CLA Report

Investigating CLA benefits for beef

Simple production approaches can support higher CLA levels in beef products, say Dr. John Basarab and Dr. Mao Long He.

CLA progress not only creates stronger marketing opportunities for the beef products available today, it introduces the possibility of creating new products that are CLA enriched.

Helping to turn this potential into reality is the aim of the CLA Network's beef production and development module, says Dr. John Basarab of Alberta Agriculture and Food, who along with Dr. Mao Long He of Agriculture and Agri-Food Canada presented an overview of module progress at the CLA Summit 2007 conference.

"To date, our major focus has been on exploring simple production approaches that may result in higher CLA levels in beef products," says Basarab, module co-leader.

Sunflower seed boosts CLA

One series of studies conducted under the beef module examined the effects of adding sunflower seed to finishing diets for steers. Because sunflower seed contains high levels of linoleic acid, the fatty acid that is converted to CLA in the rumen, researchers wanted to see if using it as a feed supplement would result in higher levels of CLA in beef.

Researchers found that by substituting a portion of the grain in the finishing diet with sunflower seed they could increase levels of CLA 9,11 and CLA 10, 12 – the two major types of CLA that have been linked to potential human health benefits.

"The level of increase depended on specific treatment," says Long He. "However, we found that we could achieve a doubling of CLA levels with relatively simple changes to typical diets." These modest changes had no significant negative impact on important factors such as dry matter intake, average daily gain and feed-to-gain ratio.

Reducing liver abscesses

A related beef module study compared the effects of diets that included dietary sunflower seed vs. typical diets that included Tylosin phosphate – an antiobiotic used as an aid in the prevention of liver abscesses. Animals fed sunflower seed showed no incidence of liver abscesses, compared to the 25 percent incidence shown in animals fed control and control/Tylosin phosphate diets.

Public pressure continues to increase for reduced use of antibiotics in livestock production, notes Long He. "The results of this study introduce an added incentive to consider adding sunflower seed to livestock diets. This practice would allow beef producers to support increased CLA levels and promote animal health at the same time."

Pasture vs. feedlot comparisons

Two additional trials were also conducted to further examine factors affecting CLA levels in the meat of steers raised under different feeding scenarios.

The first of these trials began with a large group of yearling steers and ultimately compared the effects of a total of seven different diets on CLA levels in the meat of these animals. The following tables show treatments and results:

Pasture finished steers

Steers in these groups were rotationally grazed on meadow bromegrass-alfalfa pasture for four months, each receiving different supplement treatments. All groups were then slaughtered directly off pasture. CLA levels were measured in strip loin, back fat and intermuscular fat.

		CLA level (mg/g fat)
Group	Pasture supplement	Strip	Back	Intermuscle
Group 1	None	4.0	6.0	4.8
Group 2	Barley*	4.1	6.6	5.4
Group 3	Sunflower seed**	5.2	8.4	6.4

* Cracked barley at 1.79 kg/hd/day
** Whole sunflower seed at 0.75 kg/hd/day

Feedlot finished steers

Steers in these groups were rotationally grazed on same pasture as above for two months. Each received one of two different supplement treatments during the pasture phase. All groups were then transferred to a feedlot, where each received different diets for an additional 94 days before slaughter. CLA levels were measured in strip loin, back fat and intermuscular fat.

			CLA level (mg/g fat)
Group	Pasture supplement	Feedlot diet	Strip	Back	Intermuscle
Group 4	None	Regular*	2.5	3.3	3.4
Group 5	Sunflower seed**	Regular*	2.6	3.4	3.7
Group 6	None	Sunflower seed***	3.4	4.9	4.2
Group 7	Sunflower seed	Sunflower seed***	3.4	4.6	4.2

* 83% rolled barley/10% alfalfa hay/5% barley silage/1% molasses/1% vitamin-mineral mix on dry matter basis
** Whole sunflower seed at 0.75 kg/hd/day
*** 68% rolled barley/15% whole sunflower seed/10% alfalfa hay/5% barley silage/1% molasses/1% vitamin-mineral mix on dry matter basis

The results included several key findings:

Pasture grazing/finishing increases CLA levels. For example, Group 1 steers that were pastured grazed and finished had 60% more CLA in strip loin, 82% more CLA in back fat and 41% more CLA in intermuscular fat, compared to Group 4 steers that were feedlot finished.

Sunflower seed supplementation during pasture grazing/finishing increases CLA levels even further. For example, the sunflower seed supplementation received by Group 3 steers resulted in 30% more CLA in strip loin, 40% more CLA in back fat and 33% more CLA in intermuscular fat, compared to Group 1 steers that did not receive sunflower seed supplementation.

Sunflower seed supplementation during feedlot finishing can significantly increase CLA levels. For example, the sunflower seed supplementation received by Group 6 steers resulted in 36% more CLA in strip loin, 36% more CLA in back fat and 24% more CLA in intermuscular fat, compared to Group 4 steers that did not receive sunflower seed supplementation.

These results provide some indication of best approaches for high CLA levels that in the future could help provide a basis for strategies adopted by producers, says Basarab.

However, more research is needed to confirm what levels of CLA are desirable and what is the best recipe to promote optimal CLA in the context of overall meat quality, cost considerations, market opportunity and production efficiency, he cautions.

"A number of producers are showing interest in CLA and are looking for a 'recipe' for best results," says Basarab. "We're making strong progress, but it's important to remember we're still in very preliminary stages of this research. There are a number of important questions that will need to be addressed before any recommendation can be made to producers.

"The good news for now is that clearly there are ways we can increase CLA through production strategies. This is something we can build on to help develop CLA opportunities for the beef industry to capitalize on in the future."

A second, broader trial examined the potential to increase CLA and other bioactive lipid content in beef through pasture and feedlot management strategies. Results showed that whole sunflower seed supplementation on pasture increased CLA 9,11 and vaccenic acid in fat and muscle by 30 to 60 percent as compared to pasture controls, normal feedlot finishing diets resulted in decreases of both CLA 9,11 and vaccenic acid content.

"The results for CLA were similar to the results for other bioactive lipids," says Basarab. "CLA 10, 12, vacenic acid, omega-3 and polyunsaturated fatty acid content of fat and muscles from steers finished on pasture was three to four times higher than in steers finished on a high grain diet."

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Reprintable with credit. Individual articles in the Report on CLA Summit 2007 are available for reprint, with acknowledgement of the source: The CLA Network. For broader reprint requests or reprint assistance contact the CLA Network at CLAnetwork@gov.ab.ca.