Sow environment during gestation: part II. Influence on piglet physiology and tissue maturity at birth.

Sow environment during gestation can generate maternal stress which could alter foetal development. The effects of two group-housing systems for gestating sows on piglet morphological and physiological traits at birth were investigated. During gestation, sows were reared in a conventional system on a slatted floor (C, 18 sows), demonstrated as being stressful for sows or in an enriched system in larger pens and on deep straw bedding (E, 19 sows). On gestation day 105, sows were transferred into identical individual farrowing crates on a slatted floor. Farrowing was supervised to allow sampling from piglets at birth. In each litter, one male piglet of average birth weight was euthanized immediately after birth to study organ development and tissue traits. Blood samples were collected from 6 or 7 piglets per litter at birth and 2 piglets per litter at 4 days of lactation (DL4). At birth, mean piglet BW did not differ between groups (P > 0.10); however, the percentage of light ( 0.10) between C and E piglets, but the insulin to glucose ratio was greater (P = 0.02) in C than in E piglets. Compared with E piglets, C piglets had a lighter gut at birth (P = 0.01) and their glycogen content in longissimus muscle was lower (P < 0.01). In this muscle, messenger RNA levels of PAX7, a marker of satellite cells and of PPARGC1A, a transcriptional coactivator involved in mitochondriogenesis and mitochondrial energy metabolism, were greater (P < 0.05), whereas the expression level of PRDX6, a gene playing a role in antioxidant pathway, was lower (P = 0.03) in C than in E piglets. Other studied genes involved in myogenesis did not differ between C and E piglets. No system effect was observed on target genes in liver and subcutaneous adipose tissue. On DL4, C piglets exhibited a lower plasma antioxidant capacity than E piglets (P = 0.002). In conclusion, exposure of sows to a stressful environment during gestation had mild negative effects on the maturity of piglets at birth.

Sow environment during gestation: part I. Influence on maternal physiology and lacteal secretions in relation with neonatal survival.

In pig husbandry, pregnant females are often exposed to stressful conditions, and their outcomes on maternal and offspring health have not been well evaluated. The present study aimed at testing whether improving the welfare of gestating sows could be associated with a better maternal health during gestation, changes in the composition of lacteal secretions and improvement in piglet survival. Two contrasted group-housing systems for gestating sows were used, that is, a French conventional system on slatted floor (C, 49 sows) and an enriched system using larger pens on deep straw (E, 57 sows). On the 105th days of gestation (DG105), sows were transferred into identical farrowing crates on slatted floor. Saliva was collected from all sows on DG35, DG105 and DG107. Blood samples were collected on DG105 from all sows and on the 1st day of lactation (DL1) from a subset of them (C, n=18; E, n=19). Colostrum and milk samples were collected from this subset of sows at farrowing (DL0) and DL4. Saliva concentration of cortisol was greater in C than in E sows at DG35 and DG105, and dropped to concentrations comparable to E sows after transfer into farrowing crates (DG107). On DG105, plasma concentrations of haptoglobin, immunoglobulins G (IgG) and A (IgA), blood lymphocyte counts and plasma antioxidant potential did not differ between groups (P > 0.10), whereas blood granulocyte count, and plasma hydroperoxide concentration were lower in E than in C sows (P < 0.05). Concentrations of IgG and IgA in colostrum and milk did not differ between the two groups. The number of cells did not differ in colostrum but was greater in milk from E than C sows (P < 0.05). Pre-weaning mortality rates were lower in E than C piglets (16.7% v. 25.8%, P < 0.001), and especially between 12 and 72 h postpartum (P < 0.001). Plasma concentration of IgG was similar in E and C piglets on DL4. In conclusion, differences in salivary cortisol, blood granulocyte count and oxidative stress markers between groups suggested improved welfare and reduced immune solicitation during late gestation in sows of the E compared with the C system. However, the better survival observed for neonates in the E environment could not be explained by variations in colostrum composition.

Proteomic assessment of the acute phase of dystrophin deficiency in mdx mice.

Duchenne muscular dystrophy (DMD) is caused by the absence of a functional dystrophin protein and is modeled by the mdx mouse. The mdx mouse suffers an early necrotic bout in the hind limb muscles lasting from approximately 4 to 7 weeks. The purpose of this investigation was to determine the extent to which dystrophin deficiency changed the proteome very early in the disease process. In order to accomplish this, proteins from gastrocnemius from 6-week-old C57 (n = 6) and mdx (n = 6) mice were labeled with fluorescent dye and subjected to two-dimensional differential in-gel electrophoresis (2D-DIGE). Resulting differentially expressed spots were excised and protein identity determined via MALDI-TOF followed by database searching using MASCOT. Proteins of the immediate energy system and glycolysis were generally down-regulated in mdx mice compared to C57 mice. Conversely, expression of proteins involved in the Kreb's cycle and electron transport chain were increased in dystrophin-deficient muscle compared to control. Expression of cytoskeletal components, including tubulins, vimentin, and collagen, were increased in mdx mice compared to C57 mice. Importantly, these changes are occurring at only 6 weeks of age and are caused by acute dystrophin deficiency rather than more chronic injury. These data may provide insight regarding early pathologic changes occurring in dystrophin-deficient skeletal muscle.