Effects of chokeberry pomace supplementation on biochemical, metabolic and antioxidant parameters in high-yielding dairy goats

In recent years, there has been growing interest in the use of natural feed additives with health-promoting properties in the nutrition of ruminants. A prominent example is black chokeberry (Aronia melanocarpa), a plant with exceptionally high antioxidant potential, rich in polyphenols, anthocyanins, flavonoids and vitamins (10). Poland is one of the leading global producers of chokeberry, and has exploitable processing by-products, such as dried pomace, which may serve as a valuable source of bioactive compounds in animal feeding.

Previous studies conducted in both animal models and human populations have demonstrated that chokeberry may have beneficial effects on liver function, lipid metabolism, metabolic parameters and redox-inflammatory homeostasis (5, 14, 21, 24). Because of their intensive milk production and high metabolic activity, high-yielding dairy goats are particularly susceptible to oxidative stress (21) and dysfunction of parenchymal organs and biochemical imbalances (17). The inclusion of natural plant-based supplements in their diet may support physiological functions, improve animal welfare and enhance milk quality. Despite the health-promoting properties of chokeberry being well documented, its effects on the physiology of high-yielding dairy goats have not yet been shown in exhaustive scientific data. High-producing dairy goats represent a rarely used, yet valuable model for evaluating the effects of antioxidant supplementation because of their intensive metabolic turnover and the physiological demands on them during lactation.

The aim of this study was to assess the effect of dietary supplementation with dried chokeberry pomace at two different doses on selected blood biochemical parameters in high-yielding dairy goats. The analysis included indicators of liver, kidney and muscle function; lipid profile; carbohydrate and energy metabolism (glucose and lactate); concentrations of selected macro- and microelements; enzymatic activity (aminopeptidases and lysosomal enzymes); and oxidative stress markers. Correlation analysis among these parameters was also performed to identify potential mechanisms of action of chokeberry bioactive compounds.

Dietary supplementation with natural antioxidants, such as the polyphenols found in chokeberries, is receiving increasing attention as a means of improving metabolic health and organ function in farm animals (18, 21). Lactation is a physiologically demanding period associated with enhanced oxidative stress. Effective strategies are being sought to mitigate the effects of this stress, including supplementation with natural antioxidants. Because of its strong antioxidant properties, chokeberry may help reduce oxidative stress and improve liver and kidney function, as well as the regulation of lipid, sugar and protein metabolism. Since research into the effects of chokeberry supplementation in high-yielding dairy goats is still nascent, this study sought to extend knowledge of the potential benefits of this feed additive. Despite their growing importance in milk production, the dairy goat is rarely included in studies of functional nutrition and oxidative stress. Their high metabolic activity and physiological burden during lactation make them an especially valuable model for assessing the effects of antioxidant supplementation. Transcriptional pathways related to antioxidation may be mechanisms of chokeberry bioactive action. The literature indicates that polyphenols, including anthocyanins in chokeberries, can activate nuclear factor erythroid 2-related factor 2 and modulate the expression of inflammatory cytokines such as interleukin 6 (IL-6) and tumour necrosis factor α (TNF-α) (1, 7). These mechanisms may partly explain the observed increases in GSH concentrations and activity of lysosomal and antioxidant enzymes in this study, which are consistent with previous findings on aronia supplementation (14).

Supplementation, particularly in group A2, favourably influenced metabolic and antioxidant parameters, including liver function and repair mechanisms. This suggested a hepatoprotective effect and was further supported by the significant decrease in LDH activity in this group. This reduction may have indicated a protective effect of chokeberry against cellular damage, likely due to reduced oxidative stress. Strong negative correlations with GSH and DPPH confirmed LDH’s relationship with redox balance. Positive correlations of LDH with ALT, AST and BILT suggested a link to liver function, while the correlation with CHOL reflected lipid metabolism. Together, these findings supported the hypothesis that chokeberry reduces cellular damage by improving antioxidant status and stabilising metabolic function. The significant reduction in GGT activity, particularly in group A2, suggested a hepatoprotective and potentially anti-inflammatory effect of chokeberry. Although AST, ALT, and ALP did not change significantly in this group, their overall trends supported this interpretation. These results were consistent with findings from other animal models. Chen et al. (6) documented the hepatoprotective effects of chokeberry anthocyanins on the lipid and inflammatory metabolisms in mice, while such effects under oxidative stress were shown in the liver in a cadmium-exposed rat model (14). Renoprotective effects were also reported in a murine ischemia-reperfusion model (11). Chokeberry supplementation may improve lipid metabolism, thermogenesis and gut microbiota composition through the action of polyphenols, as demonstrated in diet-induced obese rats (25). This report would not be inconsistent with improved metabolic efficiency as possibly indicated by the observed reduction in lipase activity in this study.

These findings are also consistent with previous observations from the same animals, in which chokeberry supplementation improved milk quality by increasing antioxidant enzyme activity and polyphenol content, while reducing milk fat levels (21). When considered together with the present results concerning liver, kidney, and oxidative stress markers, this supports the hypothesis of a systemic, multi-organ effect of chokeberry bioactives. In this context, the decline in cholinesterase (CHE) activity observed in the control group may reflect the physiological burden of lactation. However, its stability in the higher-dose group (A2), along with its positive correlations with key metabolic and antioxidant parameters, highlights CHE as a potential marker of systemic homeostasis and further supports the protective effect of chokeberry supplementation.

In the control group, a decrease in ALB, CK and CHE activity was observed, which could be assumed to reflect the physiological burden of lactation and increased oxidative stress. In contrast, the increase in CK activity observed in group A2 may have indicated enhanced muscle metabolism in response to supplementation. The absence of CHE reduction in group A2 further supported the potential protective effect of chokeberry, particularly in maintaining liver function. Albumin, a carrier of thiol groups, neutralises free radicals, and its concentrations correlated with hepatic, lipid and antioxidant parameters in this study, as previously reported in transcriptomic studies on periparturient goats (4, 9). Importantly, the correlation analyses in this study excluded the control group. Physiological changes in this group, associated with lactation, could have introduced artefacts. Excluding the control allowed a more accurate assessment of relationships between parameters in response to chokeberry supplementation.

In the higher-dose group (A2), the lipid profile improved, as indicated by reductions in total cholesterol, LDL, and triglycerides, along with an increase in HDL. These results are consistent with previous findings from experimental animal models, where chokeberry polyphenols have been shown to exert hypolipidemic effects. In rats with diet-induced hyperlipidaemia, administration of chokeberry juice significantly reduced total cholesterol, LDL, and triglycerides (22). Similarly, in streptozotocin-induced diabetic rats, chokeberry supplementation led to a 35–39% decrease in triglyceride levels and normalisation of lipid parameters (19). Correlations of CHOL with liver and antioxidant parameters further support the systemic action of chokeberry. This effect may be partially mediated by modulation of gut microbiota, a system shown to modulate lipid metabolism and oxidative status in response to chokeberry intake (25).

A statistically significant increase in CK activity was observed only in group A2 (P-value < 0.001), whereas a significant decrease occurred in the control group. In group A1, CK levels also declined, although not significantly. These results suggest that the higher dose of chokeberry may enhance metabolic and muscle activity, while the lack of increase in group A1 may indicate a threshold for minimal biological efficacy. Similar findings were reported by Yun et al. (23) in young mice supplemented with Aronia melanocarpa extract, which enhanced skeletal muscle metabolism and upregulated the expression of myogenic differentiation markers. However, the interpretation of these changes should consider the potential increase in serum creatinine as a possible indicator of renal burden. Supporting this, Li et al. (11) demonstrated that anthocyanins extracted from Aronia melanocarpa alleviated kidney injury in a murine ischemia–reperfusion model, significantly reducing serum creatinine and the levels of proinflammatory cytokines such as TNF-α and IL-6. The correlations observed between CK and antioxidant parameters in the present study further support the hypothesis of a systemic, multi-organ effect of chokeberry bioactives.

The lack of changes in GLU concentrations suggests that chokeberry did not directly affect carbohydrate metabolism. The observed moderate positive correlation between glucose and calcium may indicate shared regulatory pathways involving insulin secretion, glycolytic enzyme activity, or calcium-dependent signalling influenced by gut microbiota interactions. The literature suggested that chokeberry may have affected host metabolic pathways, including glucose regulation, through gut microbiota-derived short-chain fatty acids (24).

The significant increase in iron concentrations observed in groups A1 and A2 may reflect improved bioavailability or mobilisation in response to chokeberry supplementation. This effect could be linked to the antioxidant and anti-inflammatory properties of chokeberry polyphenols, which have been reported to modulate iron homeostasis indirectly (1, 7). Conversely, the significant reduction in magnesium concentrations across all groups, including the control, likely reflects the physiological burden of lactation and the increased metabolic demands during the peripartum period (4, 9). These mineral fluctuations highlight the complex metabolic changes occurring during lactation and the potential modulating effects of chokeberry supplementation.

The observed positive correlations of LACT with TRIG and α-GLU activity may have indicated concurrent carbohydrate and lipid metabolism associated with anaerobic metabolism. This may have reflected increased enzymatic activity and metabolic adaptation to the energy demands of lactation. The overall decrease in lactate concentrations across all groups, especially in those supplemented with chokeberry, could be interpreted as a sign of improved metabolic balance, greater oxygen efficiency, and reduced metabolic stress. This finding aligned with the concurrent increase in antioxidant parameters such as GSH and DPPH, suggesting a beneficial effect of chokeberry on cellular metabolism and reduced reliance on anaerobic glycolysis. The presence of consolidated positive correlations among lysosomal enzymes possibly manifested a coordinated metabolic response to lactation-induced oxidative stress which was supported by chokeberry supplementation.

The review by González-Gallego et al. (8) highlights the immunomodulatory and anti-inflammatory potential of flavonoids, including those derived from fruits such as chokeberry. In this context, changes in aminopeptidase activity (e.g. AlaAP, LeuAP and ArgAP) observed following chokeberry supplementation may reflect alterations in protein metabolism and immune function.

Chokeberry significantly affected lysosomal enzyme activity (ACP, β-GAL, β-GLU and HEX), enhancing catabolic and antioxidant potential. While these specific enzyme changes were not examined by Pei et al. (16), their findings in a T cell-transfer colitis model supported the anti-inflammatory and antioxidant properties of chokeberry in intestinal inflammation. The suppressive effect on α-glucosidase may be indirectly supported by data from Lim et al. (12), who reported a hypoglycaemic effect of chokeberry extract in a high-fat diet model; the effect may be at enzymatic level and be inhibition of carbohydrate digestion and absorption. Although inhibition of α-GLU was not directly assessed, the findings suggest metabolic benefits relevant to carbohydrate digestion and insulin regulation. The inhibitory effect on α-GLU did not result in altered blood GLU levels in the studied animals, possibly because of their physiological metabolic equilibrium. In conditions of impaired GLU homeostasis, such as insulin resistance or high carbohydrate diets, the effect might be more pronounced.

The observed increase in glutathione, polyphenol and vitamin C concentrations, along with enhanced DPPH radical scavenging activity – particularly in group A2 – confirmed the effectiveness of chokeberry in boosting the organism’s antioxidant capacity. The increase in polyphenol concentrations was significant only in group A2 (P-value = 0.013), suggesting a dose-dependent accumulation of phenolic compounds in serum. The absence of changes in group A1 possibly reflected lower bioavailability or higher metabolism at a lower intake. The correlations of these parameters with lysosomal enzyme activity suggested that chokeberry acted both through direct radical scavenging and by supporting enzymatic defence mechanisms. Additional correlations of polyphenols with HDL and ACP, as well as DPPH with CHE and calcium, further supported the systemic nature of the antioxidant effect, linking chokeberry supplementation to improved lipid metabolism, lysosomal function, and mineral balance.

This study assessed a wide panel of physiological, biochemical, and enzymatic parameters to evaluate the effects of chokeberry on key aspects of metabolic function. Although gene expression and cytokine analyses were not included, the results provided a comprehensive overview of the systemic action of chokeberry bioactives. The selection of indicators was tailored to a livestock animal model, considering their relevance in production and nutritional contexts. Future studies should incorporate molecular and proteomic analyses to better understand the mechanisms of chokeberry action, particularly in relation to oxidative, inflammatory and metabolic gene expression. Additionally, the effect of chokeberry on gut microbiota composition and activity should be investigated, as recent reports suggested it may mediate the systemic effects of polyphenols. These findings underscore the need for further research into the molecular mechanisms of chokeberry in the context of intensive animal production systems.

Dietary supplementation of dairy goats with dried black chokeberry (Aronia melanocarpa) pomace, particularly at the higher dose, elicited beneficial effects on metabolic parameters, enzymatic activity and antioxidant capacity. The observed changes indicate a systemic action of chokeberry bioactive compounds, supporting physiological homeostasis during lactation. These findings support the rationale for using chokeberry as a natural feed additive in the nutrition of high-yielding dairy goats, with potential implications for improved animal health and the quality of dairy products.