Comparative effects of diet on inflammatory responses of subcutaneous and visceral adipose tissue and liver in ponies and horses
Final Report Abstract
Two years of excessive energy intake did not induce an overall higher expression of selected proinflammatory cytokines in AT or liver in equines. Nevertheless, pro-inflammatory cytokine expression was higher in subcutaneous AT such as neck or tail head than in abdominal AT. Interestingly, hepatic metabolism revealed some differences in selected pro-inflammatory parameters and lipid metabolism between ponies and horses after two years of BW gain. These results may explain in part the greater susceptibility of ponies to obesity-associated metabolic dysregulations. However, the degree of obesity might be too low to induce adiposity related tissue inflammation. On the other hand, a low grade of inflammation which has been reported in human adiposity might be of less importance in equines. This is supported by the two individuals who developed an episode of laminitis in the second year of excessive energy intake. The two individuals revealed an impaired insulin regulation but pro-inflammatory parameters in AT and liver except for CD68 expression in the abdominal AT were within the range of the study population which did not develop insulin resistance or laminitis. Beside the well-known pro-inflammatory markers, hepatic chemerin mRNA expression has been identified as a potentially novel marker of metabolic changes associated with obesity in equines. From the present data it remains open whether chemerin has pro- or anti-inflammatory properties. Relative voluntary feed intake was higher in ponies than in horses in the second year of excessive energy intake. Beside leptin, the control of appetite might be linked to bacterial fermentation products such as acetate and entero-hormones such as ghrelin. For future studies, the link between the microbiota in the course of excessive energy intake and the impact of bacterial fermentation products such as SCFAs on metabolism needs further elucidation in equines. However, to study this issue, the main limitation of analyzing the microbiota in the feces must be overcome as fecal microbiota only represents the distal part of the equine’s hindgut.
Publications
- Effects of body weight gain on insulin and lipid metabolism in equines. Domestic Animal Endocrinology, 2019 Jul;68:111-118
Blaue, D., Schedlbauer, C., Starzonek, J., Gittel, C., Brehm, W., Einspanier, A., Vervuert I.
(See online at https://doi.org/10.1016/j.domaniend.2019.01.003) - Impact of body weight gain on hepatic metabolism and hepatic inflammatory cytokines in comparison of Shetland pony geldings and Warmblood horse geldings. PeerJ. 2019 Jun 7;7:e7069
Schedlbauer, C. Blaue, D., Gericke, M., Blüher, M., Starzonek, J., Gittel, C., Brehm, W., Vervuert, I.
(See online at https://doi.org/10.7717/peerj.7069) - Lipid classes in adipose tissues and liver differ between Shetland ponies and Warmblood horses. 2019 Mar 21;14(3):e0207568
Adolph, S., Schedlbauer, C., Blaue, D., Schöniger, A., Gittel, C., Brehm, W., Fuhrmann, H., Vervuert, I.
(See online at https://doi.org/10.1371/journal.pone.0207568)
