NUTRITION ▶▶▶


Hormones: Essential to think of when feeding sows


BY JACKELINE HORNSTRA, RESEARCHER SWINE, ROYAL DE HEUS T


he life of modern hyperprolific sows is much like running a marathon. They give birth to a large number of piglets and have to produce enough co- lostrum to give them a vital life start. A farrowing


duration with ten- to 20-minute intervals between piglets is considered to be physiologically normal and is crucial to en- sure that piglets are born alive and are vital at birth. Hor- mones, as well as nutrients, are known to play a critical role in regulating body functions during the transition period. For sows to win the farrowing marathon, a comprehensive nutritional approach is necessary, taking hormones into account.


Hormonal orchestration of a transition For the gestating sow, the change from gestation to lactation is a major transition. For that to happen, a series of co-ordi- nated hormonal signals are given to the brain and several or- gans to prepare the sow for her new production state. The changes in hormones occur in the last week of gestation, a few days before farrowing. Oestrogens, oxytocin and prolactin are key hormones that act and interact to prepare the sow’s body to give birth, express nesting and maternal behaviour and to produce colostrum and milk. For these hormones to increase as farrowing ap- proaches, progesterone, “the pregnancy hormone”, must decline (Figure 1). When progesterone levels do not drop sufficiently, or when the stress hormone levels are too high, oestrogens, prolactin and oxytocin are not produced at the proper levels. Low lev- els of these hormones near farrowing are associated with birth complications and low colostrum production in swine. Apart from reproductive and stress hormones, other hor- mones that regulate appetite, energy and calcium metabo- lism of sows are actively regulating body functions during the transition period. A few examples are the thyroid and para- thyroid hormones insulin and calcitriol (the active form of vitamin D).


Nutrition and hormonal regulation Like all molecules in the body, hormones are derived from nutrients, meaning that nutrition plays an important role in hormonal regulation. Progesterone and oestrogens are steroid (lipid) hormones derived from cholesterol. Oxytocin


Much attention is paid these days to the correct sow nutrition strategies during gestation and lactation. Yet what about hormonal levels, especially during the transition phase? In these phases of life, they play a pivotal role. As hormones are derived from nutrients, these components should not be forgotten.


and prolactin are peptides (protein) hormones, derived from amino acids. Enzymes are also involved in the production and activity of many hormones. For example, oestrogens are derived from progesterone, and this process is mediated by enzymes. En- zymes are composed of protein but require non-protein mol- ecules (cofactors and coenzymes) for proper activity. These cofactors and coenzymes can be trace minerals or vitamins. Vitamins and trace minerals are also used in the antioxidant system, which plays an important role in maintaining a hor- monal balance. A few examples of nutrients involved in hor- mone production, balance and function during transition are presented in Table 1. Around the time of parturition, the modern highly prolific sows’ requirements for vitamins and trace minerals are very high. Sow productivity increases in the first three reproduc- tive cycles and, as this happens, sow body (mineral) reserves decline. Therefore, after the third cycle sows must be pro- vided with greater amounts through the diet to meet their requirements. Deficiency of zinc, selenium, vitamin A and vi-


Figure 1 - Changes in reproductive hormone levels around the time of parturition in sows.


prolactin oxytocin


oestrogen progesterone


–9 –8 –7 –6 –5


–4 –3 –2 –1 0 days to farrow (0)


Source: Adapted from Peltoniemi and Oliviero, 2014. ▶ PIG PROGRESS | Volume 37, No. 3, 2021 35 +1 +2 +3 +4 +5 +6 +7


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44