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PubMed1999

Effect of lufenuron on chorionic and cuticular structure of unhatched larval Ctenocephalides felis (Siphonaptera: Pulicidae).

When adult cat fleas, Ctenocephalides felis (Bouché), were fed concentrations of < or = 0.08 ppm lufenuron in cattle blood, egg hatch did not differ significantly from the controls. However, as the concentration of lufenuron in blood increased from 0.125 to 1.0 ppm egg hatch decreased to 64 and 2%, respectively. Most of these eggs contained fully developed larvae. Microscopic examination of unhatched larvae, revealed that the cuticle epidermal cells, chorion, and vitelline membrane all were affected by lufenuron treatment. Larvae often produced 2 separate cuticles in response to treatment. The 1st cuticle consisted of an indistinct layer of epicuticle and a procuticle composed of randomly deposited chitin microfibrils. After the 1st layer of procuticle separated from the epidermal cells, a 2nd layer of procuticle was deposited. It was not possible to determine whether the egg tooth was functional during larval hatch. The surface of the egg tooth appeared normal, but the cuticle may have had structural abnormalities similar to those seen in other areas of the exoskeleton. Structural defects appeared to be due to the cytotoxic effects of lufenuron. The epidermal cells of treated larvae showed evidence of disintegration (i.e., the nuclei and mitochondria appeared to be degenerating and the amount of endoplasmic reticulum and other cytoplasmic organelles was decreased). The chorion of lufenuron-treated larvae consisted of an outer layer, middle and inner layers that were thinner and less electron dense than those of controls, and lacked the innermost chorionic layer found in the control larvae. The vitelline membrane also was thinner than that of the controls. Larval hatching was prevented by ruptures in the cuticle, which opened during eclosion resulting in the loss of hemolymph and desiccation of the larva. Evidently, tearing of the cuticle was caused by abnormal formation of the procuticle that was not strong enough to withstand the cuticular expansion and muscular movement of the larva within the egg shell.

Animals↗
PubMed1997

Layer performance of four strains of Leghorn pullets subjected to various rearing programs.

Two experiments were conducted using four strains of Leghorn pullets, namely Babcock, DeKalb, H & N, and Shaver. Pullets were grown on conventional or low protein diets fortified with additional amino acids. At 18 wk of age, 64 pullets from each strain and diet treatment were transferred to individual laying cages, using eight replicate groups of four adjacently caged birds. In a second experiment, pullets from the four strains were selected based on body weight at 18 wk of age (approximately 1,270 vs 1,650 g). Each weight group and strain was again represented by eight replicate groups of four birds. In Experiment 1, there were no strain or rearing diet effects on egg production (P > 0.05). Rearing diet had little long-term effect on any adult characteristics. There were significant (P < 0.01) strain effects on body weight, feed intake, and egg weight, although these were independent of rearing diet. In Experiment 2, regardless of bird strain, the pullets with smaller body weight matured more slowly (P < 0.01) and produced less total egg mass to 70 wk age (P < 0.05). These smaller birds ate less feed and produced smaller eggs (P < 0.01). There were strain effects, independent of 18-wk body weight, for egg weight and eggshell quality (P < 0.01). It is concluded that minor strain differences exist with respect to response to juvenile nutrition, although such effects are only evident in early lay. All strains of bird remain small, 18-wk body weight is reduced, and these birds subsequently eat less feed and produce smaller eggs.

Aging↗
PubMed1997

Effect of lead ingestion on concentrations of lead in tissues and eggs of laying Tsaiya ducks in Taiwan.

This experiment was conducted to investigate Pb concentrations in soft tissues and eggs from laying Tsaiya ducks (Anas platyrhynchos var. domestica), dosed via gelatin capsule with 10 or 20 mg Pb/kg BW daily for 3 mo. Body weights of ducks were not influenced by Pb treatment. In addition, no clinical syndromes involving Pb intoxication were found throughout the experiment. The two levels of Pb consistently resulted in increases in the Pb content of blood, kidney, liver, and gizzard, whereas only 20 mg Pb/kg BW per d of dose additionally increased the Pb in femoral muscle. More Pb was deposited in the kidney and liver after Pb exposure than in the gizzard or femoral muscle. Lead residues in yolk and eggshell from Pb-dosed ducks were significantly higher than in controls; however, Pb in albumen was generally low and was not influenced by Pb treatment.

Administration, Oral↗
PubMed1997

Effects of consecutive thiouracil exposures in the juvenile and adult single comb White Leghorn chicken on body weight and reproductive performance.

The effects of consecutive exposures to dietary thiouracil (TU) in juvenile and adult Single Comb White Leghorn chickens on plasma thyroxine (T4) concentrations, egg production (EP), egg weight (EW), concentrations eggshell quality were determined. Thiouracil was provided in the feed at levels of 0, 0.1, or 0.2% (PTRT) from 0 to 6 wk of age and at levels of 0 or 0.1% (TRT) from 32 to 38 wk of age. Body weight gain was simulated but T4, EW, EP, and eggshell quality were generally reduced by 0.1% TU TRT. However, TU PTRT alleviated a latent depressing effect of TU TRT on BW after 38 wk of age. Thiouracil PTRT, particularly at the 0.2% level, induced significant decreases in EW but increased EP between 32 and 50 wk. The effects of early thyroid suppression in juveniles with TU PTRT on the subsequent reproduction of adults were primarily in response to a delay in the onset of sexual maturity, and not directly to prolonged responses in T4 or BW that extended into lay.

Aging↗
PubMed2000

Paternal influences on turkey embryonic growth in the absence of changes in egg weight and eggshell conductance.

The hypothesis was proposed that embryonic growth could be influenced paternally in the absence of changes in egg weight or eggshell conductance. Sire families were established by selecting 11 sires based on blood sampling of approximately 50 commercial turkey males. Southern blot analysis was used to identify the most distantly related individuals in the subpopulation. Five hen siblings or half-siblings of the males were randomly assigned to each male to randomize effects of egg size and eggshell conductance. Artificial inseminations were performed weekly for 17 wk, using each sire with the assigned hens. Fertilized eggs were collected and set in incubators at biweekly intervals. Offspring were observed at the time of hatching for sex, body weight, and blood glucose concentration. Significant differences among sires were observed at hatching for poult weights and blood glucose concentration, and a significant correlation between the BW and glucose concentration was noted. Progeny of sires with the highest and lowest BW and blood glucose concentrations were subsequently compared. Mean BW of poults from different sires differed by as much as 10 g, although they were hatched from eggs of the same weight. Elevated blood glucose was associated with heavier BW; heavier heart, liver, and muscle weights; a rapid utilization of glycogen at pipping; and increased gluconeogenesis as measured by plasma organic acids and glucose-6-phosphatase activity. We conclude that poult embryonic growth differs even when not mediated by egg size and functional characteristics.

Animals↗
PubMed2000

Further tests for genetic linkages of three morphological traits, three blood groups, and break points of two chromosome translocations on chromosome one in the chicken.

Two matings were conducted to further test the locations of the pea comb (P*), blue egg shell color (O*), and tardy feathering (T*) loci. In each mating a different chromosome rearrangement break point (R(B)) was tested against the three loci. Independent segregation was noted between the traits and the R(B) when the R(B) was on the long arm of chromosome 1. Significant linkage was noted when an R(B) on the short arm was tested against the three markers, indicating that the loci for P*, O*, and T* are on the short arm. Three blood group loci, EAD*, EAI*, and EAP*, were simultaneously tested against the short arm R(B). Independent segregation was noted in each instance, indicating that these blood group loci are not on the short arm of chromosome 1.

Animal Husbandry↗
PubMed2000

Preventive effect of partially hydrolyzed guar gum on infection of Salmonella enteritidis in young and laying hens.

The preventive effect of partially hydrolyzed guar gum (PHGG) on the colonization of Salmonella enteritidis (SE) in young and laying hens was investigated. The effects of feed supplemented with 0.025, 0.05, and 0.1% PHGG was examined on young hens orally infected with SE. The incidence of SE in organs was decreased, the excretion of SE into feces was increased, and the agglutinating antibody titer to SE in serum was decreased by the administration of PHGG to young hens. In particular, feed supplemented with 0.025% PHGG was the most effective. It was also shown that feed supplemented with 0.025% PHGG increased the number of Bifidobacterium spp. and Lactobacillus spp., the most numerous intestinal bacteria in the cecum of young hen. The effect of the excretion of SE via feces was also observed in an experiment using laying hens. The incidence of SE on the surface of the eggshell and in egg white and egg yolk was also decreased when the feed of laying hens was supplemented with 0.025% PHGG. These results show that the administration of feed supplemented with PHGG can prevent the colonization of SE in young and laying hens, which, in turn, could be related to improvement in the balance of intestinal microflora.

Agglutination Tests↗
PubMed2000

Effects of breeder age and dietary fat source and level on broiler hatching egg characteristics.

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% corn 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.

Age Factors↗
PubMed2000

Nonphytate phosphorus requirement of laying hens with and without phytase on a phase feeding program.

An experiment was conducted to reevaluate the nonphytate P (NPP) requirement of laying hens with and without phytase. The experiment involved 12 treatments in a 6 x 2 factorial design. The hens of the control group (T1) were fed a sequence of 0.40-0.35-0.30% NPP during 30 to 42, 42 to 54, and 54 to 66 wk, respectively. The NPP was reduced in increments of 0.05% in T2 to T6. The hens of T7 to T12 were fed NPP regimens similar to T1 to T6 but with 300 units phytase/kg diet. Two digestion trials were conducted during 42 and 66 wk, and nitrogen, phytate, and total P retention were determined. In the absence of phytase, production traits were not different for hens fed a NPP regimen of 0.25-0.20-0.15% than for the unsupplemented phytase control group for the entire experiment (P > 0.05). However, production traits were inferior for hens fed the lower NPP regimens (P < 0.05). In the presence of phytase, production traits were not different for hens fed the lowest NPP regimen (0.15-0.10-0.10%) than for the unsupplemented phytase control for the entire experiment (P > 0.05). The overall effect of NPP regimens and phytase on specific gravity for the entire experiment was significant. Specific gravity was greater for hens fed the regimens with less NPP than for hens fed regimens with greater NPP, and phytase had an adverse effect on specific gravity. However, specific gravity of hens fed the lowest NPP regimen with phytase was not significantly different from the unsupplemented phytase control group. The overall effect of phytase on phytate P retention was significant during digestion trials; phytase increased phytate P retention by about 15%. Daily total P excretion was 34 to 47% less for hens fed the lowest NPP regimen with phytase than for the unsupplemented phytase control group. Significant interactions existed for a number of traits and are discussed in the text.

6-Phytase↗
PubMed2001

Optimum site for in ovo amino acid injection in broiler breeder eggs.

Three experiments were conducted to evaluate the effect of differences in in ovo amino acid (AA) injection sites in broiler breeder eggs on subsequent hatchability and BW of chicks. In Experiment 1, an AA solution was injected into eggs with 13-mm or 19-mm, 27-ga needles. Uninjected eggs served as controls. Hatchability was decreased (P < 0.05) in eggs receiving AA injections with the 19-mm needle in comparison to the control and 13-mm-injected groups. However, BW of chicks increased (P < 0.05) relative to pre-incubational egg weight by AA injection with the 13-mm needle. In order to evaluate the in ovo location of AA injections from Experiment 1, India ink was injected into eggs in Experiment 2 with a 13-or 19-mm needle. Immediately after injection, the air cell end of the egg was windowed in order to observe effects of injection site. Windowing of eggs was accomplished by removing a piece of the eggshell over the air cell and the underlying membrane at Day 7 of incubation. The amount of injected India ink was higher in the extra-embryonic coelom in eggs treated by both needles. However, the occurrence of India ink in the extra embryonic coelom was higher (P < 0.05) in the group injected with AA solution using a 13-mm needle as compared to that after injection using a 19-mm needle. The observation of India ink in the amniotic cavity was higher (P < 0.05) in the group injected with AA solution using a 19-mm needle rather than that using a 13-mm needle. In Experiment 3, treatments consisted of control (uninjected eggs) or windowed eggs. Windowed eggs received AA to the chorioallantoic membrane, the yolk, extra-embryonic coelom, or amniotic cavity at Day 7 of incubation. Hatchability was reduced, but chicks hatched when eggs were windowed and when AA were injected into the yolk sac or extra-embryonic coelom. However, chicks did not hatch when AA were administered to the chorioallantoic membrane or into the amniotic cavity. These results suggest that the best AA injection sites in ovo may be the yolk and extra-embryonic coelom.

Amino Acids↗
PubMed2001

Breeder age influences embryogenesis in broiler hatching eggs.

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.

Age Factors↗
PubMed2001

Egg marketing in national supermarkets: egg quality--part 1.

Two surveys were conducted to determine the quality of eggs offered to consumers in large supermarkets in various regions of the US. The first survey was conducted in California (CA) in 1994 and included 38 samples of large (L) and extra large (XL) white eggs in 15 markets. Individual eggs were weighed, candled, and broken out for Haugh unit (HU) determination. Regional differences in age of eggs, the number of eggs below 55 HU, and the percentage of cracked eggs were observed. The second survey was conducted in California (CA), Illinois (IL), Pennsylvania (PA), Texas (TX), North Carolina (NC), and New England (NE). This study included brown and white eggs and samples from 115 stores in 38 cities. Significant age, egg weight, HU, and cracked egg differences were observed between states. Brown and white eggs were different relative to age and HU, but egg weights and cracked eggs were statistically the same. The two surveys, 1994 and 1996, within CA demonstrated very similar measurements when L-white eggs were compared.

Animals↗
PubMed2001

Effects of light intensity from photostimulation in four strains of commercial egg layers: 1. Ovarian morphology and carcass parameters.

We examined the effects of light intensity (LI) from photostimulation to 45 wk of age on egg production parameters and egg size characteristics and on ovarian and carcass morphology at sexual maturity and 45 wk of age in four layer strains. Floor housed pullets were raised in a light-tight facility from 1 d of age until housing in individually illuminated cages at 17 wk of age. Two white egg strains, ISA-White (ISA-W) and Shaver 2000 (S2000), and two brown egg strains, ISA-Brown (ISA-B) and Shaver 579 (S579), were used. Pullets were randomly assigned to a processing group that was killed at sexual maturity (first oviposition) (Group 1) or kept to 45 wk (Group 2). Birds were photostimulated at 18 wk of age using a LI of 1, 5, 50, or 500 lx (4 x 4 factorial design). One bird from Group 1 and one from Group 2 were caged together in individually lit cages (one brown and one white egg layer). Carcass and ovarian morphology data were examined as related to Strain, LI, or the interaction of Strain and LI. The time from photostimulation to sexual maturity did not differ due to LI, but was shorter for brown egg strains (ISA-B = 19.9 d, S579 = 20.2 d) than for white egg strains (ISA-W = 26.6 d, S2000 = 28.1 d). Body weight at sexual maturity differed among all strains, with the white egg strains having the lowest BW. Ovary weight was the greatest in ISA-W birds, in which 8.0 large yellow follicles (LYF) were present compared to 6.8 in S2000 birds. The LI affected ovary development, as birds with the 1 lx exposure had lower ovary weights and fewer LYF than did 50 lx birds, suggesting that the 1 lx LI did not result in an adequate photostimulatory cueing of sexual maturation. The threshold LI for a complete morphological response to photostimulation in this study was 5 lx. Strain differences in BW observed at sexual maturity continued to 45 wk of age. Light intensity affected 45 wk BW, with 5 lx LI birds weighing 7.2 and 8.7% more than the 50 and 500 lx birds, respectively. On an absolute basis, brown egg stains carried significantly more breast muscle at 45 wk of age than did white egg strains. The fatpad was heavier on a relative basis for brown egg layers than white egg layers. The 1 lx hens had lower 45-wk ovary weights than did the other three LI treatments. These data support the conclusion that with the development of highly specific genetic strains, it is increasingly important to match the environmental management practices to a particular hen's genotype.

Animal Husbandry↗
PubMed2001

Effects of dietary 1, 4-diaminobutane (putrescine) on eggshell quality and laying performance of older hens.

We conducted an experiment to evaluate the potential for dietary 1,4-diaminobutane (putrescine) to promote eggshell quality and overall laying hen performance. A total of 128, 60-wk-old Barred Rock hens were fed a corn and soybean meal-based layer diet supplemented with 0.0 (control), 0.2, 0.4, and 0.6% free base 1,4-diaminobutane for 4 wk. The feeding of supplemental putrescine decreased feed consumption (P < or = 0.05) and egg mass (P < or = 0.05) and tended to decrease egg production (P < 0.08). Albumen quality was not significantly affected (P < 0.09) by the end of the experiment, as determined by Haugh units. Eggshell thickness was not significantly improved with lower levels of dietary putrescine (P < 0.08). Although dietary putrescine did not have any effect on the relative weights of duodenum, jejunum + ileum, or pancreas, there was a linear increase in putrescine concentrations in tissues (P < or = 0.05). Supplementation of dietary putrescine also resulted in increased putrescine and spermidine concentrations in egg (P < or = 0.05). Egg weight and eggshell deformation increased over time; however, eggshell weight, eggshell weight as percentage of egg weight, and eggshell thickness decreased (P < or = 0.05). It appeared that eggshell quality declined regardless of diet over the 4-wk experimental period. It was concluded that the lack of effect of dietary putrescine on egg parameters, with the exception of albumen quality and eggshell thickness, was due to putrescine toxicity. Hens transferred excess dietary putrescine and metabolites to eggs.

Animals↗
PubMed2002

Dietary interaction of 1,4-diaminobutane (putrescine) and calcium on eggshell quality and performance in laying hens.

An experiment was conducted to evaluate the potential dietary interaction between 1,4-diaminobutane (putrescine) and calcium on eggshell quality and overall laying performance. One hundred ninety-two 30-wk-old White Leghorn hens were fed a corn-and soybean-meal-based diet supplemented with 0.00, 0.05, 0.10, or 0.15% putrescine and 2.5, 3.0, 3.5, or 4.0% calcium in a factorial design (12 birds per diet) for 4 wk. The percentage of egg production increased linearly (P < 0.05) with increasing levels of dietary calcium. Significant interactions (P < 0.05) were observed between dietary putrescine and calcium for eggshell thickness, eggshell deformation, percentage of eggshell, calcium intake, total calcium retention, total eggshell calcium, and percentage of eggshell calcium. Interactions were due to quadratic effects of putrescine or calcium on these parameters. Eggshell thickness and percent eggshell increased when hens were fed 3.5% calcium in combination with 0.1% putrescine; however, calcium intake and calcium retention were significantly lower (P < 0.05). Eggshell quality improved with increasing dietary levels of calcium due to increased calcium retention and calcium balance. Increasing levels of dietary putrescine did not have a negative effect on eggshell quality; however, calcium intake was lower at higher-supplemented levels of putrescine. It was observed that dietary calcium in excess of requirements resulted in increased egg production and eggshell quality. Eggshell quality improved when hens were fed 3.5% calcium diet in combination with 0.10% putrescine. It was concluded that small supplements of dietary putrescine may improve eggshell quality, depending on dietary calcium concentration.

Animal Feed↗
PubMed2002

Effects of F-strain Mycoplasma gallisepticum inoculation at twelve weeks of age on performance and egg characteristics of commercial egg-laying hens.

The effects of F-strain Mycoplasma gallisepticum (FMG) inoculation during the pullet period on the subsequent performance and egg characteristics of commercial Single Combed White Leghorn hens were evaluated. In two trials, BW, feed consumption, egg production (EP), egg weight, egg size class, relative eggshell water vapor conductance, and relative percentages of eggshell, yolk and albumen weights were determined through approximately 60 wk of age. In each trial, pullets at 12 wk of age were randomly assigned to negative pressure biological isolation units. Birds in one-half of the total units were inoculated with FMG, and the other half were sham-inoculated with sterile media. In both trials, onset of lay was delayed approximately 1 wk in layers inoculated with FMG. Control birds that had not been previously inoculated with FMG laid their first egg at 18 wk of age, while birds that had been previously inoculated with FMG laid their first egg at 19 wk of age. In Trial 1, FMG-inoculated hens laid significantly fewer total eggs, which became apparent at each week after Week 42. In Trial 2, a numerical decrease in total EP occurred, and the percentage of undersized eggs laid by FMG-inoculated birds was significantly lower at 19 wk of age but was higher at 20 and 21 wk when compared to controls. Mortality was not significantly different between the treatments in either trial. These data demonstrate that when birds are housed in isolation facilities and inoculated with FMG at 12 wk of age, onset of lay is delayed. These data also suggest that FMG may lead to delays in undersize EP and decreases in total EP. However, because significant FMG effects on these parameters were observed in only one trial, additional studies may be necessary to verify these effects.

Aging↗
PubMed2002

Effects of the tricothecene mycotoxin diacetoxyscirpenol on egg production of broiler breeders.

Three experiments were conducted to determine the effects of 4,15-diacetoxyscirpenol (DAS) on egg quality and egg production of broiler breeders. In Experiment 1, feed containing 0, 1.25, 2.5, or 5.0 mg DAS/ kg was fed from 67 to 69 wk of age followed by a 3-wk recovery period on a slat-litter floor. In Experiment 2, individually caged broiler breeder females were studied from 23 to 31 wk of age. The basal diet containing 0, 5, 10, or 20 mg DAS/kg was fed from 25 to 27 wk of age. In Experiment 3, individually caged broiler breeder hens were studied from 23 to 32 wk of age. DAS was fed at levels of 0 (basal), 5, 10, and 20 mg DAS/kg for 2 wk beginning at Week 24, followed by the basal breeder diet for 7 wk. Egg production was not affected by levels of up to 5 mg DAS/kg in the older hens of Experiment 1. When fed from 25 to 27 wk of age in Experiment 2, DAS decreased egg production at the 20 mg/kg level only. When fed from 24 to 25 wk of age in Experiment 3, DAS had no significant effect on egg production or egg quality. Short-term consumption of DAS at levels that might naturally occur appears to have little effect on broiler breeder egg production.

Aging↗