Effects of an oat-based high-fibre diet on insulin, glucose, cortisol and free fatty acid concentrations in gilts

Influence of the nature of dietary fibre on digestive utilization, some metabolite and hormone profiles and the behaviour of pregnant sows

Three diets were formulated according to the nature of the fibrous components: a concentrate low fibre diet enriched in starch (diet S, neutral-detergent fibre (NDF) proportionately 0·078 of dry matter (DM)) and two high-fibre diets enriched in either sugar-beet pulp (diet BP, NDF = 0·219 of DM) or wheat bran (diet WB, NDF = 0·187 of DM). In a first experiment, the digestibility of nutrients in these diets were determined using dry sows. In a second experiment, 24 multiparous Large White sows were offered the experimental diets in a 3 x 3 Latin-square design during three 21-day periods over pregnancy in order to evaluate physiological and behavioural effects over the nycthemeral period. On the basis of the first experiment, the daily food supply was adjusted to 2·44, 2·74 and 2-90 kg/day for diets S, BP and WB, respectively, to provide the same amount of metabolizable energy to each treatment. In the hour prior to the meal, the diet effect was nil on plasma levels of glucose, insulin, glucagon and non-esterified fatty acid and limited on cortisol plasma level. After the food delivery, the peak responses of glucose and insulin to the meal were delayed in sows given the BP diet, while their level showed a higher increase for S than for WB and BP diets. Sows offered diet BP spent less time standing than sows offered diet S. The occurrence of non-feeding oral activities over the 45 min following food distribution was significantly reduced with fibrous diets. But no difference appeared during the 45-min period following the end of each meal. It was concluded that the incorporation of beet pulp in the diet was more effective than wheat bran in extending the feeding activity and the absorption of nutrients. The diet effect was limited to the 2 h after the food delivery for these sows given a restricted amount of food.

Can non-invasive glucocorticoid measures be used as reliable indicators of stress in animals?

Refinement techniques are being increasingly employed in all fields of animal research to try to ensure that the highest standards of welfare are upheld. This review concerns one of the main emerging techniques for the assessment of welfare itself, namely the non-invasive measurement of glucocorticoids (GCs) as indicators of stress. The paper is divided into three sections. The first discusses the relationship between GCs and stress. The second section considers whether factors other than stress are linked to rises in GCs, eg exercise, oestrus cycle and diet. The final part examines the reliability of the non-invasive techniques that measure GCs from samples of saliva and faeces. Although it is important to take into account some caveats associated with the methodologies employed, it is concluded, nevertheless, that these techniques can give accurate and reliable information regarding the welfare status of an individual or group of animals without the procedures themselves causing any kind of distress to the subjects.

Dietary fiber stabilizes blood glucose and insulin levels and reduces physical activity in sows (Sus scrofa)

The aim of this study was to test whether a diet with a high level of fermentable dietary fiber can stabilize interprandial blood glucose and insulin levels, prevent declines below basal levels, and reduce physical activity in limited-fed breeding sows. Stable levels of glucose and insulin may prevent interprandial feelings of hunger and, consequently, increased activity. Catheterized sows (n = 10) were fed twice daily (0700 and 1900 h) 900 g of a diet with either a low (L-sows) or a high level of fermentable dietary fiber (H-sows; sugarbeet pulp). Blood samples, taken between feeding times, were analyzed for glucose and insulin levels (basal and area under the curve) and stability of levels (variance and sum of absolute differences between levels in consecutive samples). The main focus was on samples taken after the postprandial peak. Behavior was videotaped for analysis of postures and posture changes. Basal glucose and insulin levels did not differ between treatments. H-sows had more stable levels than L-sows. Interprandial levels of H-sows were higher than or equal to basal levels. L-sows showed a decline in glucose below basal levels at 1400 h (P < 0.05). Before 1400 h, no difference in the frequency of posture changes was observed between treatments. After 1400 h, the frequency of posture changes increased more in L-sows than in H-sows. We concluded that sugarbeet pulp as a source of fermentable dietary fiber stabilizes glucose and insulin levels and reduces physical activity in limited-fed sows several hours after feeding. This may indicate a prolonged feeling of satiety.

The short-term feeding behavior of growing pigs fed foods differing in bulk content

We investigated the effects of foods of different bulk on the short-term feeding behavior (STFB) of 16 individually housed pigs. The three foods used had different bulk contents [low-control (C), medium-70% wheat bran (WB), and high-70% sugar beet pulp (SBP)]. We expected the different intakes of the foods to be reflected in differences in STFB. Three hypotheses were developed based on ideas about the way in which a physical constraint to intake could arise. H(1): there would be less diurnal variation in feeding on high-bulk foods that limit food intake. H(2): feeding patterns on the bulky foods would be less flexible than those on C. H(3): a change in food type would result in food intake and STFB being rapidly altered to become appropriate to the new food. There were significant differences in food intake and STFB between the foods as intended. Pigs fed WB and SBP spent longer eating and had a slower feeding rate (FR) than pigs fed C. H(1) was rejected, as there was no difference in diurnal variation in intake between the foods. Feeding was not extended into the night on WB and SBP and the proportion of feeding that occurred during the night was the same for all three foods. H(2) was supported, as pigs fed WB and SBP were unable to maintain food intake and performance when time of access to the feeder was reduced. There was no adaptive change in STFB. H(3) was supported as a change from WB or SBP to C, or vice versa, caused a rapid change in STFB so that it became appropriate to the new food. It is concluded that physical constraints to food intake, caused by food bulk, may bring about changes in STFB and that they are important for the regulation of intake of such foods.