• Asian-Australasian Journal of Animal Sciences
• /
• 제15권8호
• /
• pp.1103-1109
• /
• 2002

This study investigated the effect of 2-bromo-$\alpha$-ergocryptine (anti prolactin agent) on plasma levels of prolactin, oestradiol-17$\beta$ and progesterone in domestic hen during the active period of lay. Fifty healthy female White Leghorn birds were administered with anti prolactin agent (2-bromo-$\alpha$-ergocryptine, Sigma-USA., methane sulphonate salt, $C_{32}H_{40}BrN_5O_5.CH_4SO_3$) subcutaneously @100$\mu$g/kg body weight at weekly intervals from 17th to 36th week of age. Another group of fifty birds as controls were given placebo in place of bromocriptine. The level of prolactin remained lower in treated birds than in the control birds from 19 to 36 weeks of age. Level of prolactin even in the control group was found to decrease during the peak production period. Oestradiol-$17{\beta}$ and progesterone concentration in treated birds were significantly (p<0.01) higher than the controls during the treatment. Egg production, is positively correlated with oestradiol-$17{\beta}$ (r=0.02; r=0.67) and progesterone (r=0.49; r=0.90) in control and treated groups respectively where as prolactin level is positively correlated with egg production in the control birds (r=0.07). Prolactin levels were negatively correlated with egg production (r=-0.55) in treated birds; and oestradiol-$17{\beta}$ (r =-0.71; r=-0.53) and progesterone (r=-0.22; r=-0.27) respectively in control and treated groups. The total number of pause days during the treatment period decreased significantly (p<0.01) in the treated group compared to the control group. The reduction in pause days in treated group resulted in 1.76% increase in egg production over that in control group. The increase in egg laying days and the total egg production were found to be significant (p<0.01). These results indicate that a lower level of prolactin in circulatory blood enhances egg production in the domestic hen.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권2호
• /
• pp.290-296
• /
• 2003

Tsaiya ducks and Leghorn hens are the two major laying birds raised in Taiwan. They are all excellent egg layers. Tsaiya ducks are small in body size (1.3 kg) with bigger egg weight (65 g) and stronger eggshell breaking strength than eggs from hens. The eggshell consists mainly of calcium carbonate, hence calcium plays an important role in the eggshell formation. Magnesium is also present in eggshell in small amounts, which may have effect on maintaining eggshell quality. In comparison studies, it was shown that the duck eggshells contained higher calcium and lower magnesium content than chicken eggshells. The eggshell magnesium content was not affected by the dietary magnesium levels (690-2380 ppm) in ducks, but in hens, it increased linearly with dietary magnesium levels. The palisade layer ($5000{\times}$) of the eggshell was found to have a compact form for ducks while there are many hallow vesicles in chicken eggshells. The eggshell magnesium deposition model is different for ducks and hens with ducks having a one-peak and hens having a two-peak model. The calcium deposition model is similar for both birds. Both the carbonic anhydrase specific activity and total activity in the shell gland mucosa of ducks are higher than those in hens. Ducks retain higher magnesium and lower calcium in the shell gland mucosa and secret less magnesium and more calcium into the shell gland lumen for eggshell deposition. The ATPase specific activity is maintained fairly constant during the eggshell forming stage, indicating continuous calcium transport into the shell gland lumen for eggshell formation. The magnesium content in duck eggshells is much lower than that in hens indicating that the magnesium content in the eggshell may have an effect on eggshell quality.

• Asian-Australasian Journal of Animal Sciences
• /
• 제6권2호
• /
• pp.243-248
• /
• 1993

The effect of dietary lipid factors (plant and animal oil, cholesterol and ${\beta}$-sitosterol) on the liver, serum, and egg yolk cholesterol levels of the laying hen was studied. Single Comb White Leghorn laying hens, at 28 weeks of age, were fed two basal diets containing 8.0% soybean oil or 8.0% fish oil, with or without supplemental cholesterol (1.0%), ${\beta}$-sitosterol (2.0%) or combinations of both. Restricting caloric intake resulted in significantly (p<.05) decreased egg production and the total amount of cholesterol excreted via the egg was significantly (p<.05) different among treatment groups. Cholesterol supplementation to the two basal diets resulted in a significant elevation of liver, serum and egg yolk cholesterol levels. The addition of ${\beta}$-sitosterol lowered the cholesterol levels in liver and serum, while increased in the egg yolk (SO + ST, FO + ST). The anticholesterogenic effect of dietary ${\beta}$-sitosterol was not clearly exhibited in this study.

• 한국가금학회지
• /
• 제21권3호
• /
• pp.183-193
• /
• 1994

White Leghorn hens were fed a commercial formula feeds as a basal diet, which was supplemented with 3 types of plant oil safflower, evening primrose and pine seed, at the 10% level for 3 weeks. No significant changes was found between the basal diet and the oil feeding trials in the egg yolk cholesterol content, the laying rate, the egg weight, and the yolk weight, except the feed intake. In the fatty acid composition of the egg yolk lipid, however, the plant oil feedings to hens resulted in considerable increase of $C_{18:2}$ acid with a simultaneous decrease of $C_{18:2}$ acid ,and, consequently, followed by the improvement of balance with P /S and P /M /S ratio close to 1.0 and 1:1:1, which is known a desirable ratio for human health in lipid nutrition, respectively.

• 한국가금학회지
• /
• 제20권4호
• /
• pp.209-216
• /
• 1993

본 연구는 다가오는 농축산물 수입개방의 시대를 맞이하여 우리 고유의 맛을 지닌 순수한 재래계의 식별 유지 및 개량하기 위한 과학적인 방법을 제시하고자 실시되었다. 본 연구를 위하여 재래계 및 수입계인 백색 Leghorn종을 line별로 유지하면서 경제형질 (체중, 초산일령, 산란을, 난중)과 표현형 특이성 (체형, 두부, 깃털, 정강이)에 대하여 조사하였다. 또한 최첨단 기법인 유전자 지문 기법을 도입하여 재래계와 수입계의 DNA에 대한 유전자 지문을 실시하였다. 재래계의 경제형질에 있어서 체중은 산란계 품종인 White Leghron과 유사한 특징을 보였고, 초산일령 및 최고 산란기는 수입계보다 다소 늦었으며 평균 산란율 역시 수입계에 비해 다소 떨어졌다. 재래계의 난중은 수입계에 비해 약 10g 정도 가벼웠다. M13mp18 single-stranded DNA를 probe로 사용한 유전자 지문에서, 재래계는 4.4kb와 4.9kb에서 수입계는 10.6kb와 12.4kb에서 품종 고유의 구분이 확실한 다수의 band를 확인 할 수 있었다. 따라서 본 연구에서는 우리 고유의 유전자원인 재래계의 유전자 지문을 수입계의 유전자 지문과 식별할수 있는 것으로 개발하였으며, 향후 이 기술을 이용해서 구체적인 재래계의 유지 및 개량에 대한 방안이 강구되어야 할 것이다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권11호
• /
• pp.1565-1571
• /
• 2003

Physiological mechanisms, involved in unusual ovulatory sequences in domestic hen are remaining undefined. One hundred individually caged white leghorn birds were divided into two equal groups viz. control and treatment, and 2-bromo-$\alpha$-ergocryptine, was administered to birds in the treatment group to modulate prolactin (PRL) secretion from anterior pituitary gland. The effect of modulation of PRL concentrations on egg production, sequence length and intersequence pause length were studied by analysis of oviposition records of the birds from 24 to 72 weeks of age. The surviving 48 birds in the control and treatment groups averaged $34.58{\pm}1.7$ and $25.67{\pm}1.15$ sequences of oviposition, with a mean sequence length of $9.92{\pm}0.63$ and ${\pm}1.12$ days respectively. Most of the birds had a single characteristically long sequence during the entire reproductive cycle, which averaged $46.04{\pm}3.09$ days in the control birds and $59.33{\pm}4.44$ days in the treated birds. 2-bromo-$\alpha$-ergocriptine treatments had significantly decreased (p$\leq$0.01) the circulating concentrations of PRL compared to the birds of the control group. This resulted in a significant increase (p$\leq$0.01) in the number of laying days in birds of the treatment group with a concomitant decrease in the intersequence pause length. The decreased PRL levels during prime sequences in birds of the both groups, reveals the negative role of the circulating PRL levels on egg production with concomitant shorter intersequence pause length. Hence, modulation of PRL with dopamine agonist may enhance the reproductive efficiency of hens later in life.

• Asian-Australasian Journal of Animal Sciences
• /
• 제21권8호
• /
• pp.1164-1170
• /
• 2008

In this study, the effects of propolis and vitamin C (L-ascorbic acid) supplementation in diets were investigated on feed intake (FI), body weight (BW), body weight gain (BWG), feed conversion rate (FCR) and digestibility and on egg production and qualities (weight, mortality, shell thickness) in laying hens exposed to heat stress. A total of 150 Hyline White Leghorn, aged 42 weeks, hens was divided into five groups of 30 hens. Chicks were randomly divided into 1 positive control, 1 control and 3 treatment groups. The chicks were kept in cages in temperature-controlled rooms at $22^{\circ}C$ for 24 h/d (positive control, Thermoneutral, TN group) or $34^{\circ}C$ for 9 h/d from 08.00-17.00 h followed by $22^{\circ}C$ for 15 h (control, heat stress, HS group) and fed a basal diet or basal diet supplemented with vitamin C (250 mg/kg of L- ascorbic acid/kg of diet) or two levels of propolis (2 and 5 g of ethanol extracted propolis/kg of diet). Increased FI (p<0.05) and improvement in FCR (p<0.05), hen day egg (p<0.05) and egg weight (p<0.05) were found in Vitamin C and propolis-supplemented laying hens reared under heat stress conditions. Mortality rate was higher in the control group than TN, vitamin C and propolis groups (p<0.05). Digestibility of dry matter, organic matter, crude protein and ether extract improved with increasing of both dietary vitamin C and propolis (p<0.05). Vitamin C or propolis supplementation did not affect either the percentage shape index, yolk index or haugh unit and albumen index (p>0.05). However, the egg shell thickness and egg shell weight appeared to be increased in Vitamin C and propolis groups in comparison to HS group birds (p<0.05). In conclusion, dietary supplementation of laying hens with anti-oxidants (vitamin C and propolis) can attenuate heat stress-induced oxidative damage. These positive effects were evidenced by increased growth performance and digestibility, improvement of egg shell thickness and egg weight in comparison to non-supplemented birds. Moreover, supplementation with propolis (5 g/kg diet) was the most efficient treatment.

• Asian-Australasian Journal of Animal Sciences
• /
• 제10권6호
• /
• pp.657-664
• /
• 1997

432 Babcock ISA white leghorn pullets reared for 8 weeks on a standard managemental conditions were exposed to feed/nutrient and light restrictions from 9 to 20 weeks of age. Four feeding regimes i. e. 100, 85 or 70 percent of the recommended allowance and low energy (2,500 Kcal/kg) low protein (13% CP) ration were fed each in the three light regimes i. e. (A) Natural day light starting from 13.24 hr/day at 8 weeks of age and ending 10.41 hr/day at the end of 20 weeks; (B) Constant 11 hr/day light and (C) starting with 13 hr/day at 8 weeks and decreasing @ 20 min/week till 20 weeks of age. At the age of 20 weeks all the birds were shifted to separate cages under uniform lighting feeding and management. During the 21st week light was increased to 12 hr a day and thereafter with an increase of 30 min per week, increased to 16 hr a day at the age of 29 weeks. From 20 weeks onward till 72 week age, all the birds were offered commercial layer rations ad libitum, prepared according to climatic conditions. The results of the study revealed that birds reared under natural and constant light had higher weights than decreasing light, yet they could not out perform during production period. The effect of feed and nutrient restriction, on the other hand, was found significant during rearing as well as production period. The birds exposed to higher level of feed and those exposed to nutrient restriction were lighter in weight. The 100% fed birds laid their first egg at an early age. However, those reared on 85% of the recommendation excelled all other groups in terms of produced number of eggs, egg mass, hen housed and hen day production and net returns.

• 농업과학연구
• /
• 제14권2호
• /
• pp.272-285
• /
• 1987

난백내(卵白內) lysozyme을 분리(分離)하기 전(前)에 난백(卵白)의 균질(均質) 최적조건(最適條件)과 원료난(原料卵)의 lysozyme활성(活性)을 검토(檢討)하였으며, 직접(直接) 결정법(結晶法)과 Bentonite 및 Duolite의 흡착법(吸着法)을 실시(實施)하여 균질(均質)된 난백(卵白)으로부터 lysozyme의 회수율(回收率)과 순도(純度)를 조사(調査)한 결과(結果)는 다음과 같다. 1. 균질(均質)된 난백(卵白)의 효소활성(酵素活性)을 측정(測定)함에 있어서 난백(卵白)의 균질(均質) 최적조건(最適條件)은 교반시간(攪拌時間)이 10분(分), 교반속도(攪拌速度)는 2,000rpm이었다. 2. 원료난(原料卵)의 lysozyme활성(活性)에서 품종중(品種中) W. Leghorn 종(種)이 높은 활성(活性)을 보였고, 난백(卵白) 부위중(部位中) 농후난백(濃厚卵白)이 수양난백(水樣卵白)보다 약간 높은 활성(活性)을 보였으며, $4^{\circ}C$에 보존(保存)된 계란(鷄卵)의 활성잔존율(活性殘存率)은 $25^{\circ}C$나 $-20^{\circ}C$에 비하여 더 높았다. 3. 직접(直接) 결정법(結晶法)에 의하여 난백(卵白)으로부터 분리(分離)된 3차(次) 결정화(結晶化)된 lysozyme의 비활성(比活性)은 29배까지 증가되었으며, 이때의 회수율(回收率)은 64.3%이었다. 4. Bentonite의 흡착법(吸着法)에 의하여 lysozyme의 흡착율(吸着率)은 95.7%, 용출율(溶出率)은 89.1%이었고, 난백(卵白)으로부터 분리(分離)된 lysozyme의 회수율(回收率)은 85.3%이었으나, 이때의 비활성(比活性)이 13배 밖에 증가되지 않았다. 5. Duolite의 batch법(法)에 의하여 난백(卵白) $100m{\ell}$에 Duolite 20g로 90분간(分間) 흡착(吸着)시키고 3시간(時間) 용출(溶出)시켰을 때, 그 흡착율(吸着率)은 97%, 회수율(回收率)이 84.8%이었으며, 이때의 비활성(比活性)은 30배 증가되었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제18권8호
• /
• pp.1171-1175
• /
• 2005

An experiment was conducted (28 to 44 weeks) to study the laying performance, shell quality, and nutrient retention of White Leghorn layers fed different levels of non-phytate phosphorus (NPP). Six levels of NPP (0.15, 0.18, 0.21, 0.24, 0.27 and 0.30%) at a constant calcium (Ca) level (3.5%) in maize-soya-deoiled rice bran based diets were formulated, and each experimental diet was offered ad libitum for 16 weeks to five replicates with five birds in each replicate. The body weight of WL layers fed diet containing 0.15% NPP was significantly (p<0.05) lower than those fed diet with 0.30% NPP, at 44 weeks of age. However, the hen day egg production, egg weight, daily feed intake and feed consumed per dozen eggs were not influenced by the variation in the NPP levels in the diet. The bone ash content was significantly (p<0.05) higher in the birds fed 0.30% NPP as compared with those fed diets up to 0.24% NPP. Bone ash content was intermediate in the birds fed diet containing 0.27% NPP. The tibia strength followed the same trend as that of bone ash. Dietary NPP content had no influence on serum Ca and protein concentration and activity of alkaline phosphatase. However, serum inorganic P concentration increased linearly with NPP content in the diet. The concentration of P was significantly (p<0.05) higher in the birds fed 0.27% NPP or higher as compared with those fed 0.15% NPP. Levels of dietary NPP had no influence on egg quality parameters like shell wt, shell thickness, shell strength and specific gravity. The retention of nutrients such as DM, N and Ca were comparable among the WL layers fed different levels of NPP. However, the retention of P decreased linearly with increase in the level of NPP in the diet. The retention of P in the birds fed diets up to 0.24% NPP in the diet was comparable, however further increasing the content of NPP (either 0.27% or 0.30%) reduced the retention of P. Based on the results of the present study, 0.15% NPP (180 mg/b/d) in the diets of WL layers is adequate for optimum production performance during 28 to 44 weeks of age, however, WL layers require 0.27% NPP (324 mg /b/d) in the diet for optimum production with better bone mineralization.