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Prediction of loin, belly and jowl IV based on diet composition versus daily fatty acid intake
Prediction of loin, belly and jowl IV based on diet composition versus daily fatty acid intake
Tuesday, March 18, 2014: 9:30 AM
314-315 (Community Choice Credit Union Convention Center)
Abstract Text: Iodine value product (IVP) is used to predict carcass fat iodine value (CIV). When higher fat diets are employed, IVP tends to emphasize the quantity of fat more than its composition. The objective of this experiment was to compare the effectiveness in predicting CIV by IVP vs. individual fatty acid content in the diet or their daily intake. Forty-two gilts and 21 barrows (PIC 337 X C22/29) with an average initial weight of 77.8±0.38 kg were allotted based on sex and weight across 7 treatments: 3 or 6% of each of tallow (iodine value (IV)=41.9), choice white grease (IV=66.5) or corn oil (IV=123.1), and a control corn-soy based with no added fat. Pigs were housed individually to measure daily fatty acid intake. Adipose samples were collected from the jowl, loin, and belly at slaughter (d55). Iodine value was determined using GC on diet and carcass lipid samples and averaged across the three locations. Data were analyzed using PROC MIXED (SAS 9.3) with treatment and sex as fixed effects, and replicate as a random effect. PROC REG was utilized to compare the relationship between individual intakes of fatty acids and CIV, and to compare the analyzed diet IVP vs. daily fatty acid intake on CIV. Increased daily intake of palmitic acid (CIV = 72.94 – (0.06*palmitic acid intake/d (g)); R2=-0.08; RMSE=4.98) and stearic acid (CIV = 72.13 – (0.14*steraic acid intake/d (g)); R2=-0.12; RMSE=5.07) were negatively correlated with CIV but with weak coefficients of determination (P<0.05). Increased daily intake of oleic acid (CIV = 66.30 + (0.085*oleic acid intake/d (g)); R2=0.08; RMSE=4.97) and linolenic acid (CIV = 62.55 + (3040.4*linolenic acid intake/d (g)); R2=0.26; RMSE=4.45) were positively correlated with CIV but also had weak coefficients of determination (P<0.05). Increased linoleic acid intake (LAI) was positively correlated with CIV and generated a strong coefficient of determination (CIV = 60.58 + (0.121*LAI/d (g)); R2=0.611; P<0.05; RMSE=3.24). IVP of the experimental diets was approximately equal (CIV = 58.10 + (0.215*IVP); R2=0.93; P<0.05; RMSE=1.45) to the treatment means of LAI (CIV = 58.57 + (0.139*linoleic acid intake/d (g)); R2=0.94; P<0.05; RMSE=1.37) as a predictor of CIV. Under these conditions, a CIV standard of 74g/100g can be met by limiting LAI to less than 111 g/d. Linoleic acid is clearly the fatty acid that most affects CIV, but LAI offers no significant improvement over IVP in predicting CIV.
Keywords: Swine, Linoleic acid, Iodine value, fat quality