PSXII-4 Serum citrulline concentration of unweaned calves transported by road as a potential biomarker of gut functionality

In human’s serum citrulline concentration (SCC) have been proposed as a biomarker of small intestinal absorption. We hypothesize that the stress and feed restriction that unweaned calves suffer during transport impairs gut functionality reducing SCC. The aim of this study was to evaluate if road transport hours and adaptation period after arrival would affect SCC in unweaned calves. A total of 1,601 calves (3–4 wk of age; 65 ± 9 kg of BW) were transported with 8 trucks (n = 4 each journey): short transport (ST; < 9 h), and long transport with a rest stop proving feed and water to the calves (LT; > 9 h). A subset of 20 calves for each truck were sampled for SCC at arrival (t0), and 14 d after arrival (t14); in case of LT, also at arrival at the resting facility (t-1). SCC was analyzed using a commercial kit (intra- and inter-assay CV were 12.62% and 6.32%). Data was analyzed using a mixed model with journey hours and day as main effects, and calf and truck as random effects. SCC tended (P = 0.08) at t0 to be greater in LT (47.7 ± 3.39 mM) compared to ST (42.6 ± 2.46 mM). At t14 SCC increased in ST and LT calves; however, no differences were observed in SCC (55.9 ± 3.42 mM vs. 58.8 ± 2.52 mM for LT and ST, respectively). In LT calves rest stop did not affect SCC (43.2 ± 1.74 mM vs. 39.8 ± 1.76 mM for t-1 and t0, respectively), while at t14 (50.6 ± 1.86 mM) SCC was greater (P < 0.001) than t0 and t-1. The effect of transport type and evolution after transport on serum plasma citrulline concentrations may suggest that it’s a potential indicator of gut functionality in unweaned calves.

Non-targeted and targeted analysis of collagen hydrolysates during the course of digestion and absorption

Protein hydrolysates are an important part of the human diet. Often, they are prepared from milk, soy, or collagen. In the present study, four different collagen hydrolysates were tested, varying in the average molecular weight and the animal source. Three types of samples, the dissolved start products, in vitro generated dialysates (containing the digested components that are potentially available for small intestinal absorption), and human serum collected after product ingestion, were analyzed using LC-MS to compare the state of the hydrolysates before and after absorption, i.e., uptake into the blood. It was found that the composition of the collagen hydrolysates prior to and after ingestion was highly complex and dynamic, which made it challenging to predefine a strategy for a targeted analysis. Therefore, we implemented a new analytical approach to first map hydrolysate data sets by performing non-targeted LC-MS analysis followed by non-targeted and targeted data analysis. It was shown that the insight gained by following such a top down (data) analytical workflow could be crucial for defining a suitable targeted setup and considering data trends beyond the defined targets. After having defined and performed a limited targeted analysis, it was found that, in our experimental setup, Hyp-Gly and especially Pro-Hyp contributed significantly as carrier to the total Hyp increase in blood after ingestion of collagen hydrolysate.

The Effects of a Whey Protein and Guar Gum-Containing Preload on Gastric Emptying, Glycaemia, Small Intestinal Absorption and Blood Pressure in Healthy Older Subjects

A whey protein/guar gum preload reduces postprandial glycaemia in type 2 diabetes through slowing gastric emptying. However, gastric emptying has previously been assessed using a stable isotope breath test technique, which cannot discriminate between slowing of gastric emptying and small intestinal absorption. This preload also may be useful in the management of postprandial hypotension. We evaluated the effects of a whey protein/guar preload on gastric emptying, glucose absorption, glycaemic/insulinaemic and blood pressure (BP) responses to an oral glucose load. Eighteen healthy older participants underwent measurements of gastric emptying (scintigraphy), plasma glucose and insulin, glucose absorption, superior mesenteric artery (SMA) flow, BP and heart rate (HR) after ingesting a 50 g glucose drink, with or without the preload. The preload reduced plasma glucose (p = 0.02) and serum 3-O-methylglucose (3-OMG) (p = 0.003), and increased plasma insulin (p = 0.03). There was no difference in gastric emptying or BP between the two days. The reduction in plasma glucose on the preload day was related to the reduction in glucose absorption (r = 0.71, p = 0.002). In conclusion, the glucose-lowering effect of the preload may relate to delayed small intestinal glucose absorption and insulin stimulation, rather than slowing of gastric emptying.