Nutrition plays an important role in the health of dogs, particularly if they suffer from specific diseases. In fact, based on data available in the literature, targeted dietary recommendations have been established for dogs with cardiac, renal or gastrointestinal disorders, which include dedicated foods that are more digestible due to a reduced or high concentration of particular ingredients or the presence of nutraceuticals, i.e., additives that can provide additional health benefits in addition to nutritional ones.
In particular,nutrition plays a major role in the management of liver disease, which has a significant prevalence in dogs. Since individuals with liver disorders show clinical signs of gastrointestinal dysfunction in most cases, it would be important to understand whether supplementation with nutraceuticals could affect the digestibility of nutrients in food.
Nutraceutical additives are often secondary plant metabolites: one example is silibin, which is extracted from milk thistle and has health-promoting properties, particularly in terms of its protective effects on the liver; however, its impact on nutrient digestibility has not been studied at present.
To expand knowledge on this aspect, a group of researchers from Poznań University of Life Sciences, Poland, conducted a study to test the hypothesis that silibin supplementation improves liver function, without inducing adverse effects on overall health or blood parameters, in healthy dogs. In addition, researchers evaluated the effectiveness of supplementation with a liver protector containing silibin on liver function in dogs with hepatopathy.
The two hypotheses were tested with two separate experiments.
The effects of silibin on healthy dogs
In the first experiment, 18 2-year-old beagle dogs, 9 females and 9 males, were included and divided into 3 groups of 6 subjects each: the control group was fed a normal diet of commercially available dog food, while the other two received the Supplementation of the control diet with pure silibin or a silibin-based hepatoprotectant, both at a dosage of 12.75 mg per 10 kg body weight. Each group followed the treatment for 3 time periods, separated from each other by 12 wash-out days. To evaluate the effect of supplementation on nutrient digestibility and health status of the dogs, stools were collected for 5 days during the diet and blood samples were taken at the end of each treatment period.
Analysis of the samples showed that the treatment did not affect the digestibility of nutrients and dry matter. The only difference noted was in the digestibility of the ether extract, which was slightly higher in dogs in the control group, probably due to a negligible laxative effect or the presence of subclinical gastroenteritis, a rare adverse effect of silybin. No cases of diarrhea or significant changes in fecal composition were observed in the treatment groups. Regarding biochemical parameters, supplementation altered the fatty acid profile, but this had no clinical consequences; in addition, the levels of liver markers (ALT, AST, and GGT) decreased significantly. Hematological parameters remained within the reference ranges, and supplementation had no adverse effects.
Efficacy in dogs with liver disease
In the second experiment, 15 dogs diagnosed with idiopathic liver disorders and treated with thehepatoprotector containing silibin in addition to the normal diet were included: the effects of supplementation on liver function and liver microRNA concentration were evaluated.
The collected data indicated a reduction in the activity of serum markers of liver function (ALT, AST) and the concentration of liver-specific microRNA molecules (mainly miR122) associated with dietary supplementation with hepatoprotector containing silibin. Liver function indices, as a result, improved.
Conclusions
“Our experiments confirmed that silibin, either pure or included in a commercial liver protector, does not interfere with nutrient digestibility and has no adverse effect on the health and metabolism of healthy dogs,” the study authors comment. “In addition,silibin supplementation can be an effective therapeutic tool in dogs with liver disease, as it improves liver function.”
Reference
Gogulski M, Cieślak A, Grabska J, et al. Effects of silybin supplementation on nutrient digestibility, hematological parameters, liver function indices, and liver-specific mi-RNA concentration in dogs. BMC Vet Res. 2021 Jun 26;17(1):228. DOI: 10.1186/s12917-021-02929-3.
