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Accurate estimation of ileal endogenous amino acid (EAA) losses is important when formulating diets on a standardized ileal digestible amino acid basis. In addition to the undigested and unabsorbed amino acids of dietary origin, amino acids of endogenous origin, which can be basal or diet specific, are found in digesta. The improvement in the techniques used in amino acid analysis as well as a shift from sampling excreta to ileal digesta has resulted in more accurate amino acid digestibility coefficients. Despite this, however, it is important to determine the amino acids in the digesta that are of endogenous origin. Although the need for standardization and its associated advantages is still subject to debate, it is important to evaluate how values from various methodologies compare. Several methods have been used to estimate ileal EAA flow. The classical methods, including the regression method, the use of nitrogen-free diet (NFD), and the fasted cecectomized rooster method, are the most widely used. The criticisms with the last 2 methods are that birds are not in a normal physiological state and the ileal EAA flow is, therefore, underestimated. Different methods have resulted in different endogenous flow estimates, with the NFD method having the lowest values when compared with flows from the regression and highly digestible protein methods. In addition to the influence of methods on ileal EAA flows, the influence of the age of the birds on flow is important. Data on EAA losses are copious in the literature; however, variation in data across and within laboratories calls for investigation of factors contributing to the variation. This review compares results from different methods and examines the issue of repeatability and consistency of EAA losses data from different laboratories. Finally, composition of an NFD for estimating EAA losses is proposed.

Spontaneous ovulations are induced by preovulatory surges of luteinizing hormone (LH) and progesterone (P4) during ovulatory cycles in birds, but estradiol-17beta (E2) levels are relatively constant. Egg production is enhanced in restricted fed (RF) in comparison with ad libitum fed (FF) broiler breeder hens, but changes in concentrations and peripheral patterns of LH, P4, and E2 during ovulatory cycles in broiler breeder hens are poorly documented. The hypothesis of this study was that high resolution patterns of peripheral LH, P4, and E2 during preovulatory surges would not be different between FF and RF broiler breeder hens. Seven FF and 6 RF broiler breeder hens were photostimulated with 16 L:8 D at 22 wk of age. At 28 wk of age, the hens were cannulated for serial blood sampling and switched to a 24L:0D photoperiod to allow preovulatory surges of LH and P4 to run freely. Three days after cannulation, hens were serially bled every 12 min for 36 h. The FF hens were heavier than the RF hens (5.60 +/- 0.35 vs. 3.60 +/- 0.28 kg, respectively; P < 0.01). During the 10 d before cannulation, total egg production of the FF and RF hens (8.3 +/- 1.4 and 6.8 +/- 1.3 eggs, respectively; P = 0.08) and normal egg production (5.6 +/- 1.8 and 6.5 +/- 1.8 eggs, respectively; P = 0.37) were not different. The FF hens, however, had more abnormal eggs than the RF hens (2.7 +/- 1.7 and 0.3 +/- 0.8 eggs, respectively; P < 0.01). None of the hormonal measurements was different between the FF and RF hens (P > 0.05). The concentrations of hormones for the FF and RF hens, respectively, were as follows: baseline LH (2.79 +/- 0.45 vs. 2.94 +/- 0.60 ng/mL) and P4 (1.68 +/- 0.56 vs. 1.41 +/- 0.43 ng/mL), overall mean LH (3.18 +/- 0.45 vs. 3.10 +/- 0.46 ng/mL) and P4 (2.32 +/- 0.55 vs. 2.09 +/- 0.91 ng/ mL), preovulatory surge amplitude of LH (5.43 +/- 1.27 vs. 3.88 +/- 1.24 ng/mL) and P4 (6.08 +/- 2.09 vs. 6.71 +/- 3.91 ng/ mL), preovulatory surge duration of LH (7.52 +/- 1.80 vs. 5.74 +/- 3.18 h) and P4 (7.52 +/- 1.42 vs. 8.20 +/- 1.24 h), and overall mean E2 (0.25 +/- 0.05 vs. 0.23 +/- 0.05 ng/mL). In conclusion, there were no differences in total egg production or normal egg production between FF and RF broiler breeder hens, but the FF hens laid more abnormal eggs. Also, there were no differences in the concentrations or peripheral patterns of LH, P4, and E2 during preovulatory surges between the FF and RF broiler breeder hens.

Turkey hens were fed either a standard breeder diet (CON, myristic acid, C14.0, 1.1%; palmitic acid, C16:0, 16.8%; oleic acid, C18:1, 23%; linoleic acid, C18:2, 48.7%) or a diet containing 5% coconut oil (COCO) enriched with medium chain fatty acids (MCFA; lauric acid, C12:0, 22.6%; C14:0, 10.8%; C16:0, 12.5%; C18:1, 14.8%; C18:2, 24.6%). After 10 d on the diets, fresh eggs were collected for yolk lipid and fatty acid (FA) determination. An additional 60 to 95 eggs were incubated and the FA profiles of the neutral lipid (NL) and phospholipid (PL) fractions of yolk sac and liver lipids were determined. The NL fraction of the yolk sac from CON eggs contained less C12:0 (0 vs 0.49%) and C14:0 (0.7 vs 4.6%) and more C18:1 (41.3 vs 37.5%). The PL fraction of the yolk sac from both treatments contained < 1% C14:0, and there was less than a 2% difference between treatments in other FA concentrations. The hepatic NL fraction from both treatments contained < 1% C14:0 and only C18:1 showed > 1% differences between treatments (Control = 59.9%; COCO = 56.62%). There were no dietary effects on the FA profile of hepatic PL. The presence of only minimal quantities of MCFA in hepatic NL and PL suggests that absorbed yolk sac MCFA are extensively metabolized during embryonic development.

1. In two experiments, the dietary lysine concentration which supported maximal gain through 14 days of age in a subline of Japanese quail selected for 4-week body weight (HW) was higher than that needed by the random-bred population (R1) from which it was initially developed. 2. The lysine concentrations needed to minimize feather depigmentation and maximize breast and leg muscle development were higher in HW quail than in R1 quail.

Two experiments were conducted to determine if differences in response of livers to estradiol administration in male broiler chicks would be observed if fed isonitrogenous and isocaloric diets of different composition. A polymethylsiloxane tube filled with estradiol dipropionate was implanted under the neck skin to ensure a constant release of hormone. Different tube sizes were implanted in two- to three-week-old chicks fed a basal corn-soybean meal (CS) diet or a diet containing fish meal, alfalfa meal, and torula yeast (FAY) o distiller's dried grains with solubles (DDGS). Body weight gains were significantly reduced by the highest level of estradiol in chicks fed the CS diet but not chicks fed FAY or DDGS. Liver weight, deposition of lipid in liver and plasma lipid were markedly increased in proportion to the size of estradiol tube in chicks fed all diets. Increase of liver weight and lipid deposition by the highest level of estradiol in chicks fed the CS diet was significantly greater than that in chicks fed the FAY diet. Liver weight and the liver lipid response to estradiol in chicks fed the CS diet were significantly greater than that in chicks fed the FAY diet when dose response equations were compared among diets. These data show that the response on deposition of lipid in liver to estrogen administration was modified by the type of ingredients included in diets with similar energy and nutrient profiles.

The relationship between body weight gain, nutrient intake, and skeletal and muscle growth in broiler breeder pullets was studied in two experiments. A total of 720 and 540 pullets were started in Experiments 1 and 2, respectively. In the first study, growing pullets were fed either a 15% protein, 2,885 kcal ME/kg pullet grower diet or a 23% protein, 3,133 kcal ME/kg broiler starter diet from 2 to 16 wk of age. Within each dietary treatment, there were three body weight groupings (light, control, heavy) achieved by manipulating weekly feed allowances. At 8, 12, and 16 wk of age, 12 pullets from each diet and body weight grouping were killed for muscle [pectoralis major] and skeletal (shank, keel, tibia, clavicle) measurements. As body weight increased, so did skeletal growth, but there were no significant differences in skeletal measurements related to diet. At 12 and 16 wk of age, pullets fed the broiler starter diet had significantly larger p. major muscles. In Experiment 2, growing pullets were fed restricted diets: 1) the 15% protein grower diet (control), 2) the broiler starter diet adjusted weekly to the same calculated calorie intake as that obtained with the grower diet (broiler starter calorie), or 3) the broiler starter diet adjusted to the same calculated protein intake as the grower ration (broiler starter protein). At 16 wk, there were no significant differences between body weight or skeletal measurements of the control and broiler starter calorie treatments. Pullets in the broiler starter calorie treatment did have significantly larger pectoralis muscles and less abdominal fat than those fed the 15% grower diet. Pullets in the broiler starter protein treatment were significantly lighter and had shorter bones, less abdominal fat, and smaller p. major muscles than those in the control treatment.

In two experiments, a high dietary level of available phosphorus (.65%) in the presence of high chloride concentrations (.36%) was associated with a significant increase in the incidence of tibial dyschondroplasia (TD) in male broiler chickens. The level of dietary calcium and the interaction between Ca and available P had no effect on TD. Heterozygous normal (DW/DW) male broilers had a significantly lower incidence of TD than homozygous normal (Dw/Dw) chicks (Experiments 1 and 2). In Experiments 3 and 4, there were no significant differences between BW at 14 days for roaster-broiler cross and broiler chicks. At 21 and 28 days, however, the roaster-broiler cross chicks weighed significantly less than the broilers and had a significantly lower incidence of TD. Decreasing growth rates in broiler chicks after 14 days of age resulted in a significant decrease in the incidence of TD (Experiments 4 and 5), but did not decrease the severity of TD lesions at 28 days (Experiment 5). Depressed growth from 0 to 14 days decreased, but did not eliminate, TD lesions (45%) at 28 days, but it did significantly decrease the severity of the lesions compared with that in the 14 to 28-day manipulation treatments (Experiment 5). In Experiment 5, chicks were growth restricted from 0 to 14 or 14 to 21 days and then ad libitum fed the control diet until 28 days of age. The serum growth hormone concentrations at 28 days were inversely related to the rate of BW gain from 21 to 28 days of age, independent of BW at 21 or 28 days or feed consumption from 21 to 28 days. There were no differences in serum concentration of thyroxine or triiodothyronine at 28 days.

The aim of this study was to determine the effect of the standardization method and age on standardized ileal amino acid digestibility (SIAAD) of 4 meat and bone meal (MBM) samples in broiler chicks and turkey poults. The SIAAD were obtained by correcting apparent ileal digestibility (AID) values for basal ileal endogenous amino acid flow obtained from chicks and poults fed a N-free diet or a highly digestible protein diet (HDP; 100 g of casein/kg of diet). Four diets were formulated to contain 20% CP by using MBM as the only source of CP. Each diet was fed to 6 replicate cages of 30 or 8 birds/cage at 5 and 21 d, respectively, for 5 d. With the exception of all-beef MBM, chick AID values on d 21 were higher (P < 0.05) than on d 5. In poults, however, AID was not different between the 2 ages, with the exception of His, which was higher (P < 0.05) at d 21. There was no difference between methods on SIAAD on d 5 or 21 for all 4 MBM samples in either species. There was no effect of the method of standardization on SIAAD at either age for most amino acids. For chicks, however, standardization of the all-beef MBM sample with HDP resulted in higher (P < 0.05) SIAAD values for most of the amino acids (d 5). In poults at d 5, however, the SIAAD for most of the amino acids in the blended MBM were higher (P < 0.05) with HDP correction. The CV in SIAAD in chicks between the 2 methods of standardization was higher on d 5 (8.1%) relative to d 21(5.0%) for all treatments. In poults, greater variability was observed on d 21(8.2%) relative to d 5 (6.7%). Results from this study showed that at d 21, SIAAD with either the N-free or the HDP diet resulted in similar digestibility values. [ABSTRACT FROM AUTHOR]