Effects of pre-mating diets and metabolic state on subsequent piglet vitality and mammary gland development

We argued that the present development regarding newborn piglets should be investigated from the point of view of control mechanism of physiology of pregnancy - and developement of the mammary gland seems not to match the demand of the large litter. While number of piglets born per litter has gone up, the birth weight and vitality of the newborn are decreasing (Boulot et al., 2008). Instead of focusing on the number of piglets born alive, more research effort should be aimed at increasing the vitality, development of the udder and birth weight of neonates born. The proposed studies were therefore focusing on feeding – metabolism - management – physiological - behavioral interplay between the dam, fetuses, newborn, suckling and growing individuals. Furthermore, we aim to use genetic approach to study the association between transcription profiles of reproductive tissues (embryos, placenta, endometrium and CL cells) and the vitality of the newborn.

The main aims of the project were specified and modified by the steering committee as follows:

1. We evaluated the effects of different types of pre-mating diets during the last week of lactation on metabolic state after weaning in young sows. We hypothesize that dietary supplementations of L-arginine (AR) and L-carnitine (LC) increase IGF-1 concentration and microfibrillated cellulose (MFC) and sugar beet pulp (SBP) affect feed intake during lactation and thereby metabolic hormones (IGF-1, NEFA, creatinine and leptin) during the WEI.

2. We evaluated the effects of different types of pre-mating diets during the last week of lactation on follicle development after weaning in young sows. We hypothesize that dietary supplementations of AR, LC, MFC and SBP increase follicle diameters during the WEI.

3. We evaluated the effects of different types of pre-mating diets during the last week of lactation on follicle development after weaning in young sows. We hypothesize that dietary supplementations of AR, LC, MFC and SBP increase piglet mean birth weight and decrease the proportions of small piglets via a carry-over effect of pre-mating diets on follicle development.

4. We investigated how profiles of metabolic hormones and metabolites during the WEI affect follicle development in young sows. We hypothesize that concentrations of metabolic hormones and metabolites (IGF-1, NEFA, creatinine and leptin) related to higher body condition losses during lactation has a negative correlation with follicle diameters and subsequent reproductive parameters.

5. We investigated how profiles of metabolic hormones and metabolites during the WEI affect piglet birth weight at subsequent farrowing in young sows. We hypothesize that concentrations of metabolic hormones and metabolites (IGF-1, NEFA, creatinine and leptin) related to higher body condition losses during lactation have a negative correlation with piglet birth weight and litter uniformity.