Eight LW×D crossbred, castrated male pigs (mean of initial body weights was about 55kg), were used in a 8-week growth trial to investigate the effect of reddish-brown seaweed (Porphyra tenera, Nori) in diet on performance, utilization of nutrients, development of backfat and susceptibility of pork meat to oxidation during fattening. Pigs were assigned to two dietary treatments and fed a corn-soybean meal-based diet (control) or the diet supplemented with 2% of dried reddish-brown nori powder. During the 8-week trial, the DM, OM and N digestibilities were measured twice in periods of BW 50-80kg and BW 80-110kg. On day 0, 14, 28, 42 and 56 of the 8-week trial, backfat thickness and plasma thiobarbituric acid reacting substrate (TBARS) were measured. Loin sample were gotten 2 days after the slaughter and carcass grading in a commercial slaughterhouse and TBARS concentrations in the Loin stored under 4°C and fluorescent light were measured on day 0, 2 and 4 after the thawing. During the period of BW 50-80kg, feed intake of pigs fed the diet supplemented with nori compared with the control diet was significantly lowered, but there was no difference in BW gain of pigs between two dietary treatments. Therefore, there was a trend toward an improvement in feed efficiency in pigs by feeding of nori. There were no differences in performance of pigs during the period of BW 80-110kg between two dietary treatments. DM digestibility of pigs fed the diet added nori compared with the control diet was significantly improved during the period of BW 50-80kg, but there were no differences in nutrient digestibilities of pigs during the period of BW 80-110kg among two dietary treatments. Although there was no difference in backfat thickness at P2 of pigs between two dietary treatments, irrespective of measuring day, dressed carcass judged to be below standard because of over-thickness of backfat were fewer in pigs fed the diet supplemented with nori compared with the control diet. There was no difference in plasma TBARS of pigs between two dietary treatments, irrespective of measuring day. TBARS concentration in the loin of pigs fed the control diet increased by the storage under 4°C and fluorescent light, but not in the loin of pig fed the diet supplemented with nori.

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Pedigree of an actual pig strain developed by selection over 7 generations was analyzed, in order to clarify factors to be taken into consideration in establishing a method for predicting the amount of inbreeding and effective size in the process of pig strain development. In the pedigree analysis, the average inbreeding coefficient and coancestry were calculated in each generation, and the observed effective population size was obtained from the increasing rate of coancestry. The observed effective size was compared with the following two expected values : the effective population size expected under random selection (N_eR), which was computed by assuming independent binomial distributions of parental family size in the four gametic pathways, and the expected value (N_eS1) accounting for the effect of selection on the parental family size, which was obtained from the observed variance and covariance of parental family sizes. N_eR overestimated the observed value over all generations. Although the harmonic mean of N_eS1 over generations gave a closer value to the observed one, the effective population size in the later generations was seriously overestimated. These results indicate that the prediction only with the variance and covariance of parental family sizes leads to an overestimation of the effective size of population under continuous selection. A method accounting for the effect of selection on family sizes not only in the parental generation but also in the further ascending generations should be required for predicting the effective size and inbreeding in closed breeding strains of pig.

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Theory for predicting the effective population size and inbreeding under index selection on multiple traits was developed. The concept of heritability of selection index was used for the prediction model. The prediction theory was applied to an actual pig strain selected over 7 generations by a desired-gain selection index of daily gain, back fat thickness and rib eye area, and the predicted effective size and inbreeding coefficient were compared with the observed values. Although the difference between the predicted and observed effective sizes was relatively large in a few generations, the harmonic mean of the predicted effective size over generations was well agreed with that of observed values. The coancestry and inbreeding coefficient obtained from the predicted effective size were close to the observed values. These results suggest that the proposed theory could be used for designing closed breeding programs of pigs with index selection on multiple traits.

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A feeding experiment was carried out to examine the difference in growth effects between formula feed and dried fermented feed that came from by-products of food processing. Dried fermented feed was made from 5 kinds of wastes which contained bread (40% : w/w fresh matter), cooked rice (30%), vegetables (15%), dried Tofu cake (10%) and fish residues (5%). Then the feed was mixed with supplementation of Bacillus spp. Strain.and dried for five hours at 80°C. All steps have been done by Chuohkanse Co. Ltd. (Atsugi, Japan).
In the experiment, 28 WLD and 6LD pigs were fed in six pens. Each of these pens had five to six pigs. The pigs in the experiment were divided into two groups and were provided the two different feeds. The pigs had ready access to the feed and water. The weight of the pigs and the weight of any remaining feed were checked once a week. Also the water content, the levels of crude protein, crude fat, total fiber, amino acid and mineral content in the feed were monitored.
After slaughtering, carcass measurements and analyses of the fatty acids composition were conducted. The results showed that the feed intake in the experimental group were significantly inferior (control 0.87kg/day, experiment 0.40kg/day) due to the inferior preference of the fermented feed, while the meat from the experimental groups was highly evaluated because of much fat content in the muscles. From a commercial viewpoint, the results indicate that fattening pigs using fermented feed from by-products of food processing may be a possibility because this feed is cheaper than formula feed.

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