According to Livestock Inspection Standards, the piglets enter the feedlot at approximately 30 kg, and the inspection starts after the preliminary feeding period. The reason for applying the preliminary feeding period is to select inspection piglets with no diseases after the complete growth of the internal organs until 10 weeks of age. Furthermore, the age of 10 week is the time when the muscle fibers grow to their maximum size and the piglets are prepared for fat deposition at the later fattening period. In the study, a genome-wide association study (GWAS) was performed through the mlma command of the genome-wide complex trait analysis (GCTA) program with 703 purebred Landrace population, and the candidate genes associated with the weight of 10 week were searched. The GWAS identified 3 single nucleotide polymorphism (SNP) markers, which have a significant genome-wide suggestive level, on chromosome 6 (DIAS0002615; p-value=1.62×10-6, MARC0083933; p-value=4.94×10-6, ASGA0028717; p-value=5.40×10-6). The 2 genes (Ubiquitin protein ligase E3 component n-recognin 4; UBR4, WD and tetratricopeptide repeats 1; WDTC1) in which these 3 SNP markers are located are positional candidate genes of the weight of 10 week of the purebred Landrace population. 2 candidate genes have been reported to be associated with fattening. Therefore, the positional candidate genes in this study, UBR4 and WDTC1, are expected to be usable as genes for traits associated with the weight of 10 week weight and fattening through additional experimental research with other population.
The purpose of this study was to determine the effects of mixed or split-sex feeding on growth performance and behavior of Korean native chickens. Three variants of the sex ratio, FO (female only), MO (male only) and MI (mixed) were tested in Korean native chickens (Hanhyop 3) that were between the ages of 7 and 91 days. Body weight gain was the highest (p<0.05) in the MO treatment and the lowest (p<0.05) in the MI treatment. The feed intake (FI) of birds in the MO treatment was higher (p<0.05) than that of birds in the MI treatment during days 14-21, also MO treatment was higher (p<0.05) than that of birds in the MI treatment during days 21-28. However, the FI of birds in the MI group was higher (p<0.05) than that of birds in FO treatment during days 35-42. The behavioral frequency of walking, drinking, and aggressive pecking were not affected by sex ratio treatment. The behavioral frequency of feeding was higher in the FO treatment than that of birds in the other treatments. The comfort time of birds in the MI treatment was longer (p<0.05) than that of birds in the other treatments. The behavioral frequency of pecking was higher in the MO treatment than that of birds in the other treatments. The study suggests that when male and female Korean native chickens are reared together, sex ratio can influence growth performance and behavior frequency.
The objective of this study was to investigate the effect of different feed inoculation method on rumen fermentation in an in vitro. Three experimental treatments were used: control (CON, direct dispersion of feed (2 g) in rumen fluid), combinations of direct dispersion (1 g) and nylon bag (DNB, pore size: 50 μm, 1 g), and nylon bag (NB, 2 g). An in vitro fermentation experiment was carried out using strained rumen fluid for 48 h incubation time and timothy was used as a substrate. At the end of the incubation, in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), pH, volatile fatty acids (VFA), ammonia nitrogen (NH3-N), and microbial community were evaluated and gas production was estimated at 3, 6, 12, 24, 48 h incubation periods. Gas production was higher in CON than DNB and NB at 6 and 12 h incubation time (p<0.01). There were no differences in final gas production, pH, NH3-N concentration, total VFA production, and VFA profiles among treatments. The IVDMD was lowest in CON (p<0.01) but the IVNDFD was not differed by feed distribution methods. There were no significant differences in general bacteria and fungi. Protozoa count was highest in NB treatment among treatments (p<0.01). The abundance of cellulolytic bacteria, Ruminococcus flavefaciens and Fibrobacter succinogenes, was highest in the CON among treatments (p<0.01).
The objective of this study was to investigate the effects of dry-aging and wet-aging conditions on the chemical composition, meat quality traits (color, water holding capacity, cooking loss, WBSF and pH) and shelf-life TBARS (2-thiobarbituric acid reactive substances) and VBN (volatile basic nitrogen) of loin (M. longissimus thoracis), sirloin (M. glutaeusmedus) and top-round (M. semimembranosus) cuts of Hanwoo cows. The dry-aging condition (temperature ℃, relative humidity %) was done for 60 d as 2℃, 65％, 20 d＋2℃, 75％, 20 d＋4℃, 85％, 20 d while, the wet-aging was done for 60 d at 1℃, 85%. Results revealed that moisture content was significantly higher in the dry-aged samples than that of the wet-aged samples at 60 d (p<0.05). The a*- and b*-values were significantly higher in 3 cuts as compared with those treated with wet-aging condition. During the dry-aging time, the WHC significantly increased in the loin and sirloin and they were significantly higher than wet-aging condition at 40 d and 60 d (p<0.05). The WBSF values significantly decreased with increased aging time and there was no significant difference between two aging methods. The TBARS and VBN contents significantly increased with increased aging time for all the wet- and dry-aged cuts, and their levels still fell within the acceptable standard limit. Generally, the TBARS and VBN contents were significantly higher in the dry-aged cuts, probably due to the increased levels of protein and fatty acids oxidations. Based on the results obtained in the present study, it can be suggested that application of dry-aging method can improve the quality characteristics of beef.
Due to lack of established operating conditions, the swine manure management process circulates bio-liquor between the slurry pit and the bioreactor process cannot be effectively used yet. Therefore, a lab scale study comprising a single bio-reactor and slurry pit was conducted to investigate the optimal operating conditions. The main experiment was performed after conducting a preliminary study on the operating conditions. In the preliminary study, the volume ratio of the bioreactor to the slurry pit was fixed at 1 and hydraulic retention time (HRT) of the bioreactor was set as 5, 10 and 15 d. In the main experiment, the HRT of the bioreactor was fixed at 5 d based on preliminary results and the ratio of bioreactor to slurry pit was set at 1:3, 1:5, 1:7 and 1:10. Since, a decrease in bioreactor performance occurred when NH4-N loading rate reached 60 g/m3/d, the loading rate of NH4-N was required to be maintained below 55 g/m3/d to achieve stable operation. Although manure excretion can definitely increase the loading rate into the bioreactor as well as NH4-N concentration in the slurry pit, the NH4-N in slurry pit can be kept consistent with the circulation rate above 9.5Q (ratio to manure excretion). The optimal volume ratio of the bioreactor to the slurry pit and HRT of the bioreactor to fulfill these operating conditions was 1:3 and 5d, respectively. Notably, studying of the individual farm situation is very important to establish an ideal method to apply the optimal operation conditions suggested in this study.