• Korean Journal of Poultry Science
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• v.35 no.2
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• pp.123-129
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• 2008

This study was conducted to investigate the effects of antibiotic and yeast supplemental high energy diet on growth performance, blood characteristics and carcass trait in broilers. Total of four hundred-eighty broilers were randomly allocated into three treatments with eight replications for five weeks. Dietary treatments included 1) CON (control; basal diet), 2) HED (high energy diet) and 3) YD (HED; yeast added to HED instead of virginiamycin, Sacchromyces cerevisiae, $15{\times}10^{10}$). During whole period, weight gain had high tendency in HED treatment. However, there were not significant among treatments (P>0.05). Feed intake was higher in YD treatment than others. However, there were not significant among each treatments (P>0.05). Feed/Gain ratio was significantly lower in HED treatment than others (P<0.05). In blood characteristics, RBC, WBC and lymphocyte were not significant (P>0.05) among treatments. Liver weigh, LW/BW ratio, leg meat weigh, LMW/BW ratio, breast meat weigh, BMW/BW ratio, abdominal fat weigh and AF/BW ratio were not significant (P>0.05). However, body weight was improved (P<0.05) in HED treatment. In conclusion, this experiment is shown that HED treatment affects Feed/Gain ratio and body weight at final period in broilers.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.113-122
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• 2017

This study was conducted to investigate the effect of dietary supplementation with Lactobacillus, medicinal plant extracts, and plant extracts on growth performance, cecal microflora, relative organ weight, and lymphocyte profile in broiler chickens. One hundred broilers (5 wk old) were used and divided into five (treatment) ${\times}$ two (challenged Salmonella) groups containing 10 broilers. The treatments were as follows: no antibiotics group (NC), antibiotics group (PC), 0.1% lactic acid bacteria group (LB), 100 ppm medicinal plant extract group (MPE), and 100 ppm herb extract group (HE). A basal diet was formulated as 3,100 kcal/kg ME and 20% CP based on corn and soybean meal. Broilers were fed with the experimental diets with no challenge for 1 wk and with challenge of SG for 2 wk. SG were added in water as $1.0{\times}10^6cfu/L$. Final body weight and weight gain were significantly decreased following challenge with SG (P<0.05). However, with the addition of antibiotic alternatives, growth performance was improved and reduction of performance following challenge with SG was lowed compared with that of the NC treatment (P<0.05). Coliform bacteria and Salmonella but not lactic acid bacteria increased with the addition of antibiotic alternatives (P<0.05). Lactobacillus increased significantly with the addition of lactic acid bacteria compared with the NC and PC treatments (P<0.05). The weight of liver, spleen, and bursa of Fabricius increased with addition of antibiotic alternatives (P<0.05). WBC was highly reduced at 4 days after challenge with SG, but was normally maintained thereafter. There was no significant difference in coliform bacteria, Salmonella, organ weights, or WBC with the addition of antibiotic alternatives. Finally, Lactobacillus, medicinal plant extract, and herb extract can be used as antibiotic alternatives; but one alternative completely can't alternate as antibiotics. Therefore, further studies are needed to investigate the synergistic effects of two or more antibiotic alternatives.

• Toxicological Research
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• v.22 no.2
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• pp.75-85
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• 2006

This study was designed to evaluate the possible DNA damaging effects of T-2 toxin using an alkaline single cell gel electrophoresis (SCGE) comet assay and also to investigate toxic effects in chickens. A total of 20 chickens were used in these experiments. Graded concentrations of dietary T-2 toxin (0, 4, 8, and $16{\mu}g/g$ of diet) were given to groups of 5 broiler chickens. In comet assay, The DNA damage was analysed by the tail extent moment (TEM) and tail length (TL), which were used as markers of DNA strand breaks in SCGE. A significant dose-dependent increase in the extent of DNA migration as well as in the percentage of cells with tails was observed after treatment with T-2 toxin (P<0.05). Treatment with the low T-2 toxin ($4{\mu}/g$ of diet) induced a relatively low level of DNA damage in comparison with the high T-2 toxin ($16{\mu}/g$ of diet) group. The growth rate was significantly reduced by concentrations of 8, and $16{\mu}/g$ of diet (P < 0.05). The feed conversion ratio were significantly affected by any concentrations (P < 0.05). The relative weight of the spleen, and lung was decreased by the growth inhibitory concentrations. The bursa of Fabricius, thymus, and kid- ney were decreased in relative weight by concentrations of $16{\mu}/g$ of diet. The relative weight of the liver and heart were unaffected. The hemoglobin (Hb), hematocrit (HCT), and mean corpuscular hemoglobin (MCH) were decreased at concentration of $16{\mu}/g$ of diet. As compared with control chickens, there was no marked change in serum components except uric acid in T-2 treated chickens. All lymphoid tissues retained atrophic and lymphoid cell depletion throughout the three weeks trial.

• Korean Journal of Poultry Science
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• v.9 no.1
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• pp.1-16
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• 1982

Excessive fat deposition, particularly in the abdominal region, has become a problem in broiler production. When the caloric intake exceeds the body demands for energy, excess food is stored as fat in broilers. Researchers have shown that fat deposition varies with breed, strain, sex age, nutrition, exercise, ambient temperature and rearing systems. These factors affect fat deposition through their effects on the size or the number of adipose cells or a combination of both. In some measurements on live birds to predict body fat, the wet weight and percentage fat of skin in pectoral feather tract are significantly correlated with percentage abdominal fat. But these correlation coefficients are not so high. Therefore, correlation coefficients indicate that these measurements on live birds ate not useful for estimating body fat weight and percentage. Most reports show that an increase in the proportion of carcass fat, when measured at a given age, is correlated with selection for increased body weight. On the other hand some research results show that selection for body$.$weight gain dose not lead to an alteration in the proportion carcass fat when measured at a given body weight. Besides, selection for improved food conversion efficiency alone resulted in a decrease in carcass fat and an increase in protein and water when measured at either a given age or body weight, Thus eventhough it is uncertain whether carcass fat is increasing as a result of body-weight selection in broilers: however it is clear that selection for improved food conversion efficiency, either alone or in combination with growth rate, should result in leaner carcasses than selection for growth rate alone.

• Korean Journal of Poultry Science
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• v.13 no.2
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• pp.197-208
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• 1986

This experiment was conducted to find out the effects of the six different feeding methods on the development of body weight, testis, comb and pituitary gland, and the sexual maturity of White Plymouth Rock cockerels. From hatching to 22 weeks of age, the weights of whole body, testis, comb and pituitary gland, and the histological changes of testis and the semen characteristics were checked every other week. The results obtained in this expeniment were as follows: 1. The growth rates of the self-feeding groups were faster than those of the limited feeding groups (70 percent of the self-feeding) by about 2 weeks. The weights of testis and comb showed the most marked increase at 20 weeks of age in the self-feeding groups and at 22 weeks of age in the limited feeding groups, respectively. 2. The weights of pituitary gland from hatching to 22 weeks of age at all observation weeks were not recognised significantly among the compared groups except 4, 14 and 16 weeks of age. 3. Correlations between week of age, body weight, testis, comb and pituitary gland, in the course of 22 weeks, were highly significant. 4. The diameters of lumina and tubules in the seminiferous tubules increased very slowly until 10 weeks of age. They showed the most marked increase at 12 weeks of age in the self-feeding groups and at 14 weeks of age in the limited feeding groups, and then continuously increased until 32 weeks of. age. 5. Primary spermatocytes appeared at first at 8 weeks in the all treatment groups, Secondary spermatocytes appeared at first at 10 weeks in the self-feeding groups and at 12 weeks in the limited feeding groups. At 14 weeks of age spermatids and spermatozoa were found at first in the self-feeding groups but spermatids were found in the limited feeding groups. 6. Age of the first ejaculation was between 14 and 16 weeks of age in the all treatment groups. The Average semen. volume and sperm concentration ranged from 0.1-0.2$m\ell$/ ejaculate and 5.6-9.8${\times}$10$\^$8/ sperm/$m\ell$ at the age of the first ejaculation but 0.30-0.35$m\ell$/ ejaculate and 22.4-42.7${\times}$10$\^$8/ sperm int at the 20 weeks of age in the all treatment groups.

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.291-297
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• 2015

We investigated the effects of dietary pearlzyme (mudflat-bacteria origin protease) on growth performance and development of digestive organs in broilers. Two hundred forty, 4 day-old female Ross broiler chicks were divided into 2 groups (control vs. pearlzyme) which were randomly housed in 8 pens with 15 chicks/pen. They were fed one of two diets containing pearlzyme at 0 or 0.1% for 4 weeks. Dietary pearlzyme resulted in significant increase in body weight during the first week of the experiment (p<0.05). With age, weight gain and feed efficiency continued to decrease reaching significant level during the last week. Mortality was 3.3% in control but not in pearlzyme during the entire period of the experiment. Dietary pearlzyme resulted in increased weight (p<0.05) in the ceca and rectum, and increased length in the ceca (p<0.05). However, there were tendencies to increase the weight of the gizzard (p<0.071) but to decrease the length of the small intestine (p<0.068). The results of the current study show that dietary pearlzyme affects weight gain and the development of digestive organs.

• Animal Bioscience
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• v.34 no.2
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• pp.295-305
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• 2021

Objective: The objectives of this study were to compare the effects of normal and low protein content (PC) of starter diet supplemented or not with blends of branched-chain amino acids (BCAAs) on growth performance of broilers under summer conditions and to investigate whether these effects altered some quality traits and the characteristics of gastrointestinal tract. Methods: A total of 768 mixed-sex broiler chicks (Ross 308, one-d-old) with an average initial body weight (BW) of 47.6±1.03 g were allocated into six treatments with four replications in 2×3 factorial arrangement. Factors were: PC, normal (N, 22% to d 15); and low (L, 20% to d 15); and added BCAA blends, L-leucine, L-isoleucine, and L-valine at zero (0L:0I:0V); 1.0, 0.25, and 0.25 (4L:1I:1V); or 1.0, 0.25, 0.75 (4L:1I:3V) g/kg of diet. Hence, six dietary treatments were named as N0L:0I:0V, N4L:1I:1V, N4L:1I:3V, L0L:0I:0V, L4L:1I:1V, and L4L:1I:3V. Average indoor temperature and humidity were 32.8℃±1.7℃ and 61.1%±4.12%, respectively. Results: BW, feed conversion ratio (FCR) and carcass weight were not affected by PC, BCCA and their interaction (p>0.05). The L diets decreased the water holding capacity of the breast (p = 0.002) and thigh (p = 0.050) meats and dressing percentage (p = 0.005) compared to the N diets. The 4L:1I:1V diet decreased breast yield compared to the 0L:0I:0V diets (p = 0.041). The effect of PC on feed intake, mortality and gastrointestinal trait weight were depended on the L:I:V ratios under summer conditions due to interactions between factors (p<0.05). The FI and mortality of L4L:1I:1V broilers were lower than those of N4L:1I:1V birds (p<0.05). Conclusion: It was concluded that the blends of BCAAs used failed to improve performance and to promote breast yields, because diets with normal or with reduced protein supplemented or not with BCAAs up to d 15 produced a similar BW and FCR in broilers raised in hot-climate conditions.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.199-210
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• 2022

This study was conducted to investigate the effects of the type and number of enrichments on growth performance, blood characteristics, footpad dermatitis (FPD) incidence, and litter moisture in broilers. A total of 1,140 1-day-old male Ross 308 broilers were assigned to a 3 × 2 factorial arrangement based on the type of enrichment (cabbage, alfalfa block, and angle sawdust) and the number of enrichments (one or two per 38 broilers). The growth performance, blood characteristics, FPD incidence, and litter moisture of the broilers were evaluated. Body weight and feed conversion rate were significantly improved (P<0.05) in the alfalfa block and sawdust group compared to the cabbage group, but there was no interaction effect between the type and number of enrichments. The heterophil/lymphocyte ratio, a stress index, was significantly decreased (P<0.05) in the alfalfa block and sawdust groups compared with the cabbage group. The incidence of FPD was significantly decreased in the order of cabbage (3.78), alfalfa block (3.06), and sawdust (1.43) groups at 5 weeks of age. Moreover, there was a significant decrease in the incidence of FPD (P<0.05) in the one-enrichment group compared with the two-enrichment group. Litter moisture at 5 weeks of age was significantly reduced in the sawdust group compared to the cabbage and alfalfa groups, but there was no significant difference in the interaction between the type and number of enrichments. It was concluded that sawdust enrichment positively influenced both growth performance and the animal welfare of broilers. In addition, it is expected that sawdust can be used to regulate litter moisture.

• Korean Journal of Poultry Science
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• v.29 no.1
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• pp.37-43
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• 2002

This experiment was conducted to study the effect of early-life feed restriction with diet dilution on compensatory growth, feed efficiency and abdominal fat pad deposition in broilers. In this study, the chicks were randomly assigned to five treatments. Twenty chicks were assigned to each floor pen, and each dietary treatment was replicated with three pens. Birds In control group (C) were full-fed a starter diet throughout the experimental period, and all birds in four dietary treatments (T1-T4) were fed as starter diet diluted with 50% rice hulls. Birds in T1 were fed with a diluted starter diet ad libitum from 7- to 74-d. In T2,the feeding program was 1-d withdrawal alternating with 3-d feed and in T3 1-d withdrawal alternating with 2-d feed. The feeding Program in T4 was alternate days withdrawal and feeding. The feeding with the diluted starter diet (T1) did not significantly affect to growth rate as compared to the birds of C. When periods of 24 h feed withdrawal were Imposed in conjunction with the diluted diets, birds were under weight at 49 d. As the diluted diet treatment was combined with feed withdrawal (T2-T4), there were further less growth. During the 22 to 49 d Period,T1 birds had greater weight gain compared to other treatments (P<0.05) . Birds consumed less feed from 7- to 49-d when the rice hull dilution was used, and this effect was increased by imposition of feed withdrawal (P<0.07) . If rice hull was excluded from the calculation of feed intake (assumed indigestible) then Intake of the starter diet was markedly less for restricted vs. control birds. After 22 d and from 7 to 49 d, restricted birds had superior feed conversion (P<0.05) compared to control birds. Abdominal fat pad deposition and mortality were not influenced by early feed restriction by diluted diet (P<0.05) .

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.287-292
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• 2009

The objective of the current study was to evaluate the effects of garlic extract (GE) supplementation on growth performance, nutrient digestibility, carcass characteristics and meat composition in broilers. Dietary treatment were control (corn-soy based diet, 0 ppm), and diets added with 100 or 200 ppm GE. Starter and finisher diets were fed from 0 to 3 wk and 4 to 5 wk, respectively. Supplementation of GE had no effect on weight gain, but there was trend towards improvement in growth rate in birds fed diets containing 100 ppm GE during overall period, while birds fed 100 ppm GE had better feed efficiency (p<0.05) than birds fed control diet during finisher period. Birds fed GE had greater (p<0.05) nutrient digestibility of dry matter than birds fed control diet. The TBARS values of breast muscle obtained from birds fed 100 and 200 ppm GE were lower than breast muscle of control birds on day 8 and 12 of storage. The breast muscle of birds fed 200 ppm GE had higher (p<0.05) $L^*$ values than breast muscle of birds fed control and 100 ppm GE diets. The carcass characteristics, meat and bone composition, CIE $a^*$ and $b^*$ values did not differ among the dietary treatments. In conclusion, supplementation of GE enhanced feed efficiency and nutrient digestibility in broilers.