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Coproducts from the food and agricultural industries are typically high in fiber and with diverse composition and can potentially be used to replace concentrated high-value grain crops in diets for sows. Although energy digestibility and utilization are generally high in sows fed fiber-rich feedstuff, but nitrogen digestion and utilization may be compromised. The aim of this study was to quantify the apparent total tract digestibility (ATTD) of nutrients and utilization of energy and nitrogen in empty non lactating sows fed with six different fiber-rich coproducts. Brewers spent grain, pea hull, potato pulp, pectin residue, sugar beet pulp, and seed residue were mixed into a basal diet with as high an inclusion level as possible, or the basal diet was fed solely to eight empty sows in a Youden square incomplete cross-over design. The collection period consisted of a total collection period of 5 d, of which 2 d were in a respiration chamber.
The sows had a gross energy intake between 28.5 and 42.3 MJ/d; greatest for the pea hull fed sows and lowest for the potato pulp fed sows. The ATTD of dry matter, organic matter, gross energy, and N did not differ among the basal diet and the pea hull and sugar beet pulp fed sows, while the ATTDs of all nutrients and energy were intermediate for pectin residue and brewers spent grain lowest in seed residue fed sows. The differences were caused by variation in digestible and metabolizable energy content of the fiber-rich coproducts ingredients, which was lowest for seed residue, intermediate for pectin residue followed by brewers spent grain and greatest for sugar beet pulp, potato pulp, and pea hull. Total heat production did not differ among treatments but the nonactivity related heat production was highest in seed residue fed sows and lowest in pea hull and sugar beet pulp fed sows. Retention of energy was greatest following the pea hull and basal diet (7.42 and 2.19 MJ/d, respectively), intermediate for potato pulp, sugar beet pulp, and brewers spent grain fed sows (−0.22 to −0.69 MJ/d) and lowest for the pectin residue and seed residue fed sows (−4.26 and −6.17 MJ/d, respectively).
From a sow feeding perspective, sugar beet pulp and pea hull have the potential to partly replace high-value grain crops due to high ATTD of all nutrients and because sows can efficiently utilize energy and protein. In contrast, seed residue and pectin residue show low ATTD of nutrients and energy, thereby compromising the nutritive value. Potato pulp and brewers spent grain also have the potential to be included in sow diets, but caution should be taken because of compromised N utilization and thereby increased environmental impact.
Wisbech SJ, Jørgensen H, Nielsen TS, Bach Knudsen KE. Influence of fiber-rich coproducts on nutrient and energy digestibility and utilization in sows. Journal of Animal Science. 2023; 101: skad086. https://doi.org/10.1093/jas/skad086