The potential of lemon peel powder as an additive in layer quails (Coturnix coturnix Japonica): An experimental study.

The current research intended to examine the impact of dietary lemon peel powder (LPP) on laying quail performance, egg quality criteria, and the antioxidant capacity of the yolk. A total of 120 female Japanese quails (272.6±9.3 g), aged 21 weeks, were allotted to 6 trial groups, each with 5 replicates of 4 quails. Additions of 0, 1, 2, 3, 4, or 5 g/kg of LPP to the basal diet were used to create the treatment groups. Quails were fed ad libitum for 70 days. Neither performance parameters nor egg production was affected by LPP. However, eggshell-breaking strength improved by adding 2 g/kg LPP to the diet, but worsened at 5 g/kg. Moreover, the relative weight of eggshell and yolk L* value decreased with the treatments. Dietary LPP enhanced oxidative stability, reducing malondialdehyde (MDA) and increasing 1,1-diphenyl-2-picrylhydrazyl (DPPH) yolk values. The current study demonstrated that LPP, a safe and easily accessible agricultural by-product, enhanced eggshell quality when it was included in the diet of laying quails at doses of 2 g/kg. In contrast, improvement of yolk antioxidant capacity required increased amounts of LPP (4 g/kg). LPP could be advantageous to animal nutrition as an adequate substitute to reduce waste by-products.

Effects of dietary calcium and available phosphorus levels and phytase supplementation on performance, bone mineral density, and serum biochemical bone markers in aged white egg-laying hens.

Exogenous phytase supplementation increases P and Ca availability to allow for the dietary reductions without negative consequences on productivity or skeletal health. Effects of a Buttiauxella sp. phytase (BSP) supplemented in available P (avP)-reduced and Ca-reduced diets on performance, BW, eggshell quality, serum biochemical bone markers, and bone densitometry were evaluated in egg-laying hens from 68 to 78 wk of age. One hundred hens were fed 1 of 5 diets (n = 20/treatment), including a positive control (PC) with 0.35% avP and 3.5% Ca, and the PC moderately reduced in avP and Ca levels by 0.187 and 0.159% of the diet (by 53 and 4.5%), respectively, (NC1) or severely reduced by 0.231 and 0.275% of the diet (by 66 and 7.9%), respectively, (NC2). Other diets were the NC1 or NC2 supplemented with BSP at 600 FTU/kg (NC1 + BSP or NC2 + BSP, respectively). Egg production and feed conversion ratio were maintained by NC1 but were 11.9% lower and 12.3% higher, respectively, with the NC2 than the PC, which was alleviated by supplemental BSP. Diet effects on FI and eggshell quality followed a similar pattern. Body weight was 2.9% lower for NC1, and 6.1% for NC2 than the PC; BSP alleviated the decreased BW. Serum pyridinoline (bone resorption marker) was 20 to 27% higher in NC2 hens than in the other groups, with no effects on other bone markers. Total and trabecular space bone mineral density in the proximal metaphysis were 8.4 and 15.2% lower for NC1, respectively, and 12.1 and 26.7% lower for NC2, respectively, than PC. Supplemental BSP completely alleviated the decreased bone densitometry measures in NC1, but only partially in NC2. The NC1 hens maintained performance but had decreased BW and bone quality; phytase supplementation restored productivity, BW, and bone quality. The Ca and avP deficiencies in the NC2 hens relative to other groups were partially alleviated by the 600 FTU/kg BSP.

Dietary combined supplementation of iron and Bacillus subtilis enhances reproductive performance, eggshell quality, nutrient digestibility, antioxidant capacity, and hematopoietic function in breeder geese.

A 3 × 2 factorial arrangement of treatments was conducted to investigate the effects of iron (Fe, 40, 60, and 80 mg/kg) and Bacillus subtilis (2.5 × 109 and 5.0 × 109 CFU/kg) supplementation on reproductive performance, egg quality, nutrient digestibility, hormone levels, antioxidant indices, and hematological parameters in breeder geese. A total of one hundredtwenty 46-week-old Wulong breeder geese were randomly assigned to 1 of 6 dietary treatments with 4 replicates per treatment and 5 geese per replicate for 10 wk following 1 wk of adaption. Dietary Fe supplementation increased egg weight (P = 0.036), fertility (P = 0.022), serum total antioxidant capacity (P = 0.022), red blood cell (P = 0.001), hematocrit (HCT, P < 0.001), hemoglobin (HGB, P = 0.005), and mean corpuscular volume (MCV, P < 0.001). Dietary B. subtilis supplementation increased egg production (P = 0.025), eggshell thickness (P = 0.020), apparent phosphorus digestibility (P < 0.001), serum follicle stimulating hormone (P = 0.043), total antioxidant capacity (P < 0.001), HCT (P < 0.001), HGB (P < 0.001), and MCV (P = 0.025), and reduced malondialdehyde level (P = 0.008). The birds fed diets supplemented with 60 mg/kg Fe and 5 × 109 CFU/kg B. subtilis showed the highest percentage of hatched eggs (P = 0.004) and mean corpuscular hemoglobin (P < 0.001) among the 6 groups. Supplementation of 40 and 60 mg/kg Fe significantly increased the apparent digestibility of calcium compared with that of 80 mg/kg Fe in the birds fed 5.0 × 109 CFU/kg B. subtilis (P = 0.004). Supplementation with 60 and 80 mg/kg Fe in the birds fed 5 × 109 CFU/kg B. subtilis significantly decreased serum urea nitrogen level compared with other 4 groups (P = 0.022). In conclusion, the combination of Fe and B. subtilis effectively improves reproductive performance, eggshell quality, nutrient digestibility, antioxidant status, and hematopoietic function of breeder geese. Dietary addition of 60 mg/kg Fe and 5.0 × 109 CFU/kg B. subtilis was an optimum supplementation dose.

Role of long-term supplementation of 25-hydroxyvitamin D3 on egg production and egg quality of laying hen.

A study was conducted to evaluate the effect of dietary 25-hydroxyvitamin D3 (25OHD) on pullet and egg-laying hen growth performance, egg production, and egg quality. Three hundred and ninety 1-day-old Hy-Line W36 pullets were randomly allocated to 3 treatments with 10 replicated cages and 13 birds per cage. Dietary treatments were vitamin D3 at 2,760 IU/kg (D); vitamin D3 at 5,520 IU/kg (DD), and vitamin D3 at 2,760 IU/kg plus 25OHD at 2,760 IU (69 µg)/kg (25D). Body weight and feed intake were recorded at the end of each stage: starter 1 (0-3 wk), starter 2 (4-6 wk), grower (7-12 wk), developer (13-15 wk), prelay (15-17 wk), peaking (18-38 wk), layer 2 (39-48 wk), layer 3 (49-60 wk), layer 4 (61-75 wk), and layer 5 (76-95 wk). Egg production was recorded daily. Egg quality was evaluated every 8 wk starting from 25 wk. There was no difference in growth performance during the rearing period (0-17 wk). In the laying period (18-95 wk), DD showed lower feed intake at layer 2, but higher intake at layer 3 along with lower hen day production (HDP) from 22 to 48 wk compared to the other treatments. During the same period, the DD group laid smaller eggs with higher specific gravity and shell thickness compared with the other treatments or D alone at 40 wk, which may be partly due to the lower body weight. In contrast, 25D had better feed conversion ratio (feed intake per dozen of eggs) at layer 2, and higher overall (22-60 wk) HDP compared with DD. For the egg quality analysis, at 25 and 33 wk, both DD and 25D had higher Haugh unit compared with D. However, 25OHD has no effects on eggshell quality during the entire production period and no beneficial effects on egg production during the later laying period (after 60 wk). In summary, long-term and early supplementation of 25OHD has positive effects on egg production and egg quality, and the beneficial effects were mainly observed during the early laying stage.

Loss of the seipin gene perturbs eggshell formation in Caenorhabditiselegans.

Seipin, an evolutionary conserved protein, plays pivotal roles during lipid droplet (LD) biogenesis and is associated with various human diseases with unclear mechanisms. Here, we analyzed Caenorhabditis elegans mutants deleted of the sole SEIPIN gene, seip-1 Homozygous seip-1 mutants displayed penetrant embryonic lethality, which is caused by the disruption of the lipid-rich permeability barrier, the innermost layer of the C. elegans embryonic eggshell. In C. elegans oocytes and embryos, SEIP-1 is associated with LDs and is crucial for controlling LD size and lipid homeostasis. The seip-1 deletion mutants reduced the ratio of polyunsaturated fatty acids (PUFAs) in their embryonic fatty acid pool. Interestingly, dietary supplementation of selected n-6 PUFAs rescued the embryonic lethality and defective permeability barrier. Accordingly, we propose that SEIP-1 may maternally regulate LD biogenesis and lipid homeostasis to orchestrate the formation of the permeability barrier for eggshell synthesis during embryogenesis. A lipodystrophy allele of seip-1 resulted in embryonic lethality as well and could be rescued by PUFA supplementation. These experiments support a great potential for using C. elegans to model SEIPIN-associated human diseases.

Improvement of eggshell quality by dietary N-carbamylglutamate supplementation in laying chickens.

Egg quality defects seriously reduce the quality grade and increase egg breakage in egg marketing activities. In this study, the effect of N-carbamylglutamate (NCG) on eggshell quality was investigated by evaluating calcium absorption and calcification in laying hens. A total of 30 newly hatched female Hy-Line chicks were randomly assigned to the control group (basal diet) and treatment group (basal diet supplemented with 1% NCG). At 25 wk, eggs from each group were obtained to assess egg quality parameters. Blood samples were collected for analysis of mineral, hormone, and amino acids levels at 16 h after laying egg. Uterine tissues were removed and fixed in 4% neutral paraformaldehyde solution or kept in liquid nitrogen for mineral determination, quantitative PCR, and Western blot. Results showed that the egg quality (eggshell thickness, strength and percentage, egg specific gravity, and eggshell effective thickness) was significantly increased while effective thickness of mastoid layer, width of mastoid gap, and mammillary knobs were significantly decreased by dietary NCG supplementation (P < 0.05). The levels of minerals (Ca, P, Fe, Mg, Na, K) in eggshell, plasma, and uterus were remarkably elevated (P < 0.05). Meanwhile, the concentrations of calcium metabolism-related hormones (17ß-estradiol, parathyroid hormone, and calcitonin) were increased in the NCG group (P < 0.05). Moreover, expression of calbindin 1, carbonic anhydrase 2, ovalbumin, ovotransferrin, ovocleidin-17, ovocleidin-116, and clusterin mRNAs, as well as calbindin 1 and ATP2A1 proteins in uterus, duodenum, and kidney, was all upregulated in hens fed with NCG (P < 0.05). In addition, the number of blood vessels in the uterus, height of uterine mucosal folds, villus length in endometrium, and areas of uterine mucosal folds were significantly increased in the NCG group (P < 0.05). In conclusion, dietary 1% NCG supplementation during 0 to 25 wk can improve eggshell quality through changes in endometrial morphology, expression of calcium metabolism-related genes, and secretion of related hormones to promote eggshell formation in the laying hens.

Effects of phytase supplementation on eggshell and bone quality, and phosphorus and calcium digestibility in laying hens from 25 to 37 wk of age.

Effects of dietary available phosphorus (aP) and Ca levels and an Escherichia coli 6-phytase supplementation were studied in Lohmann LSL-Lite hens from 25 to 37 wk of age. Eighty-four hens were used in a completely randomized design with 7 treatments. The treatments were a positive control (PC) diet with 0.45% aP, 3.70% Ca, and 0.16% Na from 25 to 28 wk and 0.38% aP, 3.73% Ca, and 0.15% Na from 29 to 37 wk; a negative control (NC) diet, similar to the PC diet, with 0.22% aP, 3.00% Ca, and 0.13% Na from 25 to 28 wk and 0.19% aP, 3.02% Ca, and 0.13% Na from 29 to 37 wk; the NC diets supplemented with phytase at 150 (NC + 150), 300 (NC + 300), 600 (NC + 600), or 1,200 (NC + 1,200) phytase unit (FTU)/kg; and the PC diet supplemented with phytase at 1,200 (PC + 1,200) FTU/kg. Hen performance, eggshell, and bone quality were measured on a 4-wk basis. Bone breaking strength and ash and apparent ileal digestibility (AID) of P and Ca were determined at 37 wk. One- and 2-way ANOVA were conducted, and Tukey's range test was used to compare multiple means where P ≤ 0.05. No differences in hen performance, eggshell quality, bone breaking strength, bone ash, and P digestibility were observed between the PC and the NC treatments. The NC hens had lower cortical (P < 0.001) and trabecular + medullary bone mineral density (P = 0.004) and total bone mineral content (P < 0.001) than the PC hens. The PC + 1,200 increased cortical bone mineral density (P < 0.001). The reductions of aP and Ca in the NC diet were not deficient for performance but had a minor impact on bone mineralization. The NC + 600 and NC + 1,200 increased AID of P (P = 0.024), and all phytase treatments except the NC + 150 increased AID of Ca (P = 0.010) compared with the NC diet.

Dietary yeast ß-glucan supplementation improves eggshell color and fertile eggs hatchability as well as enhances immune functions in breeder laying hens.

The study was conducted to evaluate the effects of dietary yeast ß-glucan (YG) on performance and immune functions in breeder hens in a non-challenged setting. A total of 512 43-week-old Hy-Line Brown breeder hens were assigned into four treatments, and fed a basal diet with YG at 0, 50, 100 and 200 mg /kg for 8 weeks, respectively. Results showed that supplementation of YG did not affect production performance, but linearly increased hatchability (P < 0.05). Compared with the control, hens fed with 200 mg/kg YG had improved eggshell color and reduced mortality. Moreover, feeding 200 mg/kg YG significantly (P < 0.05) enhanced lymphocyte proliferation response to LPS, increased the percentage of peripheral blood CD3+ T cells and phytohemagglutinin (PHA) skin response; remarkably down-regulated splenic TLR4, IL-6 and TGF-ß mRNA levels while upregulated TLR6 and IFN-γ mRNA levels (P < 0.05). In addition, inclusion of YG at 200 mg/kg considerably promoted the production of serum cytokines, total IgA, and specific antibody titers against BSA, AIV and NDV vaccine (P < 0.05). These results suggested that dietary inclusion of 200 mg/kg YG could improve eggshell color and fertile eggs hatchability and enhance cellular and humoral immune function of breeder hens in a nonchallenged setting without disturbing immune homeostasis.

Organic trace minerals improve eggshell quality by improving the eggshell ultrastructure of laying hens during the late laying period.

The objective of this study was to investigate the effects of low inclusion levels of organic trace minerals (iron, copper, manganese, and zinc) on performance, eggshell quality, serum hormone levels, and enzyme activities of laying hens during the late laying period. A total of 405 healthy hens (HY-Line White, 50-week-old) were randomly divided into 3 treatments, with 9 replications per treatment and 15 birds per replication. The dietary treatments included a basal diet supplemented with inorganic trace minerals at commercial levels (CON), a basal diet supplemented with inorganic trace minerals at 1/3 commercial levels (ITM), and a basal diet supplemented with proteinated trace minerals at 1/3 commercial levels (TRT). The trial lasted 56 D (8 wk). Compared with the CON group, the ITM group showed decrease in (P < 0.05) egg production, eggshell strength, eggshell palisade layer, palisade layer ratio, serum estrogen, luteinizing hormone, glycosaminoglycan concentration, and carbonic anhydrase activity and increase in (P < 0.05) egg loss and mammillary layer ratio. However, the TRT group almost kept all the indices close to the CON group (P > 0.05). Furthermore, hens fed with low inclusion levels of organic trace minerals had smaller mammillary knobs (P < 0.05) than those in the CON and ITM groups. In conclusion, hens fed with low inclusion levels of proteinated trace minerals had better performance and eggshell strength than those fed with identical levels of inorganic compounds; organic trace minerals improved eggshell quality by improving the eggshell ultrastructure of laying hens during the late laying period.

Effect of Dietary Zinc Level on Egg Production Performance and Eggshell Quality Characteristics in Laying Duck Breeders in Furnished Cage System.

In order to investigate the effect of dietary Zn levels on laying performance, eggshell quality, and eggshell microstructure in Muscovy duck breeders under furnished cages. Firstly, the effects of age (35 weeks vs 40 weeks) and rearing system (littered floor vs furnished cage) on eggshell quality of laying duck breeders were studied (Exp. 1). Then, a total of 324 30-week-old Muscovy duck breeders were allotted into 3 dietary Zn groups with 6 replicates (18 ducks per replicate), including 0 mg Zn/kg (control-Zn group, C-Zn), 40 mg Zn/kg (normal-Zn group, N-Zn), and 140 mg Zn/kg (high-Zn group, H-Zn). The experimental period for 6 weeks was divided into 3 periods of 30-32, 32-34, and 34-36 weeks of age (Exp. 2). In Exp. 1, duck breeder eggs in the furnished cage system had lower the average shell thickness than birds in the littered floor system at 40 weeks of age (P < 0.05), not at 35 weeks of age. In Exp. 2, N-Zn and H-Zn groups had greater egg weight, egg production, and egg to feed ratio of duck breeders than C-Zn group (P < 0.05). Additionally, H-Zn group had higher laying rate, qualified egg ratio, and Haugh unit as well as lower mammillary cone width than C-Zn group (P < 0.05), with no differences between C-Zn and N-Zn groups (P > 0.05). Diet supplemented with 140 mg Zn/kg increased shell thickness and palisade layer thickness of duck breeders at 36 weeks of age (P < 0.05), but not at 32 and 34 weeks of age. In conclusion, diets with 40 or 140 mg Zn/kg improved egg production performance and egg quality of laying duck breeders during 30-36 weeks of age in a furnished cage system. Dietary supplementation of 140 mg Zn/kg level increased the ultrastructural palisade layer thickness contributing to greater eggshell thickness of duck breeders at 36 weeks of age.

Effects of Dietary Zinc on Performance, Zinc Transporters Expression, and Immune Response of Aged Laying Hens.

This study was to investigate the effects of dietary zinc (Zn) supplementation on performance, zinc transporter gene expression, and immune function in aged laying hens. In experiment 1, twenty 31-week-old hens (young) and twenty 60-week-old hens (old) with the same genetic background were fed with the same diet for 4 weeks. In experiment 2, a basal diet supplemented with zinc sulfate (ZnS) and zinc glycine chelate (ZnG) at 30, 60, 90, and 120 mg Zn/kg to constitute nine experimental diets. Eight hundred and ten 60-week-old layers were distributed in a completely randomized experimental design with 9 treatments, 6 replicates of 15 birds each, and birds were fed for 10 weeks. In experiment 1, results showed that zinc and metallothionein (MT) concentration in the shell gland of old hens was significantly lower than young layers (P < 0.05). Zinc transporters ZnT1, 4, 5, 6, and 7 messenger RNA (mRNA) abundance in old layers were significantly lower versus the young (P < 0.05). In experiment 2, results indicated that dietary zinc supplementation did not significantly affect the laying rate, average feed intake, egg weight, feed conversion efficiency, broken egg rate, or mortality (P > 0.05). Supplemental ZnG significantly improved eggshell breaking strength than ZnS, with a higher alkaline phosphatase (ALP) activity and more abundant ZnT4 expression in shell gland versus ZnS (P < 0.05). ZnG supplementation at 90 mg Zn/kg affected the duodenal mucus by significantly increasing ZnT1, 6, 7, ZIP13, and MT-4 mRNA level (P < 0.05). Zinc level significantly increased bovine serum albumin (BSA) antibody concentration on 14 day after BSA injection (P < 0.05). Supplementation of ZnG improved eggshell quality of aged layers by upgrading zinc transporter expression in the shell gland and intestine also enhanced humoral immunity.

Effect of high concentrations of dietary vitamin D3 on pullet and laying hen performance, skeleton health, eggshell quality, and yolk vitamin D3 content when fed to W36 laying hens from day of hatch until 68 wk of age.

The objective of this experiment was to investigate the effects of various dietary concentrations of vitamin D3 (D3) on pullet and laying hen performance, eggshell quality, bone health, and yolk D3 content from day of hatch until 68 wk of age. Initially, 440 Hy-line W36-day-old chicks were randomly assigned to 5 dietary treatments: 1,681 (control); 8,348; 18,348; 35,014; 68,348 IU D3/kg. At 17 wk of age, pullets were assigned to experimental diets with 12 replicate groups of 6 birds. At 17 wk of age, pullets fed diets containing 8,348 and 35,014 IU D3/kg had an increased bone mineral density in comparison to the control fed birds (P ≤ 0.01). Body weights of pullets fed the diet with 68,348 IU D3/kg were lower than other treatments (P ≤ 0.01). Hen-housed egg production (HHEP) of hens fed the 35,014 IU D3/kg diet was increased in comparison to control-fed hens (P ≤ 0.01), whereas HHEP of those fed 68,348 IU D3/kg diet was reduced in comparison to all other treatments (P ≤ 0.01). Shell breaking strength of eggs from hens fed 8,348, 35,014 and 68,348 IU D3/kg was increased in comparison to eggs from control-fed birds (P ≤ 0.01). Fat-free tibia ash content of hens fed any of the diets supplemented with D3 (8,348 to 68,348 IU D3/kg) was increased in comparison to control-fed hens (P ≤ 0.05). Yolk D3 content increased linearly with dietary D3 and the D3 transfer efficiency for the control, 8,348 IU, 18,348 IU, 35,014 IU, and 68,348 IU D3 treatments were 8.24, 10.29, 11.27, 12.42, and 12.06%, respectively. These data suggest that supplementation of dietary D3 up to 35,014 IU D3/kg feed maintained if not increased laying hen performance and enhanced pullet and laying hen skeletal quality as well as yolk D3 content and eggshell quality. Feeding pullets at a higher level 68,348 IU of D3 resulted in reduced growth and ultimately decreased performance of laying hens.

The effect of different dietary levels of hybrid rye and xylanase addition on the performance and egg quality in laying hens.

1. In this study, 240 ISA Brown hens were fed diets containing different levels of hybrid rye, and the influence of xylanase addition on laying performance and egg quality was evaluated. 2. Birds were allocated to 10 treatment groups with 12 replicates (cages) of two hens and were fed, from week 26 to 50, isocaloric and isonitrogenous experimental diets. A 5 × 2 experimental arrangement was applied, using diets with increasing level of rye (0%, 10%, 15%, 20% or 25%) with or without xylanase supplementation (200 mg/kg of feed; Ronozyme WX (CT) with minimum xylanase activity of 1,000 FXU/g). 3. Increasing dietary level of rye did not affect daily mass of eggs, mean egg weight or feed conversion ratio (P > 0.05). Laying rate decreased in all groups fed with rye. Egg and eggshell quality indices were unaffected by dietary rye grain (P > 0.05); however, rye inclusion significantly decreased yolk colour on the DSM scale (P < 0.05). In comparison with the control group, high dietary levels of rye (25%) significantly increased viscosity of small intestine content (P < 0.05). Diet supplementation with xylanase had no significant effect on egg production indices and egg quality (except for yolk colour) but decreased the viscosity of intestinal content in laying hens fed high levels of rye (P < 0.05). 4. The results of this experiment suggest that rye may be incorporated to a level of 25% in the diet of laying hens without any strong negative effect on egg performance, while xylanase added to high-rye grain reduced the viscosity of intestinal content; however, it did not positively affect the laying performance or egg quality.

Long-term effects of Buttiauxella sp. phytase on performance, eggshell quality, apparent ileal Ca and P digestibility, and bone properties of white egg layers.

Adequate dietary Ca and available phosphorus (avP) are essential to long-term egg production and bone health in laying hens. The effects of dietary Ca and avP levels and Buttiauxella sp. phytase (BSP) were studied in Lohmann LSL Lite hens from 30 to 70 wk of age (woa). Hens (n = 456; 4 per cage) were fed either a primary breeder recommendation-based diet (positive control; PC); the PC with avP and Ca levels reduced by 0.146 and 0.134% of the diet, respectively, without (NC) or with 300 FTU/kg BSP (NC+BSP). Egg production, BW, feed intake, FCR, and eggshell quality from 30 to 70 woa, and apparent ileal digestibility of P (AIDP) and Ca (AIDCa), and bone quality at 32, 48, and 70 woa were measured. The avP and Ca levels in the NC diet were not clinically deficient, as most parameters were unaffected by diet. Hen BW from 34 to 70 woa tended to be 2.9% greater (P = 0.076) for PC and NC+BSP compared to NC. Mid-diaphysis cortical bone mineral content (CBMC) tended to be 10% and 9% higher (P = 0.065) in the NC+BSP hens than in NC hens at 48 and 70 woa, respectively. AIDP of NC+BSP was 24% greater (P = 0.034) than of NC at 32 woa and tended to be 18% greater (P = 0.082) than AIDP of PC at 48 woa, and 25% lower than of NC and PC at 70 woa (P = 0.028). AIDCa was 25% lower for NC+BSP than PC at 48 woa only (P = 0.037). The avP and Ca sufficiency in the NC diet limited the opportunity to determine a phytase effect. Although the supplemental BSP tended to increase BW and 48 and 70 woa CBMC, and increased 32 woa AIDP, the efficacy of BSP could not be determined due to the lack of an NC effect on most parameters. Commercial laying hens can maintain health and productivity at lower than recommended levels of dietary Ca and avP; phytase supplementation may allow for even further reductions.

Propolis alleviates the negative effects of heat stress on egg production, egg quality, physiological and immunological aspects of laying Japanese quail.

The present work was carried out to investigate the effects of dietary propolis supplementation to laying Japanese quail (Coturnix coturnix japonica) on egg production, egg quality, physiological and immunological aspects under heat stress conditions. A total of 200, 21-day-old, Japanese quail females were distributed equally into standard wired cages in two identical environmentally-controlled rooms (10 cages per room, 10 birds per cage). From 29-70 d of age, the quail birds in the first room remained at a normal temperature of 24°C (C group), whereas the quail birds in the second room were kept under heat stress at 35°C (HS group). Each group was further assigned to 2 propolis subgroups (5 cages per subgroup); one of them received a basal diet without propolis supplementation (-PR subgroup), while, the other received 1 g propolis/ kg basal diet (+PR subgroup). In the present study, performance and egg production of laying quail were significantly (P<0.001) impaired by HS treatment and improved by the PR treatment. Similarly, the negative and positive effects of HS and PR, respectively, were appeared on the egg shell thickness and yolk index. Stress indicators in laying quail were significantly (P<0.001) increased by HS, while, PR significantly (P<0.05) moderated these levels in the HS+PR group when compared to the HS-PR quail group. In addition to the positive impact of PR on the plasma levels of calcium, phosphorus, and albumin, it also normalized the plasma levels of alanine aminotransferase and cholesterol in the heat-stressed quail birds. Moreover, the quail birds in the HS groups expressed lower immunological aspects than those in the C group, while, the addition of propolis to the diets enhanced the immune status of laying quail birds under HS conditions. These results strongly suggest that dietary propolis supplementation could be a successful attempt to maintain the performance and egg production of laying Japanese quail at convenient levels under heat stress conditions.

Performance and egg quality of laying hens fed with mineral sources and rosemary oil.

In order to evaluate the effect of rosemary oil and micro mineral sources on the performance and egg quality of laying hens, 288 hens were used and distributed in a completely randomized design using a 2x3 factorial (mineral sources x rosemary oil) with six different diets and six replications. Diets were formulated containing inorganic or organic minerals, with or without added rosemary oil (100 and 200 mg kg-1). The treatments showed interaction for average egg weight, yolk color, albumen and yolk percentage, with significant results from the use of organic minerals compared to inorganic minerals. The addition of 200 mg kg-1 rosemary oil in diets improved laying rate, egg mass, specific gravity, number of pores on the shell when compared to other treatments. In conclusion, the use of 200 mg kg-1 of rosemary oil improves the performance of red laying hen eggs. The association between organic minerals and 100 mg kg-1 rosemary oil in laying hen diets increases yolk color and percentage of albumen. The use of organic minerals is superior to inorganic minerals as to improve the quality of eggs, increasing average egg weight, yolk color and percentage of albumen.

Effect of supplementing graded concentrations of non-phytate phosphorus on performance, egg quality and bone mineral variables in White Leghorn layers.

1. An experiment was conducted to determine optimal non-phytate phosphorus (NPP) concentrations for White Leghorn (WL) layers (22-72 weeks) fed diet containing 38 g Ca/kg. 2. Eight diets with graded concentrations (1.5-3.25 g/kg in increments of 0.25 g) of NPP were prepared. Each diet was fed to eight pen replicates containing 88 birds in each. Performance data was evaluated in three different phases (phase I-22-37 weeks, phase II-38-53 weeks and phase III-54-72 weeks). Optimum levels of NPP were determined by fitting a quadratic polynomial (QP) regression model. 3. Egg production (EP) was not affected (P = 0.059) by the concentration of NPP and interaction between NPP and diet phase was non-significant, indicating that the lowest concentration (1.5 g/kg diet) of NPP used in the study was adequate across the three phases. However, EP was influenced by phase (P < 0.001). 4. Optimum concentration of NPP for feed intake (FI) was estimated to be 1.5, 1.71 and 2.40 g/kg diet during phases I, II and III, respectively. FI per egg mass (EM) or feed efficiency (FE) responded quadratically with NPP and also differed significantly between phases. Optimum concentration of NPP for FE during phases I, II and III was 1.5, 2.56 and 2.32 g/kg diet, respectively. 5. Egg weight (EW), EM, shell weight and thickness were not affected by NPP concentration although all of these variables (except shell weight) were influenced by phases. 6. Breaking strength of tibia and Ca contents in tibia ash were not affected by the concentration of NPP, but bone ash and P contents in tibia ash were influenced (P < 0.001) by NPP. Predicted optimal concentrations of NPP for responses for tibia ash at 44 or 72 weeks, tibia ash P at 44 weeks and tibia ash P at 72 weeks were 1.55, 2.63 and 1.5 g/kg diet, respectively. 7. Based on the results, it was concluded that WL layers required 1.5 g, 2.63 g and 2.4 g, respectively/kg diet during phase I, II and III with the calculated daily intake of 137.3, 278.3 and 262 mg NPP/b/d.

Effects of methionine hydroxyl analog chelated zinc on laying performance, eggshell quality, eggshell mineral deposition, and activities of Zn-containing enzymes in aged laying hens.

The study aimed to determine the effects of methionine hydroxyl analog chelated zinc (MHA-Zn) on laying performance, eggshell quality and mineral deposits, and the activities of Zn-containing enzymes on aged laying hens. A total of 960 layers (Hy-Line Grey, 57 wk old) were fed a basal diet (Zn: 35.08 mg/kg) without extra zinc for 2 wk. During the ensuing 14 wk, birds were randomly divided into 4 groups according to body weight and laying rate, with 8 replicates per treatment, and each group had 8 replicates of 30 hens. Four levels of Zn (ZnSO4: 80 mg/kg; MHA-Zn: 20, 40, 80 mg/kg) were added to the diet, respectively. The results shown that dietary Zn did not affect laying rate, average egg weight, average daily feed intake, or feed conversion ratio (P > 0.05); however, compared to the inorganic group, dietary supplementation with 40 or 80 mg/kg MHA-Zn decreased broken egg rate significantly in the whole period (P < 0.05), while significantly increased eggshell weight in week 62 to 72, eggshell thickness and eggshell strength in wk 66 to 72, eggshell weight percent and eggshell density in week 62 to 72 (P < 0.05). Besides, dietary supplementation with different sources and levels of Zn did not affect ash concentration of eggshell (P > 0.05), whereas dietary supplementation with 80 mg/kg MHA-Zn improved the Zn and Ca concentrations of eggshells and carbonic anhydrase (CA) activity of liver, and 40 mg/kg MHA-Zn increased Zn concentration of liver (P < 0.05). Moreover, no significant differences in alkaline phosphatase activity were observed among the treatment groups (P > 0.05). Therefore, dietary supplementation with 40 mg/kg MHA-Zn can improve eggshell quality by promoting Ca deposition and CA activity.

Epigallocatechin-3-gallate protected vanadium-induced eggshell depigmentation via P38MAPK-Nrf2/HO-1 signaling pathway in laying hens.

It has been demonstrated that tea polyphenol (TP) epigallocatechin-3-gallate (EGCG) can confer protection against vanadium (V) toxicity in laying hens; however, our understanding of the molecular mechanisms beyond this effect are still limited. In this study, 360 hens were randomly assigned to the 3 groups to study whether the potential mechanism P38MAPK-Nrf2/HO-1 signaling pathway is involved in the protective effect of EGCG on eggshell pigmentation in vanadium challenged laying hens. Treatments included a control group, a 10 mg/kg V (V10), and a V10 plus 130 mg/kg of EGCG group (V10+EGCG130). Both eggshell color and protoporphyrin IX were decreased in the V10 group compared with the control diet, while EGCG130 treatment partially improved shell color and protoporphyrin IX (P < 0.05). The V10 exposure induced higher cell apoptosis rate and oxidative stress in birds as evidenced by the histological apoptosis status, decreased uterine glutathione-S transferase (GST) and high abundance of malondialdehyde (MDA) compared with the control group, whereas EGCG130 markedly alleviated oxidative stress via reducing MDA generation (P < 0.05). Dietary vanadium reduced ferrochelatase, NF-E2-related factor 2 (Nrf2), and heme oxygenase (HO-1) mRNA expression, while EGCG up-regulated Nrf2 and HO-1 expression (P < 0.05). Protein levels of Nrf2, HO-1 and phospho-p38 (P-P38) MAPK were reduced in V10 group, while dietary supplementation with 130 mg/kg EGCG markedly increased Nrf2, HO-1 and P-P38 MAPK protein levels in the uterus compared with the V10 group (P < 0.01). In conclusion, EGCG improved eggshell color and antioxidant system in V10-challenged hens, which seems to be associated with P38MAPK-Nrf2/HO-1 signaling pathway.

Copper requirements of broiler breeder hens.

One-hundred-twenty Cobb 500 hens, 20 wk of age, were randomly allocated into individual cages with the objective of estimating Cu requirements. After being fed a Cu deficient diet for 4 wk, hens were fed diets with graded increments of supplemental Cu (0.0; 3.5; 7.0; 10.5; 14; and 17.5 ppm) from Cu sulfate (CuSO4 5H2O), totaling 2.67; 5.82; 9.38; 12.92; 16.83; and 20.19 ppm analyzed Cu in feeds for 20 weeks. Estimations of Cu requirements were done using exponential asymptotic (EA), broken line quadratic (BLQ), and quadratic polynomial (QP) models. Obtained Cu requirements for hen d egg production and total settable eggs per hen were 6.2, 7.3, and 12.9 ppm and 8.1, 9.0, and 13.4 ppm, respectively, using EA, BLQ, and QP models. The QP model was the only one having a fit for total eggs per hen with 13.1 ppm Cu as a requirement. Hemoglobin, hematocrit, and serum Cu from hens had requirements estimated as 13.9, 11.3, and 18.5, ppm; 14.6, 13.0, and 19.0 ppm; and 16.2, 14.6, and 14.2 ppm, respectively, for EA, BLQ, and QP models. Hatching chick hemoglobin was not affected by dietary Cu, whereas requirements estimated for hatching chick hematocrit and body weight and length were 10.2, 12.3, and 13.3 ppm using EA, BLQ, and QP models; and 6.8 and 7.1 ppm, and 12.9 and 13.9 ppm Cu using EA and BLQ models, respectively. Maximum responses for egg weight, yolk Cu content, and eggshell membrane thickness were 14.9, 12.7, and 15.1 ppm; 15.0, 16.3, and 15.7 ppm; and 7.3, 7.8, and 14.0 ppm Cu, respectively, for EA, BLQ, and QP models. Yolk and albumen percentage were adjusted only with the QP model and had requirements estimated at 11.0 ppm and 11.3 ppm, respectively, whereas eggshell mammillary layer was maximized with 10.6, 10.1, and 14.4 ppm Cu using EA, BLQ, and QP models, respectively. The average of all Cu requirement estimates obtained in the present study was 12.5 ppm Cu.