Plasma glucose response and glycemic indices in pigs fed diets differing in in vitro hydrolysis indices

Abstract

Different dietary starch sources can have a great impact in determining starch digestion potential, thus influencing the postprandial blood glucose response. Our objectives were to define: (i) the incremental plasma glucose response in pigs fed diets containing various sources of starch differing in in vitro digestion patterns, (ii) the in vivo glycemic index (GI) values for the same diets, (iii) the possible relationship between in vitro and in vivo data. Diets, formulated with 70% of starch from five heterogeneous sources, were characterized in depth by using two distinct in vitro evaluations. The first one was based on the Englyst-assay for nutritional classification of starch fractions, whereas the second one was based on a time-course multi-enzymatic assay up to 180 min from which the hydrolysis indices (HIs) were calculated and used as a link between the physicochemical properties of starch from diets and the in vivo responses. For the in vivo study, five jugular-catheterized pigs (35.3 6 1.1 kg body weight) were fed one of the five diets for 6-day periods in a 5 3 5 Latin square design. On day 5, blood was collected for 8 h postprandially for evaluating glucose appearance. On day 6, blood was collected for 3 h postprandially for the estimation of the GI. Starchy diets differed for rapidly digestible starch (from 8.6% to 79.8% of total starch (TS)) and resistant starch contents (from 72.5% to 4.5% of TS). Wide between-diets variations were recorded for all the kinetic parameters and for the HI calculated from the in vitro digestion curves (P , 0.05). On the basis of the obtained HI, diets contained starch with a very low to a very high in vitro digestion potential (ranging from 26.7% to 100.0%; P , 0.05). The glucose response differed among diets (P , 0.05), with marked differences between 15 and 120 min postprandial. Overall, the ranking of incremental glucose appearance among diets agreed with their in vitro HI classification: high HI diets increased plasma glucose response more (P , 0.05) than low HI diets. Lastly, different in vivo GIs were measured (ranging from 30.9% to 100.0%; P , 0.05). The relationship between HI and GI showed a high coefficient of determination (R 2 5 0.95; root mean square error (RMSE) 5 15.8; P , 0.05). In conclusion, diets formulated with starches with a wide range in HI potential can strongly affect the postprandial glucose response in pigs.Keywords: glucose, in vitro method, glycemic index, starch, pig ImplicationsStarch is the main energy source for monogastric species and knowledge about its digestive behaviour can be important in order to understand the consequently metabolic and endocrine functioning in monogastrics. This study showed that diets formulated with heterogeneous sources of starch and characterized by a wide range in enzymatic starch digestion potential modulated the postprandial glucose response in pigs. A better understanding of the nutritive role of starch and its effect on metabolism is an important nutritional topic for monogastric animals.

Effects of resistant starch on behaviour, satiety-related hormones and metabolites in growing pigs

“…In the present study, peripheral SCFA levels were elevated throughout the day (both preprandial and postprandial) in RS-fed pigs compared with PS-fed pigs, in accordance with previous studies (Topping and Clifton, 2001;Regmi et al, 2011). Moreover, postprandial glucose and insulin responses were lower in RS-fed pigs than in PS-fed pigs, reflecting a decreased influx of glucose by enzymatic digestion of RS as compared with PS, in line with other studies (Regmi et al, 2011;Giuberti et al, 2012). It should be noted that differences in dietary sugar levels were larger (13.1 and 69.4 g/kg DM for PS and RS diets, respectively) compared with a previous study on adult pigs fed similar diets (Souza da .…”

Cereal processing and glycaemic response

“…For example, Venn & Green (2007) raised various issues on the suitability of the GI data that, amongst others, border on test participants, sample preparations, suitability of the GIs obtained from one ethnic community for another, variability in the GI of a food because of differences in processing techniques, effects of nonstarch ingredients and mixed meal effects. With a relatively few exceptions, probably because of small sample sizes (Ros en et al, 2009), many studies exist in these areas (Giuberti et al, 2012;Minekus et al, 2014;Ferng et al, 2016), including those that simultaneously investigated in vivo and in vitro responses of the same samples. Knowing the limitations can only assist cautious uses of the data, and as the time-course glycaemic response contains valuable information about starch digestion, publishing typical curves will contribute to the understanding of how foods modulate glycaemia.…”

“…Both Granfeldt et al (1992) and Goñi et al (1997), for example, defined a hydrolysis index (HI) with white wheat bread as a reference and proposed linear equations to relate the HI and GI. Figure 1 shows data from various researchers, which were used to obtain the regression equations below, and the zero-intercept equation mirrors that of Giuberti et al (2012). 1).…”

Effects of dietary resistant starch content on metabolic status, milk composition, and microbial profiling in lactating sows and on offspring performance

“…Considered as a prebiotic carbohydrate, low digestibility of RS resulted in decreased apparent ileal and total tract digestibilities of nutrients (Gerrits et al., ; Cervantes‐Pahm et al., ). Hence, a low plasma glucose concentration was observed in pigs fed high‐RS diet (Giuberti et al., ). Similarly, RS also shows the ability to reduce insulin secretion and regulate production of signal molecules, like C‐peptide and ghrelin (Robertson et al., ; Regmi et al., ).…”