A total of 58 pigs (29 gilts and 29 barrows), weighing 48 (SD 4) kg were used. Ten of these pigs (5 gilts and 5 barrows) were selected based on an average representative body weight. All pigs were slaughtered at 106 (SD 3) kg live weight. The daily feed allowance was adjusted weekly after weighing the animals. The experimental treatments were arranged by supplementing three different additional energy sources, i.e. additional fNSP, additional dStarch and additional dFat to a control diet. This control diet was fed at either a low (2 x energy for maintenance) or high (3 x energy for maintenance) level of intake. By supplementation of energy sources to the control diet, protein limitation was ensured in all treatments. The feeding trial was separated into phases 1 and 2, from 48 to 80 kg and from 80 to 106 kg body weight, respectively. The experimental diets were based on cereals and soybean meal as the main ingredients. Sugarbeet pulp, maize starch and soya oil were used to provide the energy additions. Sugarbeet pulp contains some crude protein, fat and sugar, therefore addition of fNSP was achieved by formulating a basal diet that was 95.75 and 95.40% of the control diet for both weight ranges, respectively.
The additional dietary energy increased lean tissue gain at the low feeding level, but decreased it at the high feeding level (P<0.001). The extra gain of hide and subcutaneous fat from added energy was affected by sex (P<0.05), with barrows depositing more hide and subcutaneous fat than gilts. The extra gain in the refusal fraction was higher at the high feeding level (P<0.05), but was not affected by energy source or by sex (P>0.05).
In conclusion, under protein-limiting conditions, incremental energy intake from fNSP, dStarch and digestible unsaturated fat resulted in similar body fat deposition. Preferential deposition of the supplemental energy intake in various fat depots did not depend on the energy source, and the extra fat deposition was similar at the low and high levels of feed intake. Feeding level affected the fat distribution in hide and lean, but the source of energy did not change the partitioning of fat deposition throughout the body.
V Halas, L Babinszky, J Dijkstra, WAV Martin, and WJJ Gerrits, 2010, British Journal of Nutrition, 103:123-133.