• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1197-1205
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• 2006

This experiment was conducted to compare the effects of feeding DL-2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and DL-methionine (DLM) supplemented corn-soybean-cottonseed meal diets on growth performance, carcass composition, and muscle color of broilers. The trial was designed as a $2{\times}3{\times}2$ factorial experiment, including two methionine (Met) sources (HMTBA and DLM), three equimolar graded levels of Met supplementation (i.e., 0.08, 0.16, and 0.24% in the starter diet and 0.07, 0.14, and 0.21% in the grower and finisher diets, respectively), and two sexes (male and female). Additionally, one basal diet for each sex was formulated to be limiting in Met to test the dosage response of increasing supplemental Met levels. Four hundred and twenty 10-d-old broilers were randomly allotted to 14 treatments (seven each for males and females), with five replicate pens per treatment and six chicks per pen. There was no difference (p>0.05) between the two Met sources in growth performance and muscle deposition of broilers throughout the whole experimental period (d 10 to 49). With the increasing Met supplementation levels, average daily gain was increased (quadratic; p<0.01) during the starter, grower, and overall phases, average daily feed intake was increased (quadratic; p<0.01) during the starter phase, and feed:gain ratio was decreased (quadratic; p<0.05) during the grower and overall phases. At the end of finisher phase, Met supplementation increased breast muscle content (quadratic; p<0.01) and thigh muscle content (linear; p<0.05), and decreased abdominal fat content (quadratic; p<0.02). Compared to the broiler fed DLM, broilers fed HMTBA had superior breast and thigh muscle coloration (p<0.01). Male broilers had higher weight gain and feed intake and better feed conversion than female broilers (p<0.01). The fat content of thigh muscle in female broilers was higher than that of male broilers (p<0.03). The best fit comparison of HMTBA vs. DLM was determined by Schwarz Bayesian Criteria index, which indicated that the average relative bioefficacy of HMTBA vs. DLM was 120% with 95% confidence limit 67 to 172%. These results indicated that Met supplementation improved growth performance and carcass quality of broilers fed corn-soybean-cottonseed meal diets irrespective of Met sources. Compared to DLM, HMTBA has the same molar bioefficacy on improving the growth performance and carcass quality of broilers; however, HMTBA fed birds had superior meat color to DLM fed birds.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1752-1756
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• 2011

This study was conducted to explore the effects of squid ink on growth performance, immune functions and antioxidant ability of broiler chickens during a period of six weeks. Either sex Arbor Acres broilers were equally allotted to 4 groups with 3 replicates of 20 chickens each. Broilers diets for the 4 test groups were prepared separately with starter and finisher phases. Control chickens were fed with basal diet and birds of group Exp 2, Exp 4 and Exp 6 were fed with the basal diet supplemented with 2%, 4% and 6% of squid ink, respectively. Broilers were sacrificed to investigate antioxidant parameters of sera, indices of thymus, spleen and bursa of fabricius and spleen lymphocyte proliferation, as well as growth performance on the $21^{th}$ and $42^{th}$ day. The results revealed that, i) squid ink promoted growth performance of broilers during days 22 to 42 and the whole trial period (p<0.05 or p<0.01); ii) squid ink elevated relative weight of the three immune organs during the starter phase and spleen lymphocyte proliferation throughout the experiment (p<0.05); iii) squid ink increased SOD activity and decreased MDA level in sera from broilers during the whole period (p<0.05). The above results suggest that squid ink could improve growth performance, antioxidant ability and immune functions of growing broiler chickens and be employed in the development of feed additives for animals.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1776-1783
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• 2002

A population segregating for the naked neck (Na) gene was used to evaluate its effect on fast growing broilers at heat stress. An experimental stock comparable to those of modern broilers was established by backcrossing to colour synthetic male and female lines. Matings between heterozygous (Na/na) males and females produced normally feathered (na/na), heterozygous (Na/na) and homozygous (Na/Na) chicks for the present study. Day old to seven week old coloured broilers of three genotypes viz. normally feathered (na/na), heterozygous naked neck (Na/na) and homozygous naked neck (Na/Na) were compared for heat dissipation, growth performance, body conformation traits, blood biochemical parameters and carcass traits in tropical climate. In hot climate, naked neck broilers had significantly less body temperature and better heat dissipation capabilities as compared to normal broilers. The naked neck broilers had significantly higher body weight and better feed conversion ratio than na/na broilers. The Na/Na or Na/na broilers exhibited higher giblet yield, blood loss and lower feather mass compared to na/na broilers. The results indicated that the reduction in feather coverage in Na/Na and Na/na broilers facilitates better heat dissipation with lower body temperature, more body weight gain, better FCR and carcass traits compared to normal broilers.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.614-627
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• 2020

During the course of this trial, our team assessed the influence of protease upon the growth performance, the nutrient digestibility, and the expression of growth-related genes and amino acid transporters within the liver, muscle, and small intestines of broilers. During the first step, our team allocated 600 broilers into four dietary treatments for a period of 35 days in order to measure the growth performance and nutrient digestibility of the broilers selected. The separate treatments contained 10 replicates (15 birds per replicate). The treatments were composed of: 1) CON, basal diet; 2) T1, basal diet + 0.03% protease; 3) T2, basal diet + 0.06% protease; and 4) T3, basal diet + 0.09% protease. Next, the broiler chick sample tissue was harvested from the CON and T3 groups in order to conduct gene expression analysis following the feeding trials the broilers underwent. Our team discovered that the broilers fed protease diets possessed increased body weight and an average daily gain, but conversely, had lower feed conversion ratios when their dietary protease levels increased from 0% to 0.09% (p < 0.05). Additionally, significant linear improvements were identified among the nutrient digestibility of dry matter, crude protein, energy, and amino acids within broilers supplied with protease diets when contrasted and compared with broilers supplied with the basal diet (p < 0.05). In addition, the gene expression of the genes IGF1, IGF2, GH, and LEP in the liver, and the genes MYOD1 and MYOG in the breast muscles, was significantly increased after broilers were fed with a protease diet as compared to broilers that subsisted on a basal diet (p < 0.05). Protease supplementation also raised the expression levels within these amino acid transporters: SCL6A19, SLC7A1, SLC7A7, SLC7A2, SLC7A6, SLC7A9, and SLC15A1, located in the small intestine, when compared to the basal diet (p < 0.05). Our results suggest that protease supplementation in their diet improved the growth performance of broilers via an increase in the expression growth-related genes within broiler liver and muscle tissue. In addition, protease supplementation enhanced broiler digestibility via the upregulation of amino acid transporter expression within the small intestine.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.351-359
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• 2019

The purpose of this study was to compare the growth performance, nutrient digestibility, fecal microflora, blood profiles and meat quality of broilers, Korean native chickens and white semi broilers under identical feeding conditions. Sixty 1-d chicks of each type were randomly placed into 12 pens per cage (5 chicks per cage) and fed commercial diets for 28, 49, and 28 days, respectively. The broilers showed a significantly higher (p < 0.05) growth performance from 0 to 4 weeks compared with the other types. Korean native chickens had a significantly higher (p < 0.05) digestibility of dry matter and nitrogen than that of the other species. The blood glucose was significantly higher in the Korean native chickens compared to the other species, and the blood cholesterol was significantly lower. The Lactobacillus content in Korean native chickens was significantly higher (p < 0.05) compared to the other species, and the E. coli content in the broilers was significantly higher (p < 0.05) than in the Korean native chickens and white semi broilers. In terms of meat quality, the breast meat of the broilers had a high water content and pH level. The breast meat of the white semi broilers had a significantly lower (p < 0.05) shear force than that of the other species. In conclusion, there was an interspecific physiological difference due to the age and body weight of the chickens. The broilers had a higher growth performance and meat quality compared to the Korean native chickens and white semi broilers.

• Korean Journal of Poultry Science
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• v.47 no.2
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• pp.75-82
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• 2020

This study intended to investigate the growth performance and meat quality traits in broilers fed different regimens of NaCl over a period of 35 days. Seven hundred and fifty 1-day-old chicks (Cobb 500) were randomly assigned to five NaCl feeding regimens to obtain three replicates for each regimen. Broilers in CON group were provided with concentrations of 0.35% NaCl for the duration of the experimental period. The other groups were provided with two concentrations of NaCl (0.45% and 0.55%) under two durations, namely: 1) 1~28 d: 0.45% or 0.55% NaCl for 28 days then CON; and 2) 1~35 d: 0.45% or 0.55% NaCl for 35 days. Broilers fed 0.55% NaCl for 1~35 d showed improved (P<0.05) growth performance compared with broilers fed the CON regimen. Moreover, higher water holding capacity of breast meat was shown by the broilers fed 0.55% NaCl for 1~28 d when compared with that in broilers fed the CON diet (P<0.05). Broilers fed 0.45% NaCl showed an increase (P<0.05) in the lightness of the meat over CON diet and the 0.55% NaCl diet. In addition, broilers offered CON had the highest redness value and highest crude ash content in the breast meat (P<0.05). Feeding 0.45% NaCl for 1~35 d and 0.55% NaCl for 1~28 d resulted in a higher (P<0.05) protein content in breast meat. In conclusion, broilers fed diets with 0.55% NaCl for 1~35 d showed improved growth performance as well as water holding capacity and protein content of the breast meat.

• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.161-172
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• 2017

This study was conducted to determine the effect of Saccharomyces cerevisiae (SC) as a dietary probiotic and evaluated the most suitable feeding interval for this probiotic on growth performance, carcass yield, and meat quality parameters in broiler chickens. In total, 1,050 one-day-old Cobb 500 chicks were randomly assigned to one of seven dietary treatment groups, in a $2{\times}3$ factorial arrangement with 3 SC dosages (0.6%, 1%, and 1.4%) and two feeding intervals [long term (LT) for 35 days and short term (ST) for 28 days after hatching], with a negative control diet (NC; 0% SC). Triplicate experiments were performed with 50 birds per cage. Broilers fed a diet including SC showed increased (p<0.01) daily gain and feed efficiency compared to the control. Further, broilers fed the 1.4% SC supplemented diet showed a significantly increased (p<0.01) average daily gain (ADG) and feed conversion ratio (FCR) compared to broilers fed the 0.6% and 1% SC incorporated diets. Similarly, broilers fed an LT SC diet showed a greater (p<0.01) increase in ADG and FCR compared to broilers fed an ST SC diet. Moreover, broilers fed an LT SC diet displayed a reduced (p<0.05) meat pH, gizzard weight, and increased (p<0.05) meat water-holding capacity compared to broilers fed an ST SC diet. Broilers fed the 1.4% SC supplemented diet showed increased (p<0.05) thigh muscle weight compared to broilers fed the 0.6% and 1% SC supplemented diets. In conclusion, broilers fed LT SC diets showed improved growth performance and carcass quality parameters compared to broilers fed ST SC diets, and the NC diet, from hatching to day 35.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1451-1457
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• 2016

A comparative study was performed to investigate the efficacy of KiFAY as a feed additive on performance parameters, thyroid, and pancreatic hormone levels in broilers. Ninety birds (Vencobb 400) were randomly divided into three groups viz., Control (no DL-methionine supplementation), Treatment1 (containing added DL-methionine) and Treatment 2 (containing KiFAY and without DL-methionine supplementation). The performance parameters (weekly body weight, body weight gain, feed intake, and feed consumption ratio) were recorded and calculated during the whole study of 4 weeks. Analyses of insulin and insulin-like growth factor (IGF 1), triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH) were performed at the end of the study. The results show that birds on supplementation of KiFAY performed significantly (p<0.001) better than other treatments. The weekly body weight, body weight gain, feed in-take and feed consumption ratio improved in KiFAY treated birds. The study found an increase in insulin and IGF1 levels (p<0.001) in KiFAY compared with the other treatments. Serum T3, T4, and TSH levels in the Treatment 2 were higher than other treatments (p<0.001). The KiFAY supplementation was able to improve performance with associated responses at a hormonal level in broilers.

• Journal of Animal Science and Technology
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• v.63 no.3
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• pp.563-574
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• 2021

A total of 1512 Ross 308 broilers (one - day - old) were assigned (random blocks) to 1of 3 dietary treatments with 28 replicates of 18 chicks/cage. The dietary treatments were Cornsoybean-meal based basal diet supplemented with 0%, 0.1%, and 0.2% of commercial yeast hydrolysate (YH [Saccharomyces cerevisiae]). The graded level of YH supplementation has linearly increased broilers body weight gain on d 21, 35, and overall (p = 0.044, 0.029, and 0.036, respectively) experimental period. In addition, the increased level of YH supplementation has linearly reduced feed conversation ratio of broilers on d 21, 35, and overall trial period (p = 0.041, 0.052, and 0.032, respectively). However, the feed intake and mortality of broilers were not affected by the graded level of YH supplementation. Though nutrient digestibility of dry matter (p = 0.012) and nitrogen (p = 0.021) was linearly increased in broilers fed YH supplementation, at the end of the trial it fails to affect the total track digestible energy. Dietary inclusion of YH supplementation showed a beneficial effect on the microbial population as linearly improved lactobacillus (p = 0.011) and reduced Escherichia coli counts (p = 0.042). An increasing level of YH supplementation has tended to decrease NH₃ (p = 0.069) and linearly decrease H₂S (p = 0.027) of noxious gas emission in broilers. Moreover, dietary YH supplements trend to increase the glucose (p = 0.066) and reduced cholesterol (p = 0.069) level. At the end of the test, YH supplementation elicited a linear reduction in drip loss on days 5 and 7, respectively (p = 0.045, and 0.021). Furthermore, dietary inclusion of YH supplementation had linearly increased villus height (p = 0.051) but fails to affect crypt depth. Therefore, in terms of positive effects on the broiler's overall performance, we suggest that dietary supplements containing graded YH levels in the broilers diet could serve as a potential alternative for growth promoters.

• Korean Journal of Poultry Science
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• v.49 no.1
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• pp.9-14
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• 2022

This study was conducted to investigate the effects of dietary inclusion of phytase on the growth performance, organ weight, and tibia ash of broilers. A total of 1008 one-day-old Ross 308 broiler chicks (mixed gender) with body weight 42 ± 0.90 g (mean ± SD) were used in a trial for 32 d. Chicks were assigned to one of the two treatment diets. Each treatment consisted of 28 replicate cages, with 18 birds per cage. The dietary treatments were as follows: CON, basal diet; TRT1, basal diet + phytase 1,500 Fan Terminal Unit (FTU)/kg diet. Dietary inclusion of 1,500 FTU/kg phytase supplementation in broilers showed only slight improvements in daily feed intake (P=0.086) and feed conversion ratio (P=0.065) on day 9 compared with that in the control group. However, organ weights of the breast muscle, liver, spleen, kidney, and bursa of Fabricius were not affected by the dietary treatments. In addition, the dietary inclusion of 1,500 FTU/kg phytase supplementation in the broiler diet had no effect on tibia ash. The addition of 1,500 FTU/kg phytase in the basal diet of broilers did not have any adverse effect on growth performance, organ weight, and tibia ash, suggesting that phytase supplementation in broiler diets will exhibit comparable effects as that of corn-soybean meal-based diet.