It is known that dietary supplementation of 0.2% - 0.3% of ZnO alleviates intestinal villus atrophy and anorexia in weanling piglets. However, dietary ZnO is mostly excreted unabsorbed into the environment in feces contributing to environmental pollution. A new ZnO compost is encapsulated with lipid to prevent ionization of the mineral due to the acidic gastric juice in the stomach thereby maximizing the delivery of ZnO to the intestine where it is supposedly released upon digestion of the lipid capsule by lipase. The experiment was performed to investigate the effects of a lipid-encapsulated ZnO product on growth, intestinal morphology, and digestive enzyme activities in piglets. A total of 408 (Yorkshire x Landrace) x Duroc, 21-day-old weanling pigs were allotted by sex and body weight to 12 pens, with 34 animals per pen, in a randomized complete block design. The experimental treatments were: 1) ZnO-free basal diet supplemented with 125 mg ZnO (100mg Zn)/kg (ZnO-100), 2) 3125 mg ZnO/kg (ZnO-2500), or 3) 139 mg of lipid-encapsulated Zn (100 mg Zn)/kg (Encapsulated Zn-100); for 14 days, after which 24 animals were killed for examination blood and tissue samples obtained from the heart and intestinal segments corresponding to the duodenum, jejunum, and ileum.
The average daily gain of the Encapsulated Zn-100 group was greater (P<0.01) than that ZnO-100 group, but was less (P<0.01) than that of the ZnO-2500 group. The average daily feed intake was less in the Encapsulated Zn-100 than in the Zn-2500 group (P<0.01). The gain:feed ratio was not affected by the treatment. The fecal consistency (diarrhea) score was greater in the Encapsulated Zn-100 and ZnO-100 groups vs. ZnO-2500 group (P<0.01). Hepatic and circulating Zn concentrations were less (P<0.01) in the Encapsulated Zn-100 and ZnO-100 groups vs. ZnO-2500, not being different between the former two groups. The villus height, crypt depth and villus height:crypt depth ratio in the duodenum, jejunum, and ileum as well as specific activities of enzymes in were not influenced by the dietary treatment.
In conclusion, the present results indicate that supplementation of Encapsulated Zn at a physiological level is superior to that of native ZnO at the same level in supporting weight gain of weanling pigs.
Park, B.C., Jung, D.Y., Kang, S.Y., Ko, Y.H., Ha, D.M., Kwon, C.H., Park, M.J., Han, J.H., Jang, I. and Lee C.Y. 2015. Effects of dietary supplementation of a zinc oxide product encapsulated with lipid on growth performance, intestinal morphology, and digestive enzyme activities in weanling pigs. Journal of Animal Feed Science and Technology, 200; 112-117. doi:10.1016/j.anifeedsci.2014.11.016