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.