Fatty acids ratio of loin from lambs fed with increasing levels of crude glycerin in feedlot

Abstract Text:

The crude glycerin (CG) has been successfully used in ruminant nutrition as energy concentrate substitute. The objective of the study was to evaluate the effect of increasing levels of CG on loin fatty acids (FA) ratio. Lambs (24) with a mean body weight of 20.0 kg were used. Animals used in the study belong to a group of native sheep of the State of Mato Grosso do Sul, Brazil, called as "Pantaneiros". The experiment was conducted in a completely randomized design with 4 treatments: 0, 2.5, 5.0, and 7.5% of CG inclusion as a % of diet dry matter (DM). Diets were formulated to be isonitrogenous and isocaloric only varying the inclusion of CG to replace coarse ground corn, to provide an average gain of 250 g/day. Oat hay was used as roughage and concentrate was composed of corn and/or CG, soybean meal, ground soybean and mineral mix, with a roughage:concentrate ratio of 25:75. Body condition (BC) was used as slaughter criterion. As soon animals had a BC between 3.0 and 3.5 slaughter was performed. After 24h of chilling at 4°C, loin cuts obtained from deboned Longissimus between first and least lumbar vertebra of left side of the carcasses were used to determine FA profile (% of total FA) and ratio. There was no effect (P = 0.1052) of CG level on polyunsaturated (PUFA), monounsaturated (MUFA), saturated fatty acids (SFA), and ω6 percentages and on PUFA:SFA, and MUFA:SFA ratio. As CG increased, there was a linear decrease in unsaturated fatty acids (UFA) percentage (P = 0.0304; R² = 0.16; RSD = 2.49), and a linear decrease in ω3 percentage (P = 0.0084; R² = 0.26; RSD = 0.13). UFA:SFA decreased linearly with the CG inclusion (P = 0.0321; R² = 0.10; RSD = 0.09) while ω6:ω3 had a linear increase (P = 0.0289; R²= 0.18; RSD = 1.58).

Keywords: crude glycerin, fatty acids ratio, lamb loin