Single Comb White Leghorn Hens Research Articles

Effects of dietary protein, energy and β-mannanase on laying performance, egg quality, and ileal amino acid digestibility in laying hens

β-mannan is a nonstarch polysaccharide found in hulled and dehulled soybeans that can survive drying-toasting phase of processing soybeans and have antinutritive effects in poultry. β-mannanase is an active enzyme (endohydrolase) that can hydrolyze β-mannan to reduce its antinutritional effects. Two experiments were conducted to evaluate the effects of β-mannanase supplementation in low energy/protein diets on egg production, egg quality, and apparent ileal digestibility of the dry matter (DM), crude protein (CP), and amino acids in 21-week-old Single Comb White Leghorn hens (Hy-Line W-36). A total of 192 hens (8 replicates of 6 hens per treatment) for a production study (Exp. 1) and a total of 64 hens (8 replicates of 2 hens per treatment) for a digestibility study (Exp. 2) were randomly allocated to 4 experimental treatments in a 2 × 2 factorial arrangement. Four dietary treatments were control (CS) based on corn and 44% CP soybean meal (ME: 2,850 kcal/kg CP: 18.5%) and CS-low energy/protein (CSL) (ME: 2,750 kcal/kg CP: 17.5%), with or without 0.05% β-mannanase enzyme. Hens were fed the experimental diets for 14 d for the digestibility study and 8 wk for the production study. Hen-day egg production (HDEP), weekly feed intake, FCR, and biweekly egg quality parameters were measured. Significant interaction on feed intake (P < 0.01) was observed between energy/protein and enzyme. At 3, 6 and 8 wk, the feed intake and FCR of CSL with enzyme were significantly lower than those of CSL without enzymes. The main effects indicated that birds fed diets without inclusion of β-mannanase had higher feed intake than those fed diets with enzymes at 4, 7, and 8 wk. The inclusion of β-mannanase significantly increased (P < 0.05) HDEP at 2, 3, 5, and 7 wk. However, there was no significant effect of nutrient density or enzyme supplementation on egg quality parameters. The digestibility study showed that the inclusion of β-mannanase significantly improved (P < 0.01) apparent ileal digestibility of lysine, histidine and tryptophan in the diet. The results of these experiments indicate that supplementation of β-mannanase could reduce the feed intake and FCR and improve HDEP and apparent ileal digestibility of key amino acids in corn/soy diets fed to laying hens.

Egg Shell Quality and Bone Status as Affected by Environmental Temperature, Ca and Non-Phytate P Intake and in vitro Limestone Solubility in Single-Comb White Leghorn Hens

Environmental temperature (ET) often changes the nutrient intake/output for layers. Changing feed formulations based on ET may need to be utilized to obtain optimum performance, shell quality and bone status. This study was conducted to investigate the effects of temperature, Ca intake, non-phytate P (NPP) intake and in vitro limestone solubility (LS) on egg-shell quality and bone status in commercial White Leghorn hens. Egg mass and shell weight per unit surface area (SWUSA) decreased with increasing ET (p lower than 0.05), especially when ET was 29.7 C (cycling mean ET)or a constant ET was 32.2 C. Feeding layers a low soluble larger particle size limestone instead of a highly soluble limestone produced beneficial effects for SWUSA at the thermoneutral ET (21.1 C) but the beneficial effect was less or disappeared when ET was higher than 26.6 C in EXP 1 and 2. Feeding layers 245 and 353 mg NPP/h/d supported satisfactory bone status at 21.1 C, however layers housed at higher than 30 C needed an additional intake of 50 mg NPP/h/d to support bone integrity. Results of EXP 1 and 2 indicates that 48 week old layers housed in thermoneutral or warmer ET require a minimum of 4.2 g Ca/h/d for maintaining optimum shell quality and bone integrity. Feeding low LS (34.1% in vitro solubility) improved egg shell quality only for hens housed in thermoneutral ET (21.1 C) and did not improve egg shell quality at higher ET (constant or cycling). Daily NPP intake of 245 and 353 mg/h/d supported optimum egg production and bone status at 21.1 C, respectively. A higher NPP and Ca intake may be required for bone status compared to egg production, especially in older hens.

The effects of formic acid-treated shrimp meal on laying performance and egg quality in aged laying hens

An experiment was carried out to measure the suitability of using formic acid-treated shrimp meal (TSM) as a protein source for aged laying hens. Shrimp meal (SM), air-dried shrimp waste was treated with 3% formic acid (w/v) at room temperature for 20 min, sun-dried, ground to pass through 1.0 mm mesh screen and then ready to use as the TSM. A total of 56 Single Comb White Leghorn hens, 85 wk of age, were placed in individual cages and assigned randomly into 7 dietary groups of 8 birds each. A control diet, diets containing 5, 10, and 15% SM and diets containing 5, 10, and 15% TSM were prepared. Diets and water were given ad libitum during the 30-d experimental period. Hen-day egg production, egg mass, feed intake, and feed conversion ratio (FCR) were deteriorated with increasing levels of the SM in the diets (P < 0.05). In contrast, these parameters were unchanged with increasing levels of the TSM in diets and compatible with the control group. No significant improvements were observed in exterior or interior egg quality among the dietary groups, except for eggshell weight, strength and yolk color, which were significantly increased in SM and TSM groups when compared to the values in control group (P < 0.05). It is concluded that inclusion of TSM up to 15% in laying hen diets may have beneficial effects on laying performance along with improved eggshell quality and yolk color, and suggested that TSM is a promising combined source of protein and calcium in aged laying hens.

The effect of maternal canthaxanthin supplementation and hen age on breeder performance, early chick traits, and indices of innate immune function

Hen age and nutrition influence chick innate immunity. The immunomodulatory antioxidant carotenoid canthaxanthin is transferred from the hen diet to the egg. Antioxidants could protect the chick from bactericidal oxidative species produced by the immune system. Broiler breeder hen diets were supplemented with 0 (Control), 6 (Low), or 12 (High) mg/kg canthaxanthin. Chick early growth and ex vivo innate immunity were measured at 31 to 33 (Early), 45 to 47 (Mid), and 57 to 59 (Late) wk of hen age. Escherichia coli (E. coli) bactericidal capacity, phagocyte activation (number of phagocytes containing at least one E. coli), phagocytic capacity (number of phagocytes containing one or more E. coli), and oxidative burst at 1 and 4 d of age were determined. Egg and chick liver canthaxanthin and chick plasma total antioxidant capacity were measured. Differences were considered significant at P ≤ 0.05. Breeder productivity was greatest for the Low hens; diet did not affect egg yolk, albumen, or shell proportions. Egg canthaxanthin increased with maternal supplementation and plateaued after 28 days, but was not affected by hen age. Chick liver canthaxanthin increased with maternal supplementation, but decreased as hens aged. Hen diet did not affect broiler chick performance to 21 days of age. Maternal canthaxanthin at 6 mg/kg increased chick E. coli bactericidal capacity and d 1 oxidative burst; phagocytosis was unaffected. E. coli bactericidal capacity decreased as hens aged, but increased from 1 to 4 d, indicating maturation of chick innate immunity. Plasma total antioxidant capacity at d 1 increased with maternal canthaxanthin in chicks from Mid and Late hens. Canthaxanthin possesses immuno-modulatory and antioxidant properties, and hen age affected chick innate immune development. Single-comb White Leghorn hens were fed the same levels of canthaxanthin to determine the rate of incorporation into eggs. Egg canthaxanthin reached a plateau after 7 d. Canthaxanthin in the hen diet at 6 mg/kg resulted in the greatest positive effect on hen performance, with little effect on the chick.

Comparative evaluation of dietary supplementation with mannan oligosaccharide and oregano essential oil in forced molted and fully fed laying hens between 82 and 106 weeks of age

The aim of this study was to investigate the efficacy of feed-grade preparations of mannan oligosaccharides ( MOS: ) and oregano essential oil ( OEO: ) in forced molted or fully fed 82-week-old, laying hens. A 2 × 3 factorial experiment investigated the influence of molting vs. full feeding and dietary supplements [i.e., unsupplemented control, MOS (1g/kg) diet, and OEO (24mg/kg) diet] on production parameters, egg quality, serum stress indicators, blood constituents, tibial characteristics, liver antioxidant status, and cecal microflora composition. A total of 864 Single Comb White Leghorn hens were randomly assigned to 6 treatments, each with 6 replicates of 24 hens each, and studied for 25 wk. Hens were fed a molt diet containing of 50% alfalfa and 50% wheat bran ( AA+WB: ) for 12 d, then returned to the laying ration. Results indicate that molt vs. full feed impacted more on most variables measured than supplementation or supplement type. Significant (P <0.01) interactions between molting and diet were observed for the egg production, egg weight, egg mass, and feed conversion ratio ( FCR: ). In fully fed hens, MOS supplementation improved (P <0.01) the egg production, egg weight, and FCR, and an OEO addition significantly improved the egg production and FCR in forced molted hens. Molting improved egg quality despite the significant regression in ovary and oviduct weight (P <0.01), though supplements showed no influence. The bone ash (P <0.01) and mineral content (P <0.05) of molted hens were significantly lower than those of fully fed counterparts; however, poor mineralization was not reflected in the bones' mechanical properties. No significant differences were observed among treatments for hematological characteristics. Both the MOS and particularly the OEO supplementation improved (P <0.01) liver antioxidant status and mitigated the significant increase in cecal pathogenic bacteria after molt. Our results indicate that full feeding with an aa+wb diet is an effective non-feed-removal method for molted hens, the benefit of which can be improved with MOS and OEO supplementation.

Phenamil enhances the adipogenic differentiation of hen preadipocytes.

A study was conducted to examine the effect of phenamil on adipogenic differentiation and expression of key adipogenic transcripts in hen preadipocytes. Preadipocytes were isolated from 20-week old Single Comb White Leghorn hens (Gallas gallus, Lohman strain). The experiment lasted for 48 h and had six treatments. Non-treated control (C) cells, cells treated with dexamethasone, 3-isobutyl-1-methylxanthine, insulin, and oleic acid (DMIOA) (T1), DMIOA + 15 μM phenamil (T2), DMIOA + 30 μM phenamil (T3), 15 μM phenamil alone (T4), and 30 μM phenamil alone (T5). Neutral lipid accumulation and the mRNA expression of key adipogenic transcripts were measured in all treatments and compared. Lipid accumulation was detected in T1, T2, and T3 only. Expression of peroxisome proliferator receptor-activator gamma 2 (PPARγ2), the core enhancer binding protein α (C/EBPα), C/EBPβ, fatty acid binding protein 4 (FABP4), and lipoprotein lipase (LPL) as well as ETS variant 4 (ETV4) and 5 was higher (P < 0.05) in T2, T3, T4, and T5 compared to C. Expression of these transcripts was higher (P < 0.05) in T2 and T3 compared to T4 and T5. The core enhancer binding protein α, C/EBPβ, and FABP4 were highly expressed (P < 0.05) in T1 compared to C. However, the expression of PPARγ2, LPL, and ETV4 and ETV5 was not significantly different. Expression of C/EBPα, C/EBPβ, and FABP4 was higher (P < 0.05) in T2 and T3 compared to T1. Expression of sterol regulatory element binding protein 1 (SREBP1) and leptin receptor (LEPR) was not significantly different among the treatments. In conclusion, phenamil enhances DMIOA-induced adipogenic differentiation of hen preadipocytes but does not induce adipogenesis by itself.

Dynamics of anterior pituitary immunoreactive gonadotrophs in moulted hens supplemented with protein, symbiotic and probiotics.

The present work delineates redistribution patterns of the hormone-producing cells of the anterior pituitary, after the phase of moulting. Two hundred single comb White Leghorn hens at the end of their first production cycle (Age=70week) were purchased from the commercial poultry farm and were induced to moult by high-dietary zinc (3g/kg feed/day) after 1week of acclimatization, at the experimental research station, Department of Physiology and Pharmacology, University of Agriculture, Faisalabad. The moulted birds were equally (n=50) and randomly allocated to their respective groups as G1 (control; CP (Crude protein) 16%, no supplement), G2 (CP18%, no other supplement), G3 (CP16%, symbiotic at does rate of 85mg/l in drinking water daily) and G4 (CP16%, probiotic at dose rate of 85mg/l in drinking water daily). Ten birds were slaughtered in each group at 5% and at peak of post-moult production stage to collect their pituitary glands. An earlier post-moult production recovery, sustained and lengthier production span was seen in the G2 as compared to all other groups. The lowest production and an earlier production decline were seen in G1. The cell diameter and area of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) gonadotroph increased (p≤0.01) in G2 and G3 as compared to G1. The FSH gonadotroph nucleus diameter and area did increase (p≤0.01) in G2 and G3, while LH gonadotroph nucleus diameter and area decreased (p≤0.01) in G2 and G3 as compared to G1. The increased FSH and LH gonadotroph diameter in protein and symbiotic supplemented birds is accountable for the increased egg production in these groups.

Electron-Beam-Inactivated Vaccine Against Salmonella Enteritidis Colonization in Molting Hens.

Electron-beam (eBeam) irradiation technology has a variety of applications in modern society. The underlying hypothesis was that eBeam-inactivated Salmonella enterica serovar Enteritidis (SE) cells can serve as a vaccine to control SE colonization and shedding in poultry birds. An eBeam dose of 2.5 kGy (kilograys) was used to inactivate a high-titer (10(8) colony-forming units [CFU]) preparation of SE cells. Microscopic studies revealed that the irradiation did not damage the bacterial cell membranes. The vaccine efficacy was evaluated by administering the eBeam-killed SE cells intramuscularly (1 x 10(6) CFU/bird) into 50-wk-old single comb white leghorn hens. On day 14 postvaccination, the hens were challenged orally with live SE cells (1 x 10(9) CFU) and SE colonization of liver, spleen, ceca, and ovaries determined on day 23. Blood samples were collected on days 0, 14, and 23 postvaccination and the sera were analyzed to quantify SE-specific IgG titers. The vaccinated chickens exhibited significantly (P < 0.0001) higher SE-specific IgG antibody responses and reduced SE ceca colonization (1.46 ± 0.39 logi10 CFU/g) compared to nonvaccinated birds (5.32 ± 0.32 log10 CFU/g). They also exhibited significantly lower SE colonization of the ovaries (1/30), spleen (3/30), liver (4/30), and ceca (7/30) compared to nonvaccinated birds. These results provide empirical evidence that eBeam-based SE vaccines are immunogenic and are capable of protecting chickens against SE colonization. The advantages of eBeam-based vaccine technology are that it is nonthermal, avoids the use of formalin, and can be used to generate inactivated vaccines rapidly to address strain-specific infections in farms or flocks.

Development of hen antihepatitis B antigen IgY-based conjugate for ELISA assay.

Background:Chicken antibodies have many advantages to the mammalian antibodies and have several important differences against mammalian IgG with regard to their specificity and large-scale production. In this study, the production, purification, and HRP conjugation of polyclonal IgY against hepatitis virus surface antigen (HBsAg) were carried out.Materials and Methods:Single Comb White Leghorn hens were immunized intramuscularly with hepatitis B vaccine in combination with Freund's adjuvants. Blood and eggs were collected before and during ten weeks after the first immunization.Results:A highly purified of 180 KDa with specific activity of 200 mIU/ml was obtained by our purification protocol. One milligram of the purified IgY was labeled with horseradish peroxidase (HRP). Sandwich ELISA was used to determine the optimum titer of anti-HbsAg IgY-conjugate which was found to be 1:20.Conclusions:This study showed that laying hens can be used as an alternative source for production of polyclonal antibodies against HBsAg and anti-HBs IgY could be labeled with HRP enzyme and could subsequently be used successfully as secondary antibody in ELISA for detection of HBsAg in the patients sera.

Modeling ovarian follicle growth in commercial and heritage Single Comb White Leghorn hens

Approximately 84% of the energy in chicken eggs resides in the yolk. A robust model of ovarian follicle development is therefore valuable for estimating energy requirements of laying hens. The current experiment was designed to model the growth of ovarian follicles in 32-wk-old modern commercial line (CL) and unselected heritage line (HL) Single Comb White Leghorn hens. The volume of yolk deposited daily during the rapid growth phase (RGP) was estimated using a double dye technique. For 21 d, 8 CL and 8 HL hens were fed capsules (no. 1) containing Sudan IV (red) and Sudan Black dyes on alternate days. An additional 8 control CL hens were fed empty capsules. Eggs were collected, and the daily volume of yolk deposited was estimated. Significant differences are reported where P < 0.05. Dye had no significant effect on BW, ME intake, or egg weight. Maintenance ME requirements were 192 and 177 kcal/kg0.67 for CL and HL hens, respectively. Duration of the RGP was shorter (7.35 d) in the CL hens compared with the HL hens (7.95 d). A nonlinear Lomolino model described follicular weight, which varied between strains over d 2 to 9 of follicle development; at each day during development, follicle weights were higher where RGP were shorter. The volume of yolk deposited for the 8 d preceding oviposition in CL was 0.17, 0.28, 0.43, 0.99, 1.84, 2.47, 2.82, 2.86, and 2.51 cm3; and in HL was 0.17, 0.33, 0.72, 1.40, 2.15, 2.46, 2.48, 2.32, and 1.93 cm3. The HL had a higher rate of yolk deposition 7 to 5 d before oviposition, and CL had a higher rate of yolk deposition 3 to 1 d before oviposition with no significant difference between lines on d 4 before oviposition. Although growth patterns differed, there were no differences among lines in final follicle weights (14.1 g) or retained energy (42.4 kcal).

Salmonella Enteritidis Flagella may Enhance Attachment and Invasion of Hen Ovarian Granulosa Cells and Induce Protective Immune Response in Egg-laying Hens

Aims: To study the effect of flagellin on bacterial attachment and invasion of avian ovary cells in vitro by comparing the attachment and invasion of wild-type S. Enteritidis with nonmotile mutants. To assess the immunogenic properties of extracted flagellin against Salmonella Enteritidis experimental infection in laying hens. Methodology: Non-flagellated mutants for wild-type S. Enteritidis (phage type 8, 13A and 28) were produced by using a strain of S. Enteritidis, SA4502, which carried an fliC::Tn 10 to transfer fliC::Tn 10 insertion into the wild type strains using phage 22 (P22)-mediated transduction with selection for antibiotic resistance encoded within the mutant alleles. Granulosa cells were harvested from Single Comb White Leghorn hens between 18-45 weeks of age. Flagellin was purified from the studied bacterial cultures of Salmonella Enteritidis following reported methods. Laying hens were immunized with the flagellin with adjuvant Results: Non-motile mutants of S. Enteritidis phage wild types were analyzed to confirm the elimination of H1 flagellin synthesis. Wild-type and fliC mutant strains were assessed for Original Research Article British Microbiology Research Journal, 4(4): 418-427, 2014 419 their ability to adhere to hen's ovarian granulosa cells. The adherence of the mutant strain was reduced nearly ten-fold compared with that of the wild-type phage 8. Similarly, light microscopic observation of fixed cover slips from wild-type phage types and its mutant strain revealed fewer numbers of the bacterial mutants adhered to the cultured granulosa cell monolayer. Light microscopy revealed similar findings for mutant phage types 28 and 13 A when compared to the wild-type control. There was five folds rise in the egg yolk antibody during the 2-3 weeks post-immunization. No rise was detected in the egg yolk samples from the control hens injected with the placebo mixture without flagellin. Conclusion: It was concluded that Flagellin has an important role in the attachment and invasion of Salmonella Enteritidis to avian ovary cells and that it can be used as immunogenic components to induce a protective immune response in vaccinated hens against challenge infection with the wild type strains.

Impact of fowlpox-vectored Mycoplasma gallisepticum vaccine Vectormune FP MG on layer hen egg production and egg quality parameters

This study was conducted to determine the impact of vaccination with Vectormune FP MG on egg production and egg quality characteristics of Single Comb White Leghorn hens. Due to questions of the efficacy of this vaccine in preventing Mycoplasma gallisepticum-mediated pathology, the ability of this vaccine to protect against postproduction-peak egg losses associated with F-strain M. gallisepticum (FMG) vaccination was also investigated. Vaccination with Vectormune FP MG did not result in any significant change in egg production or egg quality parameters compared with control (unvaccinated) hens. Subsequent revaccination with FMG at 45 wk of age (woa) yielded no impact on egg production or egg quality parameters of Vectormune FP MG vaccinated hens, unlike prior results for postproduction-peak vaccination of M. gallisepticum-clean hens with FMG, which exhibited a drop in egg production of approximately 6%. No difference in egg size distribution was observed for any of the treatment groups before or after FMG revaccination. These results suggest that hens can be safely vaccinated with Vectormune FP MG as pullets and can be revaccinated with a live M. gallisepticum vaccine such as FMG at a later date with no deleterious effects on egg production or egg or eggshell quality parameters.

Effects of Different Induced Molting Methods on the Performance of Commercial Layers

A total of 1600 commercial strain (Nick Chick) Single Comb White Leghorn hens, 90 week of age, were used in this study to determine the effects of different induced molting programs on production and immune parameters. The hens were randomly divided into four treatment groups (three experimental and one control) of 400 hens each. The hens in the first treatment group were fed a layer ration containing 4 g/kg diet of C for 5 d and received a reduced photoperiod of 8 h/d for 5 d (Al2O3 group). In the second group, feed was withdrawn for 10 d, the photoperiod was reduced to 8 h/d and oyster shell and water were provided for ad libitum consumption. At Day 11, hens consumed corn and oyster shell ad libitum until Day 30 and at Day 31, hens was returned to a full feed layer ration and received 16 h of light/d (California group). In the third treatment, birds were provided feed and water ad libitum for one day with 8 h light. During day 2-3, feed and water were withdrawn. On 4th day water was provided but no feed was given. On 5 to 49 days, birds were offered feed 27 g each till egg production was reached upto 1%. Water was provided ad libitum. Full feed at the rate of 112 g each bird was offered from day 50 onward. Birds received 8 h of light till 49 days which was increased to 16 h on 50th day onwards (Washington group). The last group served as control. Body weight, egg production, egg size, internal egg quality, shell weight and mortality were determined. Total circulating leukocytes and differential leukocyte counts were also measured. The results demonstrated that induced molting significantly increased egg production from 65 to 75 to 81%, Haugh units from 80.1 to 85.6 to 87.0 and shell weight from 5.4 g to 6.3 to 6.5 g when compared to control. The total circulating leukocytes was significantly lower in molted hens than in control hens. Differential leukocyte counts were affected by all induced molting programs and the heterophil to lymphocyte ratio was significantly increased, reaching 0.60, whereas that of controls was only 0.19.

Effect of Enzymatic Treatment of Saudi Date Pits on Performance of Single Comb White Leghorn Hens and the Fatty Acid Profile of Their Eggs

Date pits can be considered one of the un-traditional feed for layers. These pits contain high level of linoleic and oleic acids, unsaturated fatty acids, essential for human health. Pits also contain high level of fiber (13-18%). This nutrient is difficult to digests by the birds and need to be broken down. Specific enzymes can be used to break the cellulose to improve the nutritional value of the pits. As a result, energy may be released and utilized by the birds. Having this in mind, an experiment was conducted using 4 levels of ground date pits; 0, 5, 10 and 15% with or without added enzymes and studied the effect on performance of the birds and the fatty acids content of the egg. The experiment was lasted for 12 to 2 week periods. The results of the chemical analysis showed that date fats contain high percentage of Oleic Acid which may have contributed to higher level of this fat in egg yolk of birds treated with date pits. Performance criteria results provided evidence that 10% date pits can be included in the layer diet if enzymes are present without adverse effect.

The Long Term Effects of Fairly Low-level of Supplemental Fat on the Productive Performance of Commercial Layers.

Laying hens were fed commercial diets added with supplemented fat (SFAT) at 0.6, 1.2, and 1.8% in order to study the long term dietary effects - on - their productive performance from 22 to 75 wk of age. Five hundred and seventy six Single Comb White Leghorn hens were assigned to one of the four dietary treatments. The experimental phase consisted of three periods of 18 wk each. The final body weight and gain of hens fed on diets with SFAT at 1.2% and 1.8% were lower (p<0.05) than those hens given no SFAT. The SFAT at the 1.2% and 1.8% levels improved egg production rate, egg weight and mass, as well as FCR. Mortality and feed consumption were not affected by dietary SFAT. Administration of a diet with SFAT significantly decreased the cracked-broken egg ratio (p<0.01). The beneficial effects of SFAT on egg production performance were particularly more pronounced at intermediate and later ages. Hence, SFAT by period interactions were significant for all traits studied except feed intake. Hens fed SFAT deposited significantly higher abdominal fat than those on the no-SFAT diet. As a result, SFAT at 1.2% and 1.8% inclusion levels provided benefits in terms of efficient table egg production.

Tomato pomace and safflower meal as ingredients in non-feed-removal molt diets

SUMMARY In California, where more than 90% of processed tomatoes in the United States are produced and 50% of the US production of safflower seeds is grown, there is an abundance of tomato pomace, a by-product of tomato processing, and safflower meal from decorticated safflower seeds. Diets with these 2 ingredients may produce molt and postmolt results comparable with a recommended no-added-salt non-feed-removal diet. Therefore, molt and postmolt measurements were compared in third-cycle Single Comb White Leghorn hens fed non-feed-removal diets containing 1) corn and soybean meal (CS8, control), 2) corn meal with no added salt (C-NS), 3) C-NS and safflower meal (C-NS-SM), 4) or C-NS and tomato pomace (C-NS-TP). During the molt, birds fed C-NS-TP consumed amounts of feed comparable with those of birds fed the other test diets; however, birds fed tomato pomace had lower BW and observably more diarrhea than other birds. Mortality did not differ among birds fed the treatment diets during the molt and postmolt periods. No differences were observed among treatment groups for postmolt BW, mortality, specific gravity of eggs, and eggshell thickness. Postmolt egg production was different among treatment groups, ranked as CS8 > C-NS > C-NS-SM > C-NS-TP. After molting, hens fed the C-NS-SM and C-NS-TP diets produced lower egg weights than did hens fed the CS8 and C-NS diets. The Haugh units for eggs from hens fed the C-NS, C-NS-SM, and C-NS-TP diets were higher than those for eggs from hens fed the CS8 diet. Overall, feeding safflower meal yielded results for feed consumption and BW comparable with those of feeding the no-salt diet during molt. However, except for egg production, postmolt measurements were equivalent among the C-NS, C-NS-SM, and C-NS-TP diets. We conclude that tomato pomace is useful in non-feed-removal molt diets.

Bone measurements of molted layers fed low-salt corn and soybean meal diets containing safflower meal or tomato pomace

In California, because of high levels of production of tomatoes and safflower seeds, there is an abundance of tomato pomace, an agricultural by-product of tomato processing, and safflower meal from decorticated safflower seeds. It is possible that these agricultural by-products could be used in non-feed-removal molt diets for laying hens. Third-cycle Single Comb White Leghorn hens were fed non-feed-removal molt diets, under 8 h of light, containing either corn-soybean meal (CS8, the control), corn meal with no added salt (C-NS), C-NS + safflower meal, or C-NS + tomato pomace to induce molting. A control diet with 16 h of light was included to indicate any environmental factors, excluding 8 h of light and experimental diets, that could induce molt. After 8 wk postmolt, the left tibias of 6 hens per treatment (1 per replicate pen) were examined for bone health, including mineral density, mineral content, ultimate load, ultimate stress, stiffness, and ash. Bone mineral density for hens fed C-NS + tomato pomace was statistically lower than that for hens fed CS8 (P ≤ 0.07). No differences were observed between the other diets and CS8 for bone density and all other measurements. We concluded that safflower meal and tomato pomace could be used as effective components of non-feed-removal molt diets. A postmolt source of calcium should be included when feeding tomato pomace during molt.

Changes in Peyer’s Patch and Cecal Tonsil B Lymphocytes in Laying Hens Following Challenge with Salmonella enterica Serovar Enteritidis

Two trials were conducted to determine B cell changes in Peyer's Patches (PP) and Cecal Tonsils (CT) of specific-pathogen-free Single Comb White Leghorn hens challenged with Salmonella enterica Serovar Enteritidis (SE). Prior to challenge and then weekly post challenge, 4 or 3 hens in Trials 1 and 2, respectively, were sacrificed and their intestinal tracts excised. Cells were purified from proximal and distal PP along with both CT and then aliquots of cells were incubated with antibodies to chicken immunoglobulins IgM, IgG and IgA. The B cells expressing the different immunoglobulin isotopes were identified via flow cytometric analysis. B lymphocytes expressing IgM were most prevalent, representing 40-60% and 30-50% of CT and PP B cells, respectively, while 20-30% of CT and PP lymphocytes expressed IgA. Only a small percentage of CT and PP lymphocytes, <10%, expressed IgG. Significantly more IgM+ cells were detected in CT vs proximal and distal PP and proximal PP in trials 1 and 2, respectively. Significantly more IgA+ cells were observed in proximal PP vs distal PP and CT in trial 1 but not in trial 2. Following SE infection, these differences were no longer observed. For IgG+ cells, however, no significant differences between tissues were observed prior to challenge but significantly more IgG+ cells were observed in both PP vs CT at weeks 1 and 3 post challenge in trial 1 and week 1 post challenge in trial 2. These results indicate that B lymphocyte differences do occur in PP vs CT in adult chickens and these populations can change in response to stimuli such as intestinal infection.

Evaluation of limit feeding varying levels of distillers dried grains with solubles in non-feed-withdrawal molt programs for laying hens

An experiment was conducted with 672 Hy-Line W-36 Single Comb White Leghorn hens (69 wk of age) to evaluate the effects of feeding varying levels of corn distillers dried grains with solubles (DDGS) with corn, wheat middlings, and soybean hulls on long-term laying hen postmolt performance. The control molt treatment consisted of a 47% corn:47% soybean hulls (C:SH) diet fed ad libitum for 28 d. Hens fed the other 7 treatments were limit fed 65 g/hen per day for 16 d, and then fed 55 g/hen per day for 12 d. Hens on treatments 2 and 3 were fed 49% C:35% wheat middlings (WM) or SH:10% DDGS diets (C:WM:10DDGS, C:SH:10DDGS). Hens on treatments 4 and 5 were fed 49% C:25% WM or SH:20% DDGS diets (C:WM:20DDGS, C:SH:20DDGS). Those on treatments 6 and 7 were fed 47% C:47% DDGS (C:DDGS) or 47% WM:47% DDGS (WM:DDGS) diets. Those on treatment 8 were fed a 94% DDGS diet. At 28 d, all hens were fed a corn-soybean meal layer diet (16% CP) and production performance was measured for 36 wk. None of the hens fed the molt diets went completely out of production, and only the C:SH and C:SH:10DDGS molt diets decreased hen-day egg production to below 5% by wk 4 of the molt period. Postmolt egg production was lowest (P < 0.05) for the C:WM:20DDGS treatment. No differences (P > 0.05) in egg weights were detected among treatments throughout the postmolt period. In addition, no consistent differences were observed among treatments for egg mass throughout the postmolt period. Overall results of this study indicated that limit feeding diets containing DDGS at levels of 65 or 55 g/hen per day during the molt period did not cause hens to totally cease egg production.

Effect of High Environmental Temperature on Egg Production, Serum Lipoproteins and Follicle Steroid Hormones in Laying Hens

The aim of this study was to establish which aspect of egg production, plasma lipoproteins and preovulatory follicle steroid hormones in laying hens is altered by thermal environment. In experiment 1, Single Comb White Leghorn hens (80-90wk of age) were exposed to three levels of environmental temperature by rotation (23, 27 and 31°C) for total 3 months, and feed intake, rectal temperature and egg production parameters were measured in each experimental period. In experiment 2, the hens (80wk of age) were exposed to two levels of environmental temperature (23 and 31°C) for 7 days, and concentration of plasma lipoproteins and follicle steroid hormones were determined. Feed intake in hens exposed to 31°C significantly decreased compared with that at 23 and 27°C, and rectal temperature at 31°C was significantly higher than that at 23°C. In the egg production parameter, egg yolk density was significantly smaller at 27 and 31 than at 23°C. Finally, the concentrations of very low density lipoprotein in serum, and of estradiol 17-β and progesterone in follicles were adversely affected by environmental temperature at 31°C. These results suggest that high environmental temperature negatively influences both the lipoprotein and steroid hormones and consequently reduces egg production, but the reduction in feed intake is not the only reason for a decline in egg quality in laying hens.