• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.976-982
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• 2007

This study investigated whether supplemental Cu, Fe, Zn, and Mn are needed in a practical diet for pullets. Four hundred and twenty females of an egg-laying strain (1-d-old, Lohmann Brown Layer) were randomly distributed into 4 groups, consisting of 7 replicates of 15 birds each. During the 18-week experimental period, chicks were given three basal diets in sequence, each with single or multiple Mn, Zn and Cu supplementation to improve the mineral balance gradually. In the Control, no Mn, Zn, and Cu were added; in the single Mn supplemented group (sMn) Mn was added to 120, 60, and 60 mg/kg for 1-6, 7-12, and 13-18 weeks of age, respectively; in the multiple Mn and Zn supplemented group (mMnZn), Mn was added to 180, 90, and 90 mg/kg and Zn was added to 120, 105, and 105 mg/kg for 1-6, 7-12, and 13-18 weeks of age, respectively; in the multiple Mn, Zn, Cu supplemented group (mMnZnCu), Mn, Zn, and Cu were added to the same multiple of basal Fe concentration relative to NRC (1994) recommendations. Energy and protein metabolizability were determined by subtracting energy/protein intake by energy/protein excretion (from both feces and urine) and dividing by energy/protein intake. There were no statistically significant differences between groups in terms of feed intake, final body weight or tibia length throughout the experiment. Optimal growth performance was observed in the Control, while adding trace minerals to basal diets tended to result in decreased productive performance. Protein metabolizability was increased by mMnZn and mMnZnCu treatments, but energy metabolizability was not affected. Concentrations of Mn, Zn, Cu in excreta varied greatly related to dietary content, and the retentions of Cu, Fe, Zn and Mn were all increased due to the improvement of mineral balance. Based on these results, it is suggested that the concentrations of Cu, Fe, Zn and Mn in typical basal diets used in this study were adequate for normal growth for pullets from 1 to 18 weeks of age.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.235-247
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• 2019

Serological monitoring has been conducted worldwide for early diagnosis of disease and monitoring of immune status in poultry. This study was conducted to evaluate the immune status of layers with sera submitted to the Avian Disease Laboratory, Chungbuk National University from 2015 to 2017. The test results were analyzed by the time submitted and by the age of the chicks. Low pathogenic avian influenza (LPAI) showed a low positive rate of antibody compared with those of Newcastle disease, indicating that domestic vaccination against LPAI was not sufficient. The antibody profile of infectious bronchitis (IB) depicted high level of titer and a low tendency of CV as compared to the uninfected control flocks, which indicated that most layer farms have been exposed to the field IB virus. In case of avian metapneumovirus infection (aMPV) and Mycoplasma synoviae (MS), since the introduction of the vaccine in 2011 and 2017, respectively, the positive rate and the titer level were higher than those in pevious times. No significant difference in the changes of seasonal result was observed, indicating proper vaccination and improvement in biosecurity and management.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.97-98
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• 2003

This experiment was conducted to investigate the effect of restricted feeding to pullet on growth and laying Performance, egg qualify and endocrine Profile in brown layers. 1,080 brown-layer chicks divided to three diet treatments, conventional diet and two restricted diets, for 70 weeks. Conventional diets(C) was formulated by NRC recommendation, and one of restricted diet started from seven to seventeen week of age(T1), and another started from twelve to seventeen(T2) with adjusted eighty percentage amount of conventional diet. Body weight decreased with starting restriction of feeding comparing to the C(P＜0.05), but reached to similar weight in all treatments at twenty week regardless restriction. All of birds started to lay egg around 1,400 to 1,450gram of body weight though the age was in order of C, T2 and T1. Overall e99 Production was the highest in T1 (P＜0.05) and there were not difference in C and T2. Average egg weight also showed similar to the tendency of egg production. Feed intake was higher in T1 during maximum production(P＜0.05), but there were not difference in all treatments after the peak. Overall feed conversion ratio improved in T1 compared to C and T1(p＜0.05). Restriction feeding in rearing period could be beneficial to improve egg productivity and to decrease feed cost.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.63-69
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• 2008

The objective of this study was to investigate the effect of restricted feeding to laying performance and egg quality in brown layers. A total of 1,080 brown layer chicks were divided into three treatments; conventional feeding (ad libitum) and two restricted feedings (80% of conventional diet) for 70 weeks. One of restricted feeding started from six to eighteen weeks of age, and the other started from twelve to eighteen weeks of age. Diets were formulated by NRC (1994) recommendation. Overall laying performance and feed intake were the highest in $6{\sim}18 wk$ restricted group. But there was no significant difference among treatment group (P>0.05). Feed intake was higher in $6{\sim}18 wk$ restricted group during maximum production (P<0.05), but there was no difference between treatments after the peak. Egg quality tended to decreased by aging, but there was no significant difference among the treatments (P>0.05). The result of present study indicated that restricted feeding in rearing period of layers is beneficial to improve egg productivity and to reduce feed cost.

• Korean Journal of Poultry Science
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• v.8 no.2
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• pp.55-68
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• 1981

Calcium and phosphorus are not only indispensable for the bone formation and body fluids equilibrium but also are major components of egg shell. It is nutritionally important, therefore, to investigate the metabolism of calcium and phosphorus and to search for optimum requirement of calcium and phosphorus and the availability of various sources of calcium an4 phosphorus by poultry. An attempt was made to review the nutrition of calcium and phosphorus in poultry diets. 1, Calcium and phosphorus have great interrelationship with vitamin D in their metabolisms. 2. Most of the plant-origin phosphorus are existing in phytic form and it leads to low availability when used in poultry rations, although calcium and phosphorus present in animal-origin or mineral supplements are highly available in general. 3. Calcium and phosphorus requirement from existing information indicated that 1.0% calcium and 0.7% phosphorus for broiler and egg-type chicks, and 3.5% calcium and 0.4% phosphorus for laying hen. 4. It has been recommended that calcium and phosphorus level should be increased when the feed intake was decreased or when the egg Production rate was higher or when the hens are old. 5. Mono-, ci-, tri-, calcium phosphate, calcium carbonate, bone meal, limestone and oyster shell u the most readily available among various sources of calcium phosphorus supplements. Soft rock phosphate, deflourinated phosphate and gypsum are somewhat inferior to the previous ones in bioavailability. 6. The effect of particle size of calcium supplements on egg shell quality and egg production rate is not yet clearly defined but recent works showed that oyster shell is more available when it was coarse and limestone is more available when it was fine in panicle. size. 7. Present data indicated that mixed feeding of oyster shell and limestone is superior to the single feeding of each on laying performance. 8. Significant interaction between phosphorus and sodium was observed, that is, excessive sodium decreased egg production in layer and body weight growth in broiler in the low phosphorus diets but increased them in the high phosphorus diets.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.343-354
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• 2008

The objective of this study was to investigate the effect of restricted feeding to pullet on growth and endocrine profile in layers(Isa brown). One thousand eighty brown-layer chicks were divided into three treatments; conventional feeding(ad libitum) and two restricted feedings(80% of conventional diet) for 70 weeks. One of restricted feeding started from seven to seventeen weeks of age, and the other started from twelve to seventeen weeks of age. Diets were formulated by NRC(1994) recommendation. Body weight and feed intake were measured every two weeks, and body composition and organ weight analyzed every week in rearing period and every eight weeks in laying period. Blood was collected at weighing body weight and was analyzed for the concentration of insulin-like growth factor-Ⅰand estradiol. Body weight and feed intake decreased as restriction of feeding begins comparing to ad libitum group(P<0.05), but reached to similar body weight and feed intake at 20 wk of age regardless of restriction. There were no significant differences in development of digestive tract and attached organs among the treatment groups. During rearing period, however, they were slightly higher in restricted group which was low in body weight. In terms of body composition, fat contents of restricted group were significantly lower(P<0.05) than that of ad libitum group around 1,000 grams of body weight. High concentration of IGF-Ⅰwas observed.