| The objective of the study was to investigate the effects of dietary energy sources (starch, soybean oil, soybean oil and soluble fiber) on puberty onset and reproduction peformance of gilts. Using single factor design,192gilts with initial body weight of (57.25±5.18) kg,(138±11) d of age were respectively allotted into three treatments, with64replicates per treatment and1piglet per replicate. Trial period started from feeding experiment diets to the end of the first estrus. When the gilts growed to50kg,100kg and first estrus, weight and backfat thickness were measured without feeding. Blood samples were withdrawn from the precaval vein in estrus of the second day. The results indicated that,(1)205days of age, there were no significant differences (P>0.05) in body weight of the treated gilts; the backfat thickness of fat and fat+soluble fiber group gilts, were higher than the starch group sows1.33mm and0.83mm.respectively (P<0.05).When the gilts reached to puberty, body weights of the fat+soluble fiber gilts were lower9.4kg and9.5kg than that of starch and fat group gilts, respectively (P<0.05); the backfat thickness of gilts in fat group were higher0.96mm than that in starch group (P<0.05), with the fiber group sowsthere were no significant difference between gilts in fat group and in fat+soluble fiber group (P>0.05). Compared with gilts in starch group, daily gain of gilts in fat group tended to increase during the whole period (.P=0.09), but there were no significant differences between the two groups(P>0.05). There were no significant differences (.P>0.05) among the three groups about daily gain from50kg BW to105kg BW and from105kg to the weights of puberty.There were no significant differences among the three groups of feed to gain ratio (P>0.05) however, compared with gilts in starch group, feed to gain ratio of gilts in fat group tended to decrease (P=0.095).(2) Compared with the starch group, the gilts in fat group and fat+soluble group were11days and13days earlier attained to puberty, respectively(PO.05)(3) The oestrus rate of gilts in fat+soluble fiber group was13.73%higher than that in starch group(P<0.05), there was no significant difference (P>0.05) among the other groups. Before the200-day-old,200～220-day-old,241～260-day-old and more than280days of age, there were no significant differences among the three groups (P>0.05), compaired with the starch group, oestrus rates when gilts were at the241-260days old in fat+soluble fiber group had a tendency to increase (P=0.088); when gilts were at261-280days old, the oestrus rates in starch group were higher13.73%and1.19%than that in fat soluble fiber group and fat group, respectively (P>0.05).Gilts in101-110kg body weight, the estrus rate of fat soluble fiber+group is significantly higher than starch group (21.43%VS5.0%)(P<0.05), the estrus rates of fat and fat+soluble fiber group at111-120kg were higher than that of starch group16.33%and21.8%, respectively (P<0.05), the oestrus rates of gilts at body weight>140kg in starch and fat group were significantly higher than that of fat+soluble fiber group (22.41%VS3.57%,25.00%VS3.57%)(P<0.05)。(4) The concentrations of plasma total cholesterol and triglyceride in fat group gilts were significantly higher0.21mmol/L and0.17mmol/L than that in the starch group gilts, respectively (P<0.05). There were no significant differences (P>0.05) among the three groups about blood glucose concentration (P<0.05).(5) Gilts fed fat diet had141.70ng/ml higher plasma estradiol concentration significantly than that fed starch group (P<0.05). Compaired with the starch group, the estradiol concentrations of gilts in fat+soluble fiber group had a tendency to increase (P=0.092), but did not reach a significant level.(6) There were no significant differences in litter size, live litter size, live litter size and the number of stillbirths among three groups(P>0.05), however, compared with the fat+soluble fiber group, the number of primiparous weak litter size of gilts in fat group increased by0.59(P<0.1). These results indicate that:Gilts fed fat and fat+soluble fiber diets attained to puberty early through changing serum metabolic substrates and related reproductive hormone levels, diets supplemented with fiber resulted gilts having lighter body weights on onset of puberty; dietary energy containing fat or fat+soluble fiber could improve blood triglyceride and total cholesterol concentration, and promote estradiol production, which is conducive to the onset of puberty. Added on the basis of fat soluble fiber could let oestrus concentrate heat and reduce primiparous weak litter size. |
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