번식생리 및 내분비 : Landrace와 Yorkshire 돼지에서 혈장의 Insulin-like Growth Factor (IGF)-I과 IGF-II 농도와 산자수 및 비유성적과의 관계 = Reproductive Physiology and Endocrinology : Relationships of Plasma Insulin-like Growth Factor (IGF)-I and IGF-II Concentrations to Litter Size and Lactation Performance in Landrace and Yorkshire Figs

다국어 초록 (Multilingual Abstract)

The present study was undertaken to find relationships of plasma insulin-like growth factor (IGF)-Ⅰand IGF-Ⅱ concentrations to litter size and lactation performance. Sixty pure-bred Landrace and Yorkshire pigs having similar farrowing weeks which had been selected from a large number of pregnant gilts and sows were divided into low- (<?? - 0.5SD) and high-litter size (>?? + 0.5 SD) lines under a 2 (breed) × 2 (line) factorial arrange of treatments. After adjusting the litter size to nine piglets per sow at farrowing, total litter weight was measured at three weeks postpartum at weaning as an index of milk yield. Blood samples were obtained from the jugular vein at day (d)-90 pregnancy (Px) and at d-15 postpartum. The litter size or the number of piglets born during the present experiment and the average litter size during the entire parities up to the present one were greater in the high-line than in the low-line by 3.7 and 2.4 piglets. respectively (P<0.01); effect of the breed on litter size was not significant. Plasma IGF-Ⅱ concentration at d-90 Px was greater in the high-line than in the low-line. Litter size and d-90 Px IGF-Ⅰconcentration were negatively correlated in Landrace (r=-0.46; P<0.05) and tended to be negatively correlated in Yokshire (r=-0.31; P=0.09), which resulted in a significant negative correlation between these two variables in total animals (r=-0.35; P<0.01). Litter weight at weaning was not different between the two breeds or lines. Relationships between the litter weight and IGF concentration were not consistent across the breed × physiological stage combinations. Results suggest that d-90 Px IGF concentrations may be indicative of the litter size at impending farrowing.