Effects of fat source
and vitamin E on pork quality

 

E. van Heugten and M.T. See

 

Summary

The objective of the current experiment was to determine the effect of vitamin E supplementation (0, 100, 200, 400, or 800 mg/kg of diet) on fresh pork quality of pigs fed saturated (choice white grease) or unsaturated (soybean oil) fat sources. The results of this study suggest that vitamin E accumulation in loin muscle increased linearly with supplemental vitamin E level and that this may be dependent on dietary fat type. Vitamin E supplementation and fat type had minimal effects on fresh pork quality.

 

Introduction

Pork quality is one of the main issues of concern for the pork industry in the U.S. For pork to be the meat of choice, meat quality problems associated with Porcine Stress Syndrome (PSS) need to be addressed. Sonka et al. (1994) reported in the Pork Chain Quality Audit that total cost per pig from color and Pale Soft and Exudative meat (PSE) related problems were $1.05. Of this amount, $0.79 per pig was reported to be directly controllable by pig producers. In addition, some pork processing facilities reported that up to 40% of the pigs they process have PSE related problems during the summer (Morgan et al., 1994). The main quality concerns identified by all members of the pork marketing chain are poor color and inadequate waterholding capacity (Cannon et al., 1995). Therefore, addressing these quality traits is of great priority to increase the market value of pork and to provide consumers with a desirable product. Supplementation of swine diets with vitamin E during the growing-finishing period has shown promise in improving pork quality (Buckley et al., 1995; Cannon et al., 1996). The effect of vitamin E on pork quality may depend on levels of unsaturated fats present in the muscle (Monahan et al. 1992). The objective of the current experiment was to determine the effect of vitamin E supplementation on pork quality of pigs fed saturated or unsaturated fat sources.

 

Material and Methods

The effects of short term vitamin E supplementation on pork quality of pigs initial BW) fed saturated or unsaturated types of fat was evaluated in 300 finishing pigs with an initial body weight of 88.5 kg . Pigs were allotted to 60 pens based on body weight, sex, and litter of origin and received one of 10 dietary treatments during the final 6 wk of the finisher period. Treatments were arranged in a 2 x 5 factorial randomized complete block design. Factors included: 1) fat type (choice white grease or soybean oil) and 2) supplemental vitamin E level (0, 100, 200, 400, or 800 mg/kg). The basal corn soybean meal diet contained 5% added fat from one of the two sources, 22 mg/kg of vitamin E and 0.75% lysine (Table 1).  Pigs were weighed at the initiation of the trial, after 3 weeks, and at the end of the experimental period and feed intake was recorded for each period. Pigs were slaughtered at a commercial packing plant and loin samples were obtained 24 h post-mortem. Vitamin E concentration of muscle samples, Minolta color measurements, pH (initial and ultimate), and drip loss (using the filter paper method) were determined. Data were analyzed as a randomized complete block design with a factorial arrangement of treatments using the general linear models (GLM) procedures of SAS. Factors were fat source, gender and vitamin E level.

 

Table 1.  Composition of the basal diet

Ingredient

Inclusion, %

Corn, grain

78.16

Soybean meal (48%)

14.13

Fat

5.00

Dicalcium Phosphate

0.98

Limestone

0.83

Salt

0.50

Vitamin/Mineral, 0.25%

0.25

Lysine HCl

0.15

Vitamin E Premix

Variable

 

 

Calculated Composition

%

Calcium

0.61

Phosphorus

0.50

Lysine

0.75

Crude Protein

13.30

Results and Discussion

Pig performance was not affected (P > 0.27) by fat type or vitamin E supplementation (Figures 1 to 3). Muscle vitamin E concentration increased linearly (P < 0.01) from 3.22 mg/kg to 6.65 mg/kg for pigs fed 0 to 800 mg/kg of vitamin E in diets containing soybean oil (Figure 4). In pigs fed choice white grease, muscle vitamin E concentation increased quadratically (P < 0.06) and reached a maximum (5.92 mg/kg) at 400 mg/kg of vitamin E.

Figures 1 and 2. Effect of fat source and vitamin E on Average Daily Feed Intake and Average Daily Gain.

Figures 3 and 4. Effect of fat source and vitamin E on Gain:Feed and loin vitamin E concentration.

 

Initial pH was greater in pigs fed CWG compared to pigs fed soy oil (Figure 5). Supplementation with vitamin E at 800 mg/kg resulted in a lower initial pH compared to pigs fed either 0 or 400 mg/kg of vitamin E. However, ultimate pH was not affected by fat source or vitamin E supplementation (Figure 6). Minolta L* and a* values were lower (less pale and red, respectively) for loin chops from pigs fed either 0 or 400 mg/kg of vitamin E compared with pigs fed 200 mg/kg of vitamin E (P < 0.05; Figures 7 and 8). Drip loss was not affected by treatments (P > 0.16; Figure 9).

Figures 5 and 6. Effect of fat source and vitamin E on initial pH and ultimate pH.

Figures 7 and 8. Effect of fat source and vitamin E on color L* (paleness) and color a* (redness).

Figure 9. Effect of fat source and vitamin E on drip loss.

 

Implications

These results suggest that the extent of vitamin E accumulation in loin muscle depends on dietary fat type. Vitamin E supplementation and fat type had minimal effects on fresh pork quality. Effects of vitamin E and fat source on quality characteristics of stored pork products will be evaluated in the near future.

 

Literature Cited

Buckley, D. J., P. A. Morrissey, and J. I. Gray. 1995. Influence of dietary vitamin E on the oxidative stability and quality of pig meat. J. Anim. Sci. 73:3122-3130.

Cannon, J. E., J. B. Morgan, F. K. McKeith, G. C. Smith, S. Sonka, J. Heavner, and D. L. Meeker. 1995. Pork chain quality audit packer survey: Quantification of pork quality characteristics. J. Muscle Foods: 6:369.

Cannon, J. E. , J. B. Morgan, G. R. Schmidt, J. D. Tatum, J. N. Sofos, G. C. Smith, R. J. Delmore, and S. N. Williams. 1996. Growth and fresh meat quality characteristics of pigs supplemented with vitamin E. J. Anim. Sci. 74:98.

Monahan, F. J., D. J. Buckley, P. A. Morrissey, P. B. Lynch, and J. I. Gray. 1992c. Influence of dietary fat and a-tocopherol supplementation on lipid oxidation in pork. Meat Sci. 31:229.

Morgan, J. B., G. C. Smith, J. Cannon, F. McKeith, and J. Heavner. 1994. Pork distribution channel audit report. Pork Chain Quality Audit, Progress Report, April 6, 1994. p. 30.

Sonka, S., T. Doehring, S. Hofing. 1994. An economic assessment of enhancing quality management in the pork industry. Pork Chain Quality Audit, Progress Report, April 6,1994. p. 170.