Influence of different dietary zinc levels on cashmere growth, plasma testosterone level and zinc status in male Liaoning Cashmere goats

Abstract

The experiment was conducted to investigate the influence of different levels of zinc (Zn) on cashmere growth, plasma testosterone and Zn profile in male Cashmere goats. Twenty-eight male Liaoning Cashmere goats, 3 years old and body weight at 56.2 ± 2.45 kg, were assigned to four groups. The animals were fed a basal diet containing of 45.9 mg Zn/kg dry matter (DM) basis and supplemented with 0, 20, 40 or 80 mg Zn (reagent grade ZnSO₄ ·7H₂ O) per kg DM for 90 days. There was no significant effect on growth and diameter of cashmere fibre for Zn supplemented in diets. However, the length and growth rate of wool were improved (p < 0.05) with dietary Zn. The length and growth rate of wool were higher (p < 0.05) for the groups supplemented with 40 or 80 mg Zn/kg DM compared with that of 20 mg Zn/kg DM treatment group. Plasma testosterone concentration was increased for Zn supplemented in diets, and the testosterone concentration was higher (p < 0.05) in goats fed on the diet supplemented with 40 or 80 mg Zn/kg DM compared with those fed on basal diet. Plasma Zn concentrations increased (p < 0.05) with increasing dietary Zn and supplemented with 40 and 80 mg Zn/kg DM groups improved plasma Zn concentration (p < 0.05) more than 20 mg Zn/kg DM group. Fibre Zn content was higher (p < 0.05) in groups supplemented with 40 or 80 mg Zn/kg DM compared with control group, but no difference between Zn-supplemented groups (p > 0.05). The activity of plasma alkaline phosphatase was increased (p < 0.05) due to dietary Zn supplementation; however, no difference was found between supplemented treatment groups (p > 0.05). In conclusion, Zn content (45.9 mg Zn/kg DM) in control diet was insufficient for optimal wool growth performance, and we recommended the level of dietary Zn for such goats is 86 mg/kg DM during the breeding season and cashmere fibre growing period.

Effect of Different Sources of Supplemental Zinc on Performance, Nutrient Digestibility, and Antioxidant Enzyme Activities in Lambs

“…The lower ALP activity of the control lambs is consistent with the study of Cho et al [49] who reported decreased ALP activity in Zn-deficient animals. The present results are also in agreement with Liu et al [50] who observed a significant increase in ALP activity due to dietary Zn in goats fed a basal diet (containing 45.9 mg Zn/kg) supplemented with 20, 40, or 80 mg Zn/kg. Similarly, Kumar et al [51] observed a significant increase in ALP activity attributed to dietary Zn in bulls fed a basal diet (containing 32.5 mg Zn/kg) supplemented with 35 or 70 mg Zn/kg.…”

Study on minerals status of dairy cows and their supplementation through area specific mineral mixture in the state of Jharkhand

“…When compared with critical levels for Cu (<10 ppm) and Zn (<100 ppm), 50 and 100% cows showed sub-normal levels in hair samples indicating their dietary deficiency. It has been demonstrated in several studies that concentration of Zn in hair is correlated with dietary Zn intake [35, 36]. Studies have shown the level of Zn in hair on normal diet to be 120–150 ppm in dairy cows [1].…”

Low serum zinc concentration is associated with low serum testosterone but not erectile function

“…One study with goats showed that serum testosterone concentration was increased by zinc intake in the goats' diet for 90 days, and the testosterone concentration was higher in the goats fed the diet supplemented with zinc compared with those fed a basal diet. 23 In humans, a study of hemodialyzed men with low serum zinc concentration and low sexual function showed dialytic administration of zinc increased serum testosterone concentration. 24 A double-blind study with hemodialyzed men also showed that intake of 50 mg of zinc per day for 6 months significantly increased serum concentrations of both testosterone and zinc in men in the zinc-treated group but not in those receiving a placebo.…”

“…There have also been several studies regarding the effect of zinc intake on testosterone production. One study with goats showed that serum testosterone concentration was increased by zinc intake in the goats' diet for 90 days, and the testosterone concentration was higher in the goats fed the diet supplemented with zinc compared with those fed a basal diet 23 . In humans, a study of hemodialyzed men with low serum zinc concentration and low sexual function showed dialytic administration of zinc increased serum testosterone concentration 24 .…”