Effect of hydrolysable tannins on intestinal morphology, proliferation and apoptosis in entire male pigs

ABSTRACT

This study aimed to evaluate the effect of hydrolysable tannin supplementation on morphology, cell proliferation and apoptosis in the intestine and liver of fattening boars. A total of 24 boars (Landrace × Large white) were assigned to four treatment groups: Control (fed commercial feed mixture) and three experimental groups fed the same diet supplemented with 1%, 2% and 3% of hydrolysable tannin-rich extract. Animals were housed individually with ad libitum access to feed and then slaughtered at 193 d of age and 122 ± 10 kg body weight. Diets supplemented with hydrolysable tannin affected the morphometric traits of the duodenum mucosa as reflected in increased villus height, villus perimeter and mucosal thickness. No effect was observed on other parts of the small intestine. In the large intestine, tannin supplementation reduced mitosis (in the caecum and descending colon) and apoptosis (in the caecum, ascending and descending colon). No detrimental effect of tannin supplementation on liver tissue was observed. The present findings suggest that supplementing boars with hydrolysable tannins at concentrations tested in this experiment has no unfavourable effects on intestinal morphology. On the contrary, it may alter cell debris production in the large intestine and thus reduce intestinal skatole production.

KEYWORDS:

• Apoptosis
• cell proliferation
• intestines
• morphometrics
• pigs
• tannins

Acknowledgements

The authors particularly thank Prof. Dr Milka Vrecl-Fazarinc and MSc Maksimiljan Brus for useful comments. They also thank the technical assistance of the Institute of Anatomy, Histology and Embryology at the Veterinary Faculty, University of Ljubljana. Finally, the authors thank the anonymous reviewers for helpful suggestions. Preliminary results were partly presented as an abstract at the Annual Meeting of the European Federation of Animal Science in Session: Role of Plant Bioactive Compounds in Animal Nutrition in Warsaw, Poland 31 August to 4 September 2015.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors acknowledge the financial support of the Slovenian Research Agency [Project L4-5521, core financing through programmes P1-0164, P4-0133 and P4-0053] and the Ministry of Agriculture, Forestry and Food of Republic Slovenia. Diana Bilić-Šobot was supported by a doctoral fellowship from JoinEU-SEE IV ERASMUS MUNDUS Action 2.