Effects of incubation temperatures and trace mineral sources on chicken live performance and footpad skin development.

One experiment was conducted to evaluate the effects of two incubation temperature profiles (TEM) and two trace mineral (TM) sources with their inclusion levels on performance and footpad skin development of Ross 708 chickens. A total of 1,000 eggs from 29-wk-old breeders were incubated following two TEM profiles: a standard (S) eggshell temperature (37.8±0.2°C) for 21 d of incubation and an early-low late-high (LH) TEM. The second profile had low (37.2±0.2°C) temperature for the first 3 d, and S until the last 3 d when eggshell temperature was 39.2±0.2°C. At hatch, 15 male and 15 female chicks from each TEM were selected, and footpads sampled. Additionally, 168 males per TEM were placed in 24 battery cages with 7 chickens each. The 48 cages were assigned to two TM dietary treatments: one with inorganic (ITM) sources of Zn (120 ppm), Cu (10 ppm), and Mn (120 ppm) and the other with chelated (CTM) mineral sources using lower inclusion levels of Zn (32 ppm), Cu (8 ppm), and Mn (32 ppm). At 7 and 21 d, BW gain and feed conversion ratio (FCR) were obtained and chicks sampled for footpads. Histological analysis assessed thickness and area ofstratus corneum(SC), epidermis, and dermis. Data were analyzed as a completely randomized block design in a 2×2 factorial arrangement of treatments with TEM and sex as main factors for hatch data and TEM and TM diets for 7 and 21 d data. The LH chicks were heavier than S chicks at hatch, but had more residual yolk. However, S TEM male chickens were heavier at 7 and 21 d. The S TEM had better FCR than LH TEM.Papillaedermis parameters at hatch were higher in the S TEM. At 7 d, SC height and area were increased by the S TEM. At 21 d CTM increased dermis height and area. In conclusion, TEM affected footpad skin development and broiler performance. Replacing ITM with reduced levels of CTM increased dermis development without affecting live performance or other skin layers.

Effect of broiler breeder feeding programme and feeder space change at photostimulation using maize- or wheat-based diets on broiler progeny growth performance and leg health.

1. The aim of this study was to evaluate the effects of diet type, maternal feeding programme at 29 weeks of age and breeder feeder space change at photostimulation on broiler progeny performance and leg health at 6 weeks of age. 2. Fast-feathering Cobb 500 broiler breeders were fed on either maize- or wheat-based diets that had been formulated to have similar nutrient composition during growing and layer phases. Two feeding programmes, fast or flow, were used from 14 to 29 weeks of age. At 22 weeks, 69 females from each pen were placed in a layer house where feeder space was either similar to that in rearing (6.3 to 6.5 cm/female) or was increased from 6.3 to 8.4 cm/female. Eggs produced at 32 and 44 weeks of age were collected and incubated for two broiler experiments. A total of 16 male and 16 female one-d-old chicks were placed in floor pens in two experiments, respectively, with 6 and 4 replicate pens. Broiler gait scores and leg problem prevalence were evaluated at 6 weeks of age. 3. Data were analysed as a 2 × 2 × 2 factorial design with diet type, feeding programme and feeder space change as main factors. 4. The wheat diet increased the probability of observing crooked toes in broiler progeny compared to the use of maize, but only when breeders were fed according to the fast feeding programme and given similar feeder space as during rearing. 5. Breeders given more feeder space in the laying period produced progeny with more locomotion problems compared with those provided similar feeder space, but only when maize was used and the slow feeding programme was applied to the breeders. 6. The maternal feeding programme interacted with other factors to influence progeny leg health, but it did not solely influence walking ability or leg problems of progeny. 7. In conclusion, an increased probability of observing walking impairment of broiler progeny was detected when breeders were given greater feeder space at photostimulation rather than no change and fed according to the slow feeding programme using maize diets in breeders and progeny.

Effects of breeder feeding restriction programs and incubation temperatures on progeny footpad development.

Footpad dermatitis begins early in life, and there is evidence of individual susceptibility. An experiment was conducted to evaluate the carryover effects of breeder feed restriction programs and incubation temperatures (TEM) on progeny footpad development at hatch, and 7 and 22 d. Cobb 500 fast feathering breeders were subjected to 2 dietary feed restriction programs during rearing: skip-a-day (SAD) and every-day feeding (EDF). At 60 wk of age, eggs from each group were collected and incubated according to 2 TEM, standard (S) eggshell temperature (38.1°C) and early-low late-high (LH). This second profile had low (36.9°C) eggshell temperature for the first 3 d, and standard temperature until the last 3 d when eggs were subjected to elevated (38.9°C) eggshell temperature. At hatch, 15 chicks from each treatment combination were sampled to obtain footpads for histological analysis. Seventy-two chicks per treatment were placed in 48 cages (6/cage), and raised to 22 d. At 7 and 22 d, 1 and 2 chickens, respectively, were sampled for footpads. The BW and group feed intake were recorded to obtain BW gain and feed conversion ratio at 7 and 21 d. Histological analysis assessed thickness and total area of stratus corneum (SC), epidermis, and dermis, and total papillae height. Data were analyzed as randomized complete block design in a 2 × 2 factorial arrangement of treatments. There was a negative effect of LH TEM on performance at both ages. An interaction effect on SC area and papillae height was observed at hatch. Additionally, SAD treatment increased thickness and area of footpad dermis. At 7 d, the SC parameters of the SAD progeny were increased. Epidermis thickness was affected by treatment interaction. Furthermore, LH TEM decreased epidermis thickness and dermis area. At 22 d, interaction effects were observed in thickness and area of SC and epidermis. Incubation S TEM increased thickness and area of dermis. It was concluded that breeder feed restriction programs and incubation TEM profiles may have carryover effects on histomorphological traits of footpads.

Effects of broiler breeder-feeding programme and feeder space change at photostimulation using maize- or wheat-based diets on eggshell properties and progeny bone development.

1. The effects of diet type, feeding programme and fast- or slow-feed allocation in fast-feathering Cobb 500 broiler breeder hens on eggshell properties and broiler progeny bone development were investigated in a 2 × 2 × 2 factorial experiment. 2. The birds were fed on either maize- or wheat-based diets during rearing and production and on a fast- or slow-feed allocation programme from 14 to 29 weeks of age. At 22 weeks, 69 females from each pen were placed in a layer house where feeder space (FS) either remained similar or was increased. 3. Eggs produced at 33 weeks were incubated, eggshell conductance (G) was determined and a sample of 14 chicks from each treatment combination was taken to obtain bone traits at hatching. 4. Diet type did not influence G, yolk-free body weight (BW), residual yolk weight or relative asymmetry (RA) of any bilateral traits of leg bones of hatchlings. However, breeder diet type was involved on two-way and three-way interaction effects on progeny leg bone traits. 5. Breeders feed restricted according to the slow-feeding programme laid eggs with greater G compared to those managed with the fast-feeding programme, but there was no effect of feeding programme on progeny bone traits at hatching. 6. Eggs from breeders given more FS at photostimulation had greater G than those from breeders provided with similar FS. Maternal FS change did not influence hatchling yolk-free BW; however, breeders given more FS produced progeny with heavier tibias and shanks and longer femurs compared with those provided with similar FS, but only when breeders were fed on maize. Moreover, increased maternal FS at photostimulation was associated with an increased RA of femur length in the progeny. 7. It was concluded that breeder FS change at photostimulation influenced eggshell conductance and consistently affected bone development of the broiler progeny.

Multilevel analysis of environmental Salmonella prevalences and management practices on 49 broiler breeder farms in four south-eastern States, USA.

A two-part serial survey of 49 broiler breeder farms was conducted in four south-eastern states: Arkansas, Alabama, Georgia and North Carolina. Broiler breeder farms from three to five broiler company complexes in each state were visited on two separate occasions to document management practices and perform environmental sampling for Salmonella prevalence estimation. Salmonella was detected in 88% of the broiler breeder houses that were sampled and was identified on all 49 farms enrolled. Many management characteristics were consistent across the different states and companies. Multilevel analysis was used to evaluate management characteristics as risk factors for Salmonella prevalence and to estimate the proportion of variance residing at the different hierarchical sampling levels. Management characteristics associated with increased Salmonella prevalence included treatment of the flock for any disease, having dusty conditions in the house, having dry conditions under the slats and walking through the house more than one time per day to pick-up dead birds. After adjusting for state as a fixed effect, the percentages of variance in Salmonella prevalence occurring at the complex, farm, visit, house and individual sample levels were 5.2%, 6.8%, 11.8%, 2.8% and 73.4%, respectively. The intraclass correlations for samples collected from the same house; for samples from different houses during the same visit; for samples from different visits to the same farm; and for samples from different farms in the same complex were as follows: 0.27, 0.24, 0.12 and 0.05, respectively.

Maternal antibody transfer to broiler progeny varies among strains and is affected by grain source and cage density.

Two experiments were conducted to examine the effects of broiler breeder dietary grain source and cage density on maternal antibody (MatAb) transfer to progeny in 2 genetic strains (A and B). Broiler breeders were assigned to 16 litter floor pens and fed either corn- or wheat-based diets. Breeders were administered 4 live vaccines against Newcastle disease virus (NDV). At 23 wk of age, pullets and cocks, which reflected the full BW distribution from each treatment, were moved to a cage breeder house and placed at 1 or 2 hens/cage. Breeders were artificially inseminated at 44 wk (experiment 1) and 52 wk of age (experiment 2). Eggs were collected for 8 d, incubated, and placed in individual pedigree bags at d 19 of incubation. Blood samples from 5 chicks per treatment combination were collected at hatch in both experiments. Spleen and bursa were collected from the same chicks for histomorphometry analyses in experiment 2. In the second experiment, 12 chicks per treatment were placed in cages. Progeny were provided diets based on the same grain (corn or wheat) as their parents. Serum samples were collected at 5, 9, and 13 d of age and analyzed for anti-NDV MatAb. Data were analyzed as a 2 × 2 × 2 factorial design considering strain, dietary grain source, and cage density as main factors. Interaction effects were observed in breeders and progeny. Experiment 1 showed that strain A chicks had lower levels of MatAb when hens were housed at 2 hens/cage rather than 1 hen/cage. The MatAb levels of strain B chickens were not affected by cage density in either experiment. Experiment 2 demonstrated similar effects of cage density on MatAb levels and the area of bursa follicles for both strains. Progeny of breeders fed corn-based diets had smaller spleen white pulp only when hens were housed at 2 hens/cage compared with 1 hen/cage. The results of these experiments suggest that breeder strain and cage-density conditions affected MatAb transfer to progeny and embryo development of spleen and bursa.

Broiler embryo bone development is influenced by incubator temperature, oxygen concentration and eggshell conductance at the plateau stage in oxygen consumption.

1. Four experiments were conducted to evaluate the effects of temperature (TEM) and oxygen (O(2)) concentrations during the last 4 d of incubation on bone development. Fertile eggs from two strains were obtained that either exhibited Low or High eggshell conductance (G). 2. Four experimental cabinets provided either four TEM (36, 37, 38 or 39 degrees C) or four O(2) concentrations (17, 19, 21 or 23% O(2)). Data were analysed as a 2 x 2 factorial design. In the fourth experiment, two temperatures (36 and 39 degrees C), two O(2) concentrations (17 and 23%) and the same Low and High G strains were evaluated in a 2 x 2 x 2 factorial design. 3. Body weights (BW) and residual yolks were obtained, both legs were dissected. Femur, tibia and shank weights, length and thickness were recorded. Relative asymmetry (RA) of each leg section was calculated. 4. The results indicated that elevated TEM during incubation increased RA between the two legs, mainly in the Low G strain. Chickens at the lowest O(2) concentrations had lighter and shorter tibias, lighter shanks, and increased RA of femur length compared to chickens in the 23% O(2). In the fourth experiment no interactions were observed between O(2) and TEM. High TEM depressed BW of Low G broilers, but no significant effect of treatments was observed on BW of High G broilers. Nevertheless, the high TEM or low O(2) independently caused reduced femur and tibia weights and length, shank length and thickness, and both low O(2) and high TEM together increased RA in shank weight. 5. These results suggest that late incubation conditions affect long bone development in broilers.

Effects of incubator temperature and oxygen concentration during the plateau stage of oxygen consumption on Turkey embryo long bone development.

Temperature (TEM) and O(2) concentrations during the plateau stage of oxygen consumption are known to affect yolk utilization, tissue development, and thyroid metabolism in turkey embryos. Three experiments were conducted to evaluate these incubation effects on long bone development. Fertile eggs of Nicholas turkeys were used. In each trial, standard incubation conditions were used to 24 d, when the eggs containing viable embryos were randomly divided into 4 groups. Four experimental cabinets provided 4 TEM (36, 37, 38, or 39 degrees C) or 4 O(2) concentrations (17, 19, 21, or 23% O(2)). In the third experiment, 2 temperatures (36 and 39 degrees C) and 2 O(2) concentrations (17 and 23%) were evaluated in a 2 x 2 factorial design. Body and residual yolk weights were obtained. Both legs were dissected, and shanks, femur, and tibia weights, length, and thickness were recorded. Relative asymmetry of each leg section was calculated. Chondrocyte density was evaluated in slides stained with hematoxylin and eosin. Immunofluorescence was used to evaluate the presence of collagen type X and transforming growth factor beta. Hot TEM caused reduction of tibia weights and increase of shank weight when compared with cool TEM. The lengths of femur, tibia, and shanks were reduced by 39 degrees C. The relative asymmetry of leg weights were increased at 38 and 39 degrees C. Poult body and part weights were not affected by O(2) concentrations, but poults on 23% O(2) had bigger shanks and heavier tibias than the ones on 17% O(2). High TEM depressed the fluorescence of collagen type X and transforming growth factor beta. The O(2) concentrations did not consistently affect the immunofluorescence of these proteins. The chondrocyte density was affected by TEM and O(2) in resting and hypertrophic zones. In the third experiment, high TEM depressed BW, leg muscle weights, and shank length. Low O(2) reduced tibia and shanks as a proportion of the whole body. We concluded that incubation conditions affect long bone development in turkeys.

The effect of quicklime (CaO) on litter condition and broiler performance.

High levels of phosphorus and pathogens in runoff are 2 major concerns following manure applications to fields. Phosphorus losses from fields following manure applications have been linked to the solubility of phosphorus in manure; therefore, by decreasing manure phosphorus solubility, a decrease in phosphorus loss in runoff should be apparent. The objective of this research was to develop a process using quicklime that would result in reduced phosphorus solubility and bacteria counts in broiler litter. The 4 litter treatments evaluated were T1, new wood shavings without the addition of quicklime; T2, used, untreated broiler litter; T3, used litter with 10% quicklime (based on the weight of the litter); and T4, used litter with 15% quicklime (based on the weight of the litter). Body weight, cumulative feed consumption, and feed conversion (feed:BW) were determined on a weekly basis through 42 d of age. Mortality was recorded daily. Carcass weights and percentages of carcass yield without giblets were determined prechill. Litter pH, total phosphorus, nitrogen, soluble phosphorus, litter moisture (%), and total plate counts were measured for each litter treatment on d 7 and 42 after bird placement. No significant differences were found for BW, feed consumption, feed conversion, mortality, carcass weight, or carcass yield. No breast or footpad blisters were observed. On d 7, 15% quicklime had higher (P < 0.001) pH (11.2) when compared with the other treatments. Percentages of phosphorus and nitrogen were lower (P < 0.001) for new wood shavings in comparison with the used litter treatments. Soluble phosphorus (ppm) was lower (P < 0.001) for 15% quicklime (2.75) when compared with new wood shavings (42.2), untreated broiler litter (439.2), and 10% quicklime (35.0). Although not significant, 15% quicklime had lower total plate counts (cfu/g) in comparison with the other treatments on d 1 and 10 postmixing and at 7 d after bird placement. Litter conditions on d 42 after bird placement were similar. We concluded that the use of quicklime as a treatment for broiler litter would initially reduce nitrogen and soluble phosphorus and bacteria counts without negatively affecting bird productivity.

The effect of broiler breeder genetic strain and parent flock age on eggshell conductance and embryonic metabolism.

The effect of genetic strain (Ross 308; Cobb 500) and parent flock age [young (29 wk), peak (Ross = 34 wk; Cobb = 36 wk), postpeak (40 wk), mature (45 wk), old (55 wk), and very old (59 wk)] on eggshell conductance and embryonic metabolism were examined. At each flock age, eggs from each strain were incubated for 21.5 d in individual metabolic chambers to measure embryonic O(2) intake and CO(2) output. From these data, the respiratory quotient (RQ) and metabolic heat production were calculated. Data were analyzed by the GLM procedure of SAS at P < or = 0.05. Neither strain nor flock age influenced conductance. Total embryonic O(2) consumption, CO(2) output, RQ, and metabolic heat production over the entire incubation period were not affected by strain. Daily differences existed between strains for embryonic O(2) intake (1, 7, 16, 17, 19, 20 d of incubation), CO(2) output (1 to 4, 16 to 20 d of incubation), and heat production (4, 7, 16 to 19 d of incubation). Embryos from young, mature, old, and very old flocks produced significantly more total embryonic heat over the entire 21 d (1,712, 1,677, 1,808, and 1,832, respectively) than embryos from peak (1,601) and postpeak (1,693) flocks. Average RQ for the entire incubation period was higher in embryos from mature flocks compared with all other flock ages. Daily differences among embryos from different flock ages were shown for O(2) consumption (all but d 8 of incubation), CO(2) production (all but d 7 and 9 of incubation), and heat output. The results showed that genetic strain and parent flock age influence daily embryonic metabolism, especially during the early and latter days of incubation. These daily differences coincide with the days of incubation having a higher incidence of embryonic mortality; these 2 factors may be related. Further investigation into the relationship between embryonic metabolic heat production and mortality during incubation may lead to the development of specific incubation conditions for different genetic strains and flock ages.

Influence of selenium on heat shock protein 70 expression in heat stressed turkey embryos (Meleagris gallopavo).

Heat shock protein 70 (hsp70) family of proteins, which functions as molecular chaperones, has been associated with tolerance to stressors in avian species. Selenium (Se) is an essential trace mineral incorporated into the seleno-enzymes such as glutathione peroxidase (GSHpx). GSHpx reduces oxidized glutathione (GSSG) to reduced glutathione (GSH) in the GSH/GSSG antioxidant system and protects cells from oxidative damage. This study was conducted to examine if the relationship between dietary supplementation of selenium to turkey (Meleagris gallopavo) hens and the embryonic expression of hsp70 and GSHpx activity in heat stressed embryos. Livers of embryos developing in eggs from turkey hens fed diets with or without supplemental Se were analyzed for hsp70 concentration and GSHpx activity before and after recovery from a heating episode. Before heat stress, hsp70 concentrations were equivalent in each treatment, but GSHpx activity was maximized in the SE treatment group. After recovery from the heating episode, hsp70 concentrations were significantly higher (P<0.05) in the non-Se-supplemented groups, but in the Se-supplemented groups the hsp70 concentrations were not different from pre-stress concentrations. In the pre-stress Se-supplemented group, liver GSHpx activity was significantly higher than GSHpx activity in the non-Se-supplemented embryo livers, and in the livers from embryos recovering from heat stress, GSHpx activity in the non-Se-supplemented group was lower than the pre-stress activity and significantly lower than the GSHpx activity in liver from Se-supplemented embryos recovering from heat distress. Se supplementation to the dams resulted in a significant increase in their embryos and that condition would facilitate a decreased incidence of oxidative damage to cells. A more reduced redox status in embryos from Se-supplemented dams decreased the need for cellular protection attributed to stress induced hsp70 and presumably allows heat distressed embryos to resume normal growth and development than embryos from dams with inadequate selenium nutrition.

Effect of dietary phosphorus and phytase levels on the reproductive performance of large white turkey breeder hens.

An experiment was conducted to determine the effect of dietary P levels and dietary phytase enzyme (E) inclusion on Large White turkey breeder hen reproductive performance from 31 to 62 wk of age. Hens were placed in a curtain-sided house with 48 pens (10 birds per pen; 8 pens per treatment) at 31 wk and were fed a breeder ration with treatments as follows: HP, dietary available P = 0.55%; HPE, HP + E; MP, dietary available P = 0.35%; MPE, MP + E; LP, dietary available P = 0.17%; and LPE, LP + E. Feed and water were available ad libitum for 28 wk of lay. Diets were fed in mash form, and all other nutrients were formulated to meet or exceed NRC requirements. All hens were photostimulated in January (31 wk) with 15.5 h of light daily. Production data were recorded on a pen basis. Individual bird BW and feed consumption, by pen, were determined at monthly intervals from 31 to 62 wk. Hens were observed for weekly reproductive performance for hen housed egg production, hen-day egg production, settable eggs, cumulative settable eggs, hens out of lay, and hen mortality and for biweekly performance for egg fertility, hatchability of all eggs, hatchability of fertile eggs, egg weight loss, conductance, conductance constant (k), and embryonic mortality. Egg weight, eggshell thickness, egg components, and albumen and yolk P were measured monthly. At 62 wk of age, hen tibia P, plasma P, total fecal P, and water-soluble fecal P were determined. Decreasing dietary P resulted in no decreases in reproductive performance for turkey breeder hens to 62 wk. Additionally, decreased dietary P resulted in decreased total fecal P and water-soluble fecal P. Feeding turkey breeder hens dietary phytase enzyme resulted in significantly fewer hens going out of lay; however, this was not reflected in hen housed egg production. It was concluded that phosphorus could be lowered in turkey breeder hen diets, compared with current surveyed industry levels, without impairing reproductive performance.

Accelerating embryonic growth during incubation following prolonged egg storage. 1. Embryonic livability.

The hypothesis was proposed that shorter incubation periods and faster growth rates for long-stored eggs would improve embryonic survival and poult hatchling quality. Increased incubation temperatures were tested for their efficacy in improving embryonic livability in fertilized eggs stored for 15 d prior to setting in the incubator compared to controls stored for only 3 d. Two temperature treatments were applied. In experiment 1, a 37.8 degrees C set point for dry bulb temperature was used to accelerate development for the initial 2 wk compared to the controls at 37.5 degrees C. Following treatment, the accelerated embryos were returned to the same machine as the controls. In experiment 2, higher temperature exposure was only for the initial week of incubation. The temperature and storage treatments were in a completely random 2 x 2 factorial arrangement of treatments. At the completion of 28 d of incubation, survival rates of all treatments were determined by opening all nonhatching eggs to differentiate truly fertilized eggs from unfertilized. Hatchability was determined by dividing the total number of poults on a hatching tray by the number of fertilized eggs on a tray. Incubator trays were the experimental unit. Tissues were sampled in both experiments to verify treatment effects on growth and metabolism. Hatching times were observed at 4-h intervals during the actual hatching process beginning at 25 d of incubation. It was concluded that delayed growth and depressed metabolism of fertilized turkey eggs stored for 15 d can be compensated for by exposure to higher incubation temperatures for the initial 1 or 2 wk of incubation.

Accelerating embryonic growth during incubation following prolonged egg storage. 2. Embryonic growth and metabolism.

The hypothesis was proposed that the improved embryonic livability observed when higher incubation temperatures were imposed on eggs stored for 15 d prior to setting might have basis in energy metabolism. To test the hypothesis, fertilized turkey eggs were incubated either for the first 2 wk of development (experiment 1) or only the first week of development (experiment 2) at 37.8 degrees C compared with controls incubated at 37.5 degrees C. In both experiments, eggs were stored for either 15 or 3 d prior to setting. Viable embryos were selected randomly from each storage-by-incubation period treatment combination at 25 to 28 d of incubation and were sampled for blood, heart, and skeletal muscle tissues. Tissues were weighed and assayed subsequently for glucose or glycogen content. In experiment 2, the randomly selected embryos from each treatment combination were sampled at 7, 14, 21, and 28 d of incubation. Embryos at 7 and 14 d were assayed on a whole body basis, whereas at 21 and 28 d the bodies were dissected, and heart, liver, and skeletal muscle tissues were weighed and assayed for glycogen and lactate. Blood samples were collected between 25 and 28 d of incubation as in experiment 1 and assayed for glucose, creatine kinase, lactate dehydrogenase, and thyroid hormone concentrations. In both experiments, accelerated development was noted due to higher temperature and enhanced embryonic carbohydrate metabolism, and elevated thyroid hormone concentrations were observed compared with controls. It was concluded that a possible mechanism for the improved livability of faster growing embryos observed after prolonged egg storage might be due to better utilization of carbohydrate.

Egg storage alters weight of supply and demand organs of broiler chicken embryos.

Storage of fertilized eggs for more than 10 d prior to incubation decreases embryonic viability. The hypothesis was tested that embryos may grow differently following egg storage. Eggs from which embryos survived following storage (ST) were compared to eggs from a second line that did not (NOST). Three identical, independent trials were conducted using fertile eggs from both lines at two ages (peak lay and > 53 wk). Eggs were stored for 1 or 14 d prior to setting in the incubator. At 3-d intervals during development, embryos were carefully removed from the eggs, the yolks were excised and carcasses were weighed. Beginning at 12 d of incubation whole body, heart, liver and thigh tissues were weighed to assess allometric growth of supply (heart and liver) and demand (thigh muscle) tissues. Storage of eggs from both lines and from hens of both ages decreased BW differently throughout incubation. Line, Age and Storage interacted to affect embryonic BW and organ weights. Embryo weights were consistently heavier in NOST line eggs from older breeder flocks stored for 14 d than those from ST line eggs. It was concluded that extended storage of fertile eggs prior to setting affects embryonic growth to enhance survival.

Effects of hen age, Bio-Mos, and Flavomycin on poult susceptibility to oral Escherichia coli challenge.

The effects of hen age, Escherichia coli, and dietary Bio-Mos and Flavomycin on poult performance from 1 to 21 d were studied. Day-of-hatch BUTA (BIG-6) male poults were gavaged orally (1 mL) with approximately 10(8) cfu/mL E. coli composed of four serotypes or sterile carrier broth. A mixture of the same E. coli cultures was added to the poults' water troughs to attain a concentration of approximately 10(6) cfu/mL on a weekly basis to ensure a continuous bacterial challenge. Within each E. coli split plot treatment group, poults from hens of different ages (33 and 58 wk of age) were fed diets containing Bio-Mos (1 g/kg feed), Flavomycin (2.2 mg active ingredient/kg feed), Bio-Mos plus Flavomycin, or a control diet, in a randomized complete block design. This experiment yielded eight treatments per challenge group. At Weeks 1 and 3, eight birds from each treatment from the E. coli challenged and unchallenged groups were randomly chosen for bacterial sampling of liver and intestinal tissue for coliforms, aerobic bacteria, and Lactobacillus spp. E. coli isolates from tissue samples were O serotyped. During E. coli challenge, dietary Bio-Mos and Flavomycin improved poult BW and BW gains (P < or = 0.05). When poults were not challenged with E. coli, poults from old hens had improved BW and cumulative BW gains over poults from young hens (P < or = 0.05). Cumulative 3-wk BW gains for unchallenged poults from young hens were improved by Bio-Mos and Flavomycin (P < or = 0.05) alone and in combination when compared to the control diet. Two of the four E. coli serotypes administered were recovered. Several serotypes were recovered that were not administered. It may be concluded that dietary Bio-Mos and Flavomycin can improve the overall performance of poults, especially when they are faced with an E. coli challenge.

Examining the effects of prestorage incubation of turkey breeder eggs on embryonic development and hatchability of eggs stored for four or fourteen days.

Thirty-six hundred British United Turkey hatching eggs were used in two separate trials to test whether prestorage incubation (PRESI) treatments of 0, 6, and 12 h (Trial 1) or 0, 7, and 14 h (Trial 2) could improve the hatchability of eggs stored (17 C) for 14 versus 4 d. The development of the embryos (n = 30) was staged before and after exposing eggs to the various PRESI treatments. Embryonic development was also established after storage to ascertain whether embryonic development was occurring during storage. The remaining eggs in each trial were split into three groups (n = 500) and incubated for 28 d to examine embryonic mortality and hatchability. No changes were observed in embryonic development due to egg storage. Embryos were significantly more developed as the number of PRESI h increased; therefore, embryos from different PRESI treatments were placed in storage at different stages of development. Early mortality (1 to 7 d of incubation), mortality at internal and external pipping, and hatchability of fertile eggs were significantly reduced in eggs stored for 14 versus 4 d. The various PRESI treatments did not significantly affect the mortality or hatchability of eggs stored for 4 d. However, the hatchability of eggs incubated prior to storage for 12 h and then stored for 14 d was restored to the levels reported for eggs subjected to the treatment that represents the industry norm (0 h of PRESI and 4 d storage). These results indicate that embryos of eggs stored for 14 d, which have developmentally advanced to the stage of complete hypoblast formation (PRESI for 12 h), have a survival advantage over eggs stored for 14 d that have not been subjected to any PRESI.

Egg storage effects on plasma glucose and supply and demand tissue glycogen concentrations of broiler embryos.

The hypothesis was tested that enhanced embryonic carbohydrate metabolism may enable embryos to survive egg storage effects. As lines of broiler breeders age, some lines resist detrimental effects of egg storage on embryonic survival, whereas others do not. Fertile eggs were obtained from two lines differing in storage ability. Eggs from each line by age group were stored for 1 or 14 d prior to setting. Eggs were distributed randomly into a single machine and incubated under standard conditions. Beginning at 17 d of incubation, immediately prior to the plateau stage in oxygen consumption, embryos from each of the treatment groups were sampled for BW, organ growth, glycogen concentration, and plasma glucose concentrations. Sampling continued through hatching. Plasma glucose concentrations increased significantly, and hepatic glycogen concentrations declined as embryos approached hatching. The rate at which glycogen was accrued into muscle and heart tissue displayed a significant three-way interaction among line, age, and storage. Embryos from the line that resisted storage mortality maintained greater glycogen concentrations in muscle and heart tissues than those from the line and age with diminished survival rates. It was concluded that embryonic survival rates differ following egg storage because of the ability of the embryo to accrue and maintain adequate carbohydrate for growth and function of vital demand tissues.

Degradation of aflatoxin by poultry litter.

Two trials were conducted to determine whether deep stacking of contaminated corn with poultry litter destroys aflatoxin. Contaminated corn was ground and mixed with litter to carbon:nitrogen ratios of 30:1. Moistures were adjusted by adding tap water just prior to incubation or stacking. The initial laboratory trial included only broiler litter at 40% moisture, whereas the subsequent field trial involved a 2 x 2 factorial design with litter type (turkey or broiler) and moisture (20 or 40%) as main effects. Aflatoxin assays were reduced in the laboratory trial from 433 and 402 to 54 and 8 ppb in Containers 1 and 2, respectively, after 35 d of incubation at 28 C. In the field trial, aflatoxin disappeared from broiler and turkey litter mixtures with projected moistures of 20% after 10 and 6 wk of storage, respectively, whereas disappearance in mixtures containing projected moistures of 40% required 5 and 3 wk, respectively. Differences in moisture appear to account for differences in the ability of turkey and broiler litter to detoxify aflatoxin. Hence, turkey and broiler litter would appear equal with respect to the ability to detoxify aflatoxin-contaminated corn. Disappearance of aflatoxin during storage with litter could have occurred as a result of ammonia release during storage or microbial detoxification mechanisms. However, nitrogen values suggest that microbial action was responsible for much of the detoxification, as aflatoxin disappeared from mixtures with little apparent ammonia release.