In primiparous sows, plasma insulin-like growth factor-I can be affected by lactational feed intake and dietary energy source and is associated with luteinizing hormone

Abstract

-During a 21-day lactation period, 48 primiparous sows were fed a fat-or a starch-rich diet (131 g fat and 183 g starch + sugar . kg -1 vs. 31 g fat and 351 g starch + sugar . kg -1 ) at a high or a low level of feeding (44 vs. 33 MJ net energy per day) according to a factorial design. Blood samples were collected at days 7, 14, 21, 22 (weaning), 24, 25, 26, and 27 post-partum (p.p.). IGF-I levels were higher with the starch-rich than with the fat-rich diet at days 7, 21, 22, and 24 p.p. Plasma IGF-I concentrations on day 22 p.p. were positively related with LH pulse frequency on day 22 p.p. and the height of the pre-ovulatory LH surge. Sows with low body weight at farrowing and high lactational body weight loss had lower plasma IGF-I concentrations than others, before and after weaning. These results indicate that IGF-I concentrations are affected by both feeding level and dietary energy source and are related to the secretion of LH. Furthermore, body weight at farrowing interacts with lactational body weight loss to affect IGF-I concentrations. IGF-I / sow / lactation / LH / energyRésumé -Chez les truies primipares, l'IGF-I plasmatique peut être influencé par le niveau alimentaire de lactation et la source d'énergie, et est associé à la sécrétion de LH. Pendant 21 jours de lactation, 48 truies primipares reçoivent un aliment enrichi en graisse ou en amidon (131 g graisse et 183 g amidon + sucre . kg -1 versus 31 g graisse et 351 g amidon + sucre . kg -1 ) sous deux niveaux éner-gétiques (44 versus 33 MJ énergie nette par jour) selon un schéma factoriel. Des prises de sang ont Reprod. Nutr. Dev. 41 (2001) 27-39 27

Insulin-stimulating diets during the weaning-to-estrus interval do not improve fetal and placental development and uniformity in high-prolific multiparous sows

“…Indeed in our sows, insulin and IGF-1 concentrations before weaning were negatively related to sow BW loss during lactation, and positively related to sow backfat thickness at weaning, as also observed by Hoving et al (2012) and Rojkittikhun et al (1993). After weaning, sows change towards an anabolic state, associated with restoration of plasma insulin and IGF-1 concentrations (Van den Brand et al, 2001a;Wientjes et al, 2012b). In our sows, after weaning a quick restoration of insulin secretion took place and no relations existed between pre-and postweaning insulin levels.…”

Consequences of different dietary energy sources during follicular development on subsequent fertility of cyclic gilts

“…To our understanding, insulin may be a potential mediator of these treatment effects. As mentioned previously, higher insulin levels are positively associated to LH pulsatility in sows (van den Brand et al, 2001), as it might affect the GnRH pulse generator. For instance, van den Brand et al (2000a) and Ziecik et al (2002) reported that dextrose containing feed increased insulin and IGF-1 levels (van den Brand et al, 2001) and follicle size (van den Brand et al, 2000a;Wientjes et al, 2012b).…”

“…As mentioned previously, higher insulin levels are positively associated to LH pulsatility in sows (van den Brand et al, 2001), as it might affect the GnRH pulse generator. For instance, van den Brand et al (2000a) and Ziecik et al (2002) reported that dextrose containing feed increased insulin and IGF-1 levels (van den Brand et al, 2001) and follicle size (van den Brand et al, 2000a;Wientjes et al, 2012b). Comparable effects were recently demonstrated by Quesnel et al (2007), as they showed that sows with a high and prolonged insulin response after a glucose tolerance test had more and better developed follicles.…”

“…Previous studies have investigated similar effects in lactating primiparous and multiparous sows (van den Brand et al, 2001(van den Brand et al, , 2009Wientjes et al, 2012a). However, the metabolic state of lactating sows and cyclic gilts may not be comparable, as the former are catabolic and the latter, anabolic, which may induce different metabolic responses.…”

“…In this sense, studies conducted in lactating sows reported that dextrose containing feed increased insulin and IGF-1 levels (van den Brand et al, 2001) and follicle size (van den Brand et al, 2000a;Wientjes et al, 2012b). In addition, comparable effects have been recently demonstrated by Quesnel et al (2007) in sows with a high and prolonged insulin response after a glucose tolerance test, which showed more and better developed follicles.…”