Replacing Inorganic Source of Zinc with Zinc Hydroxy Chloride: Effects on Health Status, Hemato-biochemical Attributes, Antioxidant Status, and Immune Responses in Pre-ruminant Crossbred Calves.

Abstract

The current research aimed to assess the feasibility of using Zn hydroxy chloride (ZnOHCl) as an alternative to ZnSO₄ in pre-ruminant crossbred calves. Twenty-four male crossbred calves (Tharparkar × Holstein Friesian) were categorized into four groups according to body weight and age (body weight 31 kg; age 10 days). Experimental calves were kept on a similar feeding regimen except that different groups were supplemented with either 0 mg Zn/kg DMI (Zn-0), 80 mg Zn/kg DMI as ZnSO₄ (ZnS-80), 40 mg Zn/kg DMI as ZnOHCl (ZnH-40), or 80 mg Zn/kg DMI as ZnOHCl (ZnH-80). All the calves were fed for 90 days as per ICAR (2013) feeding standard to fulfill their nutrient requirements for growth rate of 500 g/day. The study observed the influence of different sources and varying levels of Zn supplementation over a 90-day experimental period on health status, hemato-biochemical attributes, antioxidant status, immune responses, and plasma minerals and erythrocyte Zn concentrations. The data was examined using a randomized complete block design (RCBD) with fixed effects of treatment, period, and their interaction. The results indicated that irrespective of the sources and levels of Zn, supplementation did not lead to significant changes in health status as assessed by fecal score, nasal score, ear score, and eye score. Hematological parameters remained unchanged following supplementation with different sources and levels of Zn. Zn-supplemented groups showed higher levels of total protein, globulin, and alkaline phosphates (ALP) compared to the non-supplemented group. However, no significant variations were detected within the Zn-supplemented groups. Zinc supplementation significantly increased total antioxidant capacity (TAC), antioxidant enzyme activity, total immunoglobulin (Ig), immunoglobulin G (IgG), cell-mediated immunity (CMI), and humoral immunity (HI); however, no significant variations were detected among Zn-supplemented groups. Zn supplementation enhanced plasma and RBC Zn concentration without affecting the plasma concentration of other minerals. However, among the Zn-supplemented groups, 80 mg Zn/kg DMI as ZnOHCl resulted in the highest RBC Zn concentration. The study results demonstrate that Zn supplementation enhanced biomarkers of zinc status, antioxidant levels, and immune responses in pre-ruminant crossbred calves. Nevertheless, no significant variations were observed between the different Zn sources (ZnSO₄ and ZnOHCl) utilized in this study. Research suggests that ZnOHCl could be a feasible alternative to ZnSO₄ in the diet of pre-ruminant crossbred calves.