Monte Carlo computer simulation of a closed strain herd of swine was used to investigate the response to selection and degree of inbreeding assuming no matings between close relatives. Two breeding herds of 10 sires and 30 (small population) or 50 dams (large population) in a base population were modeled;each male was mated to a constant number of females. From each litter, one boar and two gilts were reared as candidates for selection. Selection was either at random, or based on phenotypic performance of the individual or on best linear unbiased prediction of breeding value. Animals were mated at random, avoiding full-sib and full- and half-sib pairings, as well as full- and half-sib and cousin pairings. Either low (0.2) or high (0.5) heritability value (h²) of a performance trait was used in the simulations. Excluding the base population, ten generations (G1-G10) were generated without overlapping, with 1000 replicates for each condition. The larger population showed a greater response to selection than the small population. However, no differences between matings were found as response to selection. Preventing full- and half-sib matings resulted in rates of about 3% with h² of 0.2 and 2.4% with h² of 0.5. These were lower rates of inbreeding than seen in random matings. Our results show that preventing matings between close relatives effectively precludes inbreeding in a closed strain herd of swine. We further conclude that mating plans can ignore matings between cousins.

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To control the amount of adipose tissue is one of the greatest concern in pig industries. In this study, we investigated the effect of varying doses and times of adding octanoate on differentiation of pig preadipocytes under culture conditions including oleate. A clonal cell line of preadipocytes established from pig subcutaneous tissue (PSPA) were exposed to 1 μM∼5 mM of octanoate in addition to adipocyte inducing factors such as insulin, dexamethasone, biotin, pantothenate, and oleate. At the concentration of more than 1 mM octanoate, number of cells significantly decreased while triglyceride (TG) accumulation increased in a dose-dependent manner. Gene expression levels by RT-PCR analysis showed that the key adipogenic transcription factors, i.e. peroxisome proliferators-activated receptor (PPAR) γ2 and CCAAT enhancer-binding protein (C/EBP) α were not affected by the addition of octanoate. However, mRNA expression patterns of proliferation and differentiation markers, such as proliferating cell nuclear antigen (PCNA), adipocyte-specific fatty acid binding protein (aP2), adiponectin and perilipin 1 were consistent with the results of cell number and TG contents. Adding octanoate at various times after cell confluence showed that octanoate should be supplemented throughout the differentiation to obtain more lipid laden-adipocytes, because TG amounts were lower in cells treated with octanoate only during the first, mid or last 4 days than the cells fully treated with octanoate during 10 days culture. Instead of low TG content, short term octanoate-treated cells had high cell numbers, indicating that they contiuned cell-cycle progression. Overall, these results suggest that function of octanoate in adipocyte differentiation is reversible and its dose of more than 1 mM would be useful to increase lipids of PSPA cells even under oleate-added condition.

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