• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1662-1668
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• 2005

This review has been done to examine sex-linked dwarf gene in broiler production in hot-humid climates. Introduction of sex-linked dwarf gene especially in hot harsh tropical environments brings a great advantage for broiler production. The heavy broiler parent suffers due to the stress of these adverse climates. Sex-linked dwarf genes reduce body weight, egg weight, but are superior for adaptability under harsh tropical environments, with a lower requirement for housing and feed, better survivability and reproductive fitness giving fewer defective eggs, more hatching eggs, better fertility, hatchability, feed conversion efficiency and resistance to disease. Overall the cost of chick production from dwarf hens is lower than from their normal siblings. Market weights of broilers from sexlinked dwarf dams is almost similar to those of broilers from normal dams with normal sires. But the net benefit of broiler production from sex-linked dwarf dams is found to be greater than that of broilers from normal dams. This will be the most important to the rural communities in Bangladesh and in other countries where the similar environment and socio-economic conditions exist. Therefore, sexlinked dwarf hens might be used in broiler breeding plan as well as broiler production in the tropics.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.8
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• pp.1123-1130
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• 2004

Two experiments were conducted to examine the effects of dietary inclusion of xylose on growth performance, nutrient digestibility and xylose absorption in the portal-drained viscera of broiler chicks. In Exp. 1, ninety male 14 day-old broilers were used to study the effects of different inclusion levels (0, 5, 10, 20 and 40%) of D-xylose in the semi-purified diets on the growth and nutrient digestibility of broilers. In Exp. 2, One hundred and eight male broilers, fed by precision feeding at 22 day-old, were used to investigate the absorption and transportation of dietary xylose in the portal-drained viscera of broiler. The results of Exp. 1 indicated that the growth of broilers was gradually decreased as the xylose level increased (p<0.01). With the xylose supplementation increased, the moisture in broiler excreta was gradually elevated (p<0.01), AME and the digestibilities of crude protein and ether extract were significantly reduced and the digestibilities of xylose and arabinose were also decreased (p<0.01). The results of Exp. 2 showed that the concentrations of ribose, xylose and galactose in serum were significantly influenced by different dietary levels of xylose (p<0.01), but there's no apparent difference among rhamnose, glucose and arabinose (p>0.05). The xylose concentration in serum was highest in Vena Cava, middle in Portal Vein and lowest in Ulnar Vein within 6 h after precision feeding. And then the xylose concentration in Portal Vein and Ulnar Vein were higher than that of Vena Cava. The concentration of ribose, xylose and galactose in serum were also significantly changed with time prolongation (p<0.01). The concentration of xylose in serum was highest in the 40% xylose treatment, middle in the 20% xylose group and lowest in the control group. The glycogen contents in liver and muscle were linearly decreased as the level of xylose increased (p<0.01). The higher the dietary level of xylose was, the lower digestibility of dietary xylose was (p<0.10). 40% xylose markedly decreased the digestibility of dietary glucose (p<0.01). In conclusion, high levels of xylose in the diets inhibited the growth and nutrient digestibility of broiler. The outputs of xylose from the hydrolyzation of wheat-based diet by xylanase should have no adverse effects on broiler performance.

• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.233-238
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• 2006

In order to study the effect of feeding rare earth(RE) on growth of broiler chicks, feed conversion ratio, and probable harmfulness of feeding high levels of RE, two feeding trials with broiler chicks were conducted; one using a commercial broiler compound feed and the other using a self mixed feed excluding any growth stimulating feed additives. The the first trial used three hundred sixty of one day old Cobb broiler chicks for six levels of dietary supplementation of RE : 0, 100, 200, 400, 800 and 1,600 mg/kg. There were significant effect of RE stimulating broiler chick growth and improving feed conversion ratio, The dietary supplementation of RE at a level of 100 mg/kg was the best of all and increased body weight gain by 8.9% (p<0.05). Chicks fed RE at a level of 1,600 mg/kg grew as good as chicks fed feeds without RE and did not show my abnormalities. The second feeding trial was conducted in the same manner as the first trial using Ross broiler chicks and self-mixed experimental diets supplemented with RE at levels of 0, 50, 100 and 150 mg/kg. Differently from Results of the first trial, body weight gain and feed conversion ratio of were the best at the level of 50 mg/kg RE supplementation(p<0.05). In this trial all the birds fed RE showed significantly lower ratio of abdominal fat against live weight than those of the control group birds. Overall, it can be said that dietary supplementation of RE will improve broiler growth and feed conversion ratio and the proper dietary level would be $50\sim100mg/kg$. These results suggested that the proper level of RE for broiler chicks would be 50 to 100 mg/kg and its effectiveness is varied depending upon RE mixture. There appears abdominal fat of broiler chicks is decreased by feeding RE but further investigation is in need.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1319-1325
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• 2002

Two experiments were conducted to evaluate the effect of early feed restriction on growth, feed conversion ratio (FCR) and mortality in unsexed broiler chickens. In Experiment 1, 350 one-day-old broiler chickens were divided into 7 groups. Each treatment group was represented by five replicates of ten broilers each. One group was fed ad libitum as the control group and the other six groups were fed 25% ad libitum (25% multiplied by amount of feed intake of ad libitum chickens at the previous day) for 4 or 6 days, 50% ad libitum for 4 or 6 days, and 75% ad libitum for 4 or 6 days. In experiment 2, 500 broiler chickens were divided into 10 groups. Each treatment group was represented by five replicates of ten broilers each. One group was fed ad libitum as the control group. Three ages of feed restriction initial timing (2, 4 or 6 days of age) and three types of feed restriction (physical restriction, meal feeding and diet dilution) were used ($3{\times}3$) in both experiments. They were feed-restricted for 6 days. Results showed that restricted broilers exhibited compensatory growth in both experiments except for diet dilution groups. In both experiments, FCR of restricted broilers was higher, whereas feed intake of them was lower during restriction period. FCR of restricted broilers was lower upon refeeding. Mortality was inconsistently affected by early feed restriction. Leg abnormality was lower in restricted broilers in both experiments. Level of feed restriction significantly influenced body weight, FCR and feed intake of restricted broilers (p<0.05), but duration of feed restriction had no effect. Type of restriction significantly affected body weight, feed intake and FCR (p<0.05). It appeared that to achieve the best result (complete compensatory growth and better FCR), broilers should be restricted at 25% ad libitum for 6 days (Experiment 1). Meal feeding started at 2 days of age would show the best performance (Experiment 2).

• Animal Bioscience
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• v.34 no.8
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• pp.1342-1349
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• 2021

Objective: The aim of the present study was to investigate the effects of dietary supplementation of β-mannanase on growth performance, carcass characteristics, excreta microflora, blood constituents, and nutrient digestibility in broiler chickens. Methods: A total of 680 one-d-old Ross 308 (as hatched) broiler chickens were used in a 35-d growth assay. Chicks were sorted into pens with 17 birds/pen and 10 pens/treatment. Treatment diets were contained either 44% or 48% crude protein (CP) soybean meal (SBM) with or without β-mannanase. Results: Using SBM containing 48% CP led to an improvement (p<0.05) in feed conversion ratio (FCR) from d 1 to 14. Addition of β-mannanase to the diets significantly improved body weight gain (BWG) and FCR from d 1 to 14. During overall experimental period, BWG was affected (p<0.05) by CP level of SBM and inclusion of β-mannanase, but FCR and feed intake were not affected. Carcass characteristics were not influenced by treatment diets. The results showed that digestibility of dry matter (DM), nitrogen (N), and energy was not affected by CP level of SBM and/or inclusion of β-mannanase. Among essential amino acids (EAA) apparent digestibility of valine, methionine, and leucine improved (p<0.05) by the addition of β-mannanase to the diets. The results demonstrated that ileal digestibility of DM, N, and energy was not affected by treatment diets. Among EAA, the ileal digestibility of valine and arginine was higher (p<0.05) in the diets containing 48% CP SBM and/or β-mannanase. Excreta Lactobacillus count increased (p<0.05) by the addition of β-mannanase to the diets. Blood urea nitrogen, creatinine, and total protein level were not affected by treatments. Conclusion: Feeding chickens with diets containing 44% CP SBM resulted in detrimental effects on growth performance and digestibility of nutrients, but addition of β-mannanase to the 44% CP diet improved the growth performance of chickens without any effects on carcass characteristics.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.457-463
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• 1994

Insulin-like growth factor-I(IGF-I) plays an important role in the regulation of mammalian and poultry growth. IGF-I has many actions in different tissues, which include metabolic, mitogenic, and differentiative actions. IGF-I induces insulin-like effects - such as increased cell glucose uptake and glycogen sysnthesis, however several physiological actions of IGF-I may not have been identified yet. In order to investigate the effect on growth in broiler chicken treated with exogenous insulin-like growth factor-I, 30 chickens were injected $50{\mu}g$ reconbinant human IGF- I (rhIGF- I ) per kg body weight as experimental group and 30 ckickens saline subcutanously as control, 3 times according to ages from 2 to 35 days. We established radioimmunoassay method by which we can measure chicken IGF- I (cIGF- I ) as in rhIGF- I assay. The results obtained were as follows; 1) The dilution curve showed in parallelism between rhIGF- I and cIGF- I in the Sep-pak $C_{18}$ cartridge plasma extracts. 2) The body weight of broiler chicken were significantly increased at 31 days($1,176.50{\pm}99.79g$) and 35 days($1,252.84{\pm}125.21g$) of age in treatment groups, compared with control group($1,011.88{\pm}40.22g,\;1,111.32{\pm}153.67g$). The liver and kidney weights on 35 days$(35.24{\pm}5.18g,\;11.05{\pm}1.47g)$ were significantly higher in rhIGF- I treated group than control group($30.95{\pm}4.04g,\;10.01{\pm}1.60g$) 3) The plasma concentration of IGF- l and total protein in rhIGF- I treated group were $58.17{\pm}1.69ng/ml$, $3.75{\pm}0.62g/dl$ respectively compared with control group $45.70{\pm}1.64ng/ml$, $2.32{\pm}0.53g/dl$. The results suggest that exogenous rhIGF- I increased total body weight, liver and kidney weights in broiler chicken, and it may increase IGF- I and total protein concentration in serum.

• Korean Journal of Poultry Science
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• v.45 no.2
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• pp.81-88
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• 2018

The present study investigated effect of supplementation of agricultural byproduct on growth performance and blood parameters of broiler chicken using meta-analysis. Total 11 studies (32 experiments) where broiler feeding trials with agricultural byproducts were included were employed in analysis. All studies were conducted at commercial farm placed in South Korea and under commercial feeding programs. Growth phases were divided into two groups based on slaughter day. For growth performance, body weight, body weight gain, feed intake and feed conversion rate (feed/gain) were investigated. Carcass weight, dressing percentage, liver and spleen weight, blood glucose, total cholesterol and triglyceride, HDL (High density lipoprotein) and LDL (Low density lipoprotein) cholesterol contents in blood were investigated. Body weight of broiler of treatment was significantly increased than the control (P<0.05), regardless of growth phase. However, body weight gain during late growth phase did not show significant difference between control and treatment. Effect evaluated by random effect model on feed intake was not significant. Effect on feed conversion rate during early growth phase was significantly negative (P<0.05). Effects on carcass weight, dressing percentage, liver and spleen weight were not significant in random effect model. Effect on abdominal fat was significantly negative (P<0.05). In blood parameters, significant effects were found at total cholesterol, triglyceride and HDL cholesterol (P<0.05). Effect on HDL cholesterol only was positive effect, and others were negative.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.9
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• pp.1313-1319
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• 2013

This study investigated the effects of low levels of water-soluble pentosans (WSP), alkaline-extractable pentosans (AEP), and xylanase on the growth and organ development of broiler chicks. Three hundred and fifty 1-d-old female broiler chicks were randomly allocated into seven experimental groups of five pen replicates, with ten chicks per replicate. The control group consumed a corn-soybean meal-based diet. Six dietary treatment groups consumed the basal diet supplemented with one of the following: WSP at 50 mg/kg (WSP50) or 100 mg/kg (WSP100); AEP at 50 mg/kg (AEP50) or 100 mg/kg (AEP100); or xylanase at 3 mg/kg (Xase3) or 6 mg/kg (Xase6). Data including the body weight, digestive organ weights, gut length, rectal digesta viscosity, and gut microflora and pH were collected on d 5, 10, and 15. When compared to the control group, WSP50 promoted body weight gain and organ growth throughout the study, calculated as 3-d averages (p<0.05). WSP100 increased weight gain and enhanced organ development (proventriculus, gizzard, and gut) on d 10 (p<0.05), but the 3-d averages were not different from the control group except for the weight of gizzard. Both Xase3 and Xase6 increased the 3-d average weight gain and the growth of the gizzard (p<0.05). WSP50 increased the digesta viscosity compared to Xase3 on d 10 and 15 (p<0.05). WSP50, Xase3, and Xase6 increased the concentration of Lactobacillus in the rectum when compared to the control group (p<0.05), but only Xase3 lowered the digesta pH in the ileum and cecum on d 10 and 15. AEP had minimal influence on the growth and organ development of broilers. The results showed that low levels of WSP, AEP, and xylanase had different effects and underlying mechanisms on the growth and organ development of broiler chicks. WSP50 could increase the growth performance of broilers fed a corn-soybean meal-based diet.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.414-419
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• 2008

A feeding trial was conducted to investigate the effects of the addition of corn distiller's dried grains with solubles (DDGS) to broiler diets on growth performance and meat characteristics. A total of 3,200 d-old, unsexed Cobb-500 broiler chicks were randomly allotted to 16 pens (replicates), with 200 chicks per pen. There were four diet treatments (0, 5, 10, and 15% DDGS), and four replicates per treatment. From 8 to 21 d of age, the birds were fed broiler starter diets containing similar energy (TMEn 3,100 kcal/kg) and protein (21.6%) contents. From 22 to 35 d of age, they were fed grower diets containing similar nutrients (3,150 kcal/kg, 19.5% crude protein). No significant difference was found in growth performances among the four treatments. As the DDGS level increased, the concentration of unsaturated fatty acids in meat increased (p<0.05). The color scores of breast and thigh muscles were not significantly influenced by DDGS, however, the yellowness of shank increased significantly by the addition of DDGS. The hardness of breast and thigh meats was not affected by the addition of DDGS. It was shown that the use of DDGS in broiler diets up to 15% could decrease the feed cost by replacing part of corn and soybean meal, without any negative effect on growth performance and meat qualities.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.258-263
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• 2011

This experiment was conducted to evaluate the effects of dietary wild-ginseng adventitious root meal (WGM) on growth performance, blood profiles, relative organ weight and meat quality of broiler chickens. A total of 480, 2-day-old male broiler chicks (BW = $42.8{\pm}1.38\;g$) were randomly allocated to 1 of 4 dietary treatments (6 cages with 20 broilers per cage). Dietary treatments were: i) CON (basal diet), ii) WGM0.1 (basal diet+0.1% WGM), iii) WGM0.2 (basal diet+0.2% WGM) and iv) WGM0.3 (basal diet+ 0.3% WGM). Birds fed WGM0.3 diet (p<0.05) had a higher feed intake (FI) than those fed the CON diet during weeks 1 to 3. During weeks 3 to 5, dietary WGM0.1 treatment led to a higher (p<0.05) BW gain (BWG) and feed intake (FI) compared with the CON and WGM0.3 treatments. Overall, birds fed WGM0.1 improved BWG and FI compared with those fed the CON treatment. A greater lymphocyte count was observed (p<0.05) in WGM0.2 and WGM0.3 treatments compared with the CON treatment; dietary WGM decreased (p<0.05) the total cholesterol concentration compared with the CON group. The inclusion of WGM increased the relative weight of spleen and bursa of fabricius (p<0.05) compared with CON, while less abdominal fat was observed in the WGM0.3 treatment (p<0.05) compared with CON. The 2-thiobarbituric acid reactive substances (TBARS) of breast muscle were decreased (p<0.05) by WGM supplementation. Overall, our results indicated that the use of WGM at the 0.1% level could enhance growth performance in broilers. The supplementation of WGM could induce a decreased TBARS, abdominal fat and serum cholesterol in broiler chickens.