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Title: Effect of feeding system and breed on n-3 and n-6 polyunsaturated fatty acid content of lamb muscles

Author
item DAVILA EL RASSI, G - Oklahoma State University
item BANSKALIEVA, V - Oklahoma State University
item Brown, Michael

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2010
Publication Date: 8/4/2010
Citation: Davila El Rassi, G., Banskalieva, V., Brown, M.A. 2010. Effect of feeding system and breed on n-3 and n-6 polyunsaturated fatty acid content of lamb muscles [abstract]. American Society of Animal Science Annual Meeting, February 6-9, 2010, Denver, CO. Available on-line: http://www.asas.org/abstracts/ASAS_Sectional_Abstracts_2010.pdf

Interpretive Summary: Abstract Only.

Technical Abstract: Katahdin (KK, n=6), Katahdin x Suffolk (KS, n=6), Suffolk x Katahdin (SK, n=6) and Suffolk (SS, n=6) wethers were used to evaluate omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acid content, and the ratio of n-6 to n-3 in muscles of these lambs, raised on concentrate or forage diets. Lambs were born spring 2007, weaned in late May and grazed on bermudagrass pasture until late August. Concentrate fed lambs were moved to drylot and three lambs of each breed group were fed on a mixed grain ration (12% CP, 76% TDN) for 88 d while remaining were pastured on bermudagrass until late September before moving to drylot and fed wheat silage for 69 d. Lambs were harvested at the Food and Agricultural Products Center, Oklahoma State University and samples of m. Longissimus lumborum (LL) and m. Semimembranosus (SM) were taken for fatty acid analyses. Data were analyzed by mixed model least squares procedures with a linear model that included fixed effects of treatment (concentrate vs. forage finished), sire breed, dam breed, muscle type (subunit effect), and all possible interactions. Random effects in the model included lamb nested in treatment, in sire breed and in dam breed, and muscle x lamb nested in treatment, in sire breed, and in dam breed. There was little evidence of interactions among fixed effects for percent n-6, percent n-3, or the ratio n-6 to n-3 in these data. There was a trend (P < 0.10) for percent n-6 to be greater in LL of forage-fed lambs than concentrate-fed lambs and percent n-3 of forage-fed lambs was greater than concentrate-fed lambs in both LL and SM (P < 0.05). The ratio n-6 to n-3 was greater in SS lambs than KK lambs in both muscles (P < 0.05) and there was evidence of a direct breed effect in favor of KK (P < 0.05) in both muscles where Katahdin-sired lambs were lesser in this ratio than Suffolk-sired lambs. In addition, forage-fed lambs were lesser than concentrate-fed lambs in the ratio of n-6 to n-3 in both LL and SM (P < 0.05). Averaged over muscle, n-6 to n-3 ratio in concentrate-fed lambs averaged 4.54, 3.69, 3.34, and 3.74 in SS, SK, KS, and KK whereas in forage-fed lambs these averages were 3.58, 3.12, 2.87, and 2.01, respectively. Results suggest that forage-fed lambs have a more favorable ratio of n-6 to n-3 as do Katahdin-sired lambs in LL and SM muscles.