Short communication: dietary vitamin A restriction may improve meat quality parameters in fat-tailed lambs

Thirty fat-tailed Mehraban ram lambs were randomly allotted into three vitamin A (VA) dietary treatment groups: either 100 (VA₁₀₀), 50 (VA₅₀), or 25% (VA₂₅) of the recommended daily vitamin A requirements. Treatment had no effect on feed intake, daily live weight gain, cold carcass weight, and dressing percentage. In M. longissimus lumborum (LL) of VA₁₀₀ lambs, malondialdehyde level was greater, but ether-extractable intramuscular fat concentration was lower. The proportion of C16:0 and C20:0 fatty acids in total fatty acids of LL was lower in VA₁₀₀ lambs, compared to VA₅₀ and VA₂₅ lambs. Conversely, greater proportions of C17:0, C17:1, C18:1, and C18:2 fatty acids were recorded in VA₁₀₀ lambs. Stearoyl-CoA desaturase activity index (the ratios of C16:0 to C16:1 and C18:0 to C18:1) was not influenced by dietary vitamin A level. Future research is needed to determine the optimum level of dietary vitamin A concentration for deposition of greater intramuscular fat in fat-tailed sheep.