Effects of realimentation after nutrient restriction during mid‐ to late gestation on pancreatic digestive enzymes, serum insulin and glucose levels, and insulin‐containing cell cluster morphology

Abstract

This study examined effects of stage of gestation and nutrient restriction with subsequent realimentation on maternal and foetal bovine pancreatic function. Dietary treatments were assigned on day 30 of pregnancy and included: control (CON; 100% requirements; n = 18) and restricted (R; 60% requirements; n = 30). On day 85, cows were slaughtered (CON, n = 6; R, n = 6), remained on control (CC; n = 12) and restricted (RR; n = 12), or realimented to control (RC; n = 11). On day 140, cows were slaughtered (CC, n = 6; RR, n = 6; RC, n = 5), remained on control (CCC, n = 6; RCC, n = 5) or realimented to control (RRC, n = 6). On day 254, the remaining cows were slaughtered and serum samples were collected from the maternal jugular vein and umbilical cord to determine insulin and glucose concentrations. Pancreases from cows and foetuses were removed, weighed, and subsampled for enzyme and histological analysis. As gestation progressed, maternal pancreatic α-amylase activity decreased and serum insulin concentrations increased (p ≤ 0.03). Foetal pancreatic trypsin activity increased (p < 0.001) with advancing gestation. Foetal pancreases subjected to realimentation (CCC vs. RCC and RRC) had increased protein and α-amylase activity at day 254 (p ≤ 0.02), while trypsin (U/g protein; p = 0.02) demonstrated the opposite effect. No treatment effects were observed for maternal or foetal pancreatic insulin-containing cell clusters. Foetal serum insulin and glucose levels were reduced with advancing gestation (p ≤ 0.03). The largest maternal insulin-containing cell cluster was not influenced by advancing gestation, while foetal clusters grew throughout (p = 0.01). These effects indicate that maternal digestive enzymes are influenced by nutrient restriction and there is a potential for programming of increased foetal digestive enzyme production resulting from previous maternal nutrient restriction.

Prenatal and Postnatal Nutrition Influence Pancreatic and Intestinal Carbohydrase Activities of Ruminants

“…Studies evaluating fetal programming of digestive enzymes have largely focused on changes in the level of DM intake of the dam through various periods of gestation. Maternal dietary restriction of beef cows during early- or early-to-mid-gestation and then realimentation to maintenance intake during late-gestation increased fetal pancreatic α-amylase per gram of protein by 3.0- and 4.1-fold, respectively ( Figure 1 ); [ 36 ]. Furthermore, fetal pancreatic α-amylase per gram of protein was not influenced when cows were restricted during either early or early-to-mid-gestation.…”

“…Interestingly, intestinal glucose transport also has been shown to differ between cattle and sheep [ 13 ]. However, it should be noted that when Keomanivong et al [ 36 ] found a programming response of fetal pancreatic α-amylase, maternal dietary restriction occurred during early or early- to mid-gestation. In general, organogenesis occurs during early-to-mid-gestation [ 3 ] and thus, functional alteration of fetal gastrointestinal organs may be more severe during early gestational nutrient restriction.…”

“…Abbreviations: CCC = cows fed to meet 100% of NRC [ 39 ] recommendations during gestation (day 30 to day 254); RCC = 60% maternal nutrient restriction of cows during early-gestation (day 30 to day 85), followed by realimentation to control diet during mid-to-late gestation (day 85 to day 254); RRC = 60% maternal nutrient restriction of cows during early-to-mid-gestation (day 30 to day 140), followed by realimentation to control diet during late gestation (day 140 to day 254). Adapted from Keomanivong et al [ 36 ].…”

The impact of diet and arginine supplementation on pancreatic mass, digestive enzyme activity, and insulin-containing cell cluster morphology during the estrous cycle in sheep

“…A representative sample of the body of the pancreas was immersion-fixed in formalin and embedded in paraffin blocks with proper and persistent orientation, and immunohistochemistry was performed as described previously [3,22]. Tissues were cut (5-μm sections), mounted on slides, deparaffinized and rehydrated.…”

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“…Nutrient restriction during late gestation may also influence fetal digestive enzymes as total fetal pancreatic trypsin content and α-amylase activity decrease with 60% of maternal nutrient restriction but there is no effect on fetal carbohydrase, glucoamylase, maltase, or isomaltase activities (TROTTA et al, , 2021. Keomanivong et al (2017) also found a decrease in α-amylase activity but no effects on pancreatic digestive enzymes.…”