This study was conducted to investigate effects of inorganic and organic sulfur supplements on cashmere growth and their differences. Thirty-six six-month-old female Liaoning cashmere goats with a body weight of approximately 25 kg and good health were randomly assigned to three treatments: control, ZnSO4 and HMBi (2-hydroxy-4-(methylthio) butyric acid isopropyl ester). The three groups were fed a basal diet, a ZnSO4 diet (supplemented with 0.63% ZnSO4.H2O) and an HMBi diet (supplemented with 1.27% HMBi), respectively. Blood and cashmere samples were collected at the end of the three-month experimental period. The plasma concentrations of total protein, urea nitrogen, ammonia and amino acids; the cashmere content of amino acids and sulfur contents; the cashmere growth rates; and the diameter of the cashmere fibres were determined. The results indicated that dietary supplementation with ZnSO4 or HMBi can decrease the plasma urea nitrogen concentration and increase concentrations of total protein and methionine in plasma. In addition, the two types of sulfur supplements appeared to increase the methionine, cysteine and sulfur contents in cashmere fibres. Furthermore, the supplements can accelerate cashmere growth, with no significant effect on cashmere fineness. The promotion of cashmere growth probably stems from the improvement in the protein metabolic balance, sulfur retention and sulfur-containing amino acids synthesis in cashmere goats following the ZnSO4 or HMBi supplementation. In general, the ZnSO4 supplement promotes greater cashmere growth than the HMBi supplement under the experimental conditions.
2-hydroxy-4-(methylthio) butyric acid isopropyl ester; amino acid; cashmere growth rate; sulfur; ZnSO4
