected by GH treatment. Self-reported quality of life was considered good before treatment, and beneficial treatment effects were observed for energy, pain, and emotional reaction as assessed by the Nottingham Health Profile. In the initial 6 months, adverse effects were reported by 84% of patients in the GH and 75% in the placebo group, with more symptoms relating to fluid retention in the GH group (48% vs. 30%; P = 0.016). Such symptoms were mild and resolved in 70% of patients despite continued treatment. Resting blood pressure did not change over the initial 6 months. In summary, GH treatment in adults with GH deficiency resulted in 1) prominent increases in serum IGF-I at the doses employed, in some cases to supraphysiological levels; 2) modest decreases in total- and low-density lipoprotein cholesterol, together with substantial reductions in total-body and truncal fat mass consistent with an improved cardiovascular risk profile; 3) substantial increases in lean tissue mass; and 4) modest improvements in perceived quality of life. The excessive IGF-I response and side-effect profile suggests that lower doses of GH may be a required for prolonged GH treatment in adults with severe GH deficiency.

Histological necrosis in soft tissue sarcoma following preoperative irradiation.

Forty-eight patients with soft tissue sarcomas that presented adverse features for treatment by limb salvage surgery and postoperative irradiation were treated by preoperative irradiation and surgery using a consistent protocol. Following resection, the extent of histological necrosis in the specimen was scored according to the criteria of Willet et al. Of the 48 cases, 16 (34%) demonstrated Grade 1 response (< 50% necrosis), 15 (31%) Grade 2 (50-80% necrosis), and 17 (35%) Grade 3 (> 80% necrosis). There was a trend toward more extensive necrosis in liposarcoma tumors (53% showing Grade 3 response compared to 26% of other sarcomas). Logistic regression analysis demonstrated a significant relationship between necrosis and tumor size (P < 0.001) with larger tumors having higher grades of necrosis. Tumor grade did not seem to affect the extent of necrosis. In comparison to the previous report of necrosis in soft tissue sarcoma following irradiation, the current analysis revealed a smaller proportion of tumors with Grade 3 necrosis.

Total parenteral nutrition in gynecology and obstetrics.

Although total parenteral nutrition (TPN) is accepted for the general surgical patient, it also has applications in management of certain gynecologic and obstetric patients. Over an 8.5-year period, 30 patients at a community hospital were referred for TPN from the obstetric and gynecologic service. The gynecologic patients were subdivided into 3 groups: those with rectovaginal fistulas, in whom colostomies were avoided; those with postoperative enterocutaneous fistulas and starvation; and those with postoperative prolonged ileus or mechanical intestinal obstruction and malnutrition, occasionally complicated by previous irradiation. Treatment with TPN obviated the need for surgery in many patients and improved the perioperative condition in others. In obstetrics, TPN was valuable in the treatment of severe hyperemesis gravidarum, inflammatory bowel disease, and the critically ill neonate. TPN can be an effective therapeutic tool in the management of a wide range of major nutritional problems facing the obstetrician-gynecologist.

Hyperalimentation and cancer.

Over an 8-year period, 106 patients with cancer who were major operative risks received intravenous hyperalimentation (IVH). All were malnourished, had gastrointestinal obstruction or had postoperative complications such as fistulas, evisceration or intra-abdominal sepsis, which left IVH as the only means of achieving anabolism. When IVH was started preoperatively and continued postoperatively (34 patients), no deaths or major complications occurred. When IVH was first started after serious complications had occurred (62 patients), the incidence of recovery was high; the mortality was 17.7%. When IVH was given to cachectic patients whose cancer was inoperable to enable them to tolerate radiotherapy or chemotherapy (10 patients), the mortality was 40.0%. Although this last group is small, IVH is worthwhile in selected patients in whom good palliation life can be obtained. With careful IVH and improvement in the quality of technique, the risk of sepsis was no greater than in patients without cancer.