Zn status of sows and piglets as affected by diet and sow parity

Exploring zinc deficiency using serum Zn levels: consequences and potential solutions in suckling pigs

Three trials were undertaken to provide an answer to different questions: 1) Are suckling pigs able to maintain physiological serum Zn levels throughout lactation and do these levels vary between high and low body weight (BW) pigs?, 2) Are serum Zn levels in pigs soon after weaning a predisposing factor for diarrhea?, and 3) Is it possible to increase serum Zn levels at weaning by supplementing Zn during lactation. In trial 1, blood samples were taken from pigs during lactation. Eight pigs (one piglet per litter) had blood drawn on days 0 (farrowing), 7, 14, 21, and 28 (weaning), and 60 pigs (selected from the whole farrowing batch with 35 sows), categorized as either heavy (8.63 kg) or light (5.50 kg) had blood drawn on day 28. Serum Zn levels at birth were 1.2 mg/L and decreased (P < 0.01) to 0.67 mg/L on day 28. Heavier pigs showed greater (P < 0.01) serum Zn levels (0.98 mg/L) than light BW pigs (0.79 mg/L). In trial 2, blood samples were obtained from 240 pigs at weaning (26.2 ± 2.5 d) with an average initial BW of 6.94 ± 1.87 kg and were distributed into 24 pens (10 pigs/pen) by BW. Diarrhea incidence was recorded daily from days 0 to 35 post-weaning. From the 240 pigs, a group of 110 pigs with uniform BW (6.5 ± 1.9 kg) was selected and separated into two groups based on serum Zn levels at weaning with 55 pigs with low serum Zn (LZn: <0.71 mg/L) and 55 pigs with high serum Zn (HZn: >0.9 mg/L). Pigs with LZn were 2.49 times as likely to have diarrhea as pigs with HZn (P < 0.02). In trial 3, a total of 96 suckling pigs were allotted four treatments that consisted of the daily administration of 0, 6, 18, or 30 mg of Zn as Zn citrate in capsule form during the last 7 d of lactation. Pigs were individually weighed, and blood samples were obtained on days 14, 21 (weaning), and 7 after weaning. Serum Zn levels linearly increased by day as Zn citrate supplementation increased (interaction, P < 0.001). However, only light pigs supplemented with 18 and 30 mg/L of Zn experienced an increase in serum Zn levels during lactation. In conclusion, a decrease in serum Zn levels occurs during lactation and is more severe in low BW pigs. Low Zn status (< 0.7 mg/L) at weaning may be a predisposing factor for diarrhea. However, Zn supplementation during lactation can mitigate this decrease in light pigs.

Effects of dietary trace mineral levels on physiological responses, reproductive performance, litter performance, blood profiles, and milk composition in gestating sows

OBJECTIVE

This study was conducted to evaluate the effects of optimal trace mineral levels on the physiological responses, reproductive performance, litter performance, blood profiles and milk composition in gestating sows.

METHODS

A total of 59 multiparous sows (Yorkshire×Landrace) with similar body weight (BW), backfat thickness (BF), and parity were assigned to one of four treatments with 14 or 15 sows per treatment using a completely randomized design. The treatments were 100% (M1), 300% (M3), 600% (M6), and 900% (M9) of the National Research Council (NRC) Nutrient Requirements of Swine. During lactation period, all the sows were fed the same commercial lactation diet.

RESULTS

No significant differences were observed in the BW, BF, reproductive performance, milk composition, or growth performance of the piglets. On day 70 of gestation, the serum zinc concentration showed a quadratic response to M6 treatment (quadratic, p<0.05). Moreover, as the dietary mineral levels increased, the zinc concentration increased linearly at 110 days of gestation (linear, p<0.05). Furthermore, copper and iron concentrations in the serum of sows at 24 h postpartum decreased linearly when high levels of dietary minerals were provided (linear, p<0.05). In the serum of piglets, serum zinc concentrations decreased linearly (linear, p<0.05), and iron concentration showed a quadratic response (quadratic, p<0.05) with an increase in trace mineral premix levels in gestation diets.

CONCLUSION

The current trace mineral requirements of NRC (2012) are suitable for gestating sows, and the addition of dietary mineral levels in the gestating diet did not show any improvements during the gestation and lactation periods.

Dynamic changes of fatty acids and minerals in sow milk during lactation

The objective of the present study was to explore the changes in fatty acids (FAs) and minerals composition in sow milk in order to improve the knowledge about FAs and mineral requirements for piglets. The FAs and minerals composition in the sow milk samples which were collected from ten sows during a period of 16 days of lactation was analysed. The proportion of FAs in sow milk has a significant increase in C8:0, C10:0, C12:0, C14:0, C16:0, C14:1 and C16:1 FAs and the sum of saturated fatty acids (SFAs) according to the lactation period (p < 0.05). The proportion of C18:2 cis-9,12 FA and the sum of polyunsaturated fatty acids (PUFAs) significantly decreased with the advancing of lactation (p < 0.05). The concentrations of minerals, including potassium, copper, manganese and zinc, were higher on day 1 and day 2 than those on day 13 and day 16 (p < 0.05). On the contrary, the lowest concentrations of calcium, sodium, magnesium and iron and the lowest molar calcium: phosphorus ratio emerged in colostrum (p < 0.05). In summary, our results demonstrated FAs profile and minerals concentrations were changed with lactation period. Better understanding of the changes of FAs and minerals may be valuable to swine nutritionists in the commercial industry. In addition, those results provided some meaningful information for sow's diet formulation during lactation.