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

ABSTRACT
A new instrument for assessing mammalian semen attributes, the Sperm Quality Analyzer(r), was evaluated as a potential tool for determining rooster sperm quality. The Sperm Quality Analyzer(r) measures the "activity" of sperm in a semen sample as the sperm motility index (SMI). The SMI is defined as the number and amplitude of deflections in a light path per second as a result of sperm movement within a capillary tube. In the present study, effects of sperm concentration, viability, and motility on the SMI were evaluated. Peterson broiler breeder males (n = 40) were used as semen donors. In the initial experiment, semen was diluted from 2- to 25-fold and SMI readings were obtained. The SMI was very low in neat semen samples but increased when semen was diluted up to threefold. However, at dilutions greater than fivefold, the SMI decreased. Apparently, sperm concentration in undiluted semen is so great that sperm are unable to move freely within the capillary tube. Maximum SMI values were obtained at sperm concentrations of approximately 1 billion sperm per milliliter. When thawed, dead sperm were mixed with incubated, live sperm, the SMI decreased with decreasing sperm viability even though sperm concentration was constant. Obviously, fewer sperm move across the light beam as sperm mortality increases. When motile, aerobically incubated sperm were mixed at different rates with immotile, anaerobically incubated sperm samples, the SMI increased with increasing concentrations of motile sperm, whereas total sperm concentration was static. In addition, the SMI was strongly correlated with motility scores obtained by microscopic analysis. The Sperm Quality Analyzer(r) provides an estimate of the overall quality of sperm from broiler breeder males by reflecting sperm concentration, viability, and motility in a single value, the SMI.

Key words: sperm motility, sperm viability, sperm concentration, fertility, broiler breeder

1998 Poultry Science 77:888-893

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

ABSTRACT
The purpose of the present study was to investigate the combined effects of breeder age (36-, 51-, or 64-wk) and different dietary fat sources (3% added corn oil, poultry fat, or lard) on lipids in fresh egg yolks and yolks of newly hatched chicks. Isocaloric breeder diets were altered by the inclusion of different types of dietary fat such that the poultry fat and lard diets had the highest levels of saturated fatty acids when compared to the corn oil diet. Fresh egg yolks obtained from 36-wk-old breeders exhibited higher levels of palmitoleic acid when compared to the levels observed in fresh egg yolks of 51- or 64-wk-old breeders. Furthermore, these levels decreased significantly by 21d of incubation only in eggs from 36-wk-old hens. At 36 wk of breeder age, the levels of oleic and arachidonic acid were higher in yolks from hatched chicks than in previous fresh egg values, regardless of type of added dietary fat; whereas the level of linoleic acid was higher only in yolks from hatched chicks compared to those of fresh eggs from 36-wk-old hens fed 3% added corn oil. These data suggest that breeder age influences the utilization of yolk lipid by developing embryos, and that the type of fat provided in the diet may have an additional influence.

Key words: age, broiler breeder, hen, chick, yolk fatty acid

1998 Poultry Science 77:47-53

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

ABSTRACT
The effects of breeder age (35, 51, and 63 wk) and added dietary fat on subsequent broiler growth, mortality, and feed conversion through 42 d were evaluated. Beginning at 22 wk of age, diets included 0, 1.5, or 3.0% added poultry fat (PF), 1.5 or 3.0% added corn oil (CO), or 3.0% added lard (LA). Broilers from hens 35 wk of age performed better between 0 and 21 d than those from 51- and 63-wk-old hens. Conversely, between 22 and 42 d, broilers from hens 51 wk of age performed better than those at 35 and 63 wk. In relation to PF, CO added to breeder diets increased 0 to 21 d BW gain in broilers; whereas, feed conversion between 22 and 42 d was reduced in broilers from hens fed PF compared to those fed CO. In conclusion, breeder age influenced broiler performance differently throughout the growout period. Fat added at the 1.5% level to breeder hen diets was an effective energy source. However, less saturated fat improved growout performance.

Key words: broiler, broiler breeder, dietary fat, feed conversion, growth

1999 Poultry Science 78:505-511

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

ABSTRACT
The effects of breeder age (35, 51, and 63 wk) and added dietary fat on subsequent broiler slaughter yield were evaluated. Beginning at 22 wk of age, diets included 0, 1.5, or 3.0% added poultry fat (PF), 1.5 or 3.0% added corn oil (CO), or 3.0% added lard (LA). Slaughter yields were greatest in broilers from 63-wk-old breeders. Added CO in broiler breeder diets significantly increased subsequent 43-d live BW and chilled carcass yields compared to LA. Furthermore, CO diets significantly increased relative front-half yields compared to PF diets; and compared to the 3.0% fat level, 1.5% added fat significantly increased 43-d live BW, regardless of fat type. In conclusion, breeder age influenced broiler slaughter yield, and fat added at the 1.5% level to breeder hen diets was an effective energy source. However, less saturated fat improved subsequent slaughter yield.

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

1999 Poultry Science 78:512-515

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608, and Ciba-Geigy Corporation, Greensboro, North Carolina 27419

ABSTRACT
Two trials were conducted to assess the effects of CGA-72662 (Larvadex^®) on White Leghorns when fed continuously through the growing period. Trial 1 was a dosimetry battery trial to 4 weeks of age and Trial 2 was conducted in floor pens through 16 weeks and in cages from 17 to 32 weeks of age. CGA-72662 was fed from hatch to 4 weeks and from hatch to 20 weeks in Trials 1 and 2, respectively.
CGA-72662 significantly depressed body weight of White Leghorn females when fed at levels greater than 250 ppm from hatch through either 4 or 20 weeks of age. Livability was not affected. Feed consumption was decreased by 1,000 ppm through 16 weeks of age (Trial 2). Egg production and feed conversion were not significantly affected by treatment. Internal and external egg quality were not affected consistently.
It was concluded that CGA-72662 has no detrimental effects on growth, livability, or reproduction when fed at up to 250 ppm continuously during rearing.

Key words: CGA-72662, larvacide, commercial layers, egg production, egg quality

1985 Poultry Science. 64:247-252

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
Supplemental ascorbic acid (AA) at 0, 50, and 100 ppm (mg/kg diet) was fed to broiler breeders throughout a complete production cycle. The effects of supplementation on egg production, fertility, hatchability, egg weight, egg specific gravity, and eggshell weight were determined.
Ascorbic acid at both 50 and 100 ppm significantly increased hen-day egg production, hatch of fertile eggs, specific gravity, and mortality. Fertility was improved at 50 ppm. Body weight gain on similar limited feed intakes was higher in AA-supplemented birds. Much of the improvement in hatch of fertile eggs was due to a decrease in early embryonic mortality.
It was concluded that supplemental AA improved nutrient utilization, which was favorable to the production of hatching eggs. Ascorbic acid at 50 ppm appeared adequate to achieve most beneficial effects in broiler breeders.

Key words: ascorbic acid, broiler breeders, egg production, shell quality, hatchability, fertility

1985 Poultry Science. 64:2041-2048

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
Two levels of protein and two levels of energy were fed to broiler breeders during the prebreeder period (18 to 23 weeks of age) after which a standard breeder diet was provided to all birds. The differences in intake during the prebreeder period was 140 g protein/bird between the high protein (HP) and low protein (LP) groups and 1145 kcal ME/bird between the high energy (HE) and low energy (LE) groups. Body weights did not differ during the prebreeder period or subsequent breeder period.
Cumulative egg production was similar among all treatments with numerical advantages for HP and LE birds due to improved production after 55 weeks of age. Significant protein X energy interactions occurred for egg weight during Weeks 25 to 44, but no significant overall effect was observed. Egg specific gravity was not affected significantly. Fertility did not differ; however, the LP birds exhibited significantly better hatch of fertile eggs and significantly decreased late deads when compared to HP birds. The HE birds exhibited significantly less early embryonic mortality but significantly more late embryonic mortality when compared to LE birds. Hatch of fertile eggs did not differ due to prebreeder energy levels.

Key words: broiler breeders, egg production, hatchability

1985 Poultry Science. 64:2335-2340

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
Broiler breeder eggs with early dead (ED) embryos possessed significantly thinner membranes and significantly thicker eggshells than were observed for shells from eggs that hatched (H), were pipped (P), or contained late dead (LD) embryos (eggshell type). Overall pore concentration was significantly greater in H than in ED eggshells and significantly greater in ED than in LD or P eggshells. At the large end, eggshells from H eggs exhibited a significantly greater pore concentration compared to all other eggshell types. Pore concentrations at the equator and small end were significantly greater in H and ED eggshells when compared to eggshells from LD and P embryos. Large end pore concentration was significantly greater than at either the equator or small end in H eggshells. Optimum hatchability may depend on a proper eggshells region-pore concentration relationship as well as a sufficiently high number of pores in all three regions of the shell. Embryonic mortality may result from insufficient pore numbers. An excessively thick shell, which may negate the compensatory effects of high pore numbers at the equator and small end, may account for some ED embryos.

Key words: broiler breeder, eggshell porosity, eggshell quality, embryonic development, hatchability

1985 Poultry Science. 64:2388-2391

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
The effects of cuticle removal on the water vapor conductance (G) by eggshells from broiler breeders were determined in five experiments. The efficacy of washing eggs in sodium hypochlorite (NaClO) as a means to remove cuticle was demonstrated in Experiment 1. Birds housed in slat litter pens were used in Experiment 2, 4, and 5, while individually caged birds were used in Experiment 3. Conductance measurements before and after cuticle removal were made in desiccators in Experiments 2, 3, and 4 and G measurements, with and without the cuticle, were made in incubators in Experiment 5. Conductance before and after cuticle removal was measured at various time periods between Weeks 33 and 66.
Water vapor conductance was increased to a highly significant degree after cuticle removal at Weeks 54, 58, and 61 in Experiment 2. Conductance was significantly higher after cuticle removal at Weeks 42, 46, 50, and 54 and significantly lower after cuticle removal at Weeks 38 and 64 in Experiment 3. Conductance was significantly higher after cuticle removal at Weeks 33, 37, 45, 49, and 61 and significantly lower after cuticle removal at Week 65 in Experiment 4. The greatest changes in conductance with cuticle removal (ΔG) were + 1.80 at Week 33 and -2.40 at Week 65 in Experiment 4. In Experiment 5, G was significantly higher with the cuticle removed than it was with the cuticle intact at Weeks 48, 54, and 66.
It was concluded that the cuticle may either impede or enhance water vapor diffusion as a function of a bird's age. The influence of the cuticle is, in turn, affected by the humidity of the air surrounding the egg.

Key words: broiler breeders, conductance, cuticle

1986 Poultry Science. 65:1034-1039

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
The effects of an induced molt on selected eggshell quality parameters, including the conductance of water vapor (G), were determined in broiler breeders in two separate trials. The parameters analyzed were: egg weight, shell weight, shell thickness, specific gravity, pore concentration at the small end, equator, and large end regions of the egg, G, and the change in G with cuticle removal (ΔG).
Molting increased specific gravity in both trials. Pore concentration increased in all three regions of the egg with molting in Trial 1 and at the equator in Trial 2. Water vapor conductance decreased after the molt in both trials, and (ΔG was lower postmolt in Trial 2. Eggshell weight and thickness were increased after the molt in Trial 2.
We concluded that molting may lead to a decrease in G despite increased pore numbers due to altered cuticle morphology, pore configuration, and increased shell thickness.

Key words: broiler breeders, cuticle, molting, conductance

1986 Poultry Science. 65:1270-1274

Department of Poultry Science, North Carolina State University, Raleigh. North Carolina 27695-7608

ABSTRACT
Relationships among selected variables of eggshell quality in broiler breeder eggs were determined over complete production cycles in three experiments. Variables measured were egg weight (EW), egg specific gravity (SG), eggshell weight (SW), water vapor conductance (G), and regional pore concentration (PC) and eggshell thickness (ST) (Experiments 1 and 2). Hatchability was examined in one experiment (Experiment 3).
Eggshell weight, ST, and SG were all positively correlated with each other and PC in three regions of the shell (small end, equator, and large end) were highly positively correlated among themselves in Experiments 1 and 2. Pore concentration showed negative correlations with SG and ST but was positively correlated with G and G per 100 g EW (G/EW) in Experiments 1 and 2. Egg weight and shell weight increased with bird age in Experiments 2 and 3; however, negative trends over time were found for SG, PC, G, and G/EW in Experiment 2 and for G/EW and hatchability in Experiment 3. Quadratic regressions were similar for G/EW, hatch of fertile eggs, and hatch of total eggs in Experiment 3. Percentage hatch of fertile eggs peaked at Week 47 and was statistically lower at Weeks 55, 59, and 63, and percentage hatch of total eggs set was statistically lower at Weeks 55 and 59 than at Weeks 35, 39, and 47.
It was concluded that eggshell quality changes with bird age. Conductance/egg weight appeared to be a useful indicator of hatchability, and the contribution of reduced G/EW to decreased hatchability was most evident late in production when eggshell surface area to egg volume ratio was lowest.

Key words: broiler breeder, hatchability, conductance, shell quality, egg weight

1987 Poultry Science. 66:596-604

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
The effects of eggshell cuticle removal and two levels of incubation humidity 28.3 C [50% relative humidity (RH)] and 30.0 C (55% RH) wetbulb temperature (WB) on embryonic mortality and hatchability were determined from broiler hatching eggs laid during 38, 42, 48, and 54 weeks of age. Variables measured were: egg weight loss during the first 17 days of incubation, hatch at Days 19.5 and 20.5 of incubation, hatch of fertile eggs, stage of embryonic mortality, and chick weight at 21.5 days of incubation.
Day 0 to 17 percentage egg weight loss was increased when the incubation humidity was lowered and the loss was greater than that observed after cuticle removal. A greater percentage of chicks hatched on Day 19.5 at 28.3 C than at 30.0 C WB. The percentage hatch of 38-week fertile eggs was improved at the higher humidity; the higher humidity also decreased late dead and increased pipped embryonic mortalities. Cuticle removal decreased early dead and increased late dead mortality. At Week 38 cuticle removal and lower humidity resulted in a decrease in chick weight at 21.5 days of incubation. For Weeks 42, 48, and 54 combined. pipped mortality was increased by higher humidity and late dead mortality was increased by cuticle removal.
Water loss from the egg was increased by cuticle removal or by lowering incubation humidity from 30.0 C to 28.3 C WB, or by both, but lowering humidity was more effective. Changes in humidity and cuticle removal may affect vital gas exchange to different degrees; however, the effect of cuticle removal on embryonic development may be dependent upon the quantity and morphology of the cuticle. Cuticle removal may provide a means to improve vital gas exchange if appropriate adjustments in humidity are made to prevent excessive water loss.

Key words: broiler breeders, cuticle, hatchability, incubation humidity, chick weight

1987 Poultry Science. 66:834-840

USDA, ARS, SEPRL, Genetics Unit, c/o UGA, Athens, Georgia and University of Georgia, Athens, Georgia 30602

ABSTRACT
Recombinant chicken growth hormone (rcGH) was administered subcutaneously twice daily to male and female Athens-Canadian randombred meat-type chickens between 2 and 14 days posthatch. Treatment groups consisted of non-injected controls, saline-injected controls, and those injected with either 50 or 250 µg/kg rcGH per injection. Body weight, body weight gain, feed consumption, and feed efficiency were determined. Body weight or body weight gain was not significantly affected by rcGH through 28 d. Feed consumption and efficiency were not significantly affected by treatment through 21 d. It was concluded that rcGH failed to demonstrate any significant growth-promoting effects in young, slow-growing randombred chickens.

1988 Growth, Development & Aging 52:133-138

Pou1try Science Department, Mississippi State University, Mississippi State, Mississippi 39762; and USDA, Agricultural Research Service, Southeast Pou1try Research Laboratory, University of Georgia, Athens, Georgia 30602

ABSTRACT
Three experiments were conducted to measure changes in plasma thyroxine (T₄) concentrations occurring in male and female Japanese quail in response to treatment with dietary thiouracil (TU) and different CP levels prior to sexual maturity and to determine the influeuce of selection for growth under TU and protein stress on this response. Selected and unselected lines of quail were fed diets containing .2% TU or two levels of CP (20 or 28%) or both from 0 to 4 wk of age. Body weight and plasma T₄ were measured at 5, 7, and 9 wk of age in Experiments 1 and 2. In experiment 3, body weight was measured at 2, 4, 5, 7, and 9 wk and T₄ at 4, 7, and 9 wk.
Thiouracil inhibited growth to a greater degree than did decreased dietary CP. However, offspring from selected quail were more resistant to dietary TU when selection diets contained TU. When fed as part of a selection regimen rather than to unselected birds, low CP, TU diets inhibited body weight increase to a greater degree and 1onger after birds were returned to control diets. Thyroxin concentrations between 4 and 9 wk were affected by TU but not by CP level. Thiouracil significantly reduced T₄ during treatment: however, T₄ was elevated by 3 wk after cessation of TU treatment. Increases in T₄ were greater and more immediate in selected than in unselected birds. These findings reveal the ability of quail to compensate for thyroid suppression after TU is removed from the diet and the influence of selection on this compensatory response.

Key words: dietary thiouracil, dietary protein, body weight, growth inhibitor, thyroid suppression

1991 Poultry Science. 70:641-650

Poultry Science Department, Mississippi State University, Mississippi State, Mississippi 39762; and SDA, Agricultural Research Service, Southeastern Poultry Research Laboratory, University of Georgia, Athens, Georgia 30602

ABSTRACT
Decreased hatchability in Japanese quail following selection for growth and relative improvements in hatchability following selection during goitrogen treatment were investigated. An unselected quail line (Line C) and lines selected for high 4-wk body weight while being fed diets containing either 20% CP and .2% thiouracil (TU) (lines P and H-CD) were used. Egg weight loss between 0 and 4, and 0 and 14 days of incubation, hatchability, and developmental stage of embryonic mortalities were determined in Experiment 1. Length of the incubation period, and percentages of body water and dry body weight were for 10- and 14-day embryos and 18-day-old chicks in Experiment 2. Eggshell quality was determined in Experiment 3.
Hatchability was lower in selected than in unselected quail due to increased early and late embryonic mortality. Egg weight loss during incubation was greater in Line P than in Line C eggs. Weight loss, measured across lines, was lower in eggs that hatched than in those in which embryos died early. Percentage body water was higher in Line C than in Lines P and T at 14 and 18 days of incubation; however, percentage body water in Line T was lower than Line P at 14 days. Percentage of dry body weight was greater in Lines P and T than in Line C at 14 and 18 days. Eggshell thickness was greater in Line H-CD when compared with Line C.
Increases in eggshell permeability occurring during selection for growth were associated with increased embryonic mortality and decreased hatchability. In selected birds, .2% dietary TU did not effect embryonic growth but decreased percentage embryonic body water. Dietary TU may impede the detrimental effects of growth selection on eggshell permeability.

Key words: dietary protein, eggshell quality, embryonic development, Japanese quail, thiouracil

1991 Poultry Science. 70:1474-1480

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

ABSTRACT
Two trials were conducted to determine the normal feed and water consumption of broiler chicks from placement to 21 days of age. Daily intakes were determined on straight-run chicks. Mash feed and water were supplied ad libitum. Prediction equations for feed and water consumption on a per chick basis were generated:

Key words: Feed consumption, water consumption, starter diet, prediction equations

1992 Journal of Applied Poultry Research. 1:160-163

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

ABSTRACT
Various physical and chemical properties of hardwood bark (HB) and pine shavings (PS) were compared. Subsequently, efficacies of these materials as broiler litter were determined in two production tria1s. Upon receipt of each material, moisture content, pH, bulk density, and moisture absorbing capacity were determined. The PS had less moisture, less bulk density, and more moisture absorbing capacity than HB. However, the pH of PS and HB were not different. Trial 1 consisted of 16 replicate pens of HB and 8 pens of PS and Trial 2 involved 8 pens of HB, 8 pens of shredded HB, and 8 pens of PS. Each pen in each trial contained 50 broilers. No consistent differences in either pH, moisture, or nitrogen content were found in the litter types during the two growout periods. Body weight gain, feed conversion, and carcass grade were not affected by litter type.

Key words: broiler growth, carcass grade, litter, hardwood bark, particle size

1992 Poultry Science. 71:467-472

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

ABSTRACT
Because ascorbic acid (AA) and the thyroid hormones are known to influence eggshell formation, the effects of AA on body weight, total plasma thyroxine (T₄), egg production, and eggshell quality of Single Comb White Leghorn (SCWL) hens concurrently and previously treated with thiouracil (TU) were determined. Hens were provided feed containing either 0 or 100 ppm AA from 47 to 67 wk of age and either 0 or .1 % TU from 47 to 57 wk of age. A three-way split-plot analysis was employed to test for the effects of AA, TU, and time, and their interactions.
Dietary TU increased body weight between 53 and 59 wk, and increased thyroid weight at 67 wk; however, TU only depressed plasma T₄ level at 51 wk. Dietary TU depressed egg production from 50 to 56 wk and egg weight at 49, 51, and 57 wk. Dietary TU depressed eggshell weight per unit surface area at 49 wk. There was no significant effect due to AA and no AA by TU interaction for any of the parameters examined. It was concluded that .1 % dietary TU from 47 to 57 wk of age did not alter eggshell quality and that dietary AA at the 100 ppm level did not influence the effects of .1 % TU on body weight, egg production, or egg weight of SCWL hens.

Key words: ascorbic acid, dietary thiouracil, eggshell quality, layers, plasma thyroxine

1992 Poultry Science. 71:553-559

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

ABSTRACT
Two trials were conducted to investigate the effects of caging density and diet on the performance of caged layers. Diets were formulated to contain .775, .725, and .675% lysine. The TSAA content was formulated to be 85% of the lysine content of each diet. Pullets were caged in 25.4 cm wide x 40.0 cm deep cages at three, two, or one bird per cage. Production data were collected for 112 days in Trial 1 and 168 days in Trial 2. As dietary protein, lysine, and TSAA increased, hen-day egg production, egg weight, and feed conversion improved (P < .05). Feed consumption and feed per dozen eggs were not consistently affected by diet. Caging density had no consistent effects on any of the production parameters. No interactions were detected between dietary treatments and cage density in either trial.

Key words: layers, lysine, total sulfur-containing amino acids, caging density, egg production

1992 Poultry Science 71:945-950

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

ABSTRACT
Broiler chickens are routinely fed diets containing the growth promotant 3-nitro-4-hydroxyphenylarsonic acid (ROX). Four trials were conducted to determine the amount of arsenic present in broiler excreta and broiler litter when broilers were fed a diet containing roxarsone. Two experimental diets were utilized in all four experiments: the control diet (CON) that contained no added roxarsone and the roxarsone (ROX) diet that contained 45.4 g of roxarsone per ton. The CON and Roxarsone diets were fed from 1 day of age until 42 days of age. From 42 to 47 days of age, both treatments received a withdrawal diet that contained no roxarsone. Weekly fecal samples were taken during experiment one. In experiments 2, 3, and 4, litter samples were collected prior to each chick placement and at the end of each growout. All fecal and litter samples were analyzed for total arsenic content. In Trial one, the total arsenic level in the feces of birds receiving the ROX diet increased from 1 - 4 weeks, the total arsenic level decreased from 4 - 6 weeks, and continued to decrease through the withdrawal period (42-47 days). In addition, The ROX birds exhibited a greater level of total arsenic in the feces than the CON birds during each week of trial one. The total arsenic level in the feces of the birds receiving the CON diet remained constant throughout Trial 1. In Trials 2, 3, and 4, the total arsenic level in ROX built-up litter did not exhibit a continuous increase with multiple growouts and remained constant in the CON built-up litter.

Key words: Roxarsone, arsenic, excretion, feces, litter

2001 J. Appl. Poult. Res.. 10:323-328.