The Growth-promoting Effect of Tetrabasic Zinc Chloride is Associated with Elevated Concentration of Growth Hormone and Ghrelin

Abstract

An experiment was conducted to investigate the mechanism for the effect of tetrabasic zinc chloride (TBZC) in enhancing growth performance of weanling piglets. Gut-brain peptides play an important role in the regulation of growth and appetite in animals. This study evaluated the effects of TBZC on blood concentrations of growth hormone (GH), ghrelin, insulin-like growth factor-I (IGF-I), cholecystokinin (CCK) and neuropeptide Y (NPY). Seventy-two weanling piglets (Landrace×Large White) with an initial body weight (BW) of 6.7±0.16 kg and aged 24±1 days were assigned to three dietary treatments: i) control diet without TBZC supplement, ii) the control diet supplemented with 2,000 mg Zn from TBZC/kg and iii) TBZC-supplemented diet pair-fed with respect to the control diet. Each treatment had six replications (pens) of four piglets. At the end of a 14-d experimental period, piglets were weighed and feed consumption was measured, and blood samples were collected for assays of GH, ghrelin, IGF-I, CCK and NPY concentrations. The inclusion of TBZC in the diet increased average daily gain (p<0.01), average daily feed intake (p<0.05), and feed conversion ratio (p<0.05). Pair-fed piglets had higher ADG, and lower FCR than (p<0.05) Control piglets. Supplementation of the diet with TBZC increased (p<0.05) serum GH and plasma ghrelin levels in weanling piglets, but did not affect (p>0.05) serum IGF-I and plasma NPY and CCK concentrations. Pair-fed piglets had lower (p<0.05) serum GH levels than TBZC-supplemented piglets, but did not (p>0.05) differ from Control piglets. These data indicated that TBZC elevated the concentration of ghrelin and GH. This observation may partly explain the beneficial effects of TBZC on growth performance of weanling piglets.

Effects of Tetrabasic Zinc Chloride on Growth Performance, Nutrient Digestibility and Fecal Microbial Community in Weaned Piglets

“…These results suggested that 1,600 mg/kg ZnO may not be sufficient to improve the growth performance and health status of weaned piglets. Additionally, serum GH and IGF-I levels were significantly increased in TBZC group, which was partially agreed with Zhang and Guo ( 25 ) that the levels of serum GH and Ghrelin were improved when 2,000 mg Zn/kg from TBZC was fed to piglets. Therefore, compared with traditional ZnO, TBZC can improve the growth performance of piglets with a lower dose.…”

“…TBZC has been shown to reduce intestinal permeability and improve mucosal barrier function ( 9 ). Dietary TBZC supplementation also involved in stimulating the secretion of ghrelin and growth hormone, thereby promoting muscle protein synthesis and cell proliferation ( 25 ).…”

Determination of the Optimal Level of Dietary Zinc for Newly Weaned Pigs: A Dose-Response Study

“…Reynolds et al [ 52 ] found that, when pigs weaned at day 28 were given the choice between a Zn unsupplemented diet and a diet supplemented with 3100 mg Zn/kg (as ZnO), up to 91 % of the total feed consumption was of the unsupplemented diet. Zhang and Guo [ 53 ] and Yin et al [ 54 ] found a higher concentration of circulating ghrelin in pigs (24–28 days of age) fed a 2000 mg Zn/kg diet compared to a 100–130 mg Zn/kg diet. Ghrelin secreted from enteroendocrine cells of the gastrointestinal tract is involved in appetite regulation, and increased ghrelin secretion stimulates appetite [ 55 ].…”

Supplemental zinc reduced intestinal permeability by enhancing occludin and zonula occludens protein-1 (ZO-1) expression in weaning piglets

“…TBZC or ZnO replaced wheat bran in the diet. The experiment lasted 14 d. Hahn & Baker ( 2 ) showed that ZnO can improve the daily gain of weaning pigs, while our previous studies demonstrated similar effects of ZnO and TBZC on the performance of weaning pigs ( 5 , 6 ) . Therefore, ZnO and TBZC were selected as two dietary Zn sources in the present study.…”