جستجوی مقالات مرتبط با کلیدواژه « مرغ تخمگذار » در نشریات گروه « دامپزشکی »

The present study was carried out to investigate the effect of using nanoliposomes vitamin D3 (NVitD) in diet on performance and egg quality of laying hens. One hundred and twenty Leghorn laying hens (Hy-line W-80 Commercial strain) were used in a completely randomized design with four treatments, five replicates and six hens per replicate for six weeks. The treatments consisted of: 1- control with 3300 IU VitD/kg of diet, 2- 4950 IU VitD/kg of diet 3- 3300 IU NVitD/kg of diet and 4- 4950 IU NVitD/kg of diet. In the second three weeks of the experiment, the hens that received 4950 IU VitD/kg in their diet had the most feed intake in comparison with others. The egg yolk VitD content was increased significantly with increasing VitD concentration in hens diet. In equal amounts of diet VitD, application of nanoliposomes reduced the VitD content of egg yolk. Egg yolk cholesterol concentrations increased when using NVitD. The results of the present experiment showed that the use of NVitD did not have a significant effect on the production performance and egg quality traits of laying hens.

The aim of the current study was to determine the effects of different levels of milk thistle extract on productive performance, blood parameters and egg quality in laying hens imposed to dexamethasone-induced stress. The 2×3 factorial experiment was managed in a completely randomized design with 72 Hy- Line (W36) laying hens in 6 treatments and 4 replicates of 3 birds each. The experiment was carried out from the age of 75 to 81 weeks. Hens were weighed and either remained uninjected or received injections dexamethasone (0 and 4 mg per bird). The milk thistle extract were included at 0, 100 and 200 mg/kg in diets. The dexamethasone injections caused reductions in egg production percentage and egg mass in the throughout the experimental period (P<0.05). Laying hens imposed to dexamethasone-induced stress had the highest feed conversion ratio (P<0.05). The highest amount of lymphocytes in blood were observed in groups supplemented with 200 mg/kg of milk thistle extract (P<0.05). HDL content in serum was increased by the inclusion of milk thistle extract (200 mg/kg) (P<0.05). Adding of milk thistle extract to the diet of laying hens caused a significant decrease in LDL content in serum (P<0.05). In general, stress induced by dexamethasone injection reduced egg production and increased feed conversion ratio and addition of milk thistle extract to the diet had no positive impact on performance in laying hens.

The present study was carried out in order to investigate the effect of different levels of herbal additives of milk thistle and nettle on performance indices, immune parameters and egg yolk cholesterol. A total of 90 laying hens were randomly assigned to 5 treatment groups, 6 replicates of 3 birds each in a completely randomized design. Dietary treatments included control group and different amounts of milk thistle (0.5 and 1.5%) and nettle (0.5 and 1.5%). Results showed that adding of milk thistle (1.5%) to laying hens ration improved egg mass and feed conversion ratio (P<0.05). Using of milk thistle and nettle had not effect on shell quality. The highest yolk index was found out in the eggs from hens that were fed 1.5% of milk thistle in contrast to hens fed the control treatment without milk thistle (P<0.05). Egg yolk cholesterol amount was not affected by different levels of milk thistle and nettle powder. There were no significant differences in concentrations of glucose, triglyceride, cholesterol and HDL in plasma. Using of milk thistle (1.5%) fortified immune indices by decrease of heterophile percentage and heterophile to lymphocyte ratio (P<0.05). Therefore, it can be concluded that the supplementation of laying hens diet with milk thistle (1.5%) has positive effects on performance and immune system.

Old laying hens are more prone to dietary calcium (Ca) and phosphorus (P) deficiencies as they absorb Ca and P less efficiently than younger hens. In a 2×2 factorial design, the influence of diets with two levels of available phosphorus (AP) and phytase enzyme on the laying performance, egg quality and tibia bone characteristics of laying hens at their late 2nd production phase was studied. The experiment used four treatments of 20 Hy-Line W36 hens of 140 weeks old. Treatments 1 and 2 received a 3.5 g kg-1 AP diet while Treatments 3 and 4 received a 2.5 g kg-1 AP diet for 12 weeks. Treatments 2 and 4 received 250 FTU kg-1 phytase in their diet. Laying performance, egg weight, shell weight and shell thickness were measured. On the last day of the experiment, all birds were weighed and blood samples were collected for serum Ca and P measurements. Ten birds from each treatment were sacrificed and both tibiae were excised, defatted, weighed and ashed for Ca and P contents, cortical thickness and bone breaking strength measurements. Hens fed with 2.5 g kg-1 AP diet without enzyme had the lowest body weight gain, serum P, tibia cortical thickness and tibia breaking strength among the treatments (p<0.05). Phytase enhanced body weight gain, egg shell thickness, serum P, tibia weight/body weight and tibia ash/body weight ratios, tibia cortical thickness and breaking strength, particularly in birds receiving 2.5 g kg-1 AP diet (p<0.05). Phytase may improve bone quality and strength of hens in the late 2nd laying period.

This experiment was conducted to evaluate the effects of different levels of fortifed Alhaji (Alhaji maurorum L.) with 1% urea on egg production, egg traits, blood biochemical parameters and blood cells of laying hens. In this experiment 192 Hy- line W36 laying hens were used from 65-76 weeks of age in 4 treatments, 4 replicates and 12 hens in each replicate in a completely randomized design. Experimental groups included: 1) control group and 2-4 groups with 1.5, 3 and 4.5 percentages of Fortifed Alhaji (FA). FA had signifcant effects on performance, egg traits, blood biochemical parameters and blood cells of laying hens (P<0.05). The highest amounts of egg weight, egg production percentage, egg mass, the best feed conversion ratio, the lowest feed cost for production each kilogram of egg, the highest egg color index and the highest amounts of Hematocrits, Hemoglobin and red blood cells were observed by using 4.5% FA. The lowest blood albumin and the highest blood HDL were obtained in treatment contained 3% FA. The overall results indicated that using 4.5% fortifed Alhaji, has positive effects on performance, egg traits, blood parameters and could reduce the production cost in laying hens.

This study was conducted to evaluate the effect of increasing levels of probiotic (Bioplus) on performance, egg traits and blood serum chemical parameters of laying hens. Experiment was conducted with two hundred and ffty six Hy-line (W36) laying hens in four treatments and four replicates with 16 hens in each replicate from 45 to 55 weeks in a completely randomized design. Experimental groups included control group and experimental groups with 0.2, 0.4 and 0.6 g/kg of probiotic (Bioplus). Different levels of probiotic signifcantly affected the performance, egg traits and blood serum chemical parameters of laying hens (P<0.05). The highest amounts of feed intake (129 g/day/hen), feed conversion (2.72) and egg specifc gravity (1.089 mg/mL3) were observed with using 0.6 g/kg of probiotic. Whereas the lowest feed price for production per kilogram of egg (853.11 toman), the lowest level of egg yolk triglyceride (437.5 mg/gr) and minimum level of blood serum phosphorus (7.42 g/dl) were observed with using 0.2 g/kg of probiotic and fnally the minimum level of blood serum cholesterol (124.33 mg.dl) were observed with using 0.4 g/kg of probiotic. The overall result of this experiment showed that the using high levels of probiotic (Bioplus) has adverse effects on performance of laying hens and not recommended.

Free radicals are involved in molecular changes and mutation and if they are not inactivated the resultant lipid peroxidation will damage all types of cellular macromolecules such as proteins, carbohydrates, lipids and nucleic acids. Natural diet containing antioxidants plays an important role in health, reproduction, performance, safety and growth in poultry. Garlic extract with a high antioxidant effect very useful against free radicals and infective agents. In this study, the effect of concentration of 0.01 and 0.02% of garlic extract in drinking water with periods of 2, 4 and 6 days a week were evaluated on lipid peroxidation. In addition to assessing the best concentration, economic aspects were also considered. So at the end of the third week, the best effect on reducing lipid peroxidation was seen in T3 which had received the concentration of 0.02% of garlic extract, two days a week. After six weeks of trial, Group T7 which had received the concentration of 0.02% garlic extract for 6 days a week, showed the best effect on reducing lipid peroxidation. Our studies also showed that garlic extract improved mass production in all groups compared to the control group. Considering the amount of lipid peroxidation at the end of the sixth week, herd performance in six weeks and calculating the average sale price of mass production, minus the cost of feed consumed per group, it is concluded that group T4 which received garlic extract concentration of 0.01% for 4 days a week (Saturday, Monday, Wednesday, Thursday) showed the best option in view of the economic conditions.

The effects of probiotic and calcium butyrate (Ca-butyrate) as feed additives on performance and immune response have been shown in laying hens. The aim of the present study was to investigate the effects of different levels of probiotic and Ca-butyrate on performance, egg quality, blood parameters and immune response in laying hens. Two hundred and eighty eight Hy-Line W-36 hens (62 to 70 wks of age) were used in a 2×3 factorial arrangement with three levels of probiotic (0, 0.07 and 0.01 percent) and two levels of Ca-butyrate (0 and 0.1 percent) in a completely randomized design of 6 treatments and 8 replicates. The results showed that feed intake, feed conversion ratio, egg production, shape index, yolk index, haugh unit, egg weight and specific gravity were not affected by probiotic and Ca-butyrate. While egg weight and egg mass were significantly (p<0.05) increased using probiotic compared with the control diet, such an effect was not observed due to Ca-butyrate addition. However, shell thickness showed significant increase (p<0.05) in response to Ca-butyrate. The interaction between different levels of probiotic and Ca-butyrate was only significant for feed conversion ratio (p<0.05). Antibody titer against sheep red blood cell (SRBC) was not affected (p>0.05) by experimental treatments. The concentration of serum albumin was significantly increased (p<0.05) by adding probiotic and Ca-butyrate to feed. Furthermore, significant increase (p<0.05) in total serum protein was pronounced in response to probiotic and Ca-butyrate. However, other serum metabolites (total calcium, triglycerides and cholesterol concentrations) were not affected by treatments. The relative percentage of heterophiles and heterophiles to lymphocytes ratio were significantly decreased (p<0.05) using probiotic. Dietary probiotic and Ca-butyrate can be considered as additives to improve immune responses in laying hens.

Cholesterol is one of causes of cardiovascular diseases in humans, but serum cholesterol has an important role for egg production in birds. There are conflicting hypothesis about dietary antioxidant effect on serum cholesterol, while very few experiment have been conducted on poultry. So this study was performed to evaluate the effect of dietary levels of antioxidant vitamins (vitamin E and C) on hen performance, egg quality, egg cholesterol, blood parameters including glucose, triglyceride as well as cholesterol and its components in laying hens. Total 168 Hy-Line W36 laying hens at 39 weeks of age were divided into 7 groups and 6 replicates with 4 hens in each replicate as completely randomized design. Treatments consisted of adding levels of 100, 200 and 400 mg vitamin E or C per kg of the basal diet. Vitamin E or C has not significant effect on hen performance. Yolk weight decreased (p<0.05) by increasing the level of antioxidant vitamins in the diet. Yolk cholesterol also decreased linearly with increasing dietary antioxidant vitamin. Vitamins, particularly vitamin C, caused a significant increase in serum glucose. Although, no significant differences were observed between groups in total serum cholesterol, but serum HDL cholesterol decreased, whereas LDL cholesterol increased (p<0.05) as dietary vitamin E or C increased in diets. It seems that vitamin E is more effective than vitamin C in modifying cholesterol contents.. ..