Mildly Pasteurized Whey Protein Promotes Gut Tolerance in Immature Piglets Compared with Extensively Heated Whey Protein

Abstract

Human milk is the optimal diet for infant development, but infant milk formula (IMF) must be available as an alternative. To develop high-quality IMF, bovine milk processing is required to ensure microbial safety and to obtain a protein composition that mimics human milk. However, processing can impact the quality of milk proteins, which can influence gastro-intestinal (GI) tolerance by changing digestion, transit time and/or absorption. The aim of this study was to evaluate the impact of structural changes of proteins due to thermal processing on gastro-intestinal tolerance in the immature GI tract. Preterm and near-term piglets received enteral nutrition based on whey protein concentrate (WPC) either mildly pasteurized (MP-WPC) or extensively heated (EH-WPC). Clinical symptoms, transit time and gastric residuals were evaluated. In addition, protein coagulation and protein composition of coagulates formed during in vitro digestion were analyzed in more detail. Characterization of MP-WPC and EH-WPC revealed that mild pasteurization maintained protein nativity and reduced aggregation of β-lactoglobulin and α-lactalbumin, relative to EH-WPC. Mild pasteurization reduced the formation of coagulates during digestion, resulting in reduced gastric residual volume and increased intestinal tract content. In addition, preterm piglets receiving MP-WPC showed reduced mucosal bacterial adherence in the proximal small intestine. Finally, in vitro digestion studies revealed less protein coagulation and lower levels of β-lactoglobulin and α-lactalbumin in the coagulates of MP-WPC compared with EH-WPC. In conclusion, minimal heat treatment of WPC compared with extensive heating promoted GI tolerance in immature piglets, implying that minimal heated WPC could improve the GI tolerance of milk formulas in infants.

Comparison of conventional heat-treated and membrane filtered infant formulas using an in vitro semi-dynamic digestion method

“…This study has shown that MEM-IMF digestion results in smaller curd particles, and a higher detection of primary amines, both of which should result in faster gastric emptying in vivo. [40][41][42][43] Navis et al 44 fed piglets using mildly pasteurized whey protein concentration (WPC) or extensively heated WPC. In line with our in vitro results, they demonstrated a higher gastric content in piglets receiving extensively heated WPC compared with piglets receiving mildly pasteurized WPC, which suggests delayed and/or incomplete gastric emptying in piglets fed extensively heated WPC.…”

Potential Benefits of Bovine Colostrum in Pediatric Nutrition and Health

“…There are similar challenges in the preservation of the natural bioactivity of human or bovine milk concentrates. In NEC-sensitive preterm pigs, untreated or gently sterilized (ultraviolet-light lower-temperature sterilization) human donor milk or bovine whey protein concentrates have superior effects to protect against NEC, intestinal inflammation and systemic infections, relative to products subjected to more intense heat [ 225 , 253 , 279 , 280 ]. The same may be true for BC.…”

“…The factors in BC that support gut development, immunity and survival in other species are heat-sensitive. When whey protein concentrates are severely heated (80–85 °C, 20–30 min), a reduction in gut-protective effects is observed [ 279 , 280 ]. In contrast, raw, frozen, and mildly heat-treated BC may retain its bioactivity to protect against gut disorders and inflammation, as demonstrated in newborn term pigs [ 144 , 224 , 283 , 284 ].…”

Molecular Analytical Assessment of Thermally Precipitated α-Lactalbumin after Resolubilization

“…Primarily, the bioactivity and anti-inflammatory or immunomodulating properties are substantially dependent on the native state of the whey proteins [ 11 , 12 , 13 ]. From a nutritional perspective, it is reported that whey proteins in their native states promote gastro-intestinal tolerance and maturation of infants [ 14 , 15 ]. Furthermore, Abbring et al [ 16 , 17 ] showed that native whey protein has a lower allergenicity than the processed, i.e., heat-treated, equivalent.…”