Nonwithdrawal Molting Programs

In the commercial egg industry the management practice of using feed withdrawal to induce a flock to molt has been under extreme scrutiny. This is because animal rights groups have voiced their concern about using this practice. Thus, about 5 yr ago, the United Egg Producers (UEP) commissioned 5 universities to conduct experiments to develop alternative molting programs that used nonwithdrawal feeding programs to molt laying hens. The studies conducted to date used techniques ranging from feeding hens without added salt in the diet to using readily available, low-cost feed ingredients to develop molt diets that are low in energy level and protein content. The results of these studies indicated that molting laying hens without feed withdrawal could be done successfully. Research at the University of Illinois found that feeding laying hens diets consisting of wheat middlings, soybean hulls, and corn (low protein and low energy) were successful in providing for acceptable postmolt egg production performance and economic benefit compared with using a standard feed withdrawal method. Therefore, after 5 yr of experimenting with nonwithdrawal molting methods done in several university settings, the egg industry has successfully adopted these methods of molting laying hens. In addition, based on the finding of these experiments, the UEP has revised their recommended molting guidelines to state that only nonwithdrawal molting methods will be permitted after January 1, 2006. Thus, these guidelines will apply to approximately 82% of the US egg industry.     

Effects of Different Forced Molting Methods on Postmolt Production,Corticosterone Level,and Immune Response to Sheep Red Blood Cells in Laying Hens

The objective of this study was to evaluate the effects of different molting methods on postmolt production, plasma corticosterone levels, and antibody production to SRBC for the welfare of laying hens. This experiment was conducted with 120 IGH-type Brown laying hens (70 wk of age), randomly divided into 3 experimental groups. The hens in one group were fed a whole-grain barley diet during the first 10 d (WB diet). On d 11, hens consumed 100 g of layer diet/d until d 28. In the second group, hens were fed a Zn diet containing 10,000 mg/kg of Zn as ZnO for 10 d (Zn diet). Hens were then provided 100 g of a layer diet from d 11 to 28. In the third group, feed was withdrawn for 10 d, and on d 11 hens were fed a cracked corn diet ad libitum until d 28 (California method; CAL diet). Hens in all groups were returned to the layer diet ad libitum on d 29. Egg weight was lower in the Zn treatment than in the other treatments. Feed intake and plasma corticosterone levels were higher and antibody production was lower in the CAL treatment than in the WB and Zn groups. The FCR was better in the WB than in the Zn group. Mortality, egg production, and egg quality were not significantly different among the molting methods. As a result, the WB molting program was the best method for postmolt production among the programs examined.     

Influence of sudden changes in management program on physiological and behavioral parameters in hens

The present study was designed to test the effects of sudden changes of food access and light duration on the physiological and behavioral parameters of hens. The physiological parameters investigated were heart rate (HR), body temperature (BT), and locomotor activity (LA) using a radiotelemetry system. After implantation of the telemetry transmitters, six hens were housed individually in cages under constant environmental conditions for 10 days with a photoperiod of 15 h light (04.00–19.00 hours), and food was available ad libitum at all times. After that, the same hens were subjected to a feed withdrawal trial, from 12.00 to 08.30 hours, followed by a lighting hour reduction trial by changing the time of lights‐off from 19.00 to 14.00 hours. The physiological and behavioral data were recorded for 2 days before each trial, as control data. With the feed withdrawal trial, during the light and dark periods, HR and BT were significantly lower in the hens without food access than in the control. Whereas, LA was significantly lower only during the light period in the hens without food access than in the control. Further, the time spent resting increased significantly, but the time spent feeding decreased significantly in the hens without food access than in the control. Also, the number of times the cage was pecked and pecking of the feeder occured at a significantly higher level, while the number of times beaks were wiped occured at a significantly lower level in the hens without food access than in the control. With the lighting hour reduction trial, during the light period, HR and BT were significantly higher, whereas LA was significantly lower in the ’sudden light‐off’ treated hens than in the control. In addition, during the dark period, HR, BT and LA were significantly higher in the sudden light‐off treated hens than in the control. Moreover, in the sudden light‐off treated hens, the time spent preening and feeding decreased significantly, but the time spent resting increased significantly than in the control. It is concluded that sudden changes in a management program might result in many significant differences as were found in the physiological and behavioral parameters of hens in the present study.     

Bitter vetch as a single dietary ingredient for molt induction in laying hens

Molting is used to increase productivity in the second laying cycle of commercial laying flocks. We report here the applicability of whole grain of bitter vetch as an alternative method for molt induction in laying hens. A total of 120 laying hens were molted by feed withdrawal (FW), a high-Zn diet (HZn), a moderate-Zn and Ca-P-deficient diet (MZn-CaP), or whole grain of bitter vetch (BV). Egg production ceased first in FW-treated hens and last in MZn-CaP-treated hens (P < 0.05). The rest period was longer (P < 0.05) in hens exposed to the BV diet, which proved to be comparable with the FW treatment for postmolt egg production. Egg mass for 4 to 16 wk after the molting was greater (P < 0.05) for hens molted by BV than hens molted by the MZn-CaP diet. Egg weight and yolk color were not (P > 0.05) significantly different among various molting induction methods. Albumen height and Haugh unit of eggs from hens molted by BV, for the most part of the experimental period, were significantly (P < 0.05) greater than for birds on the MZn-CaP diet and unmolted hens. In conclusion, use of BV grain as a single dietary ingredient proved to be effective in molt induction and improving postmolt egg production and internal egg quality when compared with unmolted hens.     

Effect of induced molting on heterophil function in White Leghorn hens.

This study was undertaken to determine the effects of induced molt on basal functional activities of heterophils from aging hens. For this purpose, heterophils from both molted and unmolted hens were examined by in vitro bioassays for functional responsiveness and efficiency. We evaluated the ability of the heterophils to migrate to chemotactic stimuli, phagocytize opsonized and nonopsonized Salmonella-enteritidis (SE), and generate an oxidative burst in response to inflammatory agonists. A significant (P < 0.001) heterophilia was found in the molted hens within 2 days after feed withdrawal and remained throughout the length of the experimental feed withdrawal period. No significant differences were found in the random migration of heterophils from either group. The chemotactic movement of heterophils from molted hens was not affected until 8 days after feed withdrawal when compared with heterophil chemotaxis from unmolted hens. A significant decrease in chemotaxis by the heterophils from molted hens was observed days 8-12 after feed withdrawal (P < 0.05). Significantly (P < 0.05) fewer heterophils from molted hens were able to phagocytize opsonized (59% vs. 38%) and nonopsonized (26% vs. 15%) SE within 2 days after feed withdrawal. Likewise, significantly (P < 0.05) fewer bacteria were phagocytized per heterophil from the molted hens when compared with the number of bacteria per heterophil from the unmolted hens. The oxidative burst of heterophils stimulated by either opsonized zymosan A or phorbol myristate acetate of heterophils from molted hens was significantly (P < 0.05) reduced when compared with that generated by heterophils from the unmolted hens. These results indicate that feed withdrawal to induce molt alters the number and function of peripheral blood heterophils. This decreased efficiency of heterophil functional activity appears to play a role in the increased susceptibility of molting hens to SE infections.     

Isolation of Salmonella Organisms from Commercial Layer Houses Where the Flocks Were Molted with a Wheat Bran Diet

To develop an alternative method to feed withdrawal for molting layers, 2 flocks consisting of approximately 26,000 commercial laying hens each at 478 (68 wk, flock 1) and 466 (67 wk, flock 2) d of age were reared in an environmentally controlled windowless house and were fed wheat bran (WB) diet. Flock 1 hens were fed WB for 25 d, and flock 2 hens were fed WB for 21 d and then fed a mixture of WB and layer feed (1:1, wt:wt) for the last 4 d of the treatment. After that, the birds in both flocks were fed a normal layer feed. The photoperiod was reduced from 16 to 9 h in both flocks. Most of the birds in both flocks ceased egg production by 10 to 15 d of feeding the WB diets. Egg production in flock 1 gradually increased to 11.4% by 31 to 40 d and 71.4% by 41 to 50 d of the treatment, whereas the egg production in flock 2 hens lagged behind by almost 10 d. The mean egg production from 61 to 140 d exceeded 86% in both flocks. The houses in the farm were naturally contaminated with several serovars of Salmonella, not Enteriditis or Typhimurium. In both flocks with the WB treatment, no marked increase in Salmonella isolation from environmental samples was observed postmolt relative to premolt levels. The study demonstrated that feeding hens WB could be successfully used as an alternative to feed withdrawal to force-rest aging hens while not exacerbating a Salmonella problem in a commercial egg-production setting.     

甜菜碱预防蛋鸡脂肪肝出血综合征的研究

本试验旨在研究甜菜碱对蛋鸡脂肪肝出血综合征的预防效果。选用300日龄海蓝褐蛋鸡120只,随机分为3组,每组4个重复,每个重复10只,在自由采食、饮水和光照16 h的条件下,分别饲喂正常日粮（代谢能11.30 MJ/kg,粗蛋白质17.20%）、高能量低蛋白质日粮（代谢能12.81 MJ/kg,粗蛋白质13.04%）和添加1000 mg/kg甜菜碱的高能量低蛋白质日粮60 d。于试验期第1、30、60天,每组取8只鸡采血制备血清和采集肝脏样品及腹脂,测定血脂含量、肝脂率和腹脂率,结合产蛋性能及病理学变化,综合判定脂肪肝出血综合征(fatty liver hemorrhagic syndrome,FLHS)的发生及甜菜碱的预防效果。结果表明,与对照组相比,饲喂高能量低蛋白质日粮30 d即可引发FLHS,饲喂60 d则病情进一步加重;而在高能量低蛋白质日粮中添加1000 mg/kg甜菜碱后,饲喂30 d时甜菜碱可显著抑制FLHS的发生,具有很好的预防作用,但饲喂60 d时甜菜碱的预防作用减弱。     

Reproductive performance of first and second parity sows fed daily or every third day

Crossbred gilts were used in a two-parity experiment to measure the effect on reproductive performance of feeding every third day during gestation.Diets were formulated with maize and soybean meal to 12% and 16% crude protein for gestation and lactation, respectively. Experimental feeding regimens were imposed from an average day 30 to an average day 109 of gestation. During this period, the gravid gilts or sows housed in confinement were fed either 1.9 kg of the gestation diet daily or permitted ad libitum access to the diet for 1 day in each 3-day period. The lactation diet was provided ad libitum from farrowing until weaning at 28 days post partum. From weaning until the dietary treatments were reimposed about 30 days post-coitus, the females were fed 1.9 kg of the gestation diet per day.First-parity females fed ad libitum every third day consumed an average of 0.4 kg more feed per day than did those restricted to 1.9 kg of diet per day. There was no effect of feeding regimen on gestation weight gain or any criteria of reproductive performance, e.g. litter size or weaning weights of piglets. During the second parity, sows allowed to eat ad libitum every third day gained significantly more weight during gestation than those fed daily, reflecting an average daily feed intake that was 1.2 kg greater than that of the control animals fed 1.9 kg day^?1. Second parity reproductive performance was not affected by treatment. Backfat thickness measured at the point of the shoulder and at the last rib on day 30 and day 109 of gestation and at weaning increased during gestation and decreased during lactation regardless of feeding regimen or parity.Feeding gravid pigs every third day did not adversely affect reproductive performance; however, average daily feed intake was increased. Although the sows seemed to adapt quickly to a three-day feeding schedule, welfare aspects need to be investigated further.     

Effects of prior coinfection with different Salmonella serovars on the progression of a Salmonella enterica serovar enteritidis infection in hens undergoing induced molt

Four trials were conducted to evaluate whether prior infection with Salmonella enterica serovar typhimurium (S. typhimurium) or Salmonella enterica serovar muenchen (S. muenchen) would modify the severity or the transmission of Salmonella enterica serovar enteritidis (S. enteritidis) challenge in hens undergoing molt via feed withdrawal. Hens were separated into two groups where one group received a prior S. typhimurium or S. muenchen infection, whereas the other group remained untreated until S. enteritidis challenge. In trials 1 and 2, one group of hens was infected with S. typhimurium 5 days prior to feed withdrawal. Both groups of hens were then challenged with S. enteritidis on day 4 post feed withdrawal. In trials 3 and 4, one group of hens received S. typhimurium or S. muenchen, respectively, 1 day after feed was withdrawn. Transmission of S. enteritidis was evaluated by challenging the center hen in rows of 11 hens per row with S. enteritidis at 4 days post feed withdrawal and following the progression of the S. enteritidis down the row of hens over time. In trials 1 and 2, where hens received S. typhimurium 5 days prior to feed withdrawal, shedding of the S. enteritidis challenge was significantly reduced in hens on day 10 postchallenge in trial 1 and on days 3 and 10 postchallenge in trial 2 compared with the hens subjected only to the molt procedure. Significantly fewer S. enteritidis were recovered in livers and spleens at day 9 postchallenge in trial 2 from hens receiving the prior S. typhimurium infection. In trial 3, where hens received S. typhimurium 1 day after feed withdrawal, S. enteritidis transmission was significantly reduced in these hens on days 3, 10, and 24 postchallenge. In trial 4, similar in methodology to trial 3 except that, rather than S. typhimurium, hens received S. muenchen, a Salmonella organism totally lacking any antigen cross-reactive with S. enteritidis, S. enteritidis transmission was significantly reduced on days 3, 10, 17, and 24 postchallenge, suggesting that factors other than specific immunity were involved in the observed resistance to S. enteritidis infection. These results indicate that prior infection of a flock with a non-S. enteritidis paratyphoid Salmonella can reduce S. enteritidis problems that may occur during a molt.     

Effect of ovarian regression and molt on plasma concentrations of thymosin beta 4 in domestic hens (Gallus domesticus).

Molt induced by infusion of a gonadotropin-releasing hormone agonist (GnRH-A, ([D-leu⁶, Pro⁹]-GnRH N-ethylamide]) or feed withdrawal (FW) has been used as a model to study interactions between ovarian activity and thymosin β₄ during molting in domestic hens. Thirty-three laying hens were divided into three groups: 1, controls, 2, GnRH-A infusion induced molt (GnRH-A), or 3, FW induced molt. All groups had reduced daylength. Blood was sampled weekly and assayed for concentrations of thymosin β₄ and progesterone (P₄). Plasma P₄ concentrations were significantly depressed in both treatment groups compared to controls, indicating ovarian regression. Plasma P₄ concentrations had returned to control values in the GnRH-A group by 28 d after the start of treatment, while P₄ was still depressed in the FW group at day 42 when the experiment ended. Plasma concentrations of thymosinβ₄ were elevated relative to controls from day 7 through day 14 in the GnRH-A group and from day 7 until day 28 in the FW group. It is concluded that plasma concentrations of thymosin β₄ are elevated during molting in domestic hens, but the elevation is not attributable to depressed P₄ concentrations.     

The Effect on Postmolt Performance of Different Crude Protein and Energy Levels During a Full-Fed Molt Procedure

There is a need to evaluate the different dietary levels of CP and ME needed by the hen and the time sequence during the molt period to feed these levels to simulate a molt similar to that of nature by utilizing full feeding molting procedures. This study was undertaken to determine that nutritional sequence information. The 4-d feed withdrawal molt procedure being used commercially was used to compare the effects of the 3 procedures studied. Very low levels of CP and ME (9.72% CP and 1,103 kcal or 9.72% CP and 1,433 kcal) were fed for 2, 3, and 4 wk to mimic the levels of nutrients consumed by hens during the first 4 wk of the 4-d molt procedure. The equivalent of zero egg production (≤0.3%) was achieved during wk 2, 3, and 4 of the study (postmolt initiation). The hens achieved 50% production during wk 7 postmolt and peak production, 6 to 8 points below the first cycle, occurred during wk 11 of the study. Body weight reduction ranged from 20 to 29%. The lowest energy level fed for 4 wk was not a desirable molting procedure. Full-fed molting procedures resulted in a significant but acceptable increase in cost of feed over the 4-d procedure.     

Effects of an 'enrichment feeder' on behavior and feather conditions of caged laying hens

The objective of this study was to compare the behaviors and feather conditions of caged laying hens fed by two different types of feeders. Seven tennis balls were placed on the feed trough to hide the feed for each of 6 experimental cages (treatment B). The same feed troughs without balls were used for 6 control cages (treatment NB). Forty-eight commercial white leghorn type hens were housed as 4 birds per cage (474 cm² per bird). The experimental period was from 22 to 32 weeks of age. At 28 weeks of age, the hens spent more time feeding in treatment NB (35%) than in B (27%). On the other hand, prefeeding behavior (extension of the neck over the trough or pecking at the balls) occupied more time in B (14%) than in NB (6%). The birds in B spent more time thrusting (thrusting other birds aside and trying to eat) than did the birds in NB (2 vs 0%). At 32 weeks of age, the mean proportion of hens feeding and prefeeding behavior in both treatments was similar to those at 28 weeks of age; however, differences of the behavior between the B and NB were relatively small. Feather damage on a scale of 0 (no damage) to 15 (denuded) increased with age, and the scores in B were less than those in NB at 27 weeks (0.75 vs 1.37), although not at 32 weeks. Egg production in the two treatments was the same, and the type of feeder used did not affect body weight. This device might provide hens with a more attractive environment than the conventional feeders; however, the enrichment feeder might need more improvement for the welfare of caged laying hens.     

Comparison of Salmonella enterica serovar enteritidis levels in crops of fed or fasted infected hens

Long-term feed withdrawal has been shown to increase ileocecal intestinal colonization and fecal shedding of Salmonella enterica serovar Enteritidis in challenged hens. Less information is available regarding effects of fasting on crop colonization. Two trials were conducted to compare effects of 14-day feed withdrawal vs. full feed on crop colonization in hens challenged with Salmonella Enteritidis. The levels of Salmonella Enteritidis in the crops of fasted hens were significantly higher than in nonfasted hens on days 3 and 10 and days 3, 9, and 16 postinfection (PI) in trials 1 and 2, respectively. Fecal shedding of Salmonella Enteritidis was significantly increased in the fasted hens on day 10 PI in trial 1. Analysis of crop IgA anti-Salmonella Enteritidis lipopolysaccharide levels in crop lavage samples of hens in trial 1 revealed a humoral response PI in both treatment groups with no significant differences, although peak response for fasted hens occurred 1 wk later. Histologic evaluation of hematoxylin and eosin-stained crop sections from trial 1 birds revealed mild to moderate heterophilic infiltration within the crop lamina propria (LP) or LP and epithelium of nonfasted infected hens at 24 and 96 hr PI. In comparison, heterophils in crops of fasted hens infected at this time point were sparse, indicating a possible diminished heterophil response in the fasted birds. Multifocal areas of tissue inflammation, as indicated by marked heterophil infiltration, with necrosis and sloughing of epithelium, were observed in crops from fasted hens at day 11 PI (14th day of feed withdrawal) but not in the fed groups. This severe heterophilic inflammation was observed in both challenged and nonchallenged fasted hens, suggesting that some factor other than Salmonella Enteritidis was responsible. These results indicate that feed withdrawal can have a dramatic effect on the integrity of the crop and its ultimate response to infection.     

Amino acid nutrition in egg production industry

The egg production industry is facing various problems that need to be solved. For amino acid nutrition to achieve scientific and economical feeding of laying hens, it is necessary to elucidate the content, digestibility, or availability of nutrients of feedstuffs and feeds and the requirement of amino acids for laying hens. In addition, improvement to quality of eggs and meat of spent hens, methods of management and development of new feedstuffs are essential. For sustainable animal production, decrease in excreta and animal welfare should be studied. The real‐time determination of content and digestibility of amino acids in feedstuffs are essential for formation of feeds. Recent advances in the near infrared reflectance analysis will be able to determine the content, digestibility and availability of nutrients in feedstuffs and feeds, if we have a supplemental amount of conventional analysis to define the calibration population. The amino acid requirements are affected by various factors. Therefore the method to quickly and exactly determine amino acid requirements in response to various factors is necessary. By using plasma free amino acid concentration as a criterion, it is possible to determine amino acid requirements in various conditions of laying hens within a short experimental period, repeatedly using the same animals. Because the amino acid requirements differ among individual animals, it should be expressed as grams per hen per day. Practically, it is impossible to formulate various feeds for individual hens. The various expressions have been developed and these expressions have advantages and disadvantages. The nitrogen excretion of laying hens is easily reduced by reducing dietary nitrogen levels and restricting the feed intake. The availability of amino acid may be improved by feeding management, and supplementing enzyme, but the quality of eggs and meat of spent hens and welfare of laying hens are not affected by amino acid nutrition.     

日粮中长期添加大豆黄酮对产蛋鸡产蛋性能及有关内分泌的影响

试验旨在探讨日粮中长期添加大豆黄酮对产蛋高峰期蛋鸡采食和生产性能的影响及有关内分泌机制。40羽180日龄产蛋鸡,均分为2组,对照组饲喂基础日粮,试验组饲喂基础日粮+大豆黄酮(6mg/kg),试验期为150d。结果显示:试验组蛋鸡采食量、产蛋率、只日蛋重、每枚蛋重均显著提高,料蛋比显著下降;血清17β-雌二醇、T3、T4水平均显著提高,而血清瘦素(leptin)水平有下降的趋势。试验结果表明,大豆黄酮可调控血液激素水平而提高产蛋鸡生产性能,并使产蛋高峰期得到延长。     

强制换羽对鸡产蛋性能及某些生化指标的影响

实验用480日龄白米航母鸡110只,随机分为断食组、加锌组和对照组。断食组停料13d,停水3d强制换羽;加锌组饲喂高锌日粮(2％)13d强制换羽,观察两种方法对母鸡的产蛋性能及血浆某些生化指标的影响。结果,强制换羽后,断食组和加锌组产蛋率高于对照组;断食组又高于加锌组;断食或加锌期间,两组血浆的孕酮含量均降低,甲状腺素(T_4)含量升高,三碘甲腺原氨酸(T_3)含量先降低而后明显升高,钙含量降低;加锌组血浆白蛋白含量低于断食组,而血浆尿素氮含量高于断食组。     

Biofortification of hens’ eggs with microelements by innovative bio‐based dietary supplement

New bio‐based dietary supplement with micronutrients for livestock was elaborated. The new preparation was tested on laying hens to determine the influence of new biological feed additives on the level of trace elements in egg content. The diet of laying hens (Hy‐Line Brown, 30 weeks of age) was supplemented with soya bean meal enriched with Cu(II), Zn(II), Fe(II) and Cr(III) by biosorption. A total of 150 laying hens were divided into five groups: one control and four experimental. In the control group, microelements were supplemented in the inorganic form, whereas in experimental groups, Cu, Zn, Fe and Cr were replaced with soya bean meal enriched with a given microelement ion. The feeding experiment was conducted for 12 weeks and was divided into three series. The results showed that adding the new feed additives to the diet of laying hens had an impact on microelement transfer to eggs, in particular with increased dosing. Eggs were biofortified with iron, zinc and copper and to a lesser extent with chromium. The microelements were accumulated primarily in the albumen because soy protein was the carrier of micronutrient ions in hens’ diet. Transfer of trace elements to eggs was not linearly dependent on the dosage of biologically bound microelements in the diet.     

发酵饲料对海兰褐蛋鸡生产性能及蛋品质的影响

旨在研究发酵饲料对海兰褐蛋鸡生产性能及蛋品质的影响。以玉米和豆粕为发酵底物,利用乳酸菌和酿酒酵母菌进行发酵。选取336日龄的海兰褐蛋鸡600只,随机分为4组,每组150只,3个重复,每个重复50只。试验Ⅰ、Ⅱ、Ⅲ组的基础日粮中分别添加3%、5%、8%的发酵饲料,对照组基础日粮中不添加发酵饲料。饲喂试验周期为4周,期间测定各组蛋鸡的生产性能及蛋品质相关指标。结果表明,基础日粮中添加不同比例的发酵饲料,均可在一定程度上改善蛋鸡的生产性能和蛋品质,其中：饲喂发酵饲料第2周,试验Ⅱ组的产蛋数与对照组相比显著（P<0.05）增加;饲喂发酵饲料第3周,试验Ⅱ组的产蛋数和总蛋重与对照组相比均显著（P<0.05）提高;饲喂发酵饲料4周后,试验Ⅱ组的产蛋数、总蛋重、产蛋率与对照组相比均显著（P<0.05）提高,并且料蛋比显著（P<0.05）下降;试验Ⅱ组的蛋壳强度显著（P<0.05）高于对照组;试验Ⅱ组和Ⅲ组的哈氏单位显著（P<0.05）高于对照组。综上提示,在基础日粮中添加不同比例的发酵饲料,可在一定程度上提高海兰褐蛋鸡的生产性能及蛋品质,其中,5%添加水平的效果最佳。     

Alterations in lycopene concentration and Z‐isomer content in egg yolk of hens fed all‐E‐isomer‐rich and Z‐isomer‐rich lycopene

Effects of feeding lycopene isomers to laying hens on egg qualities such as lycopene concentration and color of the yolk were investigated. Firstly, to evaluate the dietary transfer of lycopene to egg yolk, (all‐E)‐lycopene–rich diets (lycopene content, 100, 200, or 300 mg/kg diet) were fed to hens for 21 days. Lycopene in egg yolk could be detected after 4 days or more from the start of feeding, and the lycopene concentration increased according to the feed amount and period. Even though most of the dietary lycopene was the all‐E‐isomer, more than 65% of lycopene in egg yolk was present as Z‐isomers. Thus, the effect of lycopene Z‐isomer content in the diet (lycopene content, 200 mg/kg diet; lycopene Z‐isomer content, 35.1% or 61.3%) on egg qualities was investigated. As the Z‐isomer content increased, the lycopene concentration in the egg yolk increased, for example, when fed a diet rich in Z‐isomers (61.3%), the lycopene concentration in the egg yolk was approximately three times higher than when fed the (all‐E)‐lycopene–rich diet for 21 days. The results indicated that Z‐isomers of lycopene had higher bioavailability and/or higher transfer efficiency to the egg yolk than the all‐E‐isomer.