Prediction of the apparent digestible energy value of fats given to pigs

Abstract

Data from experimental programmes designed to investigate the effect of chemical structure of fats upon their apparent digestible energy (DE) value for pigs were subjected to regression analysis. For growing pigs, over the approximate live-weight range 30 to 90 kg, 25 data points were available, with fats evaluated having a range in the ratio of unsaturated to saturated fatty acids (U/S) from 0-66 to 15-67 and in free fatty acid (FFA) content from 8 to 818 g/kg. Sixteen data points were available for young pigs of approximately 12 kg live weight with a range in U/S from 0-62 to 5-71 and in FFA content from 54 to 756 g/kg. The wide range of values for U/S and FFA content had been obtained by blending different fats and, therefore, represented both the range and extremes likely to be found in the formulation of pig diets. Derivation of prediction equations for DE were based upon a series of non-linear regression analyses employing, in sequence, U/S, U/S + FFA content and U/S X FFA content. The DE of fats could be predicted from U/S and FFA content with equations accounting for 0-802 and 0-768 of the variation in DE values for growing and young pigs respectively. The most appropriate equation for pigs of all live weights employed U/S and FFA content additively (U/S + FFA content). The equation for growing pigs was DE (MJ/kg) = 36-898 -(0-0046FFA (g/kg)) -7-33e(-0-906U/S) and for young pigs was DE (MJ/kg) = 37-890 -(0-0051FFA (g/kg)) -8-20e(-0-515U/S). Comparisons revealed that differences between the two age groups, with lower values achieved with younger pigs, -were more pronounced the lower U/S and the higher FFA content of the fat.

Effect of fatty acids source on growth performance, carcass characteristics, plasma urea nitrogen concentration, and fatty acid profile in meat of pigs fed standard- or low-protein diets

“…The metabolizable energy (ME) of SS was calculated using the equations of Powles et al (1995) and NRC (1998). The calculated energy value was 32.34 MJ ME kg -1 .…”

Effect of Natural Antioxidant Sources on Oxidation of Olive Flounder (Paralichthys olivaceus) and Fish Feed during Storage

“…Determination of FFA values is often used as a general indication of the condition and edibility of oil (Low and Ng, 1987). Lipid availability of land animals was suppressed by high FFA in the diet (Wiseman and Salvador, 1991;Powles et al, 1995). However, since the experimental diets were stored frozen (-20C) before use throughout the feeding trial, this was not a serious concern to be considered in this study.…”

Performance, fatty acids digestibility, carcass and muscle composition of pigs fed diets enriched with vitamin E and differing in their MUFA/PUFA ratio

“…Therefore, the estimated unsaturated/saturated (U/S) fatty acid ratio was constant in all cases. This fact allowed us to assume that DE was identical in all experimental diets (Powles et al, 1995). Concentration of trans fatty acids in hydrogenated fat was below 0.3% of total fatty acids.…”