Effects of spent coffee grounds on production traits, haematological parameters, and antioxidant activity of blood and milk in dairy goats

Abstract

Spent coffee ground (SCG) is a byproduct of coffee beverage preparation and a potential source of carbohydrate, protein, and phenolic compounds for livestock feeding. In this study, the effects of SCG supplementation in the diet of lactating goats on milk production traits and health status were studied. The antioxidant status of blood and milk was also evaluated. Twenty-four Saanen goats were fed a total mixed ration containing commercial concentrate, soybean, and haylage; they were divided into three groups: control diet (CON), SCG50 (50 g/d SCG), and SCG100 (100 g/d SCG). The experiment lasted 6 weeks. Linear and quadratic contrasts were used to evaluate the effects of the byproduct doses. SCG supplementation did not affect milk production, but influenced some milk fatty acids. SCG supplementation increased the contents of C18:1, cis-9, trans-11 C18:2, odd and branched-chain fatty acids, and total conjugated linoleic acid. Most of the haematological and biochemical parameters were within the physiological range for goats. The basophil, eosinophil, and glucose contents were quadratically affected by SCG, whereas platelet count increased linearly with the SCG dose. The SCG supplementation had a positive effect on the blood antioxidant status, as evidenced by an increase in ferric reducing antioxidant power and a decrease in malondialdehyde. The SCG supplementation had no effect on the milk antioxidant status. The results show that SCG (up to 100 g/d) did not negatively affect milk production and health status in goats. However, quadratic effects on some antioxidant and biochemical parameters suggest that further investigations are necessary, especially with regard to the optimisation of the supplement dose.