White Hy-Line Research Articles

Supplemental phosphorus can be completely replaced with microbial phytase in White Leghorn layer diets

ABSTRACT 1. A study was conducted to assess the possibility of totally replacing supplemental phosphorus sources in White Leghorn (WL) layer diets (aged 28 to 45 weeks of age) with microbial phytase supplementation. One thousand commercial layers (HyLine White) of 28 weeks of age were housed in California cages fitted in open-sided poultry shed at the rate of 20 layers in each replicate. Ten replicates were randomly allotted to each treatment, and the respective diet was fed from 28 to 45 weeks of age. 2. A control diet (CD) containing the recommended levels of non-phytate phosphorus (3.6 g/kg NPP) and four other test diets (2–5) having sub-optimal levels of NPP (2.4, 2.0, 1.6 and 1.2 g/kg), but with supplemental microbial phytase (600 FTU/kg) were prepared and fed for the trial duration. 3. The layers fed with lower levels of NPP with phytase had the same laying performance as the group fed the CD. Egg production, feed efficiency, egg mass, shell defects, egg density, shell weight, shell thickness, ash content and breaking strength of the tibia and sternum were not affected by feeding the lowest concentration of NPP (1.2 g/kg) plus microbial phytase. 4. Phytase supplementation in diets with sub-optimal levels of NPP (2.4, 2 and 1.6 g/kg) significantly improved the Haugh unit score compared to those fed the CD. 5. It was concluded that supplemental phosphorus can be completely replaced with microbial phytase (600 FTU/kg) in a diet without affecting egg production, shell quality or bone mineral variables in WL layers (28 to 45 weeks).

Biochemical and molecular effects of a commercial diuretic with herbal extract on experimentally induced urolithiasis in chickens.

This study evaluated the diuretic, antioxidant, anti-inflammatory, and immunological effects of a commercial diuretic (CD) (composed of ammonium chloride, potassium citrate, sodium chloride, ascorbic acid, biotin, halfa bar extract, and hexamine) on chickens with induced urolithiasis. A total of 100 one-day-old white Hy-Line chicks were fed a basal diet containing 20% crude protein (CP) and 1% Ca until they reached 48 days of age. Then, the birds were divided into five groups (G1-G5). G1 was fed a basal diet and kept as a negative control, G2 was fed a high protein (HP) diet containing 25% crude protein, G3 was fed high calcium (HC) diet containing 5% Ca, G4 was fed HP diet supplemented with CD, and G5 was fed HC diet supplemented with CD. The CD was supplemented with drinking water (at a dose of 0.5 ml/ liter) for 1 week. The experiment was held for 78 days. Clinical signs, postmortem lesions, and mortality rates were observed. Biochemical analytes, redox status biomarkers, and expression of interleukin-6 (IL-6) and interferon-gamma (IFN-γ) were measured. Tissue samples were taken for histopathological examination. No signs of CD toxicity were observed during the toxicity test prior to the experiment. Compared to all groups, birds in G2 and G3 showed impaired renal function and alterations in biochemical, redox status, lipid peroxidation, post-mortem, and histopathological lesions along with upregulation of IL-6 and IFN-γ in the kidney and spleen. In conclusion, commercial diuretic supplementation for one week improves renal function, redox status, immune and anti-inflammatory responses in chickens with induced urolithiasis.

Paneth cells mediated the response of intestinal stem cells at the early stage of intestinal inflammation in the chicken

The rapid renewal and repair of the intestinal mucosa are based on intestinal stem cells (ISC), which are located at the crypt bottom. Paneth cells are an essential component in the crypt, which served as the niche for ISC development. However, in the chicken, how the function of Paneth cells changes during intestinal inflammation is unclear and is the key to understand the mechanism of mucosal repair. In the present study, 36 HyLine White chickens (7 d of age, n = 6) were randomly divided into 1 control and 5 lipopolysaccharide (LPS) injection groups. The chickens were injected (i.p.) with PBS in the control group, however, were injected (i.p.) with LPS (10 mg/kg BW) in the LPS injection groups, which would be sampled at 5 time points (1 h postinjection [hpi], 2 hpi, 4 hpi, 6 hpi, and 8 hpi). Results showed that tumor necrosis factor-α mRNA transcription in duodenal tissue increased gradually since 1 hpi, peaked at 4 hpi, and then reduced remarkably, indicating that 4 hpi of LPS was the early stage of intestinal inflammation. Meanwhile, the MUC2 expression in duodenal tissue was dramatically reduced since 1 hpi of LPS. The ISC marker, Lgr5 and Bmi1, in the duodenal crypt were reduced from 1 hpi to 4 hpi and elevated later. Accordingly, the hydroethidine staining showed that the reactive oxygen species level, which drives the differentiation of ISC, in the duodenal crypt reduced obviously at 1 hpi and recovered gradually since 4 hpi. The analysis of Paneth cells showed that many swollen mitochondria appeared in Paneth cells at 4 hpi of LPS. Meanwhile, the Lysozyme transcription in the duodenal crypt was substantially decreased since 1 hpi of LPS. However, the Wnt3a and Dll1 in duodenal crypt decreased at 1 hpi of LPS, then increased gradually. In conclusion, Paneth cells were impaired at the early stage of intestinal inflammation, then recovered rapidly. Thus, the ISC activity was reduced at first and recovery soon.

Biochemical and molecular investigation of oxidative stress associated with urolithiasis induced by increased dietary calcium or protein in chickens.

This study was carried out to evaluate the effects of induced urolithiasis by high dietary calcium (Ca) or protein levels on biochemical analyte levels, redox status, selected inflammatory cytokines and histopathology in chickens. A total of 90 one-day-old white Hy-Line chicks were fed basal control diets containing 20% crude protein (CP) and 1% Ca until they reached 44days of age. After that, the birds were divided into three groups (30 birds per group). All management factors (light, temperature, ventilation, stock density and diet) were identical among the three groups throughout the study except for the dietary Ca and protein percentages. Group I was fed a control diet containing 20% CP and 1% Ca, group II was fed a high-Ca diet containing 5% Ca, and group III was fed a high-protein diet containing 25% CP. Our findings clearly demonstrated that dietary imbalance (caused by high-Ca or high-CP levels) per se in chickens was physiologically harmful, as it was accompanied by post-mortem lesions; biochemical, redox status and histopathological alterations; and upregulation of inflammatory cytokines (interleukin (IL)-1β and IL-6). In particular, the birds fed the high-Ca diet clearly exhibited the most obvious alterations in most of the endpoints. In conclusion, this study constitutes the first extensive investigation of the effects of high-Ca or high-protein diets induced urolithiasis on growth performance, redox status, inflammatory cytokine levels and pathological characterization in chickens.

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.

Evaluation of the Safety and Protection Efficacy of spiC and nmpC or rfaL Deletion Mutants of Salmonella Enteritidis as Live Vaccine Candidates for Poultry Non-Typhoidal Salmonellosis.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a host-ranged pathogen that can infect both animals and humans. Poultry and poultry products are the main carriers of S. Enteritidis, which can be transmitted to humans through the food chain. To eradicate the prevalence of S. Enteritidis in poultry farms, it is necessary to develop novel vaccines against the pathogen. In this study, we constructed two vaccine candidates, CZ14-1∆spiC∆nmpC and CZ14-1∆spiC∆rfaL, and evaluated their protective efficacy. Both mutant strains were much less virulent than the parental strain, as determined by the 50% lethal dose (LD50) for three-day-old specific-pathogen free (SPF) White Leghorns and Hyline White chickens. Immunization with the mutant candidates induced highly specific humoral immune responses and expression of cytokines IFN-γ, IL-1β, and IL-6. In addition, the mutant strains were found to be persistent for almost three weeks post-infection. The survival percentages of chickens immunized with CZ14-1∆spiC∆nmpC and CZ14-1∆spiC∆rfaL reached 80% and 75%, respectively, after challenge with the parental strain. Overall, these results demonstrate that the two mutant strains can be developed as live attenuated vaccines.

The Effect of Phytase on Production Performance, Egg Quality, Calcium and Phosphorus Excretion, and Fatty Acids and Cholesterol Concentration in Hy-Line Layers Fed Diets Containing Rice Bran

SUMMARY According to low availability of phosphorus in plant protein sources like rice bran, the importance of phosphorus requirement in poultry nutrition especially layers is increasing. This experiment was conducted to investigate the effects of phytase in diets containing different levels of rice bran on production performance, egg quality, and fatty acids and cholesterol concentration which affects the nutritional value of layer eggs. A total of 120 62-wk-old white Hy-line W-36 layer hens had corn-soybean diets with different levels of rice bran (0, 15, and 25%) and with or without phytase supplementation (250 FTU/kg). The eggshell weight and thickness were higher in phytase supplemented group. Haugh unit was not significantly different between experimental groups. The highest egg and yolk weight belonged to a treatment group supplemented with 25% rice bran. Inclusion of 25% rice bran increased egg weight, but decreased hen house egg production; hence, the egg mass did not show any significant changes. Cholesterol concentration of eggs in a group with 25% rice bran decreased, but fatty acids, omega-3, and omega-6 concentration increased significantly in the experimental diets supplemented with rice bran. Phytase supplemented groups had a significant decrease in the excretion of P and Ca which reduced the environmental concerns attributed to P excretion. In conclusion, the layers fed 250 FTU/kg phytase supplemented with 25% rice bran had improved performance, egg composition, and shell quality.

Quality comparison of retorted Samgyetang made from white semi-broilers, commercial broilers, Korean native chickens, and old laying hens.

ObjectiveThe aim of this study was to compare the quality characteristics of retorted Samgyetang (Korean ginseng chicken soup) made from white semi-broilers (WSB; Ross× Hyline white, 3 weeks old), commercial broilers (CB; Ross, 4 weeks old), Korean native chickens (KNC; Hanhyup-3-ho, 12 weeks old) and old laying hens (OLH; Hyline white, 72 weeks old) and to explore the possibility of using the carcasses of KNCs and OLHs as raw material for product diversification.MethodsRaw and cooked meat quality, fatty acid composition and consumer acceptance were analyzed.ResultsAmong the chicken breeds, OLH and KNC showed a higher shear force value than WSB and CB due to high insoluble collagen contents. However, the meat of KNC was more tender than that of OLH. The meat of OLH was characterized by the lowest moisture content and highest crude fat content. The meat of KNC was characterized by a higher proportion of saturated fatty acids, α-linolenic acid and arachidonic acid than that of OLH. The meat of OLH showed the highest content of unsaturated fatty acid, particularly linoleic acid, in its thigh meat. Electronic nose readings revealed that the meat aroma pattern was clearly different across breeds. OLH had the lowest overall acceptance score, while no differences were found in flavor, texture, juiciness and appearance among WSB, CB, and KNC.ConclusionKNC shows potential as raw material for Samgyetang, while additional preprocessing methods, such as tenderization and fat removal, are required for the utilization of OLH as raw material for retorted Samgyetang.

Low-dose of organic trace minerals reduced fecal mineral excretion without compromising performance of laying hens.

ObjectiveThe objective of this study was to investigate the effects of low doses of organic trace minerals (iron, copper, manganese, and zinc) on productive performance, egg quality, yolk and tissue mineral retention, and fecal mineral excretion of laying hens during the late laying period.MethodsA total of 405 healthy hens (HY-Line White, 50-week-old) were randomly divided into 3 treatments, with 9 replicates per treatment and 15 birds per replicate. The dietary treatments included feeding a basal diet + inorganic trace minerals at commercial levels (CON), a basal diet + inorganic trace minerals at 1/3 commercial levels (ITM), and a basal diet + proteinated trace minerals at 1/3 commercial levels (TRT). The trial lasted for 56 days.ResultsCompared to CON, ITM decreased (p<0.05) egg production, daily egg mass, albumen height, eggshell strength, yolk Fe concentration, serum alkaline phosphatase activity and total protein, and increased (p<0.05) egg loss and feed to egg ratio. Whereas with productive performance, egg quality, yolk mineral retention, and serum indices there were no differences (p>0.05) between CON and TRT. The concentrations of Fe and Mn in the tissue and tibia were changed notably in ITM relative to CON and TRT. Both ITM and TRT reduced (p< 0.05) fecal mineral excretion compared to CON.ConclusionThese results indicate that dietary supplementation of low-dose organic trace minerals reduced fecal mineral excretion without negatively impacting hen performance and egg quality.

Immunological and pathological effects of vitamin E with Fetomune Plus® on chickens experimentally infected with avian influenza virus H9N2

Avian influenza virus (AIV) H9N2 infection causes economic losses on poultry farms, and immunostimulants are essential for improving chicken immunity. This study evaluated the immunological and pathological effects of vitamin E with Fetomune Plus® (a commercial product based on a yeast extract and vitamins) on chickens experimentally infected with AIV H9N2. Three groups of white Hy-Line chicks were included. The G1 group was kept as an uninfected untreated control, the G2 group was intranasally infected with the AIV H9N2 strain (0.5 ml of 106 50% egg infectious dose (EID50)), and the G3 group was infected and treated with vitamin E (200 mg/kg of diet) and Fetomune Plus® (1 ml/liter of drinking water) for four weeks. The gene expression of interferon-gamma (IFN-γ), interleukin (IL)-6, and IL-2 was determined at 3, 5 and 7 days post-infection (PI). Virus shedding titers and rates and haemagglutination inhibition (HI) antibody titers were detected. Clinical signs, mortalities and post-mortem lesions were recorded. The birds were weighed, and relative organ weights were calculated. Tissue specimens were taken for histopathological examination and immunohistochemistry (IHC). The expression of IFN-γ in the duodenum revealed a significant increase in G2 compared to G3 at 3 days PI, while the duodenal and splenic expression of IL-6 was significantly increased in G2 compared to G3 at 5 days PI. IL-2 was overexpressed in the duodenum in G3 compared to G2 at 3 and 5 days PI. A significant decrease (P ≤ 0.05) in the virus shedding titer and an increase in the HI titers were detected in G3 compared to G2. The clinical signs and the mortality rate were clearly appeared in G2 than in G3. By IHC, lower H9N2 staining intensity was observed in the examined organs from G3 than in those from G2. In conclusion, as a first report, vitamin E with Fetomune Plus® supplementation for four weeks could improve the immunological and pathological effects of H9N2 infection on chickens.

Characterization of chicken IgY produced against H5 and H9 avian influenza viruses

Avian influenza viruses are causing sever drawbacks on the poultry industry in Egypt requiring additional approaches together with vaccination to overcome its endemicity. On this study, twelve white Hy-Line layers were immunized with H5N1 and H9N2 viruses. Throughout the experiment (8 weeks), regular blood samples were collected weekly with daily egg collection. The purified IgY was tested for titres and specificity in hens' sera and egg yolk samples using Hemagglutination-inhibition(HI) and neutralization tests(NT). HI test showed that the antibodies titre values against H5N1 and H9N2 increased from the 1st week in the serum and 2nd week in the yolk until reaching a peak at the 4th week in serum and 5th week in the yolk. The peak was maintained over 3 weeks in the yolk of H5N1 and H9N2 and in the serum of H5N1 and over 4 weeks in the serum of H9N2 followed by non-significant decrease until the 8th week. The percentage of transfer of H5N1 antibodies ranged from 6.25% to 50% and for H9N2 ranged from 3.12% to 12.5%. NT showed that the neutralization index of H5N1 and H9N2 were toward homologous 3.9 and 5.04, respectively. Cross NT showed no egg protection with 100% death, but with retardation of the death time. In Conclusion, our results revealed the presence of significant titres of purified IgY against H5N1 and H9N2 influenza viruses in eggs and the possible role of egg yolk IgY in neutralization of avian influenza viruses.

EFFECT OF STRAIN, SEASON AND BREEDER'S AGE ON SOME PHYSIOLOGICAL PARAMETERS FOR LAYER DEAD EMBRYO

The effect of breederʼs strain (Hy-line Brown and Hy-line White W36) flock aged (28, 36, 46, 55, 66 weeks of age) and breeding season on some physiological measurements in egg, demand organs, dead supply organs and lymphoid organs were examined. At each age, 10 unhatched eggs from each genotype were examined on embryo weight percentage, Chorioallotoic weight %, albumen pH %, yolk pH %, residual yolk %, pectoral muscles weight %, hatch muscles weight %, heart, liver, lunges, spleen, burse weight percentage. There was a significant difference between layer breeder genotypes for lunges weight percentage the brown was higher (0.84) than the white (0.62). The breeding season had a significant effect on heart, liver, lunges weight percentages in winter higher than summer but yolk pH and residual yolk the summer higher than the winter. Breeder's age significant effect on embryo weight percentage, Chorioallotoic weight %, albumen pH %, yolk pH%, residual yolk %, hatch muscles weight % heart, liver, lunges and burse weight percentage. It could be observed that the genetic differences among layer breeder strain and age of breeders can affect the hatchery performance. Additionally, handling of hatching eggs and incubation management can play a major role to overcome numerous hatching problems. In turn, increasing the production of table eggs and achieves the balance between supply and demand of that strategic commodity in Egyptian market.

Production of chicken hyperimmune egg for immunological purposes in animals

The present study was aimed to produce hyperimmune chicken egg against rabbit hemorrhagic disease virus (RHDV) as well as studying immunogenic characters of the extracted IgY using antigen-antibody reaction tests (agar gel immunodiffusion and ELISA). The study was carried out on ten white Hy-Line layers which received initial immunization of 300µl of RHDV vaccine subcutaneously followed by three booster doses at time intervals of 2, 5 and 8 weeks after initial immunization. Throughout the experiment (14 weeks), regular blood sampling was made every week with daily collection of egg till further purification and detection of the purity of the isolated IgY by SDS-PAGE. Also, determination of the specificity and titers of purified IgY in hens' sera and their purified egg yolk samples was carried out using agar gel immunodiffusion test and indirect ELISA. Results showed presence of considerable titers of isolated IgY against RHDV. Therefore, the current study recommends immunization of hens with RHDV for production of egg yolk antibodies against such pathogen.

Consequence of Cryptosporidiosis on the immune response of vaccinated broiler chickens against Newcastle disease and/or avian influenza.

The consequence of cryptosporidiosis on the immune response of vaccinated chickens against Newcastle disease and/or avian influenza was studied by using 240, 1 day old, male, white Hy-Line chicks and divided into 8 groups and subgroups. Each group or subgroup was consisting of 30 chicks (15 × 2 replicates). The first and second groups were kept as unvaccinated control, G1uninfected and G2 infected. G3, G4 and G5 contained 2 subgroups A&B (G3A, G3B, G4A, G4B, G5A and G5B). Chicks of subgroup A were vaccinated only while chicks of subgroup B were infected and vaccinated. These chicks were orally inoculated with 5 × 10(5) oocysts of Cryptosporidium baileyi (C. baileyi) at 2 days of age. Chickens were vaccinated intraocular with live Newcastle disease (ND) vaccine (Hitchner on day 7th and LaSota on day 17th of chicken life) (G3) or vaccinated by subcutaneous route with Volvac®- H5N2- AI vaccine on day 10 of chicken life (G4). Last group (G5) was infected similarly and vaccinated with ND and AI vaccines with the same day, dose and route of vaccination for each one. Random blood samples were collected for 3 weeks post-vaccination for investigation of humoral immune response against Newcastle and/or avian influenza vaccines by the haemagglutination inhibition (HI) test. The results showed that H5N2 vaccine at day 10 of chicken life is effective in chickens indicated by the geometric mean of HI titer against AI virus. The findings of this study showed that the infection with Cryptosporidia in the broiler chicken has a depressive effect on the immune status of the birds vaccinated against ND and/or AI vaccination. Moreover, the obtained protection rates against challenge with virulent ND virus observed to be parallel to the results of HI- test. Also, by using 2 different antigens (one commercial and field prepared antigen) to avian influenza virus, lower Geometric mean (GM) HI titer were appeared in infected and vaccinated group than vaccinated group only. A study of the relative lymphoid organs weight such as bursa of Fabricius from the experimental chicks indicated that those organs were comparable between the groups infected-vaccinated and vaccinated only. Non significant variations in final live weight between uninfected control and infected groups were indicated. Also, H5N2-AI vaccination at 10 days old did not affect the final live weight. ND and/or AI Vaccination could not be a substitute to application of good hygienic measures and fecal examination of the birds especially for protozoal diseases such as cryptosporidiosis. It could be concluded that cryptosporidiosis could be one cause of ND and/or AI vaccination failure in poultry farms.

Quality of organic eggs of hybrid and Italian breed hens

The quality of eggs laid by 2 hybrid and 2 Italian dual-purpose genotypes of hens reared under organic farming system was studied. Hens belonging to Hy-Line Brown (brown eggshell, HLB), Hy-Line White (white eggshell, HLW), Ermellinata di Rovigo (brown eggshell, E), and Robusta maculata (brown eggshell, R) genotypes were reared from 24 to 43 wk of age. The trial was carried out from July to December, with environmental temperature ranging from 25°C (±5°C, summer) to 13°C (±7°C, autumn). The HLB eggs were heavier (P < 0.01) than HLW (62.9 vs. 60.4 g), and R eggs were heavier (P < 0.01) than E (56.5 vs. 54.4 g). The albumen weight differed (P < 0.01) among HLB, HLW, R, and E (40.7, 38.3, 32.7, 34.1 g, respectively). The E and R yolk weights were similar (16.2 g) and higher (P < 0.01) than hybrids; HLW yolk was higher (P < 0.05) than HLB (15.8 vs. 15.5 g). The HLB showed the highest (P < 0.01, 6.74 g) shell weight and E had the lowest (P < 0.01; 5.43 g). The yolk cholesterol content was higher (P < 0.01) in the Italian eggs than in the hybrids (258 vs. 219 mg/yolk). The HLB yolk had the lowest (P < 0.01) saturated fatty acids (33.8 vs. 34.9%), and R yolks showed the lowest (P < 0.01) monounsaturated fatty acids (36.3 vs. 38.0%) and the highest (P < 0.01) polyunsaturated fatty acids (28.7 vs. 27.4%) than the other groups. The HLW yolk showed the highest (P < 0.01) n-6/n-3 ratio (13.7) in comparison to the other 3 groups (12.8). During 21 d of storage (at 21°C and 62% RH), the E eggs showed the lowest (P < 0.01) quality (albumen height, 4.93 vs. 5.56 mm; Haugh units, 71 vs. 74). A sensory profile of boiled eggs showed differences (P < 0.05) in odor and flavor sensations and in certain yolk and albumen texture properties according to genotype. The quality of organic eggs from different genotypes differs in relation to the strain but also the interaction with the environmental conditions has to be considered.

Comparison of yolk fatty acid content, blood and egg cholesterol of hens fed diets containing palm olein oil and kilka fish oil

The purpose of this study was to compare the effects of dietary palm olein oil (POO) and Kilka fish oil (KFO) on yolk fatty acid content, ratio of fatty acids (FAs), antibody titre, and blood and yolk cholesterol of laying hens. One hundred White Hy-Line 26-wk-old (W-36) hens were allotted to 6 dietary treatments containing 0, 1.5, 3 and 4.5% POO or 2 and 4% KFO. The FAs and cholesterol content of yolk were measured at the end of three consecutive days of each period. Results reveal that the oleic acid increased and palmitic acid decreased (P<0.05) when hens were fed diets containing POO. The KFO diets reduced the blood cholesterol, yolk linoleic acid and yolk ω-6 FA (P<0.05), whereas the blood cholesterol increased by the supplementation of POO to dietary treatments. The yolk long chain polyunsaturated ω-3 FAs [Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] increased as KFO was increased in diets (P<0.001). The diets supplementation of KFO and POO thus, showed a decrease and an increase in the ratio of ω-6/ ω-3 FAs (P<0.05), respectively. It is concluded that supplementation of KFO to the dietary treatment may improve deposition of ω-3 FAs; however, the POO supplementation may improve deposition of ω-9 FAs without alteration of yolk cholesterol. Key words: Palm olein oil (POO), Kilka fish oil (KFO), hens, egg omega-9 and omega-3 fatty acid.

Production and egg quality in layers fed organic diets with mussel meal

The first limiting nutrients in typical laying hen diets are the sulphur-containing amino acids and, in particular, methionine. To fulfil the birds’ recommended requirement, conventional diets are supplemented with synthetic methionine. As this is not allowed in organic production it becomes very important to have access to alternative high-quality protein feed ingredients. An experiment was performed to evaluate the possibility to compose a diet with 100% organically approved feed ingredients using mussel meal as a major source of methionine. The experiment included 678 Lohman Selected Leghorn (LSL) and 678 Hyline White, W-98, layers during 20 to 72 weeks of age. There were 12 aviary pens with 113 birds in each. The birds were fed one of the two experimental diets containing either 3.5% or 7% dried mussel meat meal or a commercial organic diet from a Swedish feed manufacturer for comparison. Production and mortality were recorded daily per group, and egg weight was recorded once weekly. At 33, 55 and 70 weeks, 10 eggs from each treatment group were collected and analysed for internal egg quality. Diets had no significant effect on laying percentage, egg mass, feed intake, feed conversion ratio, mortality, bird live weight or proportion misplaced, cracked or dirty eggs. Egg quality, that is, shell deformation, shell breaking strength, albumen height, shell percentage and proportion of blood and meat spots were also unaffected. There was a significant difference in egg yolk pigmentation, that is, the egg yolk was more coloured when feeding 7% mussel meal compared with the other diets. Hyline hens had lower feed intake and laying percentage, and higher egg weight, but lower egg mass production than LSL birds. The age of the birds influenced all egg quality traits except for meat and blood spots. The dry matter of the excreta was significantly lower for both genotypes fed the 7% mussel meal diet. These results indicate that mussels may be a high-quality protein source and may replace fishmeal in organic diets for layers.

Chemical composition of meat and egg yolk of hybrid and Italian breed hens reared using an organic production system

A trial was done to study the chemical composition of meat and egg yolk of laying hens belonging to different genotypes reared using an organic production system. Two commercial hybrid hens (Hy-Line Brown and Hy-Line White 36) and 2 Italian dual-purpose breed hens (Ermellinata di Rovigo and Robusta Maculata) were reared from 25 to 44 wk of age. During the experimental period (July to December), the environmental temperature decreased from about 25 to 13 degrees C and the RH increased from 62 to 73%. The photoperiod was 16L:8D. Meat and egg yolks of 44-wk-old hens were analyzed. The Italian breeds showed higher meat production and lower egg production when compared with the hybrids. Genotype affected protein, lipid, and ash content of breast and thigh meat. Hy-Line White and Ermellinata di Rovigo showed the lowest (P<0.01) breast lipid and Hy-Line White had the lowest (P<0.01) thigh lipid. Hy-Line White showed higher (P<0.05) breast and thigh cholesterol. Genotype affected egg yolk cholesterol, which was higher (P<0.01) in Italian breeds than in hybrids. The fatty acid profiles of meat and yolk were significantly affected by genotype. The hybrid and Robusta Maculata meat and egg fatty acid composition may be considered to be more favorable to human health. The results indicate that the ability of laying hens to incorporate fatty acids is genetically dependent and a possible interaction between strain and environmental conditions may exist for the absorption and utilization of dietary components.

Effects of Litter Substrate and Genotype on Layers' Use of Litter, Exterior Appearance, and Heterophil:Lymphocyte Ratios in Furnished Cages

Effects of sand versus sawdust as a litter bath substrate in furnished cages for laying hens were studied. The study used 112 Hy-Line White (HYW) and 140 Hy-Line Brown (HYB) layers housed in 18 furnished cages with 14 hens in each cage, generating 4 or 5 replicates per combination of genotype and litter substrate. Traits studied were mortality, feather cover, hygiene of hens, pecking wounds, heterophil/lymphocyte ratios, and hens' use of litter baths. Hens' litter bath use was measured by direct observations and by use of the passive integrated transponder technique. The latter technique allowed for recording of an individual hen's visits to litter baths during the 420-d study. There were no indications of differences between sand and sawdust as litter substrates in mortality rates, exterior appearance, or heterophil/lymphocyte ratios. Litter baths with sand or sawdust were occupied to the same extent but dustbathing behaviors were more frequently seen in baths with sawdust. Hens of both lines visited the litter bath to the same extent but HYB performed more dustbathing. There was large variation in the number of days that individual hens visited litter baths; in fact, 30% of the hens never entered litter baths, whereas some hens visited baths almost every day. The HYB hens had inferior feather cover compared with HYW, indicating that feather pecking occurred more frequently in cages with brown hens. The HYW hens had lower body weight, longer claws, and more comb wounds than HYB. In conclusion, sawdust seems to be an acceptable alternative to sand as a litter substrate in furnished cages.

Physical-Mechanical Modifications of Eggs for Food-Processing During Storage

Physical-mechanical properties of egg constituents and their modifications during storage and poststorage greatly influence the efficiency of food processing, such as the separation of white and yolk by mechanical shelling. Thick albumen height, Haugh unit, yolk index and vitelline membrane-yolk system strength of eggs from Hy-Line White and Lohmann Brown hens were analyzed during 7 mo of storage at 0°C performing 3 poststorage treatments: i) immediately after refrigeration, T1; ii) after a further 6 h at 18°C after refrigeration, T2; and iii) after a week at 18°C after refrigeration, T3. For all qualitative parameters considered, this last poststorage treatment appeared to be the factor that produced the highest decrements; with respect to the first poststorage treatment, a further week at 18°C after refrigeration can involve mean decreases of about 19, 14, 14, and 16% in thick albumen height, Haugh unit, yolk index, and vitelline membrane-yolk system strength (in terms of maximum force), respectively. During about 7 mo of storage at 0°C, the latter parameter decreases, on average, by 10%. Increasing the storage time, physical-mechanical behavior was sometimes divergent from the observed trends.