Evaluation of different non-fasting molting methods on laying performance and egg quality during molting and post molting periods.

The study evaluated different molt-inducing methods to achieve the main goal of molting in commercial layers during molting and post-molting periods. A total of 400 60-week-old Lohmann Brown layers were randomly divided into five groups (eight replicates of 10 birds for each group). Laying hens in the fasting control group received no diet from day 1 to day 10. The second group received a molt-inducing diet recommended by the breeding company. The third group received a wheat bran-based diet. The fourth group received a commercial layer diet with 8,000 ppm zinc (as zinc oxide, ZnO). The fifth group received an induced molting diet given to the second group with 8,000 ppm zinc, respectively. Egg production in the fasting control group and groups fed a diet with ZnO were significantly lower (p < 0.001) than those in groups fed the molt-inducing and wheat bran-based diets without ZnO during molting. Egg laying in the fasting control group was rapidly reduced and stopped on the 5.9th day of molting. In both groups having molt treatment with ZnO, egg production was similarly reduced and ceased on the 6.9th day and 7.0th day of molting, respectively, none of them differed significantly from the control. Layers fed molt-inducing diet or wheat bran-based diet did not reach the cessation of laying even on the 28th d of molting period. Relative weights of the ovary and growing oocytes of layers subjected to fasting or fed diets with ZnO were significantly lower than those of other groups. During the first two weeks of post molting, layers fed molt-inducing diet with ZnO showed higher egg production than the other two groups (p < 0.01). The eggshell strength in the group fed the commercial diet with ZnO was significantly higher than those fed the molt-inducing diet or wheat bran-based diets at 6 weeks of post molting (p < 0.05). These results suggest that the non-feed withdrawal molting using ZnO is more effective in inducing molting and increasing post-molt egg production and egg quality than other methods using a molt-inducing diet alone or wheat bran-based diet without ZnO.

Age of Laying Hens Significantly Influences the Content of Nutritionally Vital Lipophilic Compounds in Eggs.

This study aimed to comparatively analyze the carotenoids, tocopherols, fatty acids, and sterols (e.g., cholesterol) in the eggs of laying hens of early (24 weeks), intermediate (42 weeks), and late age (74 weeks), utilizing high-performance liquid chromatography (HPLC), gas chromatography (GC), and GC-mass spectrometry (MS). The results revealed the significantly (p < 0.05) highest content of nutritionally vital compounds (per g of egg yolk, fresh weight), which included (all-E-)-lutein (21.8 µg), (all-E-)-zeaxanthin (13.4 µg), α-tocopherol (76.5 µg), oleic acid (C18:1n9c; 83.3 mg), α-linolenic acid (C18:3n3; 0.68 mg), γ-linolenic acid (C18:3n6; 0.47 mg), arachidonic acid (C20:4n6; 8.11 mg), docosahexaenoic acid (DHA; C22:6n3; 2.06 mg), and total monounsaturated fatty acids (MUFAs; 94.7 mg) and n-3 polyunsaturated fatty acids (PUFAs; 2.74 mg) in the eggs of early-age laying hens compared to intermediate and late-age. Surprisingly, cholesterol was not significantly different in the eggs obtained from the different age groups. In contrast, the fat quality indices, including the lowest atherogenic index (AI) and thrombogenic index (TI) values and high hypocholesterolemic/hypercholesterolemic (h/H) fatty acid ratio, indicated the health-beneficial potential associated with fat intake from the eggs of intermediate and late-age laying hens. Overall, the results of the present investigation suggest that eggs from early-age laying hens can be recommended for a higher intake of antioxidant carotenoids and tocopherols, while the eggs from intermediate and late-age hens can be recommended for the intake of good quality fats.

Evaluation of energy and amino acids of brown rice and its effects on laying performance and egg quality of layers.

Two experiments were conducted to determine apparent metabolizable energy (AME), nitrogen-corrected AME (AMEn), and ileal digestible amino acid (AA) content of brown rice (BR) and to investigate the effect of dietary supplementation of BR on laying performance and egg quality of laying hens. In Exp. 1, 72 Hy-line Brown layers (49-week-old) were allocated to two treatments using a completely randomized block design, and each treatment included six cages per treatment and six hens per cage. A semi-purified diet was formulated to include BR as the sole source of AA and energy and an N-free diet was used to determine basal endogenous loss of AA. The hens were fed a commercial layer diet for adaptation to the experimental environment and diet for 7 days from d 0, and then fed experimental diets for 5 days from d 7. Excreta were collected from d 10 to 11 and ileal digesta were collected on d 12. On a dry matter (DM) basis, the AME and AMEn of BR was determined at 3,773 and 3,729 kcal/kg, respectively. The apparent ileal digestibility (AID) of BR ranged from 32.7% for Thr to 73.7% for Arg. The range of the standardized ileal digestibility (SID) value was between 79.4% for Met and 96.6% for Lys. In Exp. 2, 252 Hy-line Brown layers (44-week-old) were divided into four groups, comprising seven replicates of nine birds each and assigned to four experimental diets containing 0 (Control), 5%, 10%, or 15% BR for 5 weeks. The BR-containing diets were formulated to be equal in the content of AMEn and digestible AA to those of the diet without BR. No significant differences were observed in laying performances. Egg quality and blood profiles were not linearly or quadratically affected by dietary treatments. These results suggest that up to 15% BR can be included into layer feed without any adverse effects on laying performance and egg quality, if its energy and digestible AA values are well evaluated.

Effects of Dietary Lycopene or Tomato Paste on Laying Performance and Serum Lipids in Laying Hens and on Malondialdehyde Content in Egg Yolk upon Storage.

The present study was undertaken to investigate the effect of dietary, synthetic lycopene or tomato paste on laying performance and egg qualities in laying hens, and on lipid oxidation of stored eggs. One hundred and sixty 38-week-old Hy-line Brown laying hens were randomly housed in cages (two birds per cage, five cages per replicate) equipped with nipples and a trough-type feeder and subjected to one of four experimental diets. Each treatment had four replicates. A corn and soybean meal base diet was added with or without either synthetic lycopene to contain 10 or 20 mg per kg of diet, or with 17 g of tomato paste per kg of diet. The feeding trial lasted four weeks. Feed intake did not differ between dietary treatments. Laying hens fed diets containing lycopene or tomato paste laid lighter eggs (P<0.05) compared with those fed on the control diet. Egg production was higher (P<0.05) in tomato paste-fed layers, but lower (P<0.05) in those fed on a diet containing 20 mg/kg of lycopene compared with the control diet-fed counterparts. Dietary lycopene did not affect egg quality, except for yolk color, nor did serum lipid profiles. Malondialdehyde (MDA) content in serum samples and eggs that had been stored at 24°C for four weeks was reduced (P<0.05) by lycopene or tomato paste. Adding lycopene or tomato paste into a diet of laying hens increased the incorporation of lycopene into the liver and egg yolk. Collectively, the present study shows that addition of low levels of lycopene or tomato paste into the layers' diet is an effective nutritional strategy to enhance oxidative stability of fresh eggs.

Effects of dietary phytoncides extracted from Korean pine (Pinus koraiensis) cone on performance, egg quality, gut microflora, and immune response in laying hens.

This study was conducted to evaluate the effects of dietary phytoncides extracted from discarded Korean pine cones (Pinus koraiensis) on the performance, egg quality, immune response and gut microflora in laying hens. A total of 400 Hy-Line brown laying hens (50-week old) were allotted into four dietary treatments including a control diet or a diet supplemented with phytoncides at 0.002%, 0.004% and 0.008%. During the 6 weeks of experimental feeding, 0.008% of dietary phytoncides improved egg production, feed conversion ratio (p < 0.05), but not feed intake, egg weight or feed efficiency. Although dietary phytoncides had no effect on egg quality, decreases in Haugh units depending on storage periods were improved by 0.008% of dietary phytoncides (p < 0.05). To investigate the roles of dietary phytoncides on the alteration of the immune response during inflammation, lipopolysaccharide (LPS) or saline was intraperitoneally injected into 10 hens per diet group on the end date of the experimental feeding period. Serum immunoglobulins and splenic cytokine expression at mRNA levels were then measured at 4 hr postinjection. Although the levels of IgA were decreased by LPS injection in all dietary groups, dietary phytoncides at 0.008% showed a higher level of IgA by LPS (p < 0.05). Interestingly, although LPS injection resulted in an enhanced expression of proinflammatory cytokines such as IL-1ß and IL-6, dietary phytoncides at 0.008% showed less increased levels of them (p < 0.05). Gut microflora was examined from 10 hens per diet group at the end of the experimental period. While the number of Lactobacillus spp. was increased (p < 0.05), Escherichia coli counts in the cecal contents were decreased by 0.008% of dietary phytoncides. Taken together, these results demonstrate that dietary supplementation of 0.008% phytoncides improved the egg production, immune responses during inflammation and gut microflora in laying hens.

Effects of dietary supplementation with detoxified Rhus verniciflua sap on egg production, yolk lipid and intestinal microflora in laying hens.

OBJECTIVE: This study was conducted to investigate the effects of dietary detoxified Rhus verniciflua sap (RVS) on production performance, egg quality, lipid fractions of egg yolk, liver and serum, and the profile of cecal microflora in laying hens. METHODS: Two hundred 52-week-old Hy-Line Brown layers were randomly divided into 4 groups with 5 replicates per group (2 hens per cage, 5 cages per replicate) and were provided with one of 4 experimental diets containing 0%, 0.05%, 0.1%, or 0.2% RVS, for 6 weeks. Due to unequal intervals of RVS doses, the interactive matrix language procedure of the SAS program was used to correct the contrast coefficients of orthogonal polynomials. RESULTS: There were no differences in feed intake and egg weight among the groups. Egg production increased (linearly and quadratically, p<0.05) with increasing levels of RVS. Eggshell thickness increased (linear, p<0.05) as the level of RVS in diets increased. The levels of blood cholesterol and activities of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were not altered by dietary treatments. Increasing level of RVS increased (linear, p<0.05) the populations of cecal lactic acid bacteria. The content of yolk cholesterol decreased (linear, p< 0.05) with increasing levels of dietary RVS, although there were no significant differences in each lipid fraction of the liver. CONCLUSION: This study indicates that dietary RVS could improve laying performance and eggshell quality, and affect cecal lactic acid bacteria in a dose-dependent manner.

Dietary effects of lutein-fortified chlorella on milk components of Holstein cows.

This study was conducted to investigate the dietary effect of conventional or lutein-fortified chlorella on milk production and lutein incorporation in milk. Fifteen Holstein cows in mid-lactation were used in a 3 × 3 Latin square design each with a 21-day period. Cows were top-dressed daily with 30 g of conventional or lutein-fortified chlorella for 3 weeks. Cows without chlorella served as the control. The feed intake and milk yield were not affected by dietary treatments. The concentrations of milk protein and solids non-fat in groups fed diets containing both conventional and lutein-fortified chlorella were significantly higher than those of the control group (P < 0.001). There was no significant difference in content of milk fat among groups. The levels of plasma glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, interferon-gamma and interleukin-2 were not influenced by the dietary treatments. Lutein content in milk was significantly increased in groups fed lutein-fortified chlorella as compared with those of conventional chlorella and control, respectively (P < 0.01). These results imply that conventional and lutein-fortified chlorella has positive effects on milk components and the use of lutein-fortified chlorella in a dairy diet is effective in the production of milk enriched with lutein.

Effect of dried Chlorella vulgaris and Chlorella growth factor on growth performance, meat qualities and humoral immune responses in broiler chickens.

This experiment was carried out to investigate the effects of dried chlorella powder (Chlorella vulgaris; DCP) and chlorella growth factor (CGF) on growth performance, serum characteristics, meat qualities and humoral immune responses in broiler chicks. A total of 1050 day-old Ross male broiler chicks were randomly divided into 35 pens (30 chicks/pen) and subjected to one of seven dietary treatments. A non-medicated corn-soybean meal base diet was considered as negative control (NC) and added with either antibiotic (PC), three levels of DCP (NC diets added with 0.05, 0.15 or 0.5 % DCP) or two levels of CGF (NC diets added with 0.05 or 0.15 % CGF). The final body weight and daily weight gain in PC and groups fed diets with 0.15 or 0.5 % DCP were heavier (p < 0.001) than those of NC and CGF-treated groups. Serum total lipid concentrations were lower (p = 0.001) in groups fed diets with 0.5 % DCP and 0.05 or 0.15 % CGF compared with PC group. The levels of serum IgG (p = 0.050) and IgM (p = 0.010) were elevated in chicks fed diets with DCP and CGF compared with the PC or NC group. Meat qualities such as cooking loss, meat color, and pH, of edible meats were not altered by dietary treatments. Collectively, these results indicate that dietary DCP, but not CGF, exerted growth-promoting effect, and both DCP and CGF affected humoral immune response in broiler chicks.

Effect of lycopene on the copper-induced oxidation of low-density lipoprotein in broiler chickens.

The present study was undertaken to investigate whether dietary lycopene (LP) could prevent the copper-mediated oxidation of low density lipoprotein (LDL), and affect growth performance, relative organ weights, plasma and meat lipid profiles, and LP contents in plasma and tissues in broiler chickens. A total of 160 day-old male broiler chicks were randomly allotted into 16 pens with rice husk as a bedding material. Each experiment had 4 replicates, 10 chicks per replicate (n = 4 per treatment). A corn-soybean meal base diet was used as a control diet (CONT). To formulate the experimental diets, the base diet was added with LP at the levels of 10 (LP10) or 20 mg/kg (LP20), or 17 g/kg of tomato paste (TP17) which was equivalent to 5 ppm of LP. The experiment lasted 4 weeks. Growth performance and relative organ weights were not affected (p > 0.05) by any of dietary treatments. Dietary LP significantly lowered (p < 0.05) triglyceride and LDL cholesterol at 2 weeks of age, but did not affect them at 4 weeks of age. Total cholesterol in thigh meats was not altered by dietary treatments. LP was not detected in leg meats in all chicks, nor in liver or plasma of the CONT group. LP was found in liver and plasma, being the former greater in the concentration, of the chicks fed diets containing LP10, LP20, or TP17. At 2 and 4 weeks, the copper-mediated oxidation of LDL was delayed (p < 0.05) in either LP- or TP-fed chickens compared with the CONT group. In conclusion, LP lowers triglyceride and LDL cholesterol, is deposited into serum and liver, and prevents the LDL oxidation in broiler chickens, confirming the role of LP in the lipid-lowering and antioxidant properties in broiler chickens.

Growth Performance, Relative Meat and Organ Weights, Cecal Microflora, and Blood Characteristics in Broiler Chickens Fed Diets Containing Different Nutrient Density with or without Essential Oils.

The present study was conducted to investigate whether dietary essential oils could affect growth performance, relative organ weights, cecal microflora, immune responses and blood profiles of broiler chickens fed on diets containing different nutrient densities. A total of eight hundred-forty 1-d-old male broiler chicks were randomly allotted into twenty-eight pens (7 pens per treatment, 30 chicks per pen). There were four experimental diets containing two different nutrient densities and supplemented with or without essential oils. Experimental period lasted for 35 days. No clear interaction between nutrient density and essential oils on any of growth performance-related parameters was observed. Live body weights were affected (p<0.05) by nutrient density at 21 days and by dietary essential oils at 35 days. Essential oils significantly (p<0.05) increased daily body weight gain and feed conversion ratio during the periods of 22 to 35 and 1 to 35 days, but failed to affect feed intake during the entire experimental period. Daily weight gain at 1 to 21 days and feed intake at 1 to 21 and 1 to 35 days were significantly impaired (p<0.05) by nutrient density. There were significant treatment interactions (p<0.05) on relative weights of bursa of Fabricius and abdominal fat contents. Finally, either essential oil or nutrient density did not influence the relative percentages of breast and leg meats, the population of cecal microflora, blood parameters and antibody titers against Newcastle disease and infectious bronchitis in broiler chickens. It was concluded that dietary essential oils, independent to nutrient density, failed to stimulate feed intake, but increased growth performance in broiler chickens.

Effects of Replacing Pork Back Fat with Canola and Flaxseed Oils on Physicochemical Properties of Emulsion Sausages from Spent Layer Meat.

The objective of this study was to investigate the effects of canola and flaxseed oils on the physicochemical properties and sensory quality of emulsion-type sausage made from spent layer meat. Three types of sausage were manufactured with different fat sources: 20% pork back fat (CON), 20% canola oil (CA) and 20% flaxseed oil (FL). The pH value of the CA was significantly higher than the others (p<0.05). The highest water holding capacity was also presented for CA; in other words, CA demonstrated a significantly lower water loss value among the treatments (p<0.05). CA had the highest lightness value (p<0.05). However, FL showed the highest yellowness value (p<0.05) because of its own high-density yellow color. The texture profile of the treatments manufactured with vegetable oils showed higher values than for the CON (p<0.05); furthermore, CA had the highest texture profile values (p<0.05) among the treatments. The replacement of pork back fat with canola and flaxseed oils in sausages significantly increased the omega-3 fatty acid content (p<0.05) over 15 to 86 times, respectively. All emulsion sausages containing vegetable oil exhibited significantly lower values for saturated fatty acid content and the omega-6 to omega-3 ratios compared to CON (p<0.05). The results show that using canola or flaxseed oils as a pork fat replacer has a high potential to produce healthier products, and notably, the use of canola oil produced characteristics of great emulsion stability and sensory quality.

The Tissue Distribution of Lutein in Laying Hens Fed Lutein Fortified Chlorella and Production of Chicken Eggs Enriched with Lutein.

Two experiments were conducted to investigate the dietary effects of conventional or lutein fortified chlorella on lutein absorptions, the tissue distributions and the changes in lutein content of eggs in laying hens. In Exp 1, a total of one hundred and fifty, 70 wk-old Hy-Line brown layers were divided into three groups with five replicates and fed with each experiment diet (control diet, diet with 1% conventional chlorella or lutein fortified chlorella) for 2 wk, respectively. The egg production in groups fed diets containing both chlorella powders were higher than that of the control group (p<0.01). With chlorella supplementations, the yolk color significantly increased, although there were no significant differences in the eggshell qualities. The lutein contents of serum, liver and growing oocytes were greatly increased by feeding conventional or lutein fortified chlorella (p<0.01). In Exp. 2, a total of ninety 60 wk-old Hy-Line brown layers were assigned into three groups with three replicates per group (10 birds per replicate). The birds were fed with one of three experimental diets (0, 0.1 or 0.2% lutein fortified chlorella) for 2 wk, respectively. The egg production was not affected by dietary treatments. The egg weight in the group fed with diet containing 0.2% of lutein fortified chlorella was higher than that of the control (p<0.05). As the dietary chlorella levels increased, the daily egg mass linearly increased, although not significantly. The yolk colors in groups fed diets containing lutein fortified chlorella were dramatically increased as compared to the control (p<0.001). The lutein in chicken eggs significantly increased when fed with 0.2% of lutein fortified chlorella (p<0.01). These results suggested that the dietary lutein derived from chlorella was readily absorbed into the serum and absorbed by the liver with growing oocyte for commercial laying hens. Particularly, the lutein fortified chlorella was a valuable natural source for the production of lutein enriched chicken eggs.

The Growth Performance, Carcass Characteristics, and Meat Quality of Egg-Type Male Growing Chicken and White-Mini Broiler in Comparison with Commercial Broiler (Ross 308).

The present study was conducted to compare the growth performance, carcass characteristics, and meat quality of the egg-type male growing chicken (EM), white-mini broiler (WB), and commercial broiler (Ross 308, CB). A total of 360 1-d-old chicks were reared together using a completely randomized design with 4 replicates for each group under the identical feeding and rearing conditions. The ADG and gain:feed were the highest in CB, intermediate in WB, and the lowest in EM (p<0.05), and the live and carcass weights of CB and EM were significantly higher than those of WB (p<0.05). The pH of breast meat from WB and CB was significantly higher (p<0.05) than that from EM with a similar body weight. The EM had the lowest moisture (p<0.05) and the highest protein content (p<0.05), whereas the fat and ash contents were not different among groups. The mystiric acid (C14:0), palmitoleic acid (C16:1 ω7), and oleic acid (C18:1 ω9) levels were significantly higher in breast meat from CB (p<0.05). The monounsaturated fatty acid (MUFA) content showed the highest (p<0.05) levels in CB. In contrast, the polyunsaturated fatty acid (PUFA) contents of breast meat, including linoleic acid (C18:2 ω6) and arachidonic acid (C20:4 ω6), were higher (p<0.05) in EM and WB than in CB. In conclusion, the EM and WB had less growth performances in comparison with CB, but they each had some unique features (taste, flavor, and physiological characteristics) when raised under the identical rearing and feeding conditions.