Circadian rhythms and dynamic dietary calcium feeding affect laying performance,calcium and phosphorus levels in laying hens

This study was conducted to determine the effects of dynamic feeding low and high Ca in layer diets on laying performance, calcium, and phosphate concentration in both serum and tibia. 180 Brown Hy-line, 41 weeks old of laying hens were randomly distributed into 3 groups with 6 replicates and each replicate was 10 birds. During the 10-week experiment period, control group (CON group) received control diet (contained 3.4% Ca) at both 0730 and 1530 h, low–high group (LH group) received low Ca diet (contained 3.2% Ca) at 0730 h and high Ca diet (contained 3.6% Ca) at 1530 h, while high–low group (HL group) received the contrary to the LH group. Blood and tibia samples were collected at 4 h intervals. The dynamic Ca feeding schedule exerted significant effects on Ca intake in the morning and afternoon, also on feed conversion ratio (FCR) of the HL group comparing to the LH group (p<0.05). Serum Ca in the LH group were lower at 0000, 0400 and 1600 h comparing with the CON group (p < 0.05), and serum Ca: P ratio values in the LH group were lower at 0000, 0800, and 2000 h comparing with the CON group (p<0.05). These results indicated that dynamic feeding Ca improved FCR and affected the circadian variation of serum Ca concentration in laying hens.     

Impact of an energy- and nutrient-reduced diet containing 10% lignocellulose on animal performance,body composition and egg quality of dual purpose laying hens

In response to ethical concerns regarding the killing of day-old male chicks of layer breeds, the use of dual purpose chickens is increasingly discussed in public while data on nutritional requirements of dual purpose laying hens are not available. The present study examined the impact of an energy- and nutrient-reduced diet containing lignocellulose on performance, body composition and egg quality of dual purpose hens. Female Lohmann Dual chicks were allocated to 12 pens and fed two different diets for 52 weeks: a control (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose. During the trial, animal performance, whole-body composition and egg quality parameters of hens were consistently ascertained. The results showed that LC-fed hens had lower body weights compared to those receiving CON (p < 0.05). During the laying period, feed intake was increased in LC-fed hens (p < 0.001). LC-fed hens showed a higher egg production and egg mass resulting in an improved feed efficiency (p < 0.05) and laid smaller eggs compared to CON-fed hens (p < 0.001). At 52 weeks of age, bodies of LC-fed hens had higher protein and lower fat contents than those fed with CON diet (p ≤ 0.001). Mean body weight was positively correlated to the body fat content (p = 0.004) and body fat content was negatively correlated to the egg production (p = 0.043). Analyses of the egg quality showed that yolk mass at all sampling points and albumen mass at 27 and 42 weeks were lower in hens fed with diet LC compared to those fed with diet CON (p< 0.05). In conclusion, the feeding of energy- and nutrient-reduced diets containing 10% lignocellulose reduced the body fat content and simultaneously improved the laying performance in dual purpose hens.     

Effects of Increasing Supplementation of Magnesium in Diets on Productive Performance and Eggshell Quality of Aged Laying Hens

Magnesium (Mg) concentrations in diets have been associated with performance and eggshell quality of laying hens, but the results have been inconclusive. In this experiment, the effects of increasing concentrations of dietary Mg on productive performance and eggshell quality of aged laying hens were evaluated. A total of 640 Hy-Line Brown laying hens of 72 weeks of age were randomly allotted to one of four dietary treatments with four replicates per treatment. A commercial-type basal diet containing 1.6 g/kg Mg was prepared, and three additional diets were prepared to contain 2.3, 2.6, or 3.0 g/kg Mg in diets by adding 1.0, 1.5, or 2.0 g of MgO to the basal diet. The diets were fed to hens ad libitum for 5 weeks. Results indicated that Mg concentrations in eggshells were increased (linear, P?<?0.01) with increasing concentrations of Mg in diets. Increasing concentrations of Mg in diets decreased (linear and quadratic, P?<?0.01) broken and shell-less egg production, but improved (linear, P?<?0.05) eggshell strength. Feed intake was decreased (linear, P?<?0.05) with the concentrations of Mg in diets, but hen-day egg production, egg weight, feed conversion ratio, and Haugh unit were not affected by increasing concentrations of Mg in diets. Hunter L* and a* values of eggshell were decreased (linear, P?<?0.05) as the concentrations of Mg in diets increased. In conclusion, feeding aged laying hens with diets containing increasing concentrations of Mg up to 3.0 g/kg improves eggshell strength, but has no detrimental effects on laying performance.     

Phase resetting of circadian peripheral clocks using human and rodent diets in mouse models of type 2 diabetes and chronic kidney disease

The expression rhythms of clock genes, such as Per1, Per2, Bmal1, and Rev-erb α, in mouse peripheral clocks, are entrained by a scheduled feeding paradigm. In terms of food composition, a carbohydrate-containing diet is reported to cause strong entrainment through insulin secretion. However, it is unknown whether human diets entrain peripheral circadian clocks. In this study, we used freeze-dried diets for type 2 diabetes (DB) and chronic kidney disease (CKD), as well as low-carbohydrate diets. After 24 h of fasting, PER2::LUC knock-in mice were given access to food for 2 days during inactive periods, and bioluminescence rhythm was then measured using an in vivo imaging system. AIN-93M, the control mouse diet with a protein:fat:carbohydrate (PFC) ratio of 14.7:9.5:75.8, caused a significant phase advance (7.3 h) in the liver clock compared with that in 24 h fasted mice, whereas human diets caused significant but smaller phase advances (4.7–6.2 h). Compared with healthy and high fat/sucrose-induced DB mice, adenine-induced CKD mice showed attenuation of a phase-advance with a normal diet. There were no significant differences in phase-advance values between human diets (normal, DB, and CKD). In addition, a normal-carbohydrate diet (PFC ratio of 20.3:23.3:56.4) and a low-carbohydrate diet (PFC ratio of 36.4:42.9:20.7) caused similar phase advances in peripheral clocks. The present results strongly suggest that scheduled feeding with human diets can cause phase advances in the peripheral clocks of not only healthy, but also DB and CKD mice. This discovery provides support to the food-induced entrainment of peripheral clocks in human clinical trials.     

Effects of Enterococcus faecalis on egg production,egg quality and caecal microbiota of hens during the late laying period

This study was conducted to determine the effects of diet supplementation of laying hens with Enterococcus faecalis (EF) on egg production, egg quality and caecal microbiota. A total of 360 Hy-Line Brown laying hens (72 weeks old) were divided into three groups with four replicates of 30 birds each. The laying hens were fed with the basal diet (Control), the basal diet + 3.75 · 10⁸ cfu EF/kg (Group I) or the basal diet + 7.5 · 10⁸ cfu EF/kg (Group II). The experiment lasted for 45 d. Eggs and caecal samples were collected at the end of the experiment. Results showed that dietary supplementation with EF did not affect the average daily egg weight, cracked egg rate, mortality and egg quality. However, EF supplementation caused a significantly increased laying rate and decreased feed/egg ratio (p < 0.05). The differences in caecal microbiota between Group II and the Control were significant. The relative abundance of Verrucomicrobia and Cyanobacteria at the phylum level, Rikenellaceae, Christensenellaceae and Veillonellaceae at the family level, and the Faecalibacterium, Christensenellaceae R-7 group and Eubacterium coprostanoligenes group at the genus level changed significantly in Group II compared with the Control (p < 0.05). In conclusion, the tested dietary supplementations with EF improved product performance and affected the caecal microbial community structure of laying hens during the late laying period.     

Effects of iron status on expression of circadian clock genes and serum lipid metabolism in sucking piglets

The aim of the study is to determine the effects of iron on circadian clock gene expression and serum lipid metabolism in sucking piglets. Twenty-four neonatal piglets were selected and randomly assigned into three groups (A, B, and C) with eight replicates. Group A were received 1 mL physiological saline by intramuscular administration at d 3 and d 10; group B were received 1 mL iron dextran (100 mg) by intramuscular administration at d 3 and 1 mL physiological saline at d 10, respectively; group C were received 1 mL of iron dextran (100 mg) by intramuscular administration at both d 3 and d 10. Our results reveal that the relative expressions of Cry1, Cry2, Per1, Per2, and Bmal in liver were significantly different in the three groups (p < 0.05). Meanwhile, the content of triglyceride (TG) and high-density lipoprotein (HDL) in serum were also affected by the iron supplementation (p < 0.05). These results indicated that iron affected hepatic circadian clock genes significantly, meanwhile, it may possible association with lipid metabolism.     

Effects of feeding deoxynivalenol (DON)-contaminated wheat to laying hens and roosters of different genetic background on the reproductive performance and health of the newly hatched chicks

A total of 216 23-week-old laying hens from two different genetic backgrounds (half of the birds were Lohmann brown [LB] and [LSL] hens, respectively) and 24 adult roosters were assigned to a feeding trial to study the effect of increasing concentrations of deoxynivalenol (DON) in the diet (0, 5, 10 mg/kg) on the reproductive performance of hens and roosters, and the health of the newly hatched chicks. Hatchability was adversely affected by the presence of DON in LB hens’ diet, while the hatchability of the LSL chicks was significantly higher than LB chicks. An interaction effect between DON in the hens’ diet and the breed was noticed on fertility, as the fertility was decreased in the eggs of LB hens receiving 10 mg/kg DON in their diet and increased in the eggs of LSL hens fed 10 mg/kg DON. Moreover, spleen relative weight was significantly decreased in the chicks hatched from eggs of hens fed contaminated diets, while gizzard relative weight was significantly decreased in LB chicks with 10 mg/kg DON in their diet compared with the control group. On the other hand, the chicks’ haematology and organ histopathology were not affected by the dietary treatment. Additionally, the presence of DON in the roosters’ diet had no effect on fertility (the percentage of fertile eggs of all laid eggs). Consequently, the current results indicate a negative impact of DON in LB hens’ diet on fertility and hatchability, indicating that the breed of the hens seems to be an additional factor influencing the effect of DON on reproductive performance of the laying hens.     

Influence of feeding a fish oil-containing diet to young,lean, adult dogs: effects on lipid metabolites,postprandial glycaemia and body weight

The aim of this study was to determine the effect of feeding a fish oil (FO)-containing diet on lipid and protein metabolism, postprandial glycaemia and body weight in young, lean, adult dogs. Eight female Beagles were randomly assigned to one of two isonitrogenous and isoenergetic diets, Control or FO, in a crossover design. At the beginning of the experiment and at 30 and 60 d, a baseline blood sample was collected and the dogs then were fed their daily ration. Nitrogen balance began at 07:00 h on day 63 of each experimental period and ended at 07:00 h on day 69. On day 66 of each period, a single dose (7.5 mg/kg) of ¹⁵N-glycine was administered orally to each dog via gelatin capsule. Postprandial glycaemia did not differ between treatments or among sampling days within treatment. Cholesterol concentration was increased (p < 0.05) on the Control treatment throughout the experiment when compared to values of day 0. Dogs fed the FO treatment had higher plasma triglyceride and ghrelin concentrations than those fed the Control treatment. Body weight and food intake did not differ between dietary treatments. Faecal excretion was increased (p < 0.05) in the FO treatment. Dry matter digestibility was decreased (p < 0.05) and fat digestibility tended (p < 0.10) to decrease in the FO treatment. Overall, feeding a FO-containing diet showed a protective effect against the rise of plasma cholesterol and it increased plasma ghrelin concentration. However, FO supplementation did not appear to affect protein metabolism or postprandial glycaemia in adult lean dogs.     

The effect of dietary methionine levels on fattening performance and selected blood and tissue parameters of turkeys

A total of 490 eight-week-old female Hybrid Converter turkeys (body weight 4.11 ± 0.03 kg) were divided into 5 groups with 7 replicates of 14 birds each. For 8 weeks, basal diets were supplemented with methionine (Met) at following levels (weeks 9–12/weeks 13–16 of age): Group 1 – 0.34/0.29%, Group 2 – 0.39/0.34%, Groups 3 and 4 – 0.45/0.38% and 0.51/0.41%, respectively, Group 5 – 0.58/0.47%. Only in the first feeding phase the body weight gain (BWG) was affected by Met levels with the significantly highest BWG in Group 3. No treatment effects were found for feed conversion ratio, carcass yield, carcass composition and meat colour. The blood superoxide dismutase activity was significantly highest in Groups 2 and 3. The concentrations of reduced glutathione in the liver were linearly increased (p = 0.018), whereas the ratio of reduced glutathione to oxidised glutathione was highest in Group 3 (quadratic contrast, p = 0.004). It can be concluded that turkeys from Group 3 (Met levels age depending 15% and 10% above recommendations by NRC) were characterised by a well-balanced physiological response. Attention should be paid to the immune response of birds to higher dietary Met levels: plasma IgA concentrations decreased, whereas IL-6 and TNF-α levels increased in turkeys fed diets with the highest Met content.     

A diet containing native or fermented wheat bran does not interfere with natural microbiota of laying hens

Wheat bran (WB) is an important side product of the milling industry and can serve as dietary fiber compound for monogastric animals. The aim of this study was to evaluate the influence of native or fermented WB on the gut physiology and microbiology of laying hens. To accomplish this, 24 laying hens were fed the following diets: conventional diet without WB; 15% native WB in the diet; 15% WB fermented with Pleurotus eryngii; and 15% WB fermented with P. eryngii and a lactic acid bacterial culture. Immediately after slaughtering, digesta samples were taken from the jejunum, ileum and cecum, respectively. Total DNA was extracted and subsequently investigated with 16S DNA amplicon sequencing. Neither native nor fermented WB supplementations negatively affected the feed conversion ratio, laying performance or the relative abundances and alpha-diversity of microbiota in the intestine. Effects of WB-based diets on gut morphology were only recognized in the jejunum (reduced villum height and mucosa thickness). Likewise, WB supplementation decreased the digestibility of DM and starch. Based on these findings, it was demonstrated that different WB variants are applicable without exerting practically negative consequences on performance or on gut microbiota. Fermentation improved the digestibility/retention of dietary fat and phosphorus. However, no further beneficial effects were observed. This study also allowed a more in-depth view on the laying hens’ gut microbiome and its variation within the gut segments.     

Effects of various LED light spectra on circadian rhythm during starvation in the olive flounder (Paralichthys olivaceus)

In aquaculture, feeding is essential for the maintenance of metabolic processes and homoeostasis of fish. However, fasting acts as a stressor. In this study, we investigated the effect of circadian rhythm under various LED wavelengths [blue (460 nm), green (520 nm) and red (630 nm)] and two light intensities (0.3 and 0.6 W m^?2) over a 9-days period in the olive flounder (Paralichthys olivaceus). We analysed clock genes like period 2 (Per 2) and cryptochrome 1 (Cry 1), and serotonin and arylalkylamine-N-acetyltransferase 2 (AANAT 2), which control circadian rhythms. Per 2, Cry 1, serotonin and AANAT 2 were significantly decreased during the starvation period compared to the normal feeding group. Nevertheless, their levels increased in the groups exposed to green- and blue LED light during the experimental period. These results confirmed that green and blue wavelengths are effective in maintaining the circadian rhythm in olive flounder.     

Interactions of flavin containing monooxygenase 3 (FMO3) genotype and feeding of choline and rapeseed cake on the trimethylamine (TMA) content in egg yolks of laying hens

To evaluate the relationship between the FMO3 genotype and dietary trimethylamine (TMA) precursors on TMA-N content in eggs, laying hens were fed with choline (500 and 4000 mg/kg diet) and, in a later trial, with rapeseed cake (0, 100 and 300 g/kg diet). Hens were genotyped for non-synonymous A/T polymorphism at position nt1034 of the cDNA of the FMO3 gene, which is associated with elevated TMA-levels in egg yolks. Genotypes were equally distributed among the experimental diets. TMA was extracted from yolks and measured as TMA-N by a colorimetric method. As expected, hens of the TT-genotype had high amounts of TMA-N in egg yolks when fed either 4000 mg choline/kg diet or the rapeseed cake diet, while hens of the AA-genotype showed low levels of TMA-N. Heterozygous AT-hens had a slightly increased level of TMA-N when fed with 4000 mg choline/kg diet but not with the rapeseed cake feed. Rapeseed cake can be fed to AA and AT hens without leading to fishy tainted eggs.     

Circadian rhythm gene expression and daily melatonin levels vary in athletes and sedentary males

The circadian rhythm is a 24-h cycle in which cells control metabolic and physiological processes throughout the day. In this study, we compared the expression patterns of major circadian rhythm-related genes: from blood of Bmal1, Ror-α, Cry1, Per2, Per1, and Nr1d1. In addition, changes in patterns of melatonin levels were observed in 16 subjects, eight males rugby players and eight males who did not exercise regularly. Blood was collected at 6:00, 10:00, 18:00, and 22:00. Bmal1, Ror-α, Cry1, Per2 (p < 0.001), Per1 (p < 0.01), and Nr1d1 (p < 0.05) genes related to circadian rhythm was higher in rugby players than in sedentary males. However, melatonin levels were higher in sedentary males than in rugby players (p < 0.05). These results indicate that long-term exercise in athletes can increase the expression of genes related to circadian rhythm and these may have an effect on daily melatonin levels as well.     

Investigations on the effects of rape oil quality,choline and methionine concentration in diets for laying hens on the trimethylamine content of the eggs,on trimethylamine metabolism and on laying performance

Abstract

An experiment was conducted to study the effects of graded levels of choline addition (0, 500, 1000 and 4000 mg/kg diet) in laying hen diets prepared either with degummed or refined rape oil on the performance, sensory properties and trimethylamine (TMA) contents of the eggs. Furthermore, the diets containing no supplemented choline or 4000 mg choline/kg diet were tested with adequate or inadequate methionine supply (4.2 vs. 2.8 g methionine/kg diet). TMA metabolism and N-balance were measured for the latter diet types, but only with the diets containing refined rape oil. Therefore, a total of 12 and 4 diets were tested in the feeding (n = 60) and balance study (n = 9). Laying performance (23 – 75 weeks of age) was not significantly influenced by increasing choline additions with the exception of feed-to-egg mass ratio which decreased significantly linearly (p _linear = 0.003). However, a significant interaction between choline addition and laying month was detected which was caused by a depression of performance of the unsupplemented control group occurring from the sixth laying month. The most obvious effect of an inadequate methionine supply was a temporary drop in performance between the third and sixth laying months. The mean TMA-concentration in pooled egg yolks [μg/g] increased with dietary choline concentration [mg/kg] in an exponentially related fashion (y = 1.14 + 4E^?10 ? x^2.71, r² = 0.962) and suggested only a minor influence of total dietary choline on TMA content up to approximately 2000 mg choline/kg. Individual TMA-concentrations varied greatly from 0.4 – 1.5 μg/g, from 2.2 – 34 μg/g and from 18.4 – 75 μg/g for eggs with a normal, aberrant and heavily aberrant odour, respectively. It is concluded that a total choline concentration of at least approximately 1500 mg/kg is necessary to maintain a maximal laying performance. An inadequate methionine supply cannot be compensated by an increased addition of choline. Neither degummed nor refined rape oil influenced the TMA content of eggs.     

Amino acid digestibility of different rye genotypes in caecectomised laying hens

This study investigated the variability of amino acid (AA) digestibility of rye grains in laying hens. Relationships between AA digestibility and physical properties (thousand seed weight, test weight, falling number, and extract viscoelasticity), chemical composition (proximate nutrients, non-starch polysaccharides, AA, minerals, and inositol phosphates), gross energy concentration, and in vitro solubility of nitrogen (N) of the grains were also examined. Twenty rye genotypes were grown under standardised agronomic and environmental conditions as part of a collaborative research project known as “GrainUp”. Each genotype was added to a basal diet at 500 g/kg at the expense of maize starch to produce 20 rye diets. The experimental design comprised four Latin Squares (6 × 6) distributed over two runs, resulting in 12 experimental periods. Caecectomised laying hens (LSL-Classic) were individually kept in metabolism cages. Excreta were collected quantitatively for 4 d, and AA digestibility of the rye genotypes was determined using a regression approach. The digestibility of AA was generally low but varied significantly among the 20 rye genotypes, especially for Lys (digestibility range 35–59%), Met (57–75%), Thr (34–54%), and Trp (36–71%). Nevertheless, physical and chemical characteristics as well as the in vitro solubility of N correlated in only a few cases with AA digestibility. Multiple linear regression was used to calculate equations to predict AA digestibility based on the analysed characteristics. However, their explanatory power, as judged by the adjusted R², was not sufficiently precise for practical application (below 0.6 for most AA). In conclusion, the AA digestibility of rye grain is generally low and varies significantly between crop genotypes. Equations based on its physical and chemical characteristics are not sufficiently precise to be useful for feed formulation.     

Effect of Selenium from Selenium-Enriched Kale Sprout Versus Other Selenium Sources on Productivity and Selenium Concentrations in Egg and Tissue of Laying Hens

A 6-week trial was conducted to compare the effect of selenium (Se) from hydroponically produced Se-enriched kale sprout (HPSeKS), sodium selenite (SS), and Se-enriched yeast (SeY) in laying hens. A total of 144 40-week-old hens were randomly divided into four groups, according to a completely randomized design. Each group consisted of four replicates with nine hens per replicate. The dietary treatments were T1 (basal diet) and T2, T3, and T4 (basal diets supplemented with 0.30 mg Se/kg from SS, SeY, and HPSeKS, respectively). Results showed that Se supplement did not affect (p > 0.05) productivity and egg quality. Hens fed Se from HPSeKS and SeY exhibited higher (p < 0.05) Se bioavailability than hens fed Se from SS. Whole egg Se concentration of hens fed Se from HPSeKS was similar (p > 0.05) to that of hens fed Se from SeY, but higher (p < 0.05) than that of hens fed Se from SS. However, the breast muscle and heart tissue Se concentrations of hens fed Se from SS, SeY, and HPSeKS were not different (p > 0.05). The results of this trial demonstrated that Se from HPSeKS and SeY was more efficient than Se from SS on Se bioavailability and whole egg Se concentration in laying hens.     

Antioxidant properties of chromium and zinc

The effects of chromium (chromium picolinate, CrPic) and zinc (ZnSO₄H₂O) supplementation on serum concentrations of malondialdehyde (MDA) (an indicator of lipid peroxidation) and serum status of some antioxidant vitamins and minerals of laying hens (Hy-Line) reared at a low ambient temperature (6.8°C) were evaluated. One hundred twenty laying hens (Hy-Line; 32 wk old) were divided into 4 groups, 30 hens per group. The hens were fed either a basal diet or the basal diet supplemented with either 0.4 mg Cr/kg of diet, 30 mg Zn/kg of diet, or 0.4 mg Cr plus 30 mg Zn/kg of diet. Digestibility of nutrients (dry matter [DM], organic matter [OM], crude protein [CP], and ether extract [EE]) increased by supplementation of chromium and zinc (p<0.05). Supplemental chromium and zinc increased serum vitamins C and E but decreased MDA concentrations (p<0.05). Additionally, supplemental chromium and zinc caused an increase in the serum concentrations of Fe, Zn, Mn, and Cr (p < 0.05). The present study showed that low ambient temperature causes detrimental effects on the digestibility of nutrients and antioxidant status and that such detrimental effects caused by low ambient temperature can be alleviated by chromium and zinc supplementation, particularly when Cr and Zn were simultaneously included into the diet. Data obtained in the present study suggest that such supplementation can be considered as a protective management practice in a diet of laying hens for alleviating negative effects of cold stress.     

Effects of feeding transgenic corn with mCry1Ac or maroACC gene to laying hens for 12 weeks on growth,egg quality and organ health

The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn–soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar to that of laying hens fed diets formulated with the non-transgenic near-isoline corn with comparable genetic backgrounds.