Artificial rearing of piglets: Effects on small intestinal morphology and digestion capacity

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 μm2), maltase and sucrase activities (P<0.05; +0.97 and +0.23 U g−1 tissue) and deeper crypts (P<0.03; +42.5 μm) 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.