The Effect of Diet Acid Detergent Fiber Content on Finishing Lamb Meat Fatty Acid Composition, Tenderness and Stability

Abstract

The effect of incrementally increasing the acid detergent fiber (ADF) content in low fiber finishing diets on meat fatty acid (FA) composition, tenderness and stability of finishing South African Mutton Merino (SAMM) wether lambs was investigated. Four dietary treatments were formulated, only differing in ADF content, namely the control (CON), ADF1, ADF2 and ADF3 at 46.8, 59.3, 63.8, and 79.9 g ADF/kg dry matter (DM), respectively. All lambs were slaughtered at a commercial abattoir at the end of a production study of 67 days. Loin chops were evaluated for FA composition, stability and tenderness. Only the α-linolenic acid (CON vs. ADF1 and ADF3) and conjugated linoleic acid (CLA c9,t11: CON vs. ADF1 and ADF2) composition of lamb muscle tissue was affected by ADF content, with both the lowest in the CON treatment. The oleic acid, total monounsaturated fatty acid (MUFA) and lipid omega-6 (n-6): omega-3 (n-3) ratio decreased, whereas linoleic acid, α-linolenic acid, CLAc9,t11, total polyunsaturated fatty acid (PUFA), n-6 and n-3 content, as well as PUFA:SFA ratio were increased following an increased ADF content. <i>Longissimus</i> color stability (apart from day 2 L* and day 8 b* values) and shear force were left unaffected. It was concluded that the ADF content of a low fiber finishing diet fed to SAMM lambs did affect meat FA composition. The n-6:n-3 ratio was favorably affected by a high ADF content and more research is needed in this regard.