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The present investigation addresses the question whether feeding piglets on formulated milk alters the insulin-like growth factor-1 (IGF-1) system differently in normal versus low birth weight piglets. In this study, both types of piglets were either sow-fed until 28 days of age or until 3 days of age and subsequently formula-fed until day 28. Formula-fed piglets had higher serum IGF-1 levels compared to suckled piglets, whereas low birth weight piglets had lower IGF-1 levels in comparison with normal birth weight piglets. In contrast, the mRNA expression of IGF-1 receptor (IGF-1R) showed lower expression in formula-fed piglets versus suckled piglets. However, the opposite effect was observed for IGF-1R protein abundance. Moreover, birth weight did not markedly affect IGF-1R mRNA or protein abundance. In conclusion, formula-fed piglets have higher IGF-1 serum levels and altered gene and protein expression of IGF-1R in the small intestine, irrespective of their birth weight.

The use of hyper-prolific sows results in large litters but also leads to an increasing number of supernumerary and underprivileged (e.g. low birth weight (LBW)) piglets. The effects of artificial rearing on the growth, small intestinal morphology and digestion capacity of these piglets remain unclear. Therefore, the aim of this study was to assess the effect of sow-feeding versus formula-feeding on piglets' structural and functional gut maturation. To this purpose, pairs of LBW and normal birth weight (NBW) piglets (n=40) were allocated to four treatment groups. Groups 1 and 2 contained piglets that suckled until either d 10 or 28 of age, respectively. Groups 3 and 4 contained animals that suckled until 3 d of age and were then formula-fed until either d 10 or 28. During d 3-10, formula-fed piglets showed reduced average daily gain (ADG; -112 g d(-1)) and lactase activities (-4.50 U g(-1) tissue) compared to suckling piglets (P < 0.01). In contrast, animals that were formula-fed until d 28 had a comparable ADG compared to sow-fed pigs. In addition, formula-fed piglets had a greater absorptive area (P < 0.01; +59.1 mu m(2)), maltase and sucrase activities (P < 0.05; +0.97 and +0.23 U g(-1) tissue) and deeper crypts (P < 0.03; +42.5 mu m) compared to suckling piglets. In general, the differences between LBW and NBW piglets were scarce. These results suggest that the combination of ad libitum access to formulated milk and an increased capacity to absorb nutrients makes artificial rearing a good alternative to raise supernumerary and/or LBW piglets. (C) 2013 Elsevier B.V. All rights reserved.

Various methods are available for reducing or replacing in vivo studies on intestinal barrier function in piglets

Oxidative stress, resulting from a deregulated equilibrium between superoxide and nitric oxide (NO) production, contributes to the progression of different vascular diseases such as atherosclerosis, hypertension, ischemia/reperfusion injury and restenosis. Despite disappointing results of various oral antioxidant treatment trials, promising findings have been reported using gene delivery of enzymes to improve NO bioavailability and decrease oxidative stress in animal models for vascular diseases. NO production can be increased by overexpression of endothelial NO synthase (eNOS) in the vascular wall. However, the complex regulation of NOS needs to be carefully considered in the context of gene therapy along with the availability of its cofactor tetrahydrobiopterin and eNOS uncoupling. Furthermore, preclinical studies demonstrated that gene delivery of antioxidative vascular wall-specific enzymes, such as heme oxygenase-1, superoxide dismutase, catalase and glutathione peroxidase, has the potential to attenuate oxidative stress and inhibit atherosclerosis. Another option is to transfect vascular disease patients with secreted antioxidants such as high density lipoprotein-associated enzymes or soluble scavenger receptors. The advantage of the latter is that gene delivery of these enzymes and receptors does not need to be endothelium specific. Nonetheless, techniques to deliver genes specifically to the vascular wall are under development and hold interesting perspectives for the treatment of vascular diseases in the future. The patents relevant to gene delivery are also discussed in this review article.

Economic losses in pig production are highly due to neonatal mortality and poor postnatal growth performances predominantly of low birthweight piglets. To explore underlying mechanisms, we describe in this paper the effects of age and birthweight on body composition and muscle energy stores. Different parameters were assessed in pairs of low birthweight (LBW, n = 32) and normal birthweight (NBW, n = 32) piglets, at Day 0 (n = 16), Day 3 (n = 16), Day 10 (n = 16) and Day 28 (n = 16) of age. In total six piglets (three LBW and three NBW) per age group were killed for chemical total body composition analysis. The M. semimembranosus of 10 additional piglets (five LBW and five NBW) per age group were sampled for the analysis of muscle lipid and glycogen contents. Fore none of the tested parameters differences related to birthweight were observed (P > 0.05). With increasing age, dry matter, fat and protein percentages increased in both LBW and NBW piglets (P < 0.01). Body ash content remained constant during growth (P > 0.05). Muscle glycogen contents decreased with increasing age for both types of piglets (P < 0.05), whereas no age effects could be observed for muscle lipid deposition (P > 0.05). In conclusion, the age of the suckling piglet has a major impact on its body composition and muscle energy stores but its birthweight unexpectedly has no influence.