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The nutrient supply for mature sows during gestation must satisfy their requirements for maintenance as well as for the development and growth of fetal tissue. Maternal nutrition plays a critical role in fetal growth and development as well as postnatal performance and health. Lysine intake during gestation has a major impact on subsequent reproductive performance. The objective of this experiment was to determine the effect of lysine intake from mid-gestation until farrowing on body condition, litter performance, blood metabolites and hormones in multiparous sows. On day 30 of gestation, 200 Landrace×Large White sows were randomly assigned to one of four groups based on body weight and parity (n = 50). The gestation diets contained 0.46, 0.56, 0.65 or 0.74% lysine.
Increasing dietary lysine concentration improved sow body condition at farrowing and increased litter weights (P < 0.05). Dietary lysine level also had a significant effect on the dry matter (P < 0.05) and protein content (P < 0.05) of colostrum. Increased lysine intake increased serum insulin concentration (P < 0.05) and there was a trend towards increased serum prolactin content (linear, P = 0.07). However, increased lysine tended to decrease blood urea N (quadratic, P = 0.05).
These results support the idea that the dietary lysine levels recommended by NRC for multiparous gestating sows (0.52-0.54%) do not maximize body condition of the sows, piglet birth weight or colostrums quality. Based on our results, the optimum dietary level of lysine for multiparous gestating sows to maximize these parameters is 0.65% lysine. Although further increases in body condition of sows, piglet birth weight or colostrums quality were obtained by feeding 0.75% lysine, these differences were not significant and feeding such levels would lower economic efficiency. Our results did not show any effect of lysine level in gestation on litter size. Therefore, when implementing feeding strategies for improving sow reproductive performance, the appropriate lysine intake for pregnant sows must be considered and depending on producer objectives, feeding higher lysine levels than those currently recommended by NRC may be considered.
RF Zhang, Q Hu, PF Li, LF Xue, XS Piao and DF Li, 2011. Asian Australasian Journal of Animal Science, 24(8): 1142 - 1147.