Polyunsaturated Fatty Acids in Beef Marbling

 

In 2006, the Mendel University of Agriculture, Czech Republic reported their research on genetic effects on the levels of polyunsaturated fatty acids (PUFA) in meat from eight different breeds.

 

There have been a number of studies on the nutritional effects on PUFA in beef, and certainly feeding has a major impact on the fatty acid composition of meat. However, this study was designed to determine genetic influences. As identified in a number of studies (ENDER et al, 1997; Pfeuffer, 2001; Raes et al 2004), there is a real benefit to consumers if  a method can be found to increase the proportion of unsaturated fatty acids – particularly long-chain n-3 acids – in intramuscular fat.

According to WOOD et al.(2004) the interest in improving the proportion of fatty acids in meat is essentially based on the need to find a way of producing healthy meat with a higher ratio of polyunsaturated (PUFA) to saturated (SFA) acids and a better balance between the PUFA n-6 and n-3.  The meat of ruminants is a relatively good source of PUFA n-3 due to the presence of 18.3 in grass.

 

In general, the level of total fat affects the composition of fatty acids. In most breeds of cattle, the level of saturated (SFA) and mono-unsaturated (MUFA) acids increase faster than the PUFA content. Therefore, in order to see genetic differences, we must look at the % of PUFA rather than the volume of PUFA, because breeds with a high volume of fat will have a high volume of PUFA - but likely a low percentage of PUFA in total fat.

 

Seven different sire groups were crossed on the local dual-purpose breed, “Czech Spotted”, cows, as follows: Angus, Blonde d’Aquitaine, Belgian Blue, Charolais, Limousin, Hereford and Piedmontese. The control group was straight-bred Czech Spotted bulls.

 

Bulls were fattened on corn silage, concentrates and alfalfa roughage. Studies on the nutritional affects from feed indicate that grass-fattened cattle actually have higher levels of PUFA, so this diet was not designed to increase PUFA proportions in the beef.

Bulls were slaughtered at an average age of 500 days and slaughter weight of 1257 lbs. Fatty acid analysis were conducted on 221 samples taken from the longissimus pars thoracis muscle at the 9th-10th thoracic vertebrae.

The following Table gives the percentages for Intramuscular Fat (IMF) or Marbling, and the various PUFA by breed.Over-all, the highest levels of polyunsaturated fatty acids - PUFA -  were found in the Piedmontese crosses, who also had the lowest Intramuscular Fat (IMF) percentage. The lowest PUFA values were seen in the Belgian Blue, Charolais and Blonde d’Aquitaine crosses who also posted lower levels of IMF. Hereford had the highest level of IMF but still ranked approximately in the low to middle range of the group for PUFA content as a percentage.

This tells us that the breeds we see to be similar to the Piedmontese (muscled lean breeds like Belgian Blue and Blonde) are, at a genetic level, very dis-similar to Piedmontese when it comes to the quality of the fatty acid composition of their beef.

 

 

 

 

 

C22:6 is a long chain fatty acid , Omega-3,  called DHA, and is considered “brain food”. Dietary supplements of DHA can help fight heart disease and combat Alzheimers.

Most animals make very little DHA metabolically, however small amounts are manufactured internally through the consumption of linolenic acid (18:3 n-3)

 

The Piedmontese crosses in this study had the highest level of DHA (C22:6) and the highest level of 18:3 which helps the body to make more DHA. The Belgian Blue and Blonde crosses posted the lowest levels of these essential fatty acids.

 

C22:5 is another long chain fatty acid commonly called DPA. It works as an intermediary between EPA (C20:5) and DHA (C22:6). Studies show that Seal Oil is a rich source of DPA (C22:5) and it is effective to reduce bad cholesterol and fight heart disease. Again, the Piedmontese have a significantly higher proportion of this fatty acid as compared to the other breeds.

C22:4 – called adrenic acid – is a long chain Omega 6 fatty acid that is related to brain function. It is one of the most abundant fatty acids found in the healthy early developing human brain. Studies indicate that nutritional imbalances in these fatty acids can have a negative affect on preterm babies. Piedmontese, again, have the highest levels of this fatty acid.

Arachidonic acid (C20:4) is an Omega 6 that is also abundant in the brain. Some mammals lack the ability to—or have a very limited capacity to— covert this acid, making it an essential part of their diet. Little or no arachidonic acid is found in plants, so our best source comes from meat, eggs and dairy products. The Piedmontese crosses again have a significantly higher level of this important fatty acid as compared to other breeds in the trial.

 

This report from the Mendel University of Agriculture notes the effect of breed on the ratio of Omega 6 and Omega 3 values in the fatty acid C18:3. (Note: C18:3 contains both Omega 3 and Omega 6 isomers).  The range of ratio (Omega 6/Omega 3) was between 0.325 at the lowest in the Czech Spotted cattle to the highest at 0.270 for the Piedmontese crosses.

 

Other research that has compared PUFA values by breed have found that Piedmontese crosses contain a higher percentage of PUFA (WEGLARZ et al.1999 and HOLLO et al. 2005).

Interestingly, in research that did not involve the Piedmontese breed, no significant differences in PUFA content were found when comparing British and European hybrids crossed with Wagyu (MIR et al. 2000). Japanese Black Cattle (Wagyu) and it’s crosses with Holstein, and Charolais also found no note-able difference between breeds for PUFA content (ZEMBAYASHI et al. 1995). Jersey and Limousin, and their crosses, also showed no significant difference in PUFA content (MALAU et al. 2000) However, a study involving Limousin crossed on Angus, Hereford and Brahman, did report a significant difference in PUFA levels (EICHORN et al. 1985).

The USDA has conducted research on Piedmontese 0-copy, 1-copy and 2-copy beef with findings that the 2-copy (Naturalean) Piedmontese was comprised of the highest percentages of PUFA in that 3-way comparison. (Genotype Effects on..Fatty Acids, Rule et al).

 

This Czech research is telling us that the Piedmontese breed has a potentially unique ability for positive affect on the levels of good polyunsaturated fat and essential fatty acids, as compared to other breeds. Even breeds with low over-all fat levels and muscling similar to the Piedmontese, such as the Belgian Blue and Blonde d’Aquitaine, are significantly lower in PUFA levels compared to Piedmontese.

Our breed does seem to be able to exhibit enough marbling (IMF) to affect juiciness and flavor, while also reducing over-all fat content.  Now, we also know that the marbling in the Piedmontese beef is comprised of the healthiest levels of essential fatty acids that consumers may only get from dietary sources.

 More quantity of high value cuts plus more quality of lean, tender and uniquely healthful beef in each carcass:

What a powerful combination !

by Vicki Johnson - Exec. Director - NAPA

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