Influence of dietary zinc and copper on digestive enzyme activity and intestinal morphology in weaned pigs1

Abstract

The current study was conducted to investigate the effects of high dietary concentrations of Zn as zinc oxide and Cu as copper sulfate on the activity of digestive enzymes in the pancreas and the intestinal mucosa, intestinal morphology, and mucin histochemistry in pigs after weaning. Thirty-two pigs were weaned at 4 wk of age. The pigs were fed standard weaning diets supplemented with Zn (100 or 2,500 ppm) and Cu (0 or 175 ppm) in a 2 x 2 factorial arrangement of treatments for a 14-d period. In pancreatic tissue, the activity of amylase, carboxypeptidase A, chymotrypsin, trypsin, and lipase increased (P < 0.01) in pigs fed 2,500 ppm of Zn, whereas the activity of carboxypeptidase B and carboxylester hydrolase was unaffected. Copper had no effect on the activity of pancreatic enzymes. In small intestinal contents, the total activity of amylase and carboxypeptidase A was greater in pigs fed 100 ppm of Zn (P < 0.05), whereas feeding 2,500 ppm of Zn increased the chymotrypsin activity (P < 0.001). The remaining enzymes were unaffected by dietary Zn concentration. The villi were longer in the cranial small intestine (P < 0.001) in pigs fed 100 ppm of Zn than in pigs fed 2,500 ppm of Zn, but otherwise there were no clear effects of Zn and Cu supplementation on intestinal morphology. In the cranial small intestine, the activity of maltase (P < 0.001), sucrase (P < 0.001), and lactase was greater in pigs fed 100 ppm of Zn, even though there was a Zn x Cu interaction (P < 0.05) in lactase activity. In the middle and caudal small intestine, no clear differences between dietary treatments were observed. The activity of gamma-glutamyl transpeptidase in the intestinal mucosa was not affected by dietary Zn or Cu. In pigs fed 100 ppm of Zn, the activity of aminopeptidase N was greater in the caudal small intestine, but dietary Zn or Cu had no effect on aminopeptidase N in the cranial and middle small intestine. No effect of dietary Zn or Cu supplementation was found on carbohydrate histochemistry in the caudal small intestine, whereas high dietary Zn increased the area of neutral, acidic, and sulfomucins in the cecum (P < 0.01) and in the colon (P < 0.001). In summary, high dietary Zn increased the activity of several enzymes in the pancreatic tissue and increased the mucin staining area in the large intestine, whereas Cu had no clear effect on these variables. However, no definite answers were found as to how the growth promoting and diarrhea reducing effects of excess dietary Zn are exerted.

Influence of tetrabasic zinc chloride and copper sulphate on growth performance and some physiological parameters in the digestive tract of weanling piglets

“…The discrepancy may be attributed to Zn source and animals used in the experiments. The lack of effect of CuSO 4 on the enzyme activities in this experiment is in agreement with previous reports (Luo and Dove, 1996;Hedemann et al, 2006). Surprisingly, the addition of CuSO 4 to the diet containing 1500 mg Zn/kg TBZC had a negative effect on trypsin activities in duodenal contents and chymotrypsin activities in both pancreatic tissue homogenates and jejunum contents.…”

“…This result is in agreement with Hedemann et al (2006) that feeding 2500 mg/kg Zn from ZnO increased the chymotrypsin activity. After weaning, a reduction in the activity of pancreatic enyzmes had been reported (Owsley et al, 1986).…”

“…The lack of effect of TBZC on the activity of trypsin is contrary to the results obtained in rats where feeding large doses of ZnO resulted in increasing the activity of trypsin in pancreatic tissue as well as intestinal contents (Szabó et al, 2004). However, Hedemann et al (2006) reported that the activity of trypsin in pancreatic tissue homogenates but not small intestinal contents was elevated after feeding a high dietary concentration of ZnO. The discrepancy may be attributed to Zn source and animals used in the experiments.…”

Effects of Supplementation of Ionized or Chelated Water-Soluble Mineral Mixture on the Live Performance, Nutrient Digestibility, Blood Profile, Egg Quality, and Excreta Microbiota of Laying Hens

“…The effect of Zn on the intestinal microflora resembles the mode of action suggested for antibiotic growth promoters (Hojberg et al, 2005). Hedemann et al (2006) reported that feeding pigs the high dietary Zn concentrations mucin secretion in the cecum and colon, perhaps as a consequence of altered microbial activity in the large intestine. In the present study, our results indicate that mineral mixture supplementation led to reduction of E. coli and Salmonella counts compared with the control treatment.…”

Proteína láctea e zinco suplementar em dietas de leitões recém-desmamados

“…Hedemann et al (2006) trabalhado com 2500 ppm de zinco (ZnO) também verificaram maior altura de vilosidades.…”