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Gestating sows are restricted in order to avoid overweight, which can lead to farrowing and locomotion problems. However, the restriction is known to cause stereotypic behaviour due to sustained feeding motivation. In this regard, feeding high dietary fibre (DF) diets have been shown to prolong the sow’s feeling of satiety and thereby reducing behavioural problems. The inclusion of high DF diets leads to an enhanced proportion of absorbed energy deriving from fermentation products, and as a consequence, decreased diurnal variation of energy absorbed from the gastrointestinal tract. By-products from vegetable food and agricultural industries are a good source of ingredients to use in animal formulation diets by the high content of DF. The aim of the present study was to examine the biochemical in?uence of feeding high DF diets formulated from by-products from the vegetable and agricultural industries to sows during early to mid-gestation. Additionally, the effect of feeding frequency (once vs. twice daily) on diurnal plasma metabolites patterns was also examined. The study included a total of 48 gestating sows from four blocks (12 gestating sows in each block). The sows were fed four different diets containing varying levels of starch (304–519 g/kg dry matter (DM)) and DF (171–404 g/kg DM) but with equal amounts of net energy. The low-DF diet (control) was based on barley and wheat, and the three high-DF diets formulated by replacing barley and wheat by pectin residue, sugar beet pulp and potato pulp, respectively. The experimental design comprised two periods of 4 weeks each. Half the sows were fed once daily at 08:00 h in the ?rst period and twice daily at 08:00 and 15:00 h during the second period, and vice versa for the other half of the sows. Plasma samples from vena jugularis were collected by venipuncture at 07:00, 09:00, 12:00 and 19:00 h.
Feeding high-DF increased plasma short-chain fatty acids (P = 0.02) and non-esteri?ed fatty acids (P < 0.001). However, there was no clear effect of DF on glucose and insulin responses. A negative correlation between amount of DF in the diets and plasma creatine (R2 = 1.00; diet effect: P = 0.02) suggested that plasma creatine concentrations was an indicator for the level of glucose–glycogen interchange. Furthermore, an explorative approach using nuclear magnetic resonance spectroscopy-based metabolomics identi?ed betaine (P < 0.001), dimethyl sulfone (DMSO2;P < 0.001) and scyllo-inositol (P < 0.001) as biomarkers for the different by-products; pectin residue was related to high plasma levels of DMSO2, sugar beet pulp to plasma betaine, DMSO2 and scyllo-inositol, and potato pulp to plasma DMSO2 and scylloinositol.
In conclusion, replacing starch by DF from different by-products from vegetable industry and agriculture, affected surprisingly few metabolites in peripheral plasma. No negative effects were found in feeding pectin residue, sugar beet pulp or potato pulp for gestating sows as judged from the minor metabolic changes.
CC Yde, HC Bertram, PK Theil and KE Back-Knudsen. Effects of high dietary fibre diets formulated from by-products from vegetable and agricultural industries on plasma metabolites in gestating sows. 2011. Archives of Animal Nutrition, 65(6):460-476.
