Effects of levels and sources of dietary fermentable non-starch polysaccharides on blood glucose stability and behaviour of group-housed pregnant gilts

A fermentable non-starch polysaccharides (fNSP)-rich diet (sugarbeet pulp; SBP) was previously shown to reduce within-day variation in blood glucose levels and reduce stereotyped behaviour. The aim of the present experiment was to study (1) whether there is a relationship between fNSP level in a diet and behavioural indicators of satiety and indicators of glucose stability and (2) whether a mixture of fNSP-sources is as effective as SBP as fNSP-source. One hundred and eight sows were used during their first gestation and were divided over six batches. They were housed in groups of three sows in six pens. Pen and batch were blocking factors in a Latin Square design with dietary treatment as the factor under study with six distinct diets. Four treatments with different levels of dietary fNSP (11%, 20%, 29% and 38% fNSP; realised concentrations) were used for the first research question. A mixture of fNSP-rich ingredients was used. The fifth treatment had 28% fNSP, comparable with the third treatment, but with SBP as the main fNSP-source. These two treatments were used for the second research question. The sixth treatment was similar to others but does not contribute to the aims of this paper. Sows were fed with a restricted amount of feed during 30-min individual housing in stalls, once per day at 7:30 h. Behavioural indicators of satiety (self-directed behaviour, substrate-directed behaviour and inactivity) were scored on each of 3 days in weeks 10, 12 and 14, during 1 h directly after feeding and 1 h in the afternoon (8 h after feeding). Days within weeks were pooled per group. Mean glucose levels in eight blood samples and indicators of glucose stability (variance, VAR; sum of absolute differences between levels in consecutive samples, SAD) were determined on one day in these weeks. Glucose was immediately measured in a drop of blood, stress-free obtained from the ear at 1-h intervals from 4 to 11 h after feeding time (i.e., eight samples). Results and conclusions were: (1) Self-directed behaviour (most pronounced directly after feeding), total oral behaviour, glucose SAD, glucose VAR and mean glucose level decreased and inactivity (most pronounced in the afternoon) increased with increasing fNSP level in the diet. The maximal effect of fNSP on behaviour and glucose parameters was apparently not yet reached by the diets used. Substrate-directed behaviour was not affected by fNSP level in the diet. (2) A mixture of fNSP-sources was equally effective as SBP as main fNSP-source (similar dietary fNSP level). (c) 2005 Elsevier BX All rights reserved.