Cysteamine administration in lambs grazing on mountain pastures: Effects on the body weight, antioxidant capacity, thyroid hormones and growth hormone secretion

Abstract

This study aimed to evaluate the effects of intravenous injection of cysteamine (CS) on body weight (BW), growth hormone (GH), thyroid hormones (TH) secretion, and antioxidant status of growing lambs grazing on mountain pastures. Fifteen lambs (3-4 months of age) were randomly allocated into three experimental groups which received different dosages of CS: 0, 20, and 50 mg/kg BW^-1 . The CS was injected on the 1st, 10th^, and 20th days of the experiment to the lambs through the jugular vein. Assessment of plasma concentration of GH and TH hormones was carried out at days 0 (a day before the start of CS injections), 15, and 30 of the experiment. The antioxidant enzymes were measured at the end of the experiment. Lambs were weighed at days 0, 10, 20, and 30 of the experiment. The results showed that treatment and time affected the BW, GH, triiodothyronine (T₃ ), and tetraiodothyronine (T₄ ) secretion. The intravenous injection of CS increased the BW of growing lambs (p < 0.01) and increased the plasma concentration of GH, T3, and T4 (p < 0.01). The treatment also enhanced glutathione peroxidase (GSH-Px; p < 0.05) and reduced malondialdehyde concentrations (MDA; p < 0.01). Total antioxidant capacity (T-AOC) level reduced in CS-1 treatment compared to GC and CS-2 treatments (p < 0.01). The levels of superoxide dismutase (SOD) and catalase (CAT) were not affected by CS. In conclusion, intravenous injection of CS improved BW, GH, and TH concentrations and antioxidant capacity in growing lambs grazing on mountain pastures.

Keywords: CAT; GSH-Px; MDA; SOD; T-AOC.

FIGURE 1

Effect of cysteamine (CS) intravenous injection on the growth performance body weight of growing lambs fed on extensive production system. Bars with different letters are significantly different (p < 0.01). Treatments: GC = control treatment (normal saline was administration without CS via i.v. infusion); CS‐1 = 20 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; CS‐2 = 50 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; Trt = effect of treatment; Time = effect of sampling time; Trt × Time = effect of treatment by sampling time

FIGURE 2

Effect of intravenous injection of cysteamine (CS) on plasma concentrations of growth hormone (GH) in growing lambs fed on extensive production system. Bars with different letters are significantly different (p < 0.01). Treatments: GC = control treatment (normal saline was administration without CS via i.v. infusion); CS‐1 = 20 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; CS‐2 = 50 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; Trt = effect of treatment; Time = effect of sampling time; Trt × Time = effect of treatment by sampling time

FIGURE 3

Effect of intravenous injection of cysteamine (CS) on plasma concentrations of T₃ in growing lambs fed on extensive production system. Bars with different letters are significantly different (p < 0.01). Treatments: GC = control treatment (normal saline was administration without CS via i.v. infusion); CS‐1 = 20 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; CS‐2 = 50 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; Trt = effect of treatment; Time = effect of sampling time; Trt × Time = effect of treatment by sampling time

FIGURE 4

Effect of intravenous injection of cysteamine (CS) on plasma concentrations of T₄ in growing lambs fed on extensive production system. Treatments: GC = control treatment (normal saline was administration without CS via i.v. infusion); CS‐1 = 20 mg/kg BW⁻¹ CS administrated via i.v. infusion each 10 days; CS‐2 = 50 mg/kg BW‐1 CS administrated via i.v. infusion each 10 days; Trt = effect of treatment; Time = effect of sampling time; Trt × Time = effect of treatment by sampling time