Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762-9665; Kemin Industries, Inc., Des Moines, IA 50301-0070.

ABSTRACT
Energy and protein nutrient specifications in broiler rations in the United States are primarily met with corn and soybean meal, respectively. Little has been done to improve the nutrient availability of corn or soybean meal because they are considered to be highly digestible. However, the energy availability of the carbohydrate portion of soybean meal in poultry is low. Research has indicated that dietary alpha-galactosidase improves the energy availability of soybean meal. We conducted this research to determine whether a dietary enzyme preparation containing -galactosidase would improve growth performance or carcass attributes of broilers fed corn and soybean meal diets.

Three thousand six hundred straight-run commercial broilers were fed diets with or without an enzyme preparation primarily containing alpha-galactosidase during periods of hot temperature conditions. Broilers in the enzyme-supplemented treatment had significantly reduced 1- to 49-d feed conversion and mortality. A subsequent battery chick trial showed no beneficial effects of the enzyme on growth performance of male chicks. Commercial broilers reared in hot temperature conditions that received corn- and soybean meal-based diets supplemented with alpha-galactosidase might have improved performance.

Key words: Broiler, enzyme, alpha-galactosidase, energy

J. Appl. Poultry Res., 2001. 10:65-70

Nutri-Quest, Inc., Chesterfield, MO 63017; O.K. Industries, Inc., Fort Smith, AR 72902; Choctaw Maid Farms, Inc., Carthage, MS 39051; Wayne Farms, Gainesville, GA 30501

ABSTRACT
A level of dietary crude protein (CP) is usually specified in least cost formulation for commercial broilers. A better understanding of less limiting amino acid needs (i.e., threonine, isoleucine, and valine) may allow nutritionists to better understand the minimum level of CP needed, thereby minimizing marginal excesses of the less limiting amino acids. The efficiency of poultry production decreases during periods of hot weather conditions, and the impact of environmental temperature on the less limiting amino acids is poorly understood. The interactive effects of dietary lysine, threonine, and the branched-chain amino acids (BCAA) were evaluated in two experiments in growing broilers reared in thermoneutral and hot temperature conditions. Experiment 1 was conducted in hot temperature conditions and indicated that threonine needs of growing and finishing broilers to optimize feed conversion may be affected by the starter level of dietary lysine. In addition, some amino acid treatments decreased hot temperature-related mortality of broilers indicating the need for amino acid-balanced diets in periods of hot temperature conditions. An isoleucine response occurred in breast meat yield in Experiment 2 indicating the importance of meeting an isoleucine minimum in dietary formulation for growing broilers.

Key words: Amino acid, breast meat, broiler, isoleucine, lysine, threonine, valine

J. Appl. Poultry Res., 2000. 9:223-233

Department of Poultry Science and the Interdepartmental Nutrition Program, North Carolina State University, Raleigh, NC 27695-7608.

ABSTRACT
Progeny immunocompetence and disease resistance from turkey hens receiving dietary supplemental zinc was investigated. Twelve hens received a diet that contained 82 mg/kg Zn. Diets were supplemented with 40 mg/kg Zn sulfate (ZnSO4) or 40 mg/kg Zn methionine (ZnM) and analyzed to contain 122 and 118 mg/kg total Zn, respectively (six replications per treatment). Progeny received a corn and soybean meal diet containing 92 mg/kg Zn. Hens supplemented with ZnM had progeny with heavier bursa of Fabricius as a percentage of poult body weight (BW). Blood monocytes were isolated from poults at 7 days of age, and hens receiving ZnM had progeny with higher blood leukocyte Zn concentrations. Cutaneous basophil hypersensitivity response elicited by phytohemagglutinin-P (PHA-P) was higher in progeny from hens supplemented with ZnM. Subsequent hypersensitivity measurements with PHA-P or pokeweed mitogen did not differ between Zn sources. Macrophage function of poults was evaluated after Bordetella avium inoculation. Poults from hens supplemented with ZnM had higher percentage macrophages adhered to glass surfaces. However, poults from hens supplemented with ZnM had depressed 21-day BW after B. avium inoculation. Results indicate that dietary ZnM supplementation to hens may aid progeny immune organ development and enhance nonspecific immunity. However, progeny from hens supplemented with ZnM had a depressed BW after B. avium infection that may have been due to a heightened immune response.

Key words: Bordetella avium, cellular immunity, macrophage, progeny, turkey, zinc methionine

J. Appl. Poultry Res., 2000. 9:414-423

Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762-9665 USA

ABSTRACT
An important objective of the least cost formulation of broiler diets is to provide sufficient amounts of the most limiting amino acids to support the needs of tissue maintenance and accretion while minimizing any excesses. Threonine is the third most limiting amino acid in broiler diets behind the total sulphur-containing amino acids and lysine. Research into the threonine requirement of broilers is sparse compared with that of methionine and lysine. However, recent work on the threonine needs of growing and finishing broilers has been invaluable in helping commercial nutritionists determine the minimum amount of threonine required in least cost diet formultations. This review summarises this recent research. It also considers threonine needs for optimal immune system functions, feather growth, glycine requirements and gastrointestinal functions, as well as under conditions causing heat stress.

Key words: Amino acid; broiler; L-threonine; poultry; threonine

World's Poultry Science Journal, 2000. 56:139-151

Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 and >Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762-9665

ABSTRACT
Two experiments (Experiment 1 and 2) were conducted to evaluate growth performance, ascites mortality, and concentrations of plasma Arg, urea, and ornithine in male broilers raised in floor pens (2x4 factorial experiment, six pens for treatment) and exposed to cool temperatures averaging 16C after 21 d of age. Broilers were fed low- or high-CP diets in both Experiments. In Experiment 1, Arg treatments consisted of control (no supplemental Arg); 0.15 or 0.3% supplemental Arg in the diet (low- and medium-Arg feed, respectively); and 0.3% supplemental Arg in the drinking water (Arg-water). Arginine levels were increased in Experiment 2 and consisted of the following: control (no supplemental Arg); 0.3 or 0.85% supplemental Arg in the diet (medium- and high-Arg feed, respectively); and 0.6% supplemental Arg in the drinking water (Arg-water). The water treatment followed a 3-d cyclic regimen, with supplemental Arg being provided for 24 h, followed by tap water for 48 h. When the broilers reached 37 d of age and all groups had consumed tap water for the previous 48 h, blood samples were collected from one per pen (Time 0, 0700 h); then supplemental Arg was provided in the Arg-water group, and additional blood samples were collected from the control and Arg-water groups at 3, 6, 12, and 36 h after Time 0. Plasma amino acids were analyzed using HPLC. Birds fed the high-CP diet were heavier at 49 d than birds fed the high-CP diet in Experiment 1, but not in Experiment 2. No differences were found in feed conversion or ascites mortality due to CP or Arg treatments in either experiment. In both experiments, plasma Arg was similar for all groups at Time 0, but increased in the Arg-water group at 3, 6, and 12 h after Arg was provided in the water. Within 12 h after returning to tap water, plasma Arg levels of the Arg-water group did not differ from the control group. Plasma urea and ornithine were parallel to plasma Arg concentrations, and the high-CP diets resulted in higher plasma levels of urea and ornithine compared with low-CP diets. These results indicate that kidney arginase was readily activated by Arg provided in the water, resulting in an immediate increase in plasma urea and ornithine. Plasma Arg was increased significantly, but no effects were observed in ascites mortality.

Key words: Ascites, arginine, urea, ornithine, nitric oxide

Poultry Science, 2001. 80:358-369

Poultry Science Department, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
Previous research has shown that the sperm quality index (SQI) of rooster semen is indicative of overall semen quality. The objectives of the present experiments were to determine the correlation of the SQI with semen characteristics and fertility and to determine if selection of young males for the SQI would improve fertility. In Experiment 1 semen was collected from 35 Peterson males and was analyzed individually for sperm concentration and viability. To determine fertility, 100 microL of diluted semen was inseminated into 10 hens for each rooster. Positive correlations of the SQI with total and live sperm concentrations as well as fertility were found. A negative correlation of the SQI with the percentage of dead sperm was observed. In Experiment 2, four semen samples were collected at 2- to 3-d intervals from each of 142, 27-wk-old Peterson roosters to determine their SQI. Males were then allocated to six treatment groups based on their average SQI readings as follows: 0 to 150, 151 to 200, 201 to 250, 251 to 300, 301 to 350, and >350. For each SQI group, semen was collected weekly for 8 wk, pooled, and used at a rate of 50 microL/hen to inseminate 40 hens. The percentage of fertilized eggs increased linearly across the SQI groups, from a minimum of 65% for the 0 to 150 SQI group to a maximum of 98% for the >350 SQI group. The SQI groups of 301 to 350 and >350 produced the slowest decline in fertility over days postinsemination. Therefore, selection of males for the SQI at an early age appears to improve flock fertility.

Key words: Sperm quality, fertility, semen, broiler breeder, hatchability

Poultry Science, 2000. 79:771-777

Department of Poultry Science, Experimental Statistics Unit, and College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
The effects of added dietary fat type and level on broiler breeder performance were evaluated in two trials. In Trial 1, diets included no added fat (NAF) or 3.0% added poultry fat (PF) for individual bird energy intakes of 430 and 467 kcal/d at peak production (PCD), or 1.5% PF or 3.0% com oil (CO) at 449 PCD. In Trial 2, diets contained NAF, 1.5 or 3.0% added CO or PF, or 3.0% lard (LA) for peak energy intakes of 463 PCD. All diets in Trial 2 were isocaloric and isonitrogenous. Feeding of experimental diets was initiated when breeders were 22 wk old in both trials, and hen BW was measured at various weeks between 22 and 47 wk in Trial 1 and between 27 and 65 wk in Trial 2. Egg production, egg weight (EW), eggshell quality, and hatchability were recorded at various weeks between 24 and 48 wk in Trial 1 and between 27 and 64 wk in Trial 2. Body weights and EW increased progressively, and eggshell quality fluctuated variably with age. Egg production peaked between Weeks 32 and 35, and hatchability was significantly depressed at Week 63. Egg weight and hatchability were not affected by dietary treatment; however, BW increased with energy level in the diet between Weeks 27 and 47. Body weight was also higher in birds fed 1.5 or 3.0% added fat compared with NAF and was higher in birds fed LA compared with CO at the 3.0% level. Egg specific gravity and shell weight per unit of surface area at Week 41 were increased by feeding low or high energy compared with moderate energy, and relative egg shell conductance was increased by using moderate compared with high energy diets and by feeding 1.5% PF compared with 3.0% PF. Egg specific gravity was increased by PF when compared with CO across fat level at Weeks 26 and 47 and by LA when compared with PF across fat level and breeder age. These data suggest that certain dietary energy and fat regimens may affect BW and eggshell quality without associated effects on EW and hatchability at various breeder ages.

Key words: broiler breeder, dietary fat, eggshell quality, energy, hatchability

Poultry Science, 2000. 79:629-639

Department of Poultry Science, Experimental Statistics Unit, and College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
The effects of breeder age and added dietary fat source and level on broiler hatching egg characteristics were evaluated. Diets included no added fat (NAF) or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen-day (PCD) or 1.5% PF or 3.0% com oil (CO) at 449 PCD. As added dietary fat was changed from CO to PF, the percentage of unsaturated dietary fatty acids, including linoleic acid, decreased. Feeding of experimental diets was initiated when breeders were 22 wk old. Total fresh egg weight; eggshell weight; percentages of yolk (PYK), albumen (PAB), and eggshell (PSHL) weights; and yolk albumen ratio were measured at various weeks between 26 and 47 wk of age. Egg weight increased progressively with hen age.
Significant increases in yolk albumen ratio occurred between Weeks 26 and 31 and between Weeks 31 and 35. Low (430 PCD) dietary energy levels significantly reduced PYK at 35 wk and increased PAB across breeder age. Eggshell weight was lower in birds fed moderate (449 PCD) compared to low energy levels at Week 26, moderate compared to high (467 PCD) energy levels at Week 41, and PF compared to CO across fat level at Week 31. At Weeks 31 and 41, PSHL was increased by the use of 3.0% PF compared to 1.5%, and PSHL was increased at Weeks 26 and 41 by using added PF compared to CO across fat level. Increased dietary energy decreased PAB and the use of added dietary CO rather than PF decreased PSHL in broiler breeders between 26 and 47 wk of age.

Key words: albumen, broiler breeder, dietary fat, energy, shell, yolk

Poultry Science, 2000. 79:698-704

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608; and Department of Poultry Science, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
We conducted an experiment to determine the effect of relative humidity (RH) during incubation on characteristics of hatched chicks from eggs produced by young broiler breeders. Eggs were collected for 6 consecutive d, every other week, in each of two trials from broiler breeder flocks at 26, 28, and 30 wk of age. The eggs were randomly distributed in machines according to RH treatments that were 43, 53, and 63% RH from set to pulling time at 21.75 and 22 d of incubation for Trials 1 and 2, respectively. The same dry bulb temperature (37.5 C) was used throughout incubation for both trials.
Body weight at hatch, but not BW at pull (removal from machine), increased significantly with increasing RH treatment. The BW at hatch and BW at pull increased with increasing hen age. Percentages of late dead and fertile hatchability were the highest for the 63% and 53% RH treatments, respectively. These data demonstrated that, although a high RH during incubation produced chicks with increased BW at hatch, this extra weight was greatly reduced by time of pull, which suggests a significant rate of evaporation even in the presence of high RH. Further, the high RH appears to have a detrimental effect on embryonic development, as evidenced by the increased percentage of late dead.

Key words: hatchability, embryo mortality, incubation, relative humidity, broiler breeders

Poultry Science, 2000. 79:827-830

Department of Poultry Science and Experimental Statistics Unit, Mississippi State University, Mississippi State, Mississippi 39762; Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695

ABSTRACT
The relationship of albumen height (AH) to the compositions of yolks and embryos in hatching eggs from a young (30 wk of age) broiler breeder flock was evaluated during incubation. On Day 2 of incubation, egg weight, yolk weight, and yolk moisture, lipid, and fatty acid contents were determined in eggs from broiler breeders previously identified as laying eggs of either low or high AH. In addition, egg weight, wet and dry embryo weight, and embryo moisture and protein contents were determined on Days 10, 12, and 16, and embryo lipid content was determined on Days 12 and 16. Yolk and embryo weights were expressed as percentages of sampled egg weight. Egg, yolk, and wet embryo weights, yolk moisture and lipid contents, and embryo moisture, protein, and lipid contents were not affected by AH; however, yolk myristic acid concentration was higher, and yolk linoleic acid concentration was lower, in low AH eggs on Day 2 of incubation. Furthermore, on Day 16, dry embryo weight was significantly higher in low AH eggs. Young breeder hens laying eggs of different AH may also produce egg yolks with different fatty acid compositions. Differences in yolk fatty acid profiles between AH groups during early incubation may impact subsequent embryo DM weight without associated effects on embryo moisture, protein, or lipid contents.

Key words: albumen height, broiler breeders, embryo, incubation, yolk

Poultry Science, 2000. 79:1373-1377

Department of Poultry Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, North Carolina 27695-7608; and Department of Poultry Science, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
Broiler hatching eggs were subjected to one RH condition (53% RH) from 0 to 16 d and switched to one of three different RH conditions (43, 53, or 63%) from transfer at 16 d to pull time at 21.67 d of incubation. The broiler breeder ages were 27, 29, and 31 wk for Trial 1, and 26, 28, and 30 wk for Trial 2 in Experiment 1. For both trials, BW at hatch, BW at pull, hatch time, and chick weight loss between hatching and pull were measured. All unhatched eggs were opened and examined macroscopically. Experiment 2 was conducted using the chicks produced in Experiment 1. The chicks were immediately placed after pull and randomly distributed by sex into brooding pens by RH treatment in Trial 1, and by sex, RH, and brooding temperature in Trial 2. Two brooding conditions, warm and cool, were used in Trial 2. Body weight at placement, BW gain to 12 d, feed conversion, and mortality were recorded.
There was no effect of RH treatment on fertile hatchability. Body weight at hatch, pull, and placement increased with hen age. Mortality was higher for the late-hatching chicks in the warm brooding conditions in Trials 1 and 2 of Experiment 2, whereas mortality was significantly greater for the early-hatching chicks and those chicks hatched at 43% RH under the cool-brooding temperature conditions. Relative humidity treatment had no effect on chick performance in the presence of warm brooding conditions. Warm brooding conditions improved BW gain to 12 d compared with cold brooding conditions. Overall, optimal chick performance was achieved at 53% RH. Chick quality problems that may be due to high or low RH during incubation can be ameliorated by proper brooding conditions.

Key words: hatchability, embryo mortality, incubation, young broiler breeders, brooding

Poultry Science, 2000. 79:1385-1391

Department of Biochemistry and Molecular Biology, Department of Poultry Science, and College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
Caprine serum was fractionated by size, and its proteinaceous material <8,000 Da [caprine serum fraction immunomodulator 2 (CSF-I2)] was evaluated for its ability to impart immunoresistance to specific-pathogen-free (SPF) layer chickens. The SPF layers were challenged with 18 to 30 cfu of Pasteurella multocida X-73 (serotype 1) at 5 wk of age. A high degree of mortality was apparent 24 and 48 h later (62 ± 14% and 88 ± 7%, respectively). Mortality observed after 48 h was minimal.
Noting the rapid onset of mortality, we administered CSF-I2 (material that expressed no direct antimicrobial activity but was believed to be an immunostimulant) 1 d before challenge and coincident to time of challenge. The group of birds that received CSF-I2 (either 5 or 10 mg per administration) expressed significant reduction in mortality throughout the l-wk study period. Reduction in mortality appeared to be dose dependent. Birds that received two administrations of 10 mg CSF-I2 had significantly fewer deaths than did the group of birds that received half that amount. No deaths were recorded through 24 h, whereas, at 48 h, the percentage mortality was 13 in CSF-I2-treated birds. This study demonstrates that one or more small molecular weight compounds isolated from caprine serum were able to reduce mortality in SPF layers infected with Pasteurella multocida.

Key words: caprine serum, CSF-I2, layers, mortality, Pasteurella

Poultry Science, 2000. 79:1424-1429

Department of Poultry Science, Experimental Statistics Unit, and College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
The effects of dietary fat and broiler breeder age on egg and embryo characteristics during incubation were investigated. Breeders were fed diets containing no added fat or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen day (pC/d), or 1.5% PF or 3.0% corn oil at 449 pC/d. Feeding of diets was initiated at 22 wk, and eggs were collected for incubation at 27 and 36 wk of age. Percentage incubational egg weight loss was determined between day of set and Days 6, 12, and 18. Percentage wet and dry embryo weights, embryo moisture content, and eggshell weights were determined at 6, 12, and 18 d of incubation. Percentage yolk sac weight and wet and dry liver weights and moisture content were determined on Days 12 and 18. Percentage gall bladder weight was determined on Day 18. There were no observed effects due to breeder diet. However, eggshell weight at Days 6, 12, and 18 was higher in 27-wk-old hens compared with 36-wk-old hens. Conversely, egg weight loss between Day 0 and Days 6, 12, and 18 and yolk sac weight across Days 12 and 18 of incubation were lower in eggs at 27 wk of age compared with 36 wk. At Day 18, dry embryo weight was higher and wet liver weight was lower at 27 wk compared with 36 wk. A slower rate of DM accumulation in embryos at Week 36 compared to Week 27 was associated with increased incubational water loss and decreased embryo moisture content, eggshell percentage, and yolk sac absorption rate. These data demonstrate that changes in eggshell characteristics with broiler breeder age can alone impact yolk uptake, growth, and body composition in subsequent embryos.

Key words: broiler breeder, embryo, liver, moisture

Poultry Science, 2001. 80:272-277

Department of Animal Sciences, Purdue University West Lafayette, Indiana 47907, USA;
Poultry Science Department, Mississippi State University, Mississippi State, Mississippi 39762. USA

ABSTRACT
The purpose of this study was to evaluate the effects of diet and broiler breeder hen age on serum cholesterol (CHOL) and very low density (VLDL) and high density (HDL) lipoproteins. In Experiment 1, breeder hens were bled at 20, 26, 32, 36, 43 and 48 wk of age, whereas in Experiment 2 hens were bled at 22, 36, 51 and 69 wk of age. Across both experiments lipids changed drastically with the onset of lay and as the breeders aged. In Experiment 1, CHOL and HDL decreased at 32 wk and remained low through 48 wk when compared to prelay values at 20 wk? A similar pattern was observed in Experiment 2. In both experiments, VLDL increased greatly with the onset of egg production. Despite the alterations in diet (saturated vs unsaturated diets) there were no differences in circulating lipids as affected by diet. The present study provides information on circulating lipids in broiler breeders through a complete production period, when challenged with various lipid diets. Even though diets were modified in lipid composition, the broiler breeder hens only exhibited changes in their circulating lipids as a function of age, a unique distinction from mammalian lipid metabolism.

Key words: Broiler breeder, serum lipoproteins, serum cholesterol, egg formation

Journal of Applied Animal Research, 2001. 19 : 73-84

Department of Poultry Science, Experimental Statistics Unit, Mississippi State University, Mississippi State, Mississippi 39762; and Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695

ABSTRACT
There is a paucity of information regarding the influence of incubational humidity on the characteristics of broiler embryos from young hens that often produce chicks of marginal quality. Therefore, the effects of broiler breeder age (26, 28, and 30 wk) in young broiler breeders and incubator humidity (43, 53, and 63% RH) on embryonic growth between 16 and 21 d of incubation, hatching chick weight, and embryo and chick body compositions were evaluated. Hatching broiler chick BW at 21 d was lower for 26-wk-old breeders compared to those at 28 and 30 wk, and the lowest RH decreased relative wet embryo weight. Embryonic growth, on wet and DM bases, was increased in eggs from the youngest hens. Embryo moisture content (EM) was lower at 16, 17, and 19 d of incubation in eggs from breeders at 26 wk when compared to those at 28 wk of age. The effects of RH on embryo crude protein and fat composition were not consistent and varied with breeder age and length of incubation. It was demonstrated that broiler breeder age affects embryogenesis and hatching chick BW. Furthermore, EM was influenced by breeder age, and changes in incubational RH between 43 and 63% affected embryogenesis without having associated effects on EM or consistent effects on embryo crude fat and protein content. Nevertheless, a depression in embryogenesis with a reduction in incubational RH to 43% may accentuate poor posthatch performance of chicks from young breeders.

Key words: broiler breeder, embryo, incubation, relative humidity

Poultry Science, 2001. 80:1299-1304

Department of Poultry Science, and Experimental Statistics Unit, Mississippi State University, Mississippi State, Mississippi 39762; and Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
The effects of broiler breeder age (26, 28, and 30 wk) and incubator relative humidity (43, 53, and 63% RH) on yolk sac weight and composition in broiler hatching eggs between 16 and 19 d of incubation were evaluated. Percentage yolk sac weight was reduced in eggs from the youngest (26 wk) breeder hens and in eggs incubated at 53% RH. Percentage yolk moisture, in eggs from the youngest hens, was lowest at 16 d and was highest at 19 d, and percentage yolk lipid was highest at 16 and 17 d of incubation in eggs from 30-wk-old hens. Percentage yolk lipid content was higher at 63% RH compared with 53% RH in eggs from 26-wk-old breeders but was lower in eggs incubated at a 43% RH compared with 53 and 63% RH from 30-wk-old breeders. Yolk stearic and arachidonic acid concentrations were higher and myristic acid concentration was lower in eggs from the 26-wk old hens. Conversely, the highest yolk concentrations of linolenic and palmitoleic acids occurred in eggs from 30 and 28-wk-old breeders, respectively. At 16, 17, 18, and 19 d of incubation, yolk oleic acid concentrations were significantly, but variably, affected by breeder age, whereas linoleic acid concentration was highest in 26-wk old breeders only at 19 d. Palmitic acid concentration at 17 d was lower in eggs incubated at 53% RH compared with 43 and 63% RH. Rate of yolk uptake from the yolk sac by embryos may be increased by incubating eggs at 53% RH, and the effects of changes in RH between 43 and 63% on yolk lipid content are influenced by breeder age.

Key words: broiler breeder, embryo, incubation, relative humidity

Poultry Science, 2001. 80:1444-1450

Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762; and Poultry Science Center, University of Arkansas, Fayetteville, AR 72701.

ABSTRACT
A dietary deficiency of Arg may suppress chick immune system functions; however, research evaluating immune function responsiveness of commercial broilers fed dietary Arg levels near NRC (1994) recommendations is sparse. Therefore, three experiments were conducted to evaluate growth and immunity of broilers fed varying Arg levels near NRC (1994) specifications. Because Arg and Lys are similar in structure and are known to compete in intestinal absorption, dietary Lys treatments [near NRC (1994) recommendations] were evaluated to determine if Arg and Lys interact to affect broiler immunity. There were four dietary treatments in Experiment 1 representing a 2x2 factorial design of additional Arg (120% of NRC) or additional Lys (120% of NRC) added to a control diet containing 100% of NRC Arg and Lys (six replications per treatment). Experiment 2 contained the following four treatments: the control diet; the control diet plus L-Arg (0.20% Arg of diet); the control diet plus L-Lys HCl (0.20% Lys of diet); and the control diet plus L-Arg - L-Glu (0.10% Arg of diet). Graduations of Arg were fed from 90 to 120% of NRC in 10% increments in Experiment 3. Also, half of the birds were exposed to vaccinations of Newcastle disease virus and infectious bronchitis virus in Experiment 3 to derive a 2x4 factorial design. Experiments 1 and 2 were conducted from Days 1 to 18 and Experiment 3 was conducted from Days 1 to 15 in Petersime battery brooders. No interactions occurred between dietary Lys and Arg in Experiment 1. Increasing dietary Arg, but not Lys, from 100 to 120% of the NRC recommendation increased (P < 0.05) Day 18 BW gain. Treatment differences in the cutaneous basophil hypersensitivity assay in Experiment 1 did not occur. In Experiment 2, treatment differences in growth responses, lymphoid organ development, and primary antibody titers to SRBC did not occur. Unvaccinated birds in Experiment 3 fed an Arg-deficient diet had lower (P < 0.05) feed conversion in comparison with vaccinated birds fed an Arg-deficient diet. Vaccinated birds had lower (P < 0.05) Day 15 BW than unvaccinated birds, but higher (P < 0.05) titers to Newcastle disease virus. Increasing dietary Arg in Experiment 3 increased plasma Arg (P < 0.05), but did not affect plasma Lys. Although increased dietary Arg improved BW gain in Experiment 1, minimal effects were noted in growth and immune system parameters throughout this study. A dietary Arg level near the NRC (1994) recommendation should support proper immune system functions in healthy chicks.

Key words: arginine, broiler, immunity, lysine

Poultry Science, 2001. 80:1535-1542

Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762, USA; Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA; College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA; Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA

ABSTRACT
The effects of in ovo peptide YY (PYY) or epidermal growth factor (EGF) administration on chick growth, yolk absorption and yolk stalk function in posthatch (0-5 days) meat-type or broiler chicks were determined. At Day 18 of incubation, treated eggs were injected into the air cell with 100 µl of either PYY (Trial 1) or EGF (Trial 2) at a dosage of 600 µg/kg egg weight. Saline-treated control eggs were injected similarly with 0.9% saline. At hatch, 200 µl of ⁵¹Cr-labeled microspheres were injected into chick yolk sacs. Epidermal growth factor increased ileal wet weight adjusted for body weight as well as ileal serosal dry matter. Body weight, feed consumption and excreta weight per bird, and relative weights of the yolk sac, intestine and liver were significantly affected by age of the chick in both trials. Relative radioactivity of the yolk sac, yolk stalk, blood, liver, and kidneys were affected by bird age in Trial 2; however, there were no significant effects due to PYY or EGF treatments on relative radioactivity of the tissues and organs examined. These data suggest that PYY and EGF had no effect on yolk absorption or yolk stalk function through 5 days in the posthatch chick.

Key words: Chicks; Epidermal growth factor; Growth; In ovo; Peptide YY; Yolk sac; Yolk stalk

Comparative Biochemistry and Physiology, 2001. Part A 130:741-749

Department of Poultry Science and Experimental Statistics Unit, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
The effects of energy level, fat type, and fat level in breeder hen diets on subsequent offspring market age live BW, carcass yield, and liver characteristics from breeder hens at 29 and 36 wk of age were evaluated. At 22 wk of age, six dietary treatments were imposed. Dietary treatments contained: 1) 3.0% added poultry fat (PF) and 467 (high energy) kcal/hen per day at peak production (CPP), 2) no added fat and high energy, 3) 3.0% added PF and 430 (low energy) CPP, 4) no added fat and low energy, 5) 1.5% added PF and 449 (moderate energy) CPP, and 6) 3.0% added com oil (CO) and moderate energy. Breeder age influenced Day 43 broiler live BW, percentage total carcass and front-half yields, and liver moisture contents. Furthermore, wet and dry liver weights were higher in female broilers compared to those of male broilers from 29-wk-old breeder hens. Live BW was higher in broilers from hens fed low-energy diets compared with moderate-energy diets and 3.0% compared to 1.5% PF diets. Percentage liver DM was higher in females compared to male broilers from hens fed 3.0% CO and moderate energy and was highest in male and female broilers from hens fed 1.5% PF and moderate energy. Percentage wet liver weight and liver DM were higher and liver moisture content was lower in broilers from hens fed 1.5% compared to 3.0% PF diets. Overall, energy and fat levels in breeder diets had subsequent influences on market age weight and liver characteristics of broilers.

Key words: broiler, broiler breeder, carcass quality, dietary fat, liver

Poultry Science, 2002. 81:23-29

Laboratory of Endocrinology & Population Ecology, Department of Biology, College of William and Mary, Williamsburg, VA 23185, USA. Telephone: (804) 253-4240

ABSTRACT
1. Serum thyroxine concentrations were determined and found to be reduced in reproductively inhibited deermice selected from controlled growth laboratory populations.
2. Daily injections of 1 µg thyroxine in reproductively inhibited male deermice were shown to significantly increase testis weight and the number of spermatids with acrosome formation.
3. Daily feeding of thyroxine to a controlled growth population promoted an increase in the mean weights of the reproductive organs of both sexes that was intermediate between reproductively inhibited and capable deermice. Also, two females in the population produced the first surviving young after 250 days of inhibition.

Compendium of Biochemical Physiology, 1984. Vol. 77A, No.2, pp. 293-298