Biofuel co-products as swine feed ingredients: Combining corn distillers dried grains with solubles (DDGS) and crude glycerin

The objective of this study was to examine the effects of combining corn DDGS with crude glycerin on growth performance and carcass traits to determine if a high level of crude glycerin supplementation could counteract the impact of corn DDGS on fatty acid profile of pork adipose. The experimental design was a 3×2 factorial arrangement of treatments with three levels of corn DDGS (0, 150, or 250g/kg diet) and two levels of crude glycerin (0 or 100g/kg diet). Pigs were fed one of six experimental diets over a 3-phase feeding program for 84d with each diet within phase formulated to be equal in metabolizable energy (ME) and standardized ileal digestible lysine (SID Lys). Pigs and feeders were weighed every 14d to determine average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency (G:F). On d-84, pigs were weighed and scanned using real-time ultrasound to obtain fat depth and longissimus dorsi muscle (LM) area. Pigs were then harvested at a commercial abattoir and a sample of adipose was collected from the jowl of each pig. Because there was no interaction between level of corn DDGS and crude glycerin fed, only main effects are presented. Pig performance and carcass characteristics were not affected by dietary treatment (P≥0.05). Differences in fatty acid composition were present due to dietary treatment. Increasing the level of corn DDGS reduced concentration of both saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) and increased the concentration of polyunsaturated fatty acids (PUFA) in pork jowl adipose (P<0.01). Pigs fed 100g crude glycerin/kg diet had higher concentrations of MUFA and lower concentrations of PUFA (P<0.05). Diets containing up to 250g corn DDGS/kg and 100g crude glycerin/kg support growth of finishing pigs. However, increasing dietary levels of corn DDGS increased the concentration of unsaturated fatty acids in pork jowl adipose and this was not ameliorated by feeding 100g/kg crude glycerin.