Restricted selection procedures aimed at achieving predetermined relative changes for all traits are widely used in swine breeding programs in closed herds in Japan. The present study compared responses to selection made by using different restricted selection procedures in a simulated closed herd. The base population consisted of 10 males and 50 females. Three traits (average daily gain, backfat thickness, and loin eye muscle area) of 10 generations were simulated. Selection was made on the basis of an index of individual phenotype for desired gain (RSI) and restricted best linear unbiased prediction of breeding (RBLUP) values. Two types of restriction for RBLUP were imposed on breeding values:the same restrictions on all animals (AR-BLUP) and restriction on only some animals (PR-BLUP). Ten relative desired changes were used in each restricted selection procedure. The cumulative response to selection was greater for selection on RBLUP than on RSI, as expected. The cumulative genetic gain with PR-BLUP was slightly higher than that with AR-BLUP, but no differences between them were statistically significant at generation 10 in any relative desired change. Average inbreeding coefficients were about 9% at generation 5 and 19% at generation 10 for RBLUP selection in all relative desired changes, and no differences in selection between AR-BLUP and PR-BLUP were found in any generation. These results show that selection based on PR-BLUP results in similar genetic gains to that based on AR-BLUP for the three selected traits if the relative desired changes and genetic parameters are in the range of values used in the present study.

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We studied the validity of roasting perilla seed for storage of feed containing perilla seed under high temperature and high humidity. In the experiment, feed containing 3% non-roasted perilla seed (NPS diet) and that containing 3% roasted perilla seed (RPS diet) were used for storage at 30.0°C and 80% relative humidity for 5 weeks. In both of the NPS and RPS diets, acid values rose during storage, and there were significant differences (P<0.05) between the non-stored and 2-week or 5-week-stored feed. The RPS diet showed lower acid values than the NPS diet during the entire experimental period. The peroxide values in both the NPS and RPS diets did not change during the experimental period, remaining at almost the same level. For fatty acid composition of the NPS diet, C18 : 3 content in the lipid of the 5-week-stored feed was significantly lower than that of the non-stored feed (P<0.05), and the n-6/n-3 ratio in the 5-week-stored feed was significantly higher than that in the non-stored feed. In the RPS diets, C18 : 2 content in the 5-week-stored feed was significantly higher than that in the 2-week-stored feed, and there were no significant differences for the other fatty acids analyzed. In the feeding experiment, twelve crossbred pigs (LW×D) were assigned to one of three dietary treatments : NPS diet non-stored (NPS0), NPS diet 5-week-stored (NPS5), and RPS diet 5-week-stored (RPS5). Average daily weight gain was significantly higher in RPS5 than that in NPS0 (P<0.05). For the fatty acid composition of adipose tissues, C14 : 0 and C16 : 0 contents in the perirenal fat were significantly lower in RPS5 than in NPS5 (P<0.05), and C18 : 3 contents in perirenal fat and back fat were significantly lower in NPS5 than in NPS0 (p<0.05), and the n-6/n-3 ratio was significantly higher in NPS5 than in NPS0 (P<0.05). For fatty acid composition of intramuscular fat, the C18 : 3 was significantly lower in NPS5 than in NPS0 (P<0.05), but there was no significant difference in the n-6/n-3 ratio between in NPS5 and in NPS0. In the comparison between RPS5 and NPS0, there was no significant difference in the perirenal fat, back fat and intramuscular fat. These results indicate that the use of roasted perilla seed is effective in preventing the oxidation of lipids in feed containing perilla seed during the storage.

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