Present experiment was conducted to learn the effect of walking exercise (accumulated distance : 60 km) on physiological response and carcass quality of fattening pigs. Six crossbred (LWD) pigs, 4 barrows and 2 females, were used in this study and they were 150 days-old weighing 72.2±1.9 kg. Animals were classified into following two groups under the same mean body weight and same sex ratio : the free-moving group as a control and the walking exercise group. Experimental period was 40 days. The pigs in the control group had a time moving freely in their pen and the pigs in walking exercise group forced to walk in the distance of 1,500 m under the fixed speed at once in a day during the experimental period. The walking course was in the piggery and course size was follows ; long side : 20 m, short side : 10 m, one lap : 60 m. Heart rate, respiration rate, rectal temperature and body surface temperature were determined as a physiological response. Their determination was conducted at 5 times every 10 days from start point to finish of experiment (190 days-old). Condition of physiological response determination was quiet in the control and quiet before exercise and immediately of exercise in walking exercise group. Body size measurement was also conducted in the same days. Carcass weight, carcass width, carcass length and back fat thickness were determined after slaughtering in the finish point of experiment.
The values of physiological response except for heart rate tended to be large in accordance with walking exercise period, but the heart rate tended to be small oppositely. In the gain of body size that was obtained in comparison with start point and finish point, body length gain in the walking exercise group was significantly (P<0.05) smaller than that of control group. There was no significant difference in the other results, while the chest depth, chest circumference, chest width and back width in the walking exercise group showed small values and cannon circumference, withers height and front width in the walking exercise group showed large values. Carcass weight, carcass width, carcass length and back fat thickness were also showed no significant difference, but the back fat thickness tended to be thin by the walking exercise.

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Selenium (hereafter, Se) concentrations were measured in the whole blood of brood sows taken at each stage of pregnancy and the whole blood of piglets at each stage of growth, as well as Se levels in the sow's milk. Results showed the whole blood Se level of pregnant sows decreased in middle to late pregnancy (89 ng/L in week 8 and 96 ng/L in week 16) compared to the 186 ng/L in early pregnancy (3 weeks), but recovered to 207 ng/L after parturition (at 18 weeks). Meanwhile, Se levels in piglet whole blood were 225 ng/L for 4-months old piglets and 223 ng/L for 6-months old piglets, showing consistent high levels in the later stages of growth, while the Se contents of piglet blood were low at birth and at weaning, 149 ng/L and 141 ng/L, respectively. Also, high Se content was observed in the sow's milk from at birth (248 ng/L) to 2 days after birth (175 ng/L), but decreased to 89 ng/L at weaning (21 days after birth). Further, the correlation was recognized between the Se contents in whole blood of sows one week before parturition and those in colostrum. These results suggest the need for a prompt supplementation of Se, toward middle pregnancy to improve and maintain the blood Se levels in sow and piglet.

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The traceability system using genetic markers is a useful method for discerning the breed, strain and individuality of farm products, and has been adapted for actual market foods such as pork, rice, strawberries and so forth. In this study, we examined the possibility of applying traceability to pork using mtDNA variation which discerns the maternal lineage of the porcine “Fuji-York” strain that was bred in our experiment station.
First, we determined the sequences of the mitochondrial DNA (mtDNA) major non-coding region of 15 animals that represent the genetic background of the maternal lineage of the “Fuji-York” strain. In addition, mtDNA sequences were determined from 14 samples of the Large White breed introduced from three other prefectural animal breeding centers (Gifu, Tokushima, Toyama).
We found that 10 mtDNA haplotypes consisting of 26 nucleotide variations within the “Fuji-York” strain and the Large White breed, and two haplotypes (Ide5 and Ide8) within the “Fuji-York” strain had unique nucleotide substitution sites when compared to other haplotypes obtained from DNA databases.
To apply PCR-RFLP analysis that distinguished these two haplotypes from others, we designed primers and selected restriction enzymes that recognized the unique nucleotide substitution of each haplotype. In fact, we could also distinguish the two unique haplotypes of the “Fuji-York” strain from the other eight types by employing PCR-RFLP analysis.
To evaluate the rareness of these two haplotypes, we surveyed the mtDNA variations of an additional 198 pigs slaughtered at the meat center in Shizuoka Prefecture using PCR-RFLP analysis. It was revealed that the nucleotide substitutions of these two haplotypes were rare, because haplotype Ide5 and Ide8 were detected in only three and no samples respectively, out of a total of 198 individuals. According to the uniqueness of the two haplotypes, we are able to discern pork with the “Fuji-York” strain by constructing the maternal population that has rare types of mtDNA.

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