In a paper published in Journal of Animal Science, J.W. Lee and colleagues at the University of Illinois, Urbana describe their experiment to test the hypothesis that the reduced carcass fat quality that is often observed in pigs fed diets containing DDGS may be ameliorated if corn germ, beef tallow, palm kernel oil or glycerol is added to diets fed during the finishing period.

A total of 36 barrows and 36 gilts (initial bodyweight = 43.7±2.0kg) were individually housed and randomly allotted to one of six dietary treatments in a 2×6 factorial arrangement, with gender and diet as main factors.

Each dietary treatment had 12 replicate pigs. A corn-soybean meal control diet and a diet containing corn, soybean meal and 30 per cent DDGS were formulated. Four additional diets were formulated by adding 15 per cent corn germ, three per cent beef tallow, three per cent palm kernel oil or five per cent glycerol to the DDGS-containing diet.

Growth performance, carcass characteristics, and LM quality were determined, and backfat and belly fat samples were collected for fatty acid analysis.

There was no gender × diet interaction for any of the response variables measured.

For the entire finisher period (days 0 to 88), diet had no effect on average daily gain but pigs fed the palm kernel oil diet tended (P<0.10) to have lower average daily feed intake and greater gain:feed ratio than pigs fed the control diet.

Barrows had greater (P<0.01) average daily gain and average daily feed intake and lower feed efficiency (P<0.001) gain:feed ratio than gilts.

Pigs fed the DDGS diet had reduced (P<0.05) loin eye area compared with pigs fed the control diet but diet had no effect on other carcass characteristics.

Barrows had greater (P<0.001) final bodyweight at the end of both phases, greater (P<0.001) hot carcass weight and backfat thickness and tended (P=0.10) to have greater dressing percentage, but less (P<0.001) fat-free lean percentage than gilts.

Backfat of pigs fed the five DDGS-containing diets had lower (P<0.05) L* values than pigs fed the control diet and backfat of gilts had greater (P<0.001) a* and b* values than barrows.

Pigs fed the control diet had greater (P<0.05) belly flop distance compared with pigs fed the five DDGS-containing diets but no differences were observed among pigs fed the diets containing DDGS.

Barrows had heavier (P<0.001) bellies and greater (P<0.001) belly flop distances than gilts.

Diet had no effect on carcass fat iodine value but gilts tended (P=0.07) to have greater backfat iodine value and greater (P=0.05) belly fat iodine value than barrows.

Lee and colleagues concluded that the carcass fat quality of pigs fed diets containing DDGS was not improved by inclusion of corn germ, beef tallow, palm kernel oil or glycerol in finishing diets in their study.

Reference

^{Lee J.W., D.Y. Kil, B.D. Keever, J. Killefer, F.K. McKeith, R.C. Sulabo and H.H. Stein. 2013. Carcass fat quality of pigs is not improved by adding corn germ, beef tallow, palm kernel oil, or glycerol to finishing diets containing distillers dried grains with solubles. J. Anim. Sci. 91(5):2426-2437.}

August 2013