• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.90-97
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• 2010

An experiment was conducted to evaluate the effects of low concentrations of organic and inorganic dietary trace minerals on broiler performance and trace mineral digestibility along the small intestine of 35-day-old broiler chickens reared under floor-pen conditions. Eight hundred male, day-old Cobb broiler chickens were randomly allocated to 4 dietary treatments (25 birds per pen with 8 replicates per treatment). Broilers fed diets supplemented with 4, 20, 40 and 30 mg/kg, respectively, of Cu, Fe, Mn and Zn from organic chelates and inorganic salts achieved the same body weight gain as those supplemented at the NRC levels (8 mg Cu, 40 mg Fe, 60 mg Mn and 40 mg Zn/kg, respectively) from inorganic salts. However, birds fed a control diet without any supplementation at dietary levels of 7.4-8.8, 60.1-69.2, 14.6-15.4 and 19.1-20.6 mg/kg of Cu, Fe, Mn and Zn, respectively, had decreased feed intake and growth rate. There was no significant difference in the digestibility of Cu in all regions of the small intestine. Throughout the small intestine the apparent absorption of Mn from both organic and inorganic sources was small, whereas the digestibility of Zn seemed to be more complex, exhibiting differences in the apparent absorption due to both mineral source and intestinal site. Therefore, the digestibility of organic Zn was improved (p<0.01) in the ileum compared to inorganic Zn. The digestibility of Zn in the duodenum was smaller (p<0.05) than that in the ileum.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1781-1794
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• 2018

Objective: This meta-analysis was conducted to evaluate the overall effect of direct-fed microbial (DFM) or probiotic supplementation on the log concentrations of culturable gut microbiota in broiler chickens. Methods: Relevant studies were collected from PubMed, SCOPUS, Poultry Science Journal, and Google Scholar. The studies included controlled trials using DFM supplementation in broiler chickens and reporting log concentrations of the culturable gut microbiota. The overall effect of DFM supplementation was determined using standardized mean difference (SMD) with a random-effects model. Subgroups were analyzed to identify pre-specified characteristics possibly associated with the heterogeneity of the results. Risk of bias and publication bias were assessed. Results: Eighteen taxa of the culturable gut microbiota were identified from 42 studies. The overall effect of DFM supplementation on the log concentrations of all 18 taxa did not differ significantly from the controls (SMD = -0.06, 95% confidence interval [-0.16, 0.04], p = 0.228, $I^2=85%$, n = 699 comparisons), but the 18 taxa could be further classified into three categories by the direction of the effect size: taxa whose log concentrations did not differ significantly from the controls (category 1), taxa whose log concentrations increased significantly with DFM supplementation (category 2), and taxa whose log concentrations decreased significantly with DFM supplementation (category 3). Category 1 comprised nine taxa, including total bacterial counts. Category 2 comprised four taxa: Bacillus, Bifidobacterium, Clostridium butyricum, and Lactobacillus. Category 3 comprised five taxa: Clostridium perfringens, coliforms, Escherichia coli, Enterococcus, and Salmonella. Some characteristics identified by the subgroup analysis were associated with result heterogeneity. Most studies, however, were present with unclear risk of bias. Publication bias was also identified. Conclusion: DFM supplementation increased the concentrations of some beneficial bacteria (e.g. Bifidobacterium and Lactobacillus) and decreased those of some detrimental bacteria (e.g. Clostridium perfringens and Salmonella) in the guts of broiler chickens.

• Journal of Animal Environmental Science
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• v.19 no.1
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• pp.33-38
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• 2013

We conducted investigations of the information and welfare of broiler chickens in Korea. The livestock housing of all broiler chicken farms were windowless type, bell feeder and nipple waterer were used, and stocking density was relatively higher (ranging from 18.2 $birds/m^2$ to 24.2 $birds/m^2$) than RSPCA's welfare standards for chicken hens (less than 19 $birds/m^2$). The ratios of sandwich panel, urethane form, slate, and steel plate in roofing materials were 61%, 21%, 13%, and 5%, respectively. The ratios of sandwich panel, urethane form, brick, and steel plate in wall materials were 61%, 21%, 13%, and 5%, respectively. The ratios of soil and concrete in flooring materials were 10% and 90%. The mist spray, fan, and cooling pad in cooling facilities were 42%, 32%, and 26%, respectively. Thus we believe that present data contribute to develop the animal welfare certification for broiler chickens and to improve animal welfare in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1291-1300
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• 2018

Objective: This experiment was conducted to investigate the effects of dietary crude protein (CP) level and exogenous protease supplementation on growth performance, serum metabolites, carcass traits, small intestinal morphology and endogenous protease activity in broiler chickens reared under a tropical climate. Methods: A total of 480 day-old male broiler chicks were randomly assigned to eight dietary treatments in a $4{\times}2$ factorial arrangement. The main effects were CP level (21.0%, 19.7%, 18.5%, or 17.2% from 1 to 21 days and 19.0%, 17.9%, 16.7%, or 15.6% from 22 to 35 days) and protease enzyme supplementation (0 ppm or 500 ppm). All experimental diets were fortified with synthetic feed-grade lysine, methionine, threonine and tryptophan to provide the minimum amino acid recommended levels for Cobb 500. Results: Reducing dietary CP linearly reduced (p<0.05) growth performance, serum albumin, total protein, and carcass traits and increased (p<0.05) serum triglycerides and abdominal fat. There was no consistent effect of reducing dietary CP on morphological parameters of the intestine and on the pancreatic and intestinal endogenous protease activity (p>0.05). Protease supplementation improved (p<0.05) feed conversion ratio, body weight gain, carcass yield and intestinal absorptive surface area. Conclusion: Protease supplementation, as measured by growth performance, intestinal morphology and carcass yield, may alleviate the detrimental effects of low protein diets in broiler chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.650-654
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• 2011

An experiment involving 180 straight run one-day-Cobb broilers was conducted to evaluate the effect of supplementation of L-leucine with different levels of crude protein (CP) on carcass composition and sensory characteristics of broiler grower-finisher chickens. Six experimental diets comprising two levels of crude protein (CP) i.e., 20 and 20% with three levels of L-leucine i.e. 0, 0.5 and 0.67%, were offered to birds from 21-42 d of age. The birds were randomly divided into 36 experimental pens, 5 chickens in each pen, and there were 6 replicates under each diet. L-leucine supplementation did not affect the bone and lean, whereas fat was decreased (p<0.05) when L-leucine was added at 0.5%. Similarly, there were no significant differences (p>0.05) in the lean, fat and bone among chickens fed two levels of CP. No significant differences between dietary treatments were observed on any sensory characteristics affected by dietary L-leucine and CP. From this study, it is obvious that supplementation of up to 0.5% L-leucine reduced fat. However, other characteristics were not affected by supplementation of L-leucine. Similarly, reduction of body composition and sensory characteristics were not apparent on a diet low in CP.

• Animal Bioscience
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• v.36 no.9
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• pp.1393-1402
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• 2023

Objective: In this study effects of three types of beddings on broiler leg health and bone biomechanics were evaluated. Methods: A total of 504 male chicks (Ross 308) were randomly placed on three beddings (4 replicates/group; 42 birds/pen), zeolite-added litter (ZL), plastic-grid flooring (PF), and wood shavings (WS). On day 42, chickens were weighed, slaughtered, and samples (bone, muscle, and drumstick) were collected. Bones were subjected to leg health tests, morphometric measurements, biomechanical testing, and ash analysis. Results: Broilers in PF and WS groups showed higher live weight than the ZL group (p<0.001), and the incidence of tibial dyschondroplasia (TD) and varus valgus deformity due to distal bending was significantly higher in PF (p<0.001). Multinomial logistic regression showed that bedding has a significant (p = 0.038) contribution toward the development of TD. Tibial strength (p = 0.040), drumstick width (p = 0.001), and total femur and epiphyseal ash contents (p = 0.044, 0.016) were higher in the ZL group. Chicken live weight was correlated with tibial length and weight (r = 0.762, 0.725). Conclusion: Flooring and the type of bedding material directly affect broiler bone length, strength and leg health. Plastic bedding improves the slaughter weight of chickens on the expense of leg deformities, and zeolite litter improves leg health and bone strength.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.3
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• pp.394-400
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• 2004

To investigate the efficacy of alternatives to antibiotics, the present study was conducted to compare the effects of antibiotic, lactic acid, a blend of commercial essential oils (EOs) and EOs in combination with lactic acid on growth performance and the functional activity of the gut in broiler chickens. A total of 168 broiler chickens were given the basal diet supplemented with 10 ppm colistin (T1), 0.1% lactic acid (T2), 25 ppm EOs (T3), 25 ppm EOs+0.1% lactic acid (T4), 50 ppm EOs (T5) or 50 ppm EOs+0.1% lactic acid (T6) in the period 3 to 35 days of age. As a result, the broiler chickens assigned to T4 group throughout the experimental period had apparently (p<0.05) greater body weight and total gain than these assigned to T1, T2, T3 and T5 groups. However, there was no difference in growth performance among the birds fed the diets supplemented with antibiotic (T1), lactic acid (T2) and EOs (T3 and T5) alone. The weights of digestive organs and the number of lactobacilli and E. coli in the lower ileum were not affected by dietary treatments. Total trypsin activity was significantly (p<0.05) greater in T4 than T1, T2, T3 and T5 groups. Total and specific pancreatic $\alpha$-amylase activities were significantly (p<0.05) enhanced in the broiler chickens fed T4 diet compared with these fed T1, T2 and T3 diets. However, there were no differences in growth performance and digestive enzyme activities including pancreatic trypsin and $\alpha$-amylase between T4 and T6 groups fed the diets supplemented with either low or high EOs levels in combination of lactic acid. In conclusion, a blend of commercial EOs combined with lactic acid showed significant increases in digestive enzyme activities of the pancreas and intestinal mucosa, leading to increase in growth performance.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.4
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• pp.537-544
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• 2013

This study examined whether pre-treating palm kernel expeller (PKE) with exogenous enzyme would degrade its fiber content; thus improving its metabolizable energy (ME), growth performance, villus height and digesta viscosity in broiler chickens fed diets containing PKE. Our results showed that enzyme treatment decreased (p<0.05) hemicellulose and cellulose contents of PKE by 26.26 and 32.62%, respectively; and improved true ME (TME) and its nitrogen corrected value ($TME_n$) by 38% and 33%, respectively, compared to the raw sample. Average daily gain (ADG), feed intake and feed conversion ratio (FCR) of chickens fed on different dietary treatments in the grower period were not significantly different. Although there was no difference in feed intake (p>0.05) among treatment groups in the finisher period, ADG of chickens in the control (PKE-free diet) was higher (p<0.05) than in all treatment groups fed either 20 or 30% PKE, irrespective of with or without enzyme treatment. However, ADG of birds fed with 20% PKE was higher than those fed with 30% PKE. The FCR of chickens in the control was the lowest (2.20) but not significantly different from those fed 20% PKE diets while birds in the 30% PKE diets recorded higher (p>0.05) FCR. The intestinal villus height and crypt depth (duodenum, jejunum and ileum) were not different (p>0.05) among treatments except for duodenal crypt depth. The villus height and crypt depth of birds in enzyme treated PKE diets were higher (p<0.05) than those in the raw PKE groups. Viscosity of the intestinal digesta was not different (p>0.05) among treatments. Results of this study suggest that exogenous enzyme is effective in hydrolyzing the fiber (hemicellulose and cellulose) component and improved the ME values of PKE, however, the above positive effects were not reflected in the growth performance in broiler chickens fed the enzyme treated PKE compared to those received raw PKE. The results suggest that PKE can be included up to 5% in the grower diet and 20% in the finisher diet without any significant negative effect on FCR in broiler chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.82-89
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• 2010

An experiment was conducted to determine the influence of dietary inorganic (copper sulfate) and organic (copper proteinate) forms of copper and energy level on performance and nutrient utilization of broiler chickens. Two hundred day-old commercial Vencobb broiler chicks were purchased and randomly distributed to 20 cages of 10 birds each. These replicates were randomly assigned to one of five treatments in a (($2{\times}2$)+1) factorial arrangement. These two factors were sources of Cu ($CuSO_{4}$ vs. Cuproteinate) and dose of Cu supplements (200 mg and 400 mg/kg dietary dry matter) and the control (no supplemental Cu). After the starter period (up to 3 weeks), from d 22 onwards another factor i.e. energy at two levels (2,900 vs. 2,920 kcal/kg diet) was introduced with the previous factorial arrangements by subdividing each replicate into two equal parts, for two energy levels, without disturbing the dose and source of Cu supplement. Cu-salt supplementation linearly increased (p<0.01) live weight (LW), live weight gain (LWG) and feed conversion ratio (FCR) at 3 weeks, whereas cumulative feed intake (CFI) was unaffected (p>0.05). LWG and FCR were higher (p<0.01) in Cu-proteinate supplemented birds compared to $CuSO_{4}$ supplementation. A linear dose response (p<0.01) of Cu was found for the performance of broiler chickens. Birds having a higher energy level in the finisher stage increased (p<0.01) LWG and FCR. Cumulative feed intake was similar (p>0.05) across the groups up to the 5th week. Cu-proteinate increased performance of broiler chickens compared to $CuSO_{4}$. Dose of supplemental Cu-salt irrespective of source showed a linear response (p<0.01) for performance. Supplementation of Cu-proteinate increased metabolizability of DM (p<0.01), NFE (p<0.05), total carbohydrate (p<0.01) and OM (p<0.01) at the starter period. Increased dose of Cu-salt linearly increased (p<0.01) metabolizability of DM, CP, CF, NFE and OM. Higher energy level in the diet improved DM (p<0.05), EE (p<0.01), NFE (p = 0.01), total carbohydrate (p<0.01) and OM (p<0.01) metabolizability. Cu-proteinate supplementation showed better nutrient utilization compared to CuSO4. Dose of Cu linearly increased DM, CP, EE, NFE, total carbohydrate and OM metabolizability. CF metabolizability was unaffected (p>0.05) among the treatments. In conclusion, dietary supplementation of Cu-salt more than the requirement may improve performance and nutrient utilization in broiler chickens even with a high energy finisher diet. Cu-proteinate showed better performance and nutrient utilization compared to $CuSO_{4}$.