Effect of milk protein composition and amount of β-casein on growth performance, gut hormones, and inflammatory cytokines in an in vivo piglet model

摘要

The objective of this work was to better understandthe effect of differences in milk protein composition,and specifically, a change in β-casein to total casein ina milk-based matrix, on growth performance and metabolicand inflammatory responses using a piglet model.Three formulas were optimized for piglets, with similarmetabolizable energy, total protein content, and otheressential nutrients. Only the protein type and ratiovaried between the treatments: the protein fraction ofthe control diet contained only whey proteins, whereas2 other matrices contained a whey protein to caseinratio of 60:40, and differed in the amount of β-casein(12.5 and 17.1% of total protein). Piglets fed formulacontaining whey proteins and caseins, regardless of theconcentration of β-casein, showed a significantly higheraverage daily gain, average daily feed intake, and feedefficiency compared with piglets consuming the formulawith only whey protein. Consumption of the formulacontaining only whey protein showed higher levels ofplasma glucagon-like peptide-1 and ghrelin comparedwith the consumption of formula containing caseinand whey protein. A positive correlation was observedbetween postprandial time and glucagon-like peptide-1response. The intestinal pro-inflammatory cytokinetumor necrosis factor α increased significantly in pigletsfed the whey protein/casein diet compared withthose fed whey protein formula. All formula-fed pigletsshowed a lower level of IL-6 cytokine compared withthe ad libitum sow-fed piglets, regardless of composition.No significant differences in the anti-inflammatoryIL-10 concentration were observed between treatmentgroups. Milk protein composition contributed to theregulation of piglets‘ metabolic and physiological responses,with whey protein/casein formula promotinggrowth performance and a different immune regulatorybalance compared with a formula containing only wheyprotein. Results indicated no differences between treatmentscontaining different levels of β-casein.