Changes in intramuscular fat, fatty acid profile and cholesterol content induced by zeranol implantation strategy in hair lambs

BACKGROUND: The effect of zeranol implantation strategy on intramuscular fat, fatty acid profile and cholesterol content of the longissimus dorsi muscle of hair lambs was studied. Four treatments were tested: C, control group; Z12, 12 mg zeranol; Z24, 24 mg zeranol in a single application; and RZ12, 12 mg zeranol given twice. One‐way analysis of variance was employed to estimate the effect of treatments ( P < 0.05). To separate the effect of the mean, orthogonal contrasts were tested: C1, C versus Z12 + Z24 + RZ12; C2, Z12 versus Z24 + RZ12; and C3, Z24 versus RZ12. RESULTS: A decrease ( P < 0.05) in intramuscular fat content was observed from implanting (C1 effect) and zeranol reimplantation (C3 effect). Implanted lambs exhibited an increase ( P < 0.05) in monounsaturated fatty acids compared with control group (40.60% versus 35.35%). All contrasts were significant for the sum of n‐6 and n‐3, with values lower ( P < 0.05) in the control (n‐6: 0.84% and n‐3: 1.38%) and higher in the RZ12 treatment (n‐6: 7.55% and n‐3: 14.9%). Cholesterol decreased by 78% with implantation and increasing the dose. CONCLUSION: The results indicate that it is possible to induce favorable changes in the fatty acid profile and cholesterol content using a zeranol implantation strategy on hair lambs. Copyright © 2011 Society of Chemical Industry