• Asian-Australasian Journal of Animal Sciences
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• v.26 no.12
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• pp.1665-1671
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• 2013

Real-time quantitative PCR (qRT-PCR) is one of the important methods for investigating the changes in mRNA expression levels in cells and tissues. Selection of the proper reference genes is very important when calibrating the results of real-time quantitative PCR. Studies on the selection of reference genes in goat tissues are limited, despite the economic importance of their meat and dairy products. We used real-time quantitative PCR to detect the expression levels of eight reference gene candidates (18S, TBP, HMBS, YWHAZ, ACTB, HPRT1, GAPDH and EEF1A2) in ten tissues types sourced from Boer goats. The optimal reference gene combination was selected according to the results determined by geNorm, NormFinder and Bestkeeper software packages. The analyses showed that tissue is an important variability factor in genes expression stability. When all tissues were considered, 18S, TBP and HMBS is the optimal reference combination for calibrating quantitative PCR analysis of gene expression from goat tissues. Dividing data set by tissues, ACTB was the most stable in stomach, small intestine and ovary, 18S in heart and spleen, HMBS in uterus and lung, TBP in liver, HPRT1 in kidney and GAPDH in muscle. Overall, this study provided valuable information about the goat reference genes that can be used in order to perform a proper normalisation when relative quantification by qRT-PCR studies is undertaken.

• Animal Bioscience
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• v.35 no.9
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• pp.1340-1350
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• 2022

Objective: Luxi Black Head sheep (LBH) is the first crossbreed specialized for meat production and was developed by crossbreeding Black Head Dorper sheep (DP) and Small Tailed Han sheep (STH) in the farming areas of northern China. Research on the genomic variations and selection signatures of LBH caused by continuous artificial selection is of great significance for identifying the genetic mechanisms of important traits of sheep and for the continuous breeding of LBH. Methods: We explored the genetic relationships of LBH, DP, and several Mongolian sheep breeds by constructing phylogenetic tree, principal component analysis and linkage disequilibrium analysis. In addition, we analysed 29 whole genomes of sheep. The genome-wide selection signatures have been scanned with four methods: heterozygosity (H_P), fixation index (F_ST), cross-population extended haplotype homozygosity (XP-EHH) and the nucleotide diversity (𝜃_π) ratio. Results: The genetic relationships analysis showed that LBH appeared to be an independent cluster closer to DP. The candidate signatures of positive selection in sheep genome revealed candidate genes for developmental process (HoxA gene cluster, BCL2L11, TSHR), immunity (CXCL6, CXCL1, SKAP2, PTK6, MST1R), growth (PDGFD, FGF18, SRF, SOCS2), and reproduction (BCAS3, TRIM24, ASTL, FNDC3A). Moreover, two signalling pathways closely related to reproduction, the thyroid hormone signalling pathway and the oxytocin signalling pathway, were detected. Conclusion: The selective sweep analysis of LBH genome revealed candidate genes and signalling pathways associated with developmental process, immunity, growth, and reproduction. Our findings provide a valuable resource for sheep breeding and insight into the mechanisms of artificial selection.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.261-266
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• 2023

The skeletal muscles of livestock play a crucial role as protein sources for humans, and the consumption of poultry meat is steadily increasing worldwide. Numerous genes, including myogenic regulatory factors, are involved in myogenesis, and precise regulation of them is essential. In this study, genes specifically expressed in muscles were selected, and their promoters were cloned and analyzed. The analysis of gene expression in various tissues of animals revealed that many genes exhibited specific expression patterns in skeletal muscles, with TNNT3, TNNC2, and MYF6 genes showing similar patterns in poultry. The promoter regions of three genes were amplified by polymerase chain reaction to sizes of 1.2 kb, 1.03 kb, and 1.43 kb, respectively. These fragments were then inserted at the front of the enhanced green fluorescent protein gene in vectors. It was confirmed that the sequences of three promoters closely matched the chicken genome sequences. Upon introducing vectors with each promoter into QM7 quail muscle cells, all three promoters successfully induced the expression of the green fluorescent protein. The brightness of the green fluorescence in each promoter was approximately seven times dimmer compared to the control, CMV-IE promoter. It is predicted that more than 230 transcription factors can bind to each promoter, especially various transcription factors expressed in muscles, including myogenic regulatory factors such as MYF5, MYOD, and MYOG. These promoters can be valuable for studying gene expression in poultry muscle cells, and further research is needed to precisely investigate the regulatory region of gene expression in promoters.

• Korean Journal of Poultry Science
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• v.45 no.4
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• pp.261-272
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• 2018

This study was conducted to evaluate the difference in the quality of chicken thigh meat from conventional and animal welfare farms during refrigeration storage over 9 days. Chicken thigh meat from conventional (CTC, n = 30) and animal welfare farms (CTW, n = 30) was tested. The pH value was significantly lower in CTW (6.28) than in CTC (6.37) on day 1; however, no significant differences were found on subsequent days. The yellowness of CTW was higher than that of CTC on day 1, but CTW showed lower yellowness than did CTC on day 7 and 9. The cooking loss, water holding capacity, lightness, redness, and coliform levels of CTC did not show any significant difference when compared with CTW during storage. The shear force of CTW was significantly higher than that of CTC on day 1, 3, 7, and 9. Total microorganism and coliform in CTC and CTW increased with increasing storage days. On day 7 and 9, the total microorganism level of CTW was lower than that of CTC. The thiobarbituric acid value of CTW was lower than that of CTC on day 9. The volatile basic nitrogen (VBN) of CTW was lower than that of CTC during storage. Anserine content and 1,1-diphenyl-2-picryl-hydrazyl(DPPH) scavenging activity of CTW was significantly higher than CTC on day 1. These results suggest that CTW stayed fresher for longer than did CTC because of low total microorganism level on day 7 and 9, and VBN during refrigerated storage.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.57-65
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• 2013

This study was conducted to evaluate the effect of dietary Weissella koreensis (Wk), a prominent kimchi lactic acid bacteria supplementation on growth performance, nutrients utilization, gut microbiota and meat characteristics in broiler chicken. Both live and killed Wk was compared to know which could be more efficacious as a feed probiotics. Three Wk supplemented groups and no Wk supplemented group were designated according to supplementation levels and cell status. Those were; Control (no Wk), 0.1 % live Wk (LWk 0.1), 0.5% live Wk (LWk 0.5) and 0.5% killed Wk (KWk 0.5). Body weight gain and feed conversion efficiency were improved (P<0.05) by dietary LWk supplementation. KWk did not exert any benefit on growth performance. Crude protein utilizability of KWk supplemented diet was lower (P<0.05) than that of other diets. However, there were no differences among treatments in other nutrients utilization. Serum IgG concentration and relative weight of bursa of Fabricius was highest (P<0.05) in broiler chicken fed KWk 0.5 diet. Cecal anaerobic lactic acid bacteria count of LWk groups were higher (P<0.05) than those of control and KWk 0.5 groups. Dietary Wk supplementation failed to lower the count of cecal and fecal E. coli. There was no effect of dietary Wk on TBARS values and fatty acids profile of broiler leg meat. However, the dietary supplementation of Wk exerted characteristic difference on electronic nose flavor of broiler meat. This study showed that dietary supplementation of LWk was able to improve body weight gain, feed conversion efficiency and cecal lactic acid bacterial count in broiler chicken. Further, the result of this study implemented that a live kimchi lactic acid bacteria, LWk, but not killed Wk, could be used as a probiotic feed supplement for broiler.

• Korean Journal of Poultry Science
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• v.36 no.1
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• pp.9-14
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• 2009

This study was conducted to evaluate the effect of three types of transportation distance (short: less than 40 km; intermediate: 70~80 km; long: 140~150 km) on quality of whole chicken and chicken meat cuts. In whole chicken, $1^+$ grade chicken incidence after transportation of short, intermediate, and long distance transportation was 61.3, 56.3, and 43.8%, respectively. Bruise was not shown in breast and thigh, while wings with bruise after short and long distance transportation were 16.7% and 27.3%, respectively. For chicken meat cuts, $1^+$ grade chicken breast incidence after short distance transportation was 14% higher than that after long distance transportation. Bruised chicken breast after short and long distance transportation were 10 and 12%. Pale, soft, and exudative (PSE) chicken breast incidence after long distance transportation was higher (18.3%) than that after short distance transportation (7.0%). Chicken thigh cuts with $1^+$ grade after short and long distance transportation were shown 91.2% and 88.3%, respectively. Also, chicken wing cuts showed similar result to chicken thigh cuts' and $1^+$ grade incidence of chicken wings after short distance transportation was 11% higher than that of after long distance transportation. These results suggest that shorter transportation distance from farm to slaughter house result in high grade whole chicken and chicken meat cuts.

• Korean Journal of Poultry Science
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• v.37 no.4
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• pp.389-398
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• 2010

The present experiment was carried out to compare performance, carcass characteristics and meat quality among three major meat-type duck strains in Korea. Two commercial duck (CD) strains, produced from parent stocks (PS) (Cherry Valley and Grimaud), and $F_1$ strains, self-produced by farmers, were used in an 8-week feeding experiment. Both feed conversion ratio and production index were significantly higher in Cherry Valley strain compared with the other two at the ends of 6 and 8 weeks (p<0.05). However, no differences were found in carcass characteristics and meat quality, with the exception of abdominal fat weight where Grimaud were higher than the others. Overall, the results of the current study show that Cherry Valley CD strain had higher performance among three strains tested.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.279-286
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• 2009

An experiment was conducted to investigate the effects of dietary supplementation of cerium (Ce), a rare earth, individually and in combination with lanthanium (La), a rare earth, in the basal diet on growth performance, nutrient digestibility, bone composition, breast meat composition, carcass characteristics and meat color in broiler chicks. A total of 1,600 day-old broiler chicks were randomly allotted to four dietary treatments with four replicates in a completely randomized block design. Treatments were T1) CON (control diet), T2) 100 ppm Ce, T3) 100 ppm La, T4) 100 ppm Ce+100 ppm La. There were no significant differences in feed intake among dietary treatments during the whole experimental period (0 to 5 weeks). Body weight gain for the first three weeks was greater in birds T4 than birds fed T3 diet. Feed conversion ratio (FCR) was better in birds fed T4 diet (p<0.05) than birds fed T3 diet during 0~3 weeks, and better FCR for 0~5 weeks was noticed in birds fed T4 diet than birds fed T1 diet. Nutrient digestibility was greatest in birds fed T3 diet (p<0.05) compared with other treatments. Bone composition, carcass characteristics and meat color were no statistically different among the treatments. These results suggest that Ce supplementation, alone and combination with La could improve performance of broilers.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.247-253
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• 2008

This study was performed to evaluate change of lipid oxidation, microbes, and color of chicken meat containing 6, 8, and 10% of water uptake rate(WUR) during cold storage. pH of chicken containing 6, 8, and 10% of WUR showed 6.00, 6.04, and 6.05%, at day 3, respectively. Lightness($L^*$) of chicken containing 6, 8, and 10% of WUR was 73.40, 75.27, and 75.31, at day 3, respectively. Redness($a^*$) of chicken with 10% of WUR was 2.52, which was the highest value, while no difference was found between chicken with 6 and 8% of WUR. Yellowness($b^*$) of chicken containing 6, 8, and 10% of WUR was 4.31, 4.33, and 4.36. Thiobarbituric acid reactive substances(TBARS) value of chicken containing 6, 8, and 10% of WUR was 0.107, 0.104, and 0.113 mg malondialdehyde/kg meat. The higher WUR, the higher TBARS value was shown. Total microbial number of chicken with 6, 8, and 10% of WUR was 4.04, 4.12, and 4.56 $log\;CFU/cm^2$ at day 3. E. coli of chicken with 6, 8, and 10% of WUR was 0.93, 1.40, and 1.28 $log\;CFU/cm^2$. From this result high WUR increases $L^*$ value, TBARS, and microbes of chicken meat during storage. Therefore, lower WUR would be beneficial to extend shelf life of chicken meat during storage.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.111-117
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• 2007

This experiment was conducted to research the effects of Yellow Clay(YC) on the sensory evaluation of cooked meat in broiler chicks. A total of 216 one day old broiler chicks were divided into 6 groups at random. The six groups are consisted of one control group, to which no YC was added, and 5 groups to which an amount of YC was differently added. Diets contained 0.5, 1.0, 2.0, 4.0 and 8.0% of YC and fed to the 5 group broilers for 6 weeks. The lightness of meat in the broilers treated with YC was significantly higher than that of the control group in after-cooking(P<0.05). Besides, the lightness of meat was higher after-cooking than before-cooking. The properties of hardness, gumminess and chewiness were significantly lowered in the groups treated with Yellow Clay, as the amount of Yellow Clay increased at before-cooking and after-cooking(P<0.05). The turbidity of stock was higher in the groups treated with Yellow Clay as the percentage level of Yellow Clay increased, compared with the control group(P<0.05). The acceptability of color, flavor, and texture of meat and stock was higher in the groups treated with Yellow Clay, when compared with that of the control group(P<0.05). In total, the group treated with the 4 percentage of Yellow Clay was the highest in the overall preference(P<0.05).