# Effects of Tetrabasic Zinc Chloride as Alternative to High Doses of Zinc Oxide on Growth Performance, Nutrient Digestibility, Intestinal Morphology, Immune Function, and Gut Microbiota in Weaned Piglets

## TL;DR

This study shows that tetrabasic zinc chloride improves piglet growth and gut health better than traditional zinc oxide.

## Contribution

The study introduces tetrabasic zinc chloride as a safer and more effective zinc source for weaned piglets.

## Key findings

- TBZC improved growth performance and antioxidant capacity in weaned piglets.
- TBZC regulated gut microbiota by promoting beneficial bacteria and inhibiting harmful ones.
- TBZC showed better biosafety and intestinal health benefits compared to zinc oxide.

## Abstract

Zinc, an essential trace element for piglets, has a crucial role in promoting their growth and development, as well as maintaining vital physiological functions. Currently, the prevalent zinc source additives, such as zinc oxide and zinc sulfate, typically exhibit limitations due to their low bioavailability. As a novel zinc source additive, tetrabasic zinc chloride (TBZC) possesses advantages such as relatively high bioavailability, pronounced growth-promoting effects, and superior stability, thus emerging as a potential high-quality alternative zinc source. In this study, TBZC was employed to assess the growth performance, serum indicators, and intestinal health of piglets. The results indicate that a dietary supplementation of 680 mg/kg of TBZC enhances the growth and development of 28-day-old weaned piglets, while also boosting their antioxidant capacity. Furthermore, the TBZC supplementation facilitated the colonization of beneficial bacteria while inhibiting the proliferation of harmful bacteria. The findings from this study reveal that incorporating TBZC into the diet enhances the overall health and intestinal well-being of weaned piglets. While TBZC is widely employed as a trace mineral supplement, its chronic effects on swine health require validation. This study confirms that TBZC exhibits enhanced biosafety over conventional ZnO, with longitudinal trials demonstrating negligible impacts on further growth metrics. TBZC sustains intestinal homeostasis via redox modulation and microbiota regulation, positioning it as a sustainable ZnO alternative for swine production.

This study aimed to investigate the effects of dietary supplementation with TBZC on the growth performance, diarrhea incidence, antioxidant ability, immune function, and intestinal health of weaned piglets. A total of 120 weaned piglets were randomly allocated to one of three dietary treatments with six replicate pens and eight piglets per pen: CON—a basal diet; ZnO—a basal diet with 1500 mg Zn/kg from ZnO; and TBZC—a basal diet with 680 mg Zn/kg from TBZC. Following a 42-day period of consuming the zinc-enriched diet, the piglets were switched to a basal diet for the remaining 28 days of the trial. The dietary TBZC increased the average daily feed intake of weaned piglets (ADFI) from days 1 to 14 and the average daily growth (ADG) from days 43 to 70 compared with the ZnO group (p < 0.05). The supplementation with TBZC decreased the acid-binding capacity compared with the ZnO group (p < 0.05). Moreover, dietary TBZC decreased the MDA concentration and increased the GSH-Px concentration on day 14 and increased the SOD activity on day 28 and the GSH-Px concentration on day 70 compared with the ZnO group (p < 0.05). Compared with the ZnO group, the dietary TBAC supplementation increased (p < 0.05) the relative abundance of cecal Lactobacillus spp. and Blautia spp., while decreasing Blautia spp. in the colonic contents; increased (p < 0.05) the relative abundance of Prevotella spp. and Clostridium_sensu_stricto_1; and reduced (p < 0.05) Streptococcus spp. Therefore, replacing 1500 mg/kg of ZnO with 680 mg/kg of TBZC improves growth performance and antioxidant capacity and regulates gut microbes in weaned piglets.