Effect of Zilpaterol Hydrochloride and Zinc Methionine on Growth, Carcass Traits, Meat Quality, Fatty Acid Profile and Gene Expression in Longissimus dorsi Muscle of Sheep in Intensive Fattening

Abstract

Zilpaterol hydrochloride (ZH) redistributes ingested energy and improves feed efficiency by increasing muscle mass and reducing fat in sheep and cattle carcasses in fattening; however, by increasing lipolysis and reducing intramuscular fat (IMF), it can affect meat quality in terms of the attributes of tenderness, juiciness, taste and color; in contrast, Zn methionine (ZM), due to its lipogenic effect, can improve meat marbling without affecting production efficiency. In the current study, 36 male Suffolk sheep were used (25 ± 0.58 kg live weight, LW) to evaluate the supply of ZH and ZM on growth, carcass traits, meat quality, fatty acid content and expression of genes which regulate the deposition of fatty acids (FA) in IMF. A completely randomized design was used, with factorial arrangement of 2 × 2 ZH (0 and 0.2 mg kg−1 LW) and ZM (0 and 80 mg Zn kg−1 dry matter, DM). The results showed that ZH increased (p < 0.05) carcass yield, compactness index and chop eye area and decreased greasing (p < 0.02). The content of ether extract in meat increased (p < 0.05) in sheep with ZM plus ZH, and in sheep with ZM (p < 0.01). ZH (p < 0.05) reduced (p < 0.02) the meat’s color index L*, a*, b*, C* and H*. The content in IMF of stearic (C18:0) and arachidic (C20:0) FA was reduced (p ≤ 0.05) by the effect of ZH, but the palmitoleic (C16:1), eicosatetraenoic (C20:4n6) and conjugated linoleic FA were increased (p ≤ 0.05) by the effect of ZH. ZM increased (p ≤ 0.05) palmitoleic (C16:1) and conjugated linoleic FA; the ZH interaction with ZM increased (p ≤ 0.05) linoleic (C18:2 c 9 c 12), linolenic (C18:3 c 9c12c15) and eicosatetraenoic (C20:4n6) FA. The ZH interaction with ZM influenced (p ≤ 0.05) the total saturated fatty acids (SFA), unsaturated fatty acids (UFA) and polyunsaturated fatty acids (PFA). ZH increased (p ≤ 0.05) the relative expression of mRNA from the enzymes lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), glycerol -3-phosphate acyltransferase (GPAT1) and diglyceride acyltransferase (DGAT1). ZM increased (p ≤ 0.05) the relative expression of mRNA from the enzyme gene acetyl-CoA carboxylase (ACC) and HSL, monoglyceride lipase (MGL). The ZM interaction with ZH increased (p ≤ 0.05) the relative expression of mRNA genes of the enzymes HSL and ACC. It was concluded that ZH improved feed conversion (FC), increased yield and reduced fat in carcasses; ZM increased IMF in Longissimus dorsi. ZH and ZM influenced the FA composition, reduced the SFA and increased the UFA and PFA; both additives also influenced the relative mRNA expression of genes involved in fatty acid metabolism.

Effects of Duration of Calcium Propionate Supplementation in Lambs Finished with Supplemental Zilpaterol Hydrochloride: Productive Performance, Carcass Characteristics, and Meat Quality

“…In recent decades, research on feedlot ruminants has primarily focused on finding technologies that improve feed efficiency and growth rates during the fattening process [1,2]. The final phase of finishing is characterized by lower growth efficiency in lambs, mainly because their gain consists predominantly of fat rather than muscle [3].…”

“…The final phase of finishing is characterized by lower growth efficiency in lambs, mainly because their gain consists predominantly of fat rather than muscle [3]. Thus, one of the main objectives during finishing is to augment the proportion or weight of muscles while decreasing the fat content in the carcass [1,2]. An alternative approach to achieve this goal is through the use of growth promoters, such as gluconeogenic precursors or β-adrenergic agonists (β-AA).…”

“…When administered at a rate of 4 to 8 mg/kg diet during the final 20-40 d of fattening, it enhances growth performance, dietary energy utilization efficiency, and carcass traits in lambs [11]. The advantages of using ZH during the finishing phase of fattening have primarily been attributed to alterations in the composition of tissue gain [2,12]. Receptors in muscle and fat are activated by ZH, leading to augmented lipolysis, reduced lipogenesis, and increased protein accumulation, either individually or in combination [13].…”

Effects of Zilpaterol Hydrochloride with a Combination of Vitamin D3 on Feedlot Lambs: Growth Performance, Dietary Energetics, Carcass Traits, and Meat Quality.

“…According to studies by [29,30], supplementing with ZH for 30 d can increase the toughness of the LM by 20.0 to 56.4%, which is consistent with our research showing a 21.5% increase in WBSF. However, other reports by [29,41] have not found any differences in WBSF between lambs treated with ZH and the control group. The final pH of the meat is a crucial factor in determining its quality, and lambs supplemented with ZH have been observed to produce meat with an elevated pH of 3.2 to 8.9% [42].…”

“…β-agonists have been studied for their effect on the fatty acid profile of ruminants. In a study by [41] lambs treated with ZH showed an increase in polyunsaturated fatty acids in intramuscular fat. In their study on lambs, [44] found that administering Salbutamol, a β-agonist, led to a decrease in saturated fatty acids and an increase in total unsaturated fatty acids.…”