Improve Shell Quality Research Articles

Intestinal and eggshell calbindin, and bone ash of laying hens as influenced by age and molting

A series of trials was conducted in order to study the effects of age and molt on intestinal and eggshell gland (ESG) calbindin, and on bone ash. For this purpose an ELISA for chicken calbindin was developed. Age did not significantly affect duodenal or ESG calbindin. Bone ash increased (but not significantly in this study) from 8 to 16 months of age. During molt induction, egg laying was arrested, duodenal and ESG calbindin almost completely disappeared and ovary mass, plasma estradiol and total calcium (Ca) decreased markedly, whereas bone ash and body mass (BW) decreased moderately. During the non-laying period that followed the feed withdrawal period, duodenal and ESG calbindin remained low, whereas plasma estradiol and other estrogen-dependent variables, such as plasma total Ca and bone ash, increased slightly. At the onset of egg production following molting, duodenal and ESG calbindin levels were similar to pre molt level. Bone ash was higher than at the pre molt period. Body mass, small yellow follicles, ovary and oviduct mass and plasma estradiol were lower than their values prior to molt induction. Bone ash contents in the molted hens at the ages of 583 and 820 days were similar to or even slightly higher than those in the non-molted hens, whereas duodenal and ESG calbindin were not significantly different. These results suggest that the improvement of shell quality in the molted birds does not involve mechanisms associated with calbindin synthesis.

Effects of reducing dietary protein, methionine, choline, folic acid, and vitamin B12 during the late stages of the egg production cycle on performance and eggshell quality

A series of four experiments was conducted to determine whether-shell quality during the late stages of egg production can be improved by using diets that are effective in reducing egg size. The experiments involved dietary manipulation of protein, methionine, choline, folic acid, and vitamin B12. In experiment 1, reducing dietary protein in combination of reducing the dietary methionine and choline or this diet without supplemental folic acid and vitamin B12 resulted in reduced egg weight and improved shell quality. However, egg production also was drastically reduced. In experiment 2, reducing the dietary level of methionine, without adding supplemental choline, folic acid, and vitamin B12 reduced egg size and improved shell quality, but egg production was reduced as well. In this experiment reducing the dietary methionine without supplemental folic acid and vitamin B12 reduced egg size and improved shell quality with no adverse effect on egg production. In experiment 3, reducing the dietary level of methionine and choline or reducing the dietary level of choline, folic acid, and vitamin B12 reduced egg size and improved shell quality without adverse effects on egg production. On the other hand, reducing dietary methionine, folic acid, vitamin B12, and supplemental choline reduced egg weight and improved shell quality but lowered egg production. In experiment 4, reducing dietary methionine together with reducing choline and vitamin B12 reduced egg size and improved shell quality with no adverse effect on egg production. The results of this series of experiments generally indicate that certain manipulations of the combination of methionine, choline, folic acid, and vitamin B12 have the potential to reduce egg weight and improve shell quality without affecting egg production during the latter stages of the egg production cycle.

Inability to Demonstrate an Effect of Eggshell #49 on Shell Quality in Older Laying Hens

Short term studies were conducted with older laying hens to evaluate the efficacy of Eggshell #49 (Alltech, Inc., Nicholasville, KY) in improving shell quality. The product is a combination of several trace mineral proteinates, most prominently manganese and zinc. Both these trace minerals are essential for proper eggshell formation.Results of these studies failed to show a positive effect of the test product on eggshell quality, as measured by specific gravity. It should be noted, however, that levels of manganese and zinc in the basal diet contained ample margins of safety. Whether the test product would have given positive results with marginal levels of inorganic trace mineral supplementation was not addressed in these studies.

Influence of supplemental phytase on calcium and phosphorus utilization in laying hens

A 6-wk study was conducted to determine the influence of supplemental phytase on Ca and P utilization in commercial laying hens. Diets were arranged factorially with three levels of dietary Ca (2.5, 2.8, and 3.1%), fed at two levels of nonphytate P (0.1 and 0.3% NPP) with and without supplemental phytase. Each diet was replicated eight times, with 16 hens per replicate. Criteria evaluated included egg specific gravity, feed consumption, egg production, egg weight, eggshell weight, bone quality, and body weight. Increasing dietary Ca significantly improved shell quality within 1 wk. A significant improvement in shell quality due to phytase supplementation was also observed during the 1st wk. Increasing NPP from 0.1 to 0.3% had not effect on egg specific gravity until Week 3, suggesting that the phytase benefit during Weeks 1 and 2 was related to improved Ca utilization. From Weeks 3 to 6, a significant P by phytase interaction was observed in which the magnitude of shell quality improvement was greatest when the 0.1% NPP diet was supplemented with phytase. This interaction was also observed from Weeks 3 to 6 for feed consumption and egg production and during Weeks 4 and 6 for egg weights. Phytase supplementation completely overcame the adverse effects associated with low dietary P and significantly reduced the impact of low dietary Ca on hen performance.

The Design of the Ballistic Furnace and Initial Microshells Formation Experiments

The design and operation of a new “Ballistic Furnace” facility at the Lebedev Physical Institute for producing large plastic shells from solid polystyrene granules is presented, along with the results of the first experimental trials. Good quality shells with diameters up to 1.7 mm have been produced, though surface debris is a serious problem. AFM surface characterization of these shells is presented. The formation of several shells from a single initial granule has been experimentally observed. Based on our initial experimental results, the problems, possible routes to their solution, and other upgrade possibilities for the Ballistic Furnace that will result in improved shell quality will be discussed.

Responses of Laying Hens to Forced Molt Procedures of Variable Length With or Without Light Restriction

The importance of the length of the rest period and of photoperiod as components of the forced molt procedure was evaluated in 650- and 560-d-old Lohman hens. The procedure included an 8-d feed withdrawal phase and rest periods varying from 0 to 35 d, during which the birds were fed for maintenance only. In the first trial, forced molt was applied with or without omission of artificial illumination. The rest period varied between 2 and 20 d. In the second trial, all treatments included omission of artificial illumination, and a variable rest period between 0 and 35 d. Egg production ceased, after 4 to 5 d of feed withdrawal and resumed 8 to 15 d after the end of the rest period, without any consistent response to its length. Forced molt stimulated egg production rate and diminished its age-dependent rate of decline, reduced the proportion of broken and shell-less eggs, and improved shell quality. Following wide oscillations proportional to the length of the rest period, egg weight stabilized at levels similar to that of the unmolted controls. Feed intake was stimulated by forced molt to levels exceeding those of the control hens. Body weight increased during the postmolt period to levels slightly exceeding those of unmolted controls.Results of one trial show that omission of artificial illumination was essential for the full expression of the molt responses. In the other trial, production rate and shell quality were improved and the percentage of broken eggs was reduced when the length of the rest period was increased. Maximal improvements appears to have been reached with rests periods of 14 to 21 d.

Effect of estrogen on egg production, shell quality and calcium metabolism in molted hens

Force-molted White Leghorn laying hens were implanted with 0.25, 0.5, 1 and 3 Compudose 200 pellets (24 mg 17β estradiol/pellet). Plasma estradiol increased with increasing E 2 dosages in a linear manner and decreased over time in a quadratic manner ( P < 0.01). E 2 treatment had a nonlinear effect on total plasma calcium. Oviduct weight, shell thickness and egg weight were not significantly affected by exogenous estradiol whereas tibial bone ash percentage was increased at only one dose ( P < 0.05:0.5 pellet group). Physiological supplementation with estradiol does not improve shell quality.

The Effect of Indomethacin on Eggshell Quality

The objective of the present study was to determine whether indomethacin, an inhibitor of prostaglandin synthesis, could improve shell quality in birds laying a high incidence (>15%) of soft-shelled (SS) and shell-less (SL) eggs and in birds laying exclusively hard-shelled (HS) eggs. Treatments consisted of two injection types, indomethacin or oil (controls), and two injection times, 4 h or 16 h postentrance of the egg into the uterus. Indomethacin delayed oviposition in both HS and SS or SL egg layers, with indomethacin being more effective in delaying oviposition when injected at 16 h as compared with 4 h postentrance of an egg into the uterus. Indomethacin increased shell thickness of the first egg laid following injection in the SS or SL groups but not in the HS groups. Egg weight was not affected by indomethacin injection. It was concluded that indomethacin delayed oviposition and prevented the premature expulsion of some SS or SL eggs. This delay in oviposition resulted in thicker shells of the first egg laid postinjection.

Egg Shell Quality and Cholecalciferol Metabolism in Aged Laying Hens

Calcium-binding protein D28K (calbindin) synthesis, vitamin D metabolism and shell quality were investigated in young and aged laying hens fed diets containing either cholecalciferol (CC) or its 1-hydroxylated derivatives. Duodenal calbindin concentration was similar in the young and in the aged laying hens. Exogenous 1-hydroxylated CC derivatives increased duodenal calbindin concentration, regardless of age. Shell weight and shell density (mg/cm2) were significantly lower (P less than 0.01) in the aged than in the young hens. Egg shell weight and density tended to decrease along the clutch. The rate of decline was higher in aged than in young hens. Feeding aged hens a diet containing 5 micrograms 1,25-dihydroxycholecalciferol [1,25(OH)2CC] or 1 alpha-hydroxycholecalciferol per kilogram improved shell quality, slowed down the progressive reduction in shell quality during the clutch and increased culling and mortality. The results indicate a) that the capacity for expression of 1,25(OH)2D3 in the intestine is not altered by age and b) that prolonged feeding of 1-hydroxylated derivatives of vitamin D3 improves shell quality in aged laying hens and increases culling and mortality.

Significance of Growing Photoperiod and Light Stimulation at Various Ages for Leghorn Pullets Subjected to Regular or Ahemeral Photoperiods

Leghorn pullets were cage reared to 15 or 19 wk of age in environmentally controlled rooms that provided either 8 h or 14 h of light per day. In Experiment 1, birds were moved to laying cages at 15 wk of age and subjected to either 14 h light (L):10 h (D) dark or ahemeral 14L:14D photoperiods. Feed intake, egg weight, shell quality, and egg production were monitored to 67 wk of age. In Experiment 2, pullets were moved at 19 wk of age and subjected to 14L:10D or 17L:7D light programs. Production parameters were measured as previously described. No significant (P>.05) interactions were observed between rearing and laying photoperiods, suggesting that increase in the length of photoperiod around time of maturity is not essential for adequate performance. In Experiment 1, ahemeral lighting resulting in reduced egg production, whereas egg shell quality and egg weight were improved (P<.05). In both experiments, the 14-h rearing program resulted in improved egg size together with improved eggshell quality (P<.05). Whereas increased egg size may relate to body weight, no explanation is apparent for the consistent pattern with respect to shell quality. In Experiment 2, poorer shell quality was observed with 17 vs. 14 h light per day.It is concluded that light stimulation at maturity has little effect on overall egg production. Improved shell quality observed with birds reared under 14 h light vs. those reared under 8 h per day may relate to a less rapid attainment of peak egg production.

Studies Concerning Possible Explanations for the Varying Response of Different Phosphorus Levels on Eggshell Quality

Abstract Four experiments were conducted to determine if differences in phosphorus (P) source or differences in dietary calcium (Ca) level were responsible for the changes in egg specific gravity observed when dietary P levels are increased or reduced. Individually caged hens (685) and 23 dietary treatments involving various Ca, P levels, and P sources (dicalcium phosphate and phosphoric acid) were used. The criteria were egg specific gravity, egg weight, egg production, feed consumption, serum calcium, and serum P. The results indicate that hens consuming various quantities of P (288 to 384 mg/hen/day) had similar, reduced, or increased egg specific gravities compared to that from hens receiving 714 to 819 mg P/hen/day. Hens with higher P intakes (1455 to 1710 mg/hen/day) had reduced egg specific gravity. There was no indication that P source or dietary calcium level influenced the observed response. Phosphorus intakes of 384, and 307 mg/hen/day maintained production in two experiments, but P intakes of 288, 310, 322, and 329 mg/hen/day did not in two other experiments. Although all low P treatments in which serum P was measured reduced serum P, there was little or no indication that this influenced egg specific gravity. Egg weight, feed consumption, and serum calcium varied among treatments. Results indicate that differences in ability of hens to utilize Ca from limestone vs. phosphate source or different calcium levels would not explain the variation in response to different P levels previously reported. It was concluded that until mechanisms responsible for varying responses to different P levels are known, reducing P levels to improve shell quality should be used cautiously.

The Effect of Marginal Levels of Calcium, Fish Meal, Torula Yeast and Alfalfa Meal on Feed Intake, Hepatic Lipid Accumulation, Plasma Estradiol, and Egg Shell Quality Among Laying Hens

In two 2 × 3 factorial-design experiments, Single Comb White Leghorn (SCWL) laying hens were fed either a corn-soy (CS) diet or one containing 5% each of fish meal, alfalfa meal, and torula yeast (FAY), each with 2.0, 2.75, or 3.5% calcium in Experiment 1 and 2.5, 3.5, or 4.5% in Experiment 2. Duration of the experiments were 6 and 8 weeks, respectively. Low dietary calcium resulted in decreased efficiency of energy utilization in both experiments and significantly elevated energy consumption in Experiment 2. Liver lipids and body weight were unaffected by dietary calcium level, and declines in both egg production and shell quality were observed in both studies. In Experiment 1, overall plasma estradiol and tibial bone ash were significantly reduced with lowered dietary calcium, but this was not observed in Experiment 2. Egg weight was significantly increased by decreased dietary calcium in Experiment 1. Plasma calcium was not affected by dietary calcium in either trial. Feeding FAY resulted in significantly lower liver lipid than feeding CS in both experiments, and similar but nonsignificant trends were realized for plasma estradiol. Tibial bone ash and egg-breaking strength were significantly higher for hens fed FAY in Experiment 1. In Experiment 2, plasma total calcium was lower and the percent shell was higher in hens fed FAY with 3.5% calcium than in hens fed CS with 3.5% calcium. No differences were observed between CS and FAY in feed consumption, body weight, or egg production. These studies indicate that feeding a more complex diet to laying hens may change calcium metabolism and improve shell quality at marginal levels of calcium compared with feeding a simplified CS diet.

Use of Methionine Intake Restriction to Improve Egg Shell Quality by Control of Egg Weight

The purpose of these experiments was to determine if the increase in egg weight that occurs with increasing age of hens could be reduced by the control of methionine intake to improve egg shell quality. Four methionine intakes were compared with diets in which all other nutrient intakes remained constant. Daily methionine intakes were 300, 285, 270, and 255 mg per bird. Each treatment was fed to 15 replicates of three birds each. The three-bird replicates received 300 g feed per three-hen cage per day. During Experiment 1, the diets were fed to smaller size pullets of a commercial egg strain from 38 to 62 weeks of age. In the second study, the birds were selected from the larger body size population and fed the diets from 38 to 70 weeks. This was followed by an 8-week force-molt and then continued from 78 to 102 weeks.The reduced methionine intake (255 mg in Experiment 1 and 270 and 255 mg in Experiment 2) significantly reduced the egg weight increase when compared to the 300 mg intake. The same results were obtained during the postmolt period.Egg shell quality, as measured by specific gravity, was improved in both trials when methionine intake was restricted. Shell quality of eggs produced by hens fed 255 mg daily was significantly superior to eggs produced by birds fed 300 mg. Improvement in shell quality when hens reached 50 weeks of age occurred with all treatments as compared to 300 mg. Hen-day egg production was not adversely affected.

Diallel cross of six long-term selected leghorn strains with emphasis on heterosis and reciprocal effects.

Six strains under long-term selection for egg production and other economically-important traits were crossed in a full diallel, and tested with two commercial stocks and two control strains at two stocking rates (1 bird per 20.3-cm cage and 3 birds per 30.5-cm cage) and two diets (with and without an oyster shell supplement). The mean of the 30 strain crosses exceeded the mean of the six selected strains for egg production and egg quality traits, sexual maturity and viability, which in turn exceeded the performance of both of the control strains. The performance of several of the 30 strain crosses was similar to the commercial stocks. The only significant genotype X environment interaction was for Haugh units at 450 d. Performance at the lower stocking rate was generally superior to that at the higher stocking rate. General combining ability was important for the complete array of traits measured. Specific combining ability was important for the majority of traits. Heterosis was important for all traits except specific gravity, Haugh units, blood spots and laying house viability to 272 or 496 d at the higher stocking rate. The magnitude of heterotic effects was generally greater at the higher stocking rate. Reciprocal effects were important for egg production traits, sexual maturity, egg quality traits and viability. The dietary oyster shell supplement resulted in an improvement in shell quality as measured by specific gravity.

Influence of Premolt Production on Postmolt Performance with Explanation for Improvement in Egg Production Due to Force Molting

Performance of force-molted hens as influenced by premolt production was determined in two experiments using 720 Babcock hens. Hens selected to be laying at a low (41%), average (59%), and high (75%) rate of production were divided into two groups. One half of the hens were force molted (FM) and the other half served as controls (CON). On completion of the fasting period, blood was collected for chemical analyses from 10 hens per group. These hens were then necropsied and weights of the ovary, oviduct, liver, and fat pad determined. During the last 4 weeks of the postmolt period, dietary calcium was increased from 3.5 to 4.5% in half of each group.Postmolt production was directly related to premolt production. The hens laying the highest rate premolt showed no improvement, whereas those laying at the lowest rate showed the greatest improvement. The FM hens exhibited a lower incidence of shell-less eggs than CON hens. Premolt production appeared to have little influence on postmolt egg weight, organ weights, and blood constituents. However, shell weight and egg specific gravity were significantly improved by force molting. Increasing dietary calcium had no significant influence on shell weight and specific gravity in FM hens in either experiment but significantly increased specific gravity and shell weight of CON hens during Experiment 2.It was concluded that most of the improvement in production in force-molted hens was caused by a reduction in shell-less eggs and not by an increase in ovulation. Also, only a portion of the improvement in shell quality could be explained by an increase in feed intake (calcium intake) after molting due to the increase in production. An improvement in calcium metabolism was postulated to be a major cause of improved shell quality.

Effect of gradual acclimation to high ambient temperatures on egg‐shell quality of the Sinai Bedouin fowl, the commercial white leghorn and their crossbreds

1. The effect of gradual acclimation to high ambient temperatures on egg‐shell quality was studied in the Sinai fowl, the commercial White Leghorn, and their reciprocal crossbreds. 2. The Leghorn egg was characterised by a thinner and weaker shell compared with the Sinai and the crossbreds, at all the experimental temperatures. 3. In contrast to other reports, high ambient temperatures for a long period had only mild effects on egg‐shell quality. 4. The results suggest that gradual acclimation to high ambient temperatures might improve the efficiency of the physiological mechanisms involved in the hen's response to heat. Consequently, the reproductive process adapts to the hot environmental conditions. 5. The results indicate that the Sinai breed might be used for future selection of a breed, highly resistant to extreme environmental conditions and with an improved shell quality.

Dietary Phosphorus Requirements of Force-Molted Leghorn Hens

Two studies were conducted to determine the phosphorus requirements of force-molted Leghorn hens. In the first study, diets containing .8, .6, or .4% total phosphorus and 4% calcium were fed. In the second study diets with levels of .7, .6, .5, or .4% total phosphorus and 3.8% calcium were fed.Decreasing the phosphorus level improved shell quality as measured by specific gravity and shell thickness. However, egg production and egg weight decreased as phosphorus level decreased. Thus, in these studies a total phosphorus level of >.5% and <.7% was required for egg production and egg shell quality in force-molted Leghorn hens.

Limited Access to Feed During Egg Formation and the Shell Quality of Eggs Laid in the Afternoon

The effect of limiting hens access to feed during formation of eggs laid in the afternoon on the shell quality of these eggs was examined using 225 SCWL laying hens, 50 weeks of age. The hens were housed in individual cages in an enclosed, fan-ventilated room, with lights on from 0500 to 2100 hr. Access to feed by 105 hens was progressively limited over a period of five days until feeders were covered from 0800 to 1600 hr daily. The remaining 120 hens were fed ad libitum as controls. All hens were fed a 16.0% protein laying ration containing 3.25% calcium and .53% total phosphorus. Time of lay (±15 min), egg weight, and shell quality data were collected for 12 consecutive days, beginning one week after full feed limitation.Egg specific gravity, shell thickness, and shell weight (mg) per square centimeter egg surface area were significantly greater for eggs from both feeding systems laid after 1300 hr than for eggs laid in the morning. Mean shell weight was significantly greater for eggs laid after 1300 hr than for eggs laid between 0901 and 1300 hr. Eggs laid in the early morning were the heaviest and, although mean egg weight, and hence egg surface area, progressively decreased throughout the day, the increased shell weight of eggs laid after 1300 hr was primarily responsible for the significant improvement in shell quality in eggs laid in the afternoon.

Egg Shell Quality: 1. Effect of Dietary Manipulations of Protein, Amino Acids, Energy, and Calcium in Aged Hens on Egg Weight, Shell Weight, Shell Quality, and Egg Production

Sixteen dietary treatments (including four protein, four energy, and eight calcium levels) were fed to 560 aged hens for 8 weeks in an attempt to improve shell quality by reducing egg weight without reducing shell deposition. Decreasing the dietary protein from 20 to 11.5% in isocaloric diets resulted in a decrease in egg weight, shell weight, and serum calcium. No improvement in egg specific gravity and no adverse effect on egg production and feed consumption were noted. The response of hens to the 16 or 13.5% protein diet was similar to that of the hens fed the 20% protein diet. Increasing the dietary calcium level from 3 to 4.25% did not prevent the decline in shell weight. Exaggerating the protein deficiency by increasing the dietary energy level from 2.42 to 3.30 kcal ME/g in graded increments and calcium from 2.56 to 4.94%, respectively, also did not prevent the decline in shell weight as egg weight decreased. Body weight decreased as the protein level decreased. Percent yolk increased while percent shell and albumin decreased as egg size decreased. Within 3 weeks after returning the hens to the control feed (16% protein), there was no significant difference in egg weight, shell weight, or feed consumption.It was concluded that reducing egg size by dietary manipulation of protein, amino acids, energy, and calcium also reduced shell deposition, thus preventing any improvement in shell quality; and that the dietary protein level can be reduced to as low as 11.5% in old hens for at least 1 to 2 months prior to hen disposal without any adverse affect on production.

The Effects of Dietary Phosphorus, Vitamin D3, and 25-Hydroxy Vitamin D3 Levels on Feed Intake, Productive Performance, and Egg and Shell Quality in Two Strains of Force-Molted White Leghorns

A total of 576 force-molted hens were used to investigate the effect of dietary phosphorus level, and the source and level of vitamin D3 on egg production and shell quality. The experiment was a 2 × 2 × 2 × 3 factorial design with two strains of hens, two levels of available phosphorus (.34 and .60%), and two sources of D3 (25-hydroxy vitamin D3 and vitamin D3) at three levels (8, 16, 24 μg/kg); the diets were provided ad libitum for 84 days (from 646 to 730 days of age). Egg and shell quality measurements were taken on eggs laid over a 4-day period when the hens were 727 days of age. Dietary phosphorus level, and D3 source and level had no significant (P>.05) effect on 730-day body weight, feed intake and efficiency, egg production and yield, shell weight, percent shell, shell weight per unit surface area, Haugh units, blood spots, egg specific gravity, nondestructive deformation, compression fracture force, and shell thickness. There were significant differences among strains for the aforementioned variables except feed intake, egg weight, Haugh units, and blood spot incidence. Few interactions were found between the main effects. Results indicate that no improvement in shell quality of eggs from force-molted hens was obtained by decreasing the level of phosphorus or substituting 25-hydroxy vitamin D3 for vitamin D3 in the diet.