The Impact of Duration of Feeding and Saturation of Dietary Fats on Changes in Body Fat Over Time and on Final Carcass Lipid Iodine Values

The inclusion of unsaturated fats in pig diets has raised issues related to pork carcass lipid quality. The objective of this experiment was to understand how withdrawal from the diet of unsaturated dietary fat prior to slaughter impacts the composition of jowl fat during the finishing period and at market. Fifty pigs (PIC 337 X C22/29; initial BW = 59.3±3.64 kg), were allotted to an 82d experiment based on sex and initial BW to 10 treatments: 3 dietary fat withdrawal times prior to slaughter (21, 42 or 63d) by 3 fat sources ( 5% animal-vegetable blend (AV; iodine value (IV)=90.7), 2.5% corn oil (2.5%CO; IV=122.7), 5% corn oil (5%CO), plus a control diet with no added fat (CNTR) fed throughout the duration of trial. Pigs were individually housed to measure ADFI and dietary fat intake. Pigs were weighed and jowl adipose samples were collected on days 0, 21, 42, 63 and at harvest on d82. Carcass measurements were recorded at harvest using a durometer compression measurement (1 least firm; 100 most firm). Data were analyzed using PROCMIXED with treatment and sex as fixed effects, and pen as a random effect. Carcass IV (CIV) was affected by dietary fat inclusion duration across all lipid source treatments (P\u3c0.01). Dietary fat source affected firmness measured bydurometer (CNTR=36, 2.5%CO=39, AV=40, 5%CO=31; P\u3c0.05). Sex did not affect CIV (P\u3e0.30) or firmness (P\u3e0.13). Duration of lipid inclusion did improve gain to feed (CNTR=0.31 kg, 21d=0.31 kg, 42d=0.33 kg, 63d=0.34 kg; P\u3c0.001). In conclusion, 2.5% CO and 5% AV maintained CIV below 74 g/100g, while a 21d withdrawal of 5% corn oil was required to maintain CIV below 74 g/100g

A Comparison of Fresh and Frozen Chops and Roasts from Gilts, Physical Castrates, Entire Males, and Immunologically Castrated Males

The objective of this study was to evaluate the effect of gender treatment, including immunological castrates, on meat quality and sensory characteristics of fresh and frozen pork. This experiment included gilts (G), physical castrates (PC), entire males (EM), and immunologically castrated males (IC). Pigs were harvested at a BW=145.0 ± 8.6 kg. Loins were collected and cut into roasts and chops. Fresh and frozen chops and roasts were evaluated for meat quality, namely - loin purge %, pH, marbling score, color score, Minolta L*, a*, and b* score, % cook loss, and star probe force. No significant differences (P \u3c 0.05) were found among gender treatments in the fresh samples for any of the carcass meat quality criteria evaluated. However, NPPC marbling score was significantly different among treatments in frozen samples (G=1.58b, PC=2.05a, EM=1.46b, IC=1.73ab; P \u3c 0.005). A trained sensory panel evaluated samples for boar aroma, juiciness, tenderness, pork flavor, and off flavor. No significant differences were found among genders for juiciness, tenderness, chewiness or off flavor. Boar aroma and pork flavor results are presented in Table 3. These results suggest that gender treatment was similar between fresh and frozen product, and that injection against GnRF (gonadotropin releasing factor) removes aroma and flavor issues associated with meat from intact males

Prediction of Loin, Belly and Jowl IV Based on Diet Composition Verses Daily Fatty Acid Intake

Iodine value product (IVP) is commonly used to predict carcass fat iodine value (CIV). However, when higher fat diets are employed, IVP tends to emphasize the quantity of fat in the diet more than the composition of that fat. The objective of this experiment was to compare the effectiveness in predicting CIV by IVP versus individual fatty acid content in the diet or their daily intake. Forty-two gilts and 21 barrows (PIC 337 × C22/29) with an average initial weight of 77.8 ± 0.38 kg were allotted based on sex and weight across 7 treatments: a control diet with no added fat, and 6 diets containing either 3 or 6% of tallow, choice white grease, or corn oil. Pigs were individually housed to measure daily fatty acid intake. Adipose samples were collected from the jowl, loin, and belly at harvest (d 55). Of all the fatty acid intakes measured, only increased linoleic acid intake (LAI) generated a strong coefficient of determination in a positive correlation with CIV (CIV = 60.58 + (0.121× LAI/d (g)); R2 = 0.611; P \u3c 0.05; Root MSE = 3.24). Comparison of IVP of the experimental diets was approximately equal (CIV = 58.10 + (0.215 × IVP); R2 = 0.93; P \u3c 0.05; Root MSE = 1.45) to the treatment means of LAI (CIV = 58.57 + (0.139 × linoleic acid intake/d (g)); R2 = 0.94; P \u3c 0.05; Root MSE = 1.37) as a predictor of CIV. Under the conditions of this experiment, a CIV standard of 74 g/100 g can be met by limiting LAI to less than 111 g/d. Linoleic acid is clearly the fatty acid that most affects CIV

Relationship of Pork Longissimus Muscle Fatty Acid Profile with Pork Loin Texture and Sensory Traits

The objective this project was to determine the contribution of lipid composition and lipid profile to textural and sensory properties of fresh pork. Loins from pigs (n=2009; from 306 sires and 1030 dams) were used to determine the contribution of lipid composition and lipid profile to textural and sensory properties of fresh pork. Total lipid content was correlated with saturated fatty acids and negatively correlated with unsaturated fatty acids. Myristic acid was positively correlated with tenderness and negatively correlated with star probe. Negative correlations between stearic acid and the traits of tenderness and juiciness were detected. No other fatty acid component was determined to have a strong correlation with pork texture or sensory traits. The results suggest that when pigs are fed a similar diet, normal variations in pork loin fatty acid profile do not contribute to differences in pork texture and sensory traits

Effects of Triticale-Based Diets on Finishing Pig Performance and Pork Quality in Deep-Bedded Hoop Barns

Effects of triticale-based diets on finishing pig performance and pork quality in deep-bedded hoop barns were evaluated. Triticale is a synthetic small grain resulting from a cross between durum wheat and rye. The study consisted of four trials: two in winter (November 2003 through March 2004) and two in summer (May 2004 through September 2004) at the ISU Western Research and Demonstration Farm, Castana, IA. Each trial consisted of six pens of ten pigs (five barrows, five gilts) in three smallscale hoop barns (6.0 × 10.8 m). Pens were randomly assigned one dietary treatment: 1) corn-soybean meal control, 2) 40% Trical 815 triticale diet (by weight) or 3) 80% Trical 815 triticale diet (by weight). The 40 and 80% triticale diets had corn and soybean meal added. Animals had ad libitum access to feed and water during the study. Pigs were started on experiment at approximately 72 kg and fed for 49 d. At the end of each trial all pigs were scanned for backfat thickness and loin muscle area. Barrows from one winter and one summer trial were evaluated for meat and fat quality and sensory evaluation of pork. End weights and ADG were greater during the winter than summer (treatment × season interaction P \u3c 0.01) and decreased as triticale inclusion increased (P \u3c 0.001). Feed intake was similar. Pigs fed the control diet had the greatest G:F, those fed the 80% triticale diet had the least, with pigs fed the 40% triticale diet having intermediate G:F. During the summer, pigs fed the control diet had more BF (P \u3c 0.05) than those fed the triticale diets. Also during summer, pigs fed the control diet had the largest loin muscle area (LMA) (47.5 ± 1.72 cm2); pigs fed the 40% triticale diet had intermediate LMA (45.5 ± 1.72 cm2) and those fed the 80% triticale diet had the smallest LMA (43.4 ± 1.73 cm2). Dietary treatment had no effect on carcass weight, BF, LMA, percentage lean of barrows or sensory evaluation or fatty acid profile of loin chops. Ultimate pH was higher (P \u3c 0.001), percentage loin purge was less (P \u3c 0.05) and shear force (kg) was less (P \u3c 0.05) during summer than winter. Total monounsaturated fatty acids (MUFA) were greater (P \u3c 0.05) and total PUFA in loins were less (P \u3c 0.01) during the winter than summer. Replacing corn with triticale in finishing pig diets in hoops slightly decreased growth performance, but did not affect pork quality. Increasing the amount of triticale in finishing pig diets decreased dietary soybean meal and dicalcium phosphate levels. This may reduce dietary costs. However, pigs fed triticale had 10% less average daily gain and 13% poorer feed conversion at the greater inclusion rate (80% of the diet). This may offset the potentially lower dietary costs. Triticale can be fed to pigs without compromising pork or fat quality. There was no difference in pork eating quality from pigs fed corn-based or triticale-based diets, according to a trained sensory evaluation panel. Further research on triticale-based swine diets is warranted. Triticale-based diets in deep-bedded hoop barns should be evaluated when dietary fat is added, as finishing pig performance may be enhanced. An economic analysis should be conducted on utilization of triticale as a feedstuff in swine diets fed to finishing pigs in deep-bedded hoop barns. From the results of this study, triticale has potential as a feed grain crop in integrated crop and livestock enterprises in the Midwest U. S

Effects of Triticale-Based Diets fed in Deep-Bedded Hoop Barns on Finishing Pig Performance and Pork Quality

Triticale is a synthetic small grain that results from an intergeneric cross between durum wheat and rye. Triticale has shown potential as a feedstuff in swine diets. Producers who may find this to be an attractive crop may also raise swine in an alternative swine production system. The objective of the present study was to evaluate the effects of triticale-based diets on pork quality and finishing pig performance of pigs reared in deep-bedded hoop barns

Economic Analysis of Increased Levels of Intramuscular Fat in Pork: Producer and Industry Opportunities

Ultrasound technology is available for accurately measuring intramuscular fat (IMF) in live pigs. This report provides information on the costs for pig producers and processors to implement this technology and what consumers are willing to pay for pork with improved levels of intramuscular fat. About half the participants in the willingness to pay study preferred the high IMF chop. They paid a premium of 25 percent over the low IMF chop.ultrasound technology, measure intramuscular fat live pigs, pig producer cost, pig processor costs, consumer willingness to pay, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Farm Management, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Marketing,

Influence of lipid content on pork sensory quality within pH classification

The objective of this project was to determine the contribution of lipid content to textural and sensory properties of fresh pork within defined pH classifications. Pigs (n = 1,535; from 248 sires and 836 dams) from the 1991, 1992, and 1994 National Barrow Show Sire Progeny Test were used in this study. The test included purebred Berkshire (107), Chester White (113), Duroc (249), Hampshire (220), Landrace (165), Poland China (101), Spotted (181), and Yorkshire (399) barrows (901) and gilts (634). Diets were uniform across breeds within test. The halothane (Hal 1843) genotype (1346 NN and 189 Nn) was determined. Pigs were slaughtered at 105 kg of BW, and samples of the LM were obtained from each carcass at the 10th rib. Star probe, sensory traits, and lipid content were determined on the LM from each pig. A pH classification of LM was assigned as follows: class A, \u3e5.95, n = 186; class B, ≥5.80 to 5.95, n = 236; class C, ≥5.65 to 5.80, n = 467; class D, ≥5.50 to 5.65, n = 441; class E, \u3c5.50, n = 205. Data were analyzed using a mixed linear model including pH classification, test, sex, halothane genotype, breed, and breed × sex interaction as fixed effects, with sire and dam within breed included as random effects. Correlations were determined within pH class. Lipid content was a significant source of variation for models predicting star probe values in class C and D and for chewiness in class B, C, and D. Increasing lipid content tended to increase sensory tenderness in pH class D. Sensory tenderness was not affected by lipid content in pH class A, B, or E. Lipid content was not a significant source of variation for juiciness scores within any pH class. Intramuscular lipid is correlated with sensory texture traits primarily in classes C and D. Within class C and D, correlations indicate that increasing lipid content is associated with high sensory tenderness, low sensory chewiness, and low star probe values. It is concluded that lipid content is a small source of variation in texture and tenderness of pork loin with pH between 5.80 and 5.50, but not at a greater or lesser pH

Contributions of pH and Intramuscular Lipid to Sensory Quality of Fresh Pork Loin

The results suggest that high pH product (above pH 5.8) can be expected to be superior to lower pH product with regard to sensory quality, texture, and cook loss. In general, at high pH, greater lipid content does not improve sensory tenderness, sensory chewiness, sensory juiciness or star probe values. At low pH (below pH 5.5), pork is of inferior quality in virtually every category. At low pH, greater lipid content does not improve sensory quality. Lipid content does contribute to pork sensory traits in pork loins with intermediate pH (between pH 5.5 and 5.8). The effects of lipid content within the intermediate pH classifications indicate that only a small portion of the variation in sensory quality can be attributed to variation in lipid content

Survival of Methicillin-Resistant Staphylococcus aureus During Thermal Processing of Frankfurters, Summer Sausage, and Ham

Infections from antibiotic-resistant bacteria are a major concern for human health professionals around the world. Methicillin-resistant Staphylococcus aureus (MRSA) is just one of the resistant organisms of concern. MRSA prevalence has also been recently reported in retail meat products at rates higher than originally thought. Although the risk of contracting an infection from handling contaminated meat products is thought to be low, very little is known about this organism from a food safety perspective. The objective of this study was to determine the survival of MRSA during thermal processing of frankfurters, summer sausage, and boneless ham. Frankfurters, summer sausage, and boneless ham were manufactured using formulations and processing procedures developed at the Iowa State University meat laboratory. Thermal processing resulted in a significant log reduction (