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

• Journal of Animal Science and Technology
• /
• v.47 no.6
• /
• pp.1017-1024
• /
• 2005

This study was investigated the effect of the length of stunning time on pH, water holding capacity(WHC), cooking loss(CL), meat color and incidence rate of blood spot in broiler carcass. One-hundred and forty broiler chickens were slaughtered by three different length of stunning times(5 sec., 8 sec., 11 sec.) with the same electrical frequency(255Hz) and 50 voltage in a commercial abattoir. The WBS values and cooking loss of breast muscle were increased with increasing the stunning time, while WHC of breast muscle were decreased. Lightness(L* value) and yellowness(b* value) scores of leg muscle and skin stunned with 50V, 255Hz, 8 sec, 11 sec. were higher than those of broilers stunned with 50V, 255Hz, 5sec(P<0.05). But, there was no significant difference in color on breast and wing muscle. In subjective evaluation, frequence of the first grade had a trend of being increased by extending the stunning time. There was only a few cases of PSE chicken with 0.02%, while blood spot was observed at the highest rate for the 5 sec. treatment. TBARS indicated that a longer length of stunning resulted in a higher rate of fat oxidation. This experiment demonstrated that the length of stunning time has a significant effect on meat quality and its stability during chiller storage.

• Korean Journal of Poultry Science
• /
• v.36 no.1
• /
• pp.29-37
• /
• 2009

This study was conducted to determine the effects of dietary supplementation with chitosan feeding levels and feeding forms on the performance, proximate composition, pH, thiobarbituric acid reactive substance (TBARS), water holding capacity (WHC), shear force, meat color, and fatty acid of chicken thigh meat. Two hundred broilers (Arbor Acre Broiler, male) were randomly assigned to five groups and were fed for five weeks and slaughtered. Thigh muscle was evaluated in this experiment. The amounts of proximate composition, crude fat of control and T3 for the chitosan-treated groups were significantly higher as compared with T2 (P<0.05), but no significant effects were detected on moisture, crude protein, and crude ash. By comparison, pH was significantly increased when chitosan was included at 2% into diet or more than 1% into drinking water. TBARS was significantly lower at chitosan treated groups it was decreased with increasing chitosan level in the diets (P<0.05). Therefore, chitosan had the possibility to improve shelf life of chicken meat. Higher chitosan levels and feeding additive increased high density lipoprotein cholesterol (HDL-C) and reduced total cholesterol and low density lipoprotein cholesterol (LDL-C) (P<0.05). $L^*$ and $a^*$ of chitosan treated group was higher than the control. As the dietary chitosan levels increase, the composition of palmitic acid and oleic acid levels was increased, however, those but the rates of linoleic acid and arachidonic acid were decreased. It is concluded that dietary chitosan has a positive effect on increasing HDL-C and oleic acid and decreasing total-C, LDL-C and TBARS values. Therefore, the treatment with the most significant effects in the current study was the high level of chitosan.

• Korean Journal of Poultry Science
• /
• v.44 no.1
• /
• pp.29-39
• /
• 2017

This study examined the effects of adding dried blood mixed with Macsumsuk to the feed of broiler chickens. The blood had been dried at $200^{\circ}C$ in an ultra-high-temperature injection system and mixed in a 70:30 proportion of blood meal to Macsumsuk. The experiment consisted of four treatment groups of 150 chickens each. The control group received common broiler feed only, while treatment groups T1, T2, and T3 received feed supplemented with 0.5, 1.0, and 3.0% of the blood meal/Macsumsuk mixture, respectively. The diets were fed for a total of 35 days. Compared with the controls, body weight gain was improved in groups T1 (1,621 g), T2 (1,749 g), and T3 (1,739 g) (1,621-1,749 g vs. 1,448.5 g, respectively) and feed efficiency increased (p<0.01). The carcass rate in group T3 was higher by 83.26% than that in the controls (75.96 %) (p<0.01). The water holding capacity (WHC) increased in groups T1 and T2 (62.27 and 63.80% respectively) compared with controls (p<0.01). The intestine length was longer in groups T1 and T2 (53.98-55.48) than in controls (45.81) (p<0.01). Adding 0.5-1.0% of the dried blood meal Macsumsuk supplement resulted in a significant reduction in the cholesterol content (39.28~47.34 mg/100 g) compared with the controls (50.44 mg/100 g) (p<0.001); furthermore, the proportions of fatty acids including oleic (C18:1n9), ${\gamma}-linoleic$ (C18:3n6), eicosenoic (C20:1n9), and arachidonic (C20:4n6) acids were significantly increased (p<0.01). Compared with controls, the proportion of unsaturated fatty acids (UFA), mono-unsaturated fatty acids (MUFA), and proportion of UFA / SFA in group T1 was (68.66 vs. 69.35%, 51.22 vs 52.00%, and 2.19 vs. 2.26%, respectively) (p<0.05). However, the amino acid content of cystine and methionine of the treatment group (0.43~0.57%) was significantly higher than that of controls (0.38~0.46%) (p<0.05). Overall, supplementing the feed with 0.5-1.0% of the mixture of blood meal Macsumsuk improved productivity by increasing weight gain and feed efficiency, improved meat quality by increasing the water-holding capacity and levels of unsaturated fatty acids, and improved meat color.

• Korean Journal of Poultry Science
• /
• v.18 no.1
• /
• pp.43-55
• /
• 1991

This experiment was conducted to study the sparing effects of animal proteins on weight gain, nutrients utilizability and economic analysis of broiler. Experiment diet contained different ratio of animal and plant protein and were supplemented different levels of methionine and lysine for the respective protein levels. A total of 264 broiler chicks were fed four diets of control, $T_1$, $T_2$ and $T_3$ for 42 days from April 7, 1990 to May 19, 1990. Dietary protein levels of control, $T_1$, $T_2$ and $T_3$ for starter and finisher were 20~18, 18~16, 18~16 and 22~20%, respectively. Methionine and lysine levels of control, $T_1$, $T_2$ and $T_3$ were 0.4~1.1, 0.44~1.21, 0.48~1.32 and 0.48~1.32% for starter diet, respectively, and were 0.32~0.90. 0.35~0.99, 0.38~1.08 and 0.38~1.08% for finisher diet, respectively. The results obtained were summarized as follows. 1. The birds fed control diet gained most for overall period. $T_3$ treatment which was high in protein, methionine and lysine levels gained most for finisher period. 2 The birds fed control diet consumed most feed, and the birds fed T$_3$ diet consumed least feed. for overall period. Feed conversion during 1~4 weeks was better in $T_1$ (1.51) and $T_2$ (1.53) than in control (1.61) and $T_3$ (1.63) . During 4~6weeks, feed conversion was better in $T_3$ (1.37) and control(1.58) than T, (2.05) and T, (2.16) (P＜0.01) 3. Dry matter, crude fiber and NFE utilizability were increased for 1~4 weeks and decreased for 4~6 weeks as methionine and lysine levels increased and crude protein utilizability tended to be increased as protein levels increased. 4. Abdominal fat content was lowest in bird fed control diet and was high in birds fed low protein diet Carcass percentage was highest at control and the abdominal fat content was higher in bird fed lower protein diet than bird fed other protein diets(P＜0.05). 5. Feed cost per kg weight gain was lowest at $T_3$ which contained more soybean oil meal than other feeds and next was control. According to the results of this experiment, it was revealed that optimum protein, methionine and lysine levels for starter and finisher broiler diet were 20~18, 0.4~0.32 and 1.1~0.9%, respectively.

• Korean Journal of Poultry Science
• /
• v.47 no.3
• /
• pp.159-167
• /
• 2020

This study investigated the effect of different light sources in the poultry house on performance, meat quality, and blood composition of finishing broilers. Two hundred and forty male broilers (1-day-old, 42.2±0.1 g) were divided into three groups and subjected to different light source treatments (incandescent, LED, and fluorescent lamps) from 3 weeks of age (four replications/treatment, 20 birds/replication). After breeding for 6 weeks, the carcass yield and meat quality of broilers with similar body weight (BW; 3.4±0.07 kg) were investigated, and blood components were analyzed. Corn-soybean meal-based feed was provided as starter (CP 22.5%, ME 3,020 kcal/kg), early (CP 18.5%, ME 3,050 kcal/kg), and finishing (CP 18%, ME 3,100 kcal/kg). Performance, carcass yield, meat quality, and blood components were evaluated. BW, BW gain, feed intake, and feed conversion ratio did not show any significant differences among treatments. There was no significant difference on live weight and carcass yield among treatments. There was no significant difference on meat color, shear force, and water holding capacity; however, cooking loss at 17.2% was the highest in the LED treatment (P<0.05). There was no significant difference on blood components except for glucose (blood biochemistry component) among treatments. Glucose was 234.5 mg/dL, 256.9 mg/dL, and 250.1 mg/dL in the three treatments, respectively, with a significant difference between incandescent and LED treatments (P<0.05). These results are used useful as basic data for investigating the effect of lighting in broilers production.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.8
• /
• pp.1252-1257
• /
• 2007

This study was conducted to determine the effect of dietary soy isoflavone (ISF, 0 and 20 mg/kg) on performance, meat quality and antioxidative property in male broilers. Six replicates of 45 birds (42 d old) were used for each treatment. The birds were fed soybean meal-free diets containing 3% oxidized fish oil (acid value, 6.76 mg potassium hydroxide/g; and peroxide value, 6.18 meq/kg) for 3 wk. The results showed that average daily gain, feed intake, feed conversion and carcass traits were not affected by soy ISF. Compared with the control group, breast muscle color redness value and water holding capacity were increased (p<0.05) by ISF supplementation. The activity of plasma catalase was increased by supplementing with 20 mg ISF/kg diet. In breast muscle, Broilers fed 20 mg ISF/kg had decreased production of malondialdehyde and lactic acid. The ISF supplementation elevated total antioxidative capacity and activities of total superoxide dismutase and glutathione peroxidase. The results indicated that dietary ISF could increase redness and water holding capacity of meat, and antioxidative property of meat in male broilers fed oxidized fish oil diet.

• Korean Journal of Agricultural Science
• /
• v.49 no.4
• /
• pp.927-936
• /
• 2022

The effects of seasonal differences and crating densities on the preslaughter losses, breast meat quality, and physiological indices of broilers were determined. A total of 600 broilers aged 35 days were divided into 10 treatment groups based on five crating densities (10.3, 11.5, 12.8, 14.1, 15.4 birds·m^-2) with two seasons (i.e., summer and winter) to give six replicates and were placed at various locations in the truck. The birds were transported in crates having dimensions of 1.0 m × 0.78 m × 0.26 m. The transportation distance was 20 km for 40 minutes (average 30 - 50 km·h^-1) during the early morning. The results revealed that broilers transported at densities of 14.1 and 15.4 birds·m^-2 recorded lower (p < 0.05) pH, water-holding capacity (WHC), and muscle redness compared to those at densities of 11.5 birds·m^-2. Furthermore, higher (p < 0.05) cooking loss was found in birds stocked at more than 14.1 birds·m^-2 compared to the other treatments. However, no effect (p > 0.05) with different crating densities on body weight loss, carcass traits, glucose, lactate, or muscle yellowness was observed. Crating density of 14.1 birds·m^-2 showed lower (p < 0.05) cortisol contents compared with birds at 10.3 and 15.4 birds·m^-2. Winter transportation had higher (p < 0.05) relative breast meat weight, cooking loss, muscle redness, and cortisol contents whereas summer transportation had higher (p < 0.05) glucose and lactate contents in the blood plasma of broilers. In conclusion, the stocking of 12.8 birds·m^-2 is recommended to minimize stress responses and undesirable changes that could negatively affect muscle quality.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.6
• /
• pp.845-855
• /
• 2013

Requirements of dietary chloride (dCl) and chloride salts were determined by using $4{\times}2$ factorial arrangement under four phase feeding program. Four levels (0.31, 0.45, 0.59 and 0.73%) and two sources ($NH_4Cl$ and $CaCl_2$) of the dCl were allocated to 1,472 chicks in eight dietary treatments in which each treatment was replicated four times with 46 birds per replicate. The four phase feeding program was comprised of four dietary phases: Prestarter (d 1 to 10), Starter (d 11 to 20), Grower (d 21 to 33) and Finisher (d 34 to 42); and diets were separately prepared for each phase. The cations, anions, pH, dissolved oxygen (DO), temperature, electrical conductivity (EC), total dissolved solids (TDS) and salinity were analyzed in drinking water and were not affected by dietary treatments. BW gain (BWG; $p{\leq}0.009$) and feed:gain (FG; $p{\leq}0.03$) were improved in $CaCl_2$ supplemented diets during d 1 to 10. The maximum response of BWG and FG was observed at 0.38% and 0.42% dCl, respectively, for d 34 to 42. However, the level of dCl for BWG during d 21 to 33 ($p{\leq}0.04$) and d 34 to 42 ($p{\leq}0.009$) was optimized at 0.60% and 0.42%, respectively. The level of dCl for optimized feed intake (FI; $p{\leq}0.006$), FG ($p{\leq}0.007$) and litter moisture (LM; $p{\leq}0.001$) was observed at 0.60%, 0.38% and 0.73%, respectively, for d 1 to 42. Water intake (DWI) was not affected by increasing dCl supplementation (p>0.05); however, the ratio between DWI and FI (DWI:FI) was found highest at 0.73% dCl during d 1 to 10 ($p{\leq}0.05$) and d 21 to 33 ($p{\leq}0.009$). Except for d 34 to 42 ($p{\leq}0.006$), the increasing level of dCl did not result in a significant difference in mortality during any phase. Blood pH and glucose, and breast and thigh weights (percentage of dressed weight) were improved while dressing percentage (DP) and gastrointestinal health were exacerbated with $NH_4Cl$ as compared to $CaCl_2$ supplemented diets ($p{\leq}0.001$). Higher plasma $Na^+$ and $HCO_3{^-}$ and lower $Cl^-$ and $Ca^{{+}{+}}$ were observed in $NH_4Cl$ supplemented diets ($p{\leq}0.001$). Increasing supplementation of dCl increased plasma $Cl^-$ ($p{\leq}0.04$; quadratically) and linearly reduced plasma $K^+$ ($p{\leq}0.001$), $Ca^{{+}{+}}$ ($p{\leq}0.003$), $HCO_3{^-}$ ($p{\leq}0.001$), and $Na^+$ ($p{\leq}0.001$; quadratically). Consequently, higher requirements of dietary chloride are suggested for feed intake; nevertheless, lower levels of dietary chloride are sufficient to support optimal BWG and FG with increasing age. The $NH_4Cl$ supplemented diets ameliorate breast and thigh meat yield along with overall energy balance (glucose).

• Korean Journal of Poultry Science
• /
• v.15 no.1
• /
• pp.21-29
• /
• 1988

This study was conducted to obtain more detailed information on the characteristics of body fat distribution, genetic variation and correlation of fat amount at different location in broiler type chicken. A total of 429 offsprings, produced by mating 13 sires with 52 dams of WPR, were used for this study. All experimental analyses were made on dressed carcasses of 8 weeks of age. The average live body weight was 1,856g in male and 1,483g in female, the proportions of each part to live body weight were higher in male group except skin and abdominal fat pad. The total body fat was more in male (40.76g), but fat rate of total body, skin, and abdomen to live body weight were significantly higher in female group. The fat percentages in each body location were significantly higher in the fatty group and in each sex. The rates of abdominal fat to total body fat were increased by fattening, while subcutaneous fat percentages were lowered. There were high correlations between body weight and fat deposit in each location. The genetic correlation coefficients of body weight to fat percentages of skinned carcass, skin, abdomen, and total body fat to live body weight were negative in both sexes, but those to total body fat, eviscerated carcass fat, and skin fat were positive. In conclusion, the fat weight and fat percentage in individual chickens became higher by fattening however, genetic correlation between live body weight and percentages total body fat to live body weight were so low(negative) that decreasing body fat could be possible without decreasing body weight.