Effect of coffee grounds in the diet of sheep on digestion and digestibility of nutrients

The studies were conducted at the experimental yard of the L.K. Ernst Federal Research Center for Animal Husbandry on Katahdin sheep with chronic Basov's rumen fistulas, which were used as a model for ruminants. The chemical analysis of the coffee grounds revealed its low nutritional value, with a crude fiber content of approximately 34%, a crude protein content of less than 8%, and a crude fat content of over 11%. In the diet of the experimental group of sheep, the grounds were included in the amount of 90 grams per head per day, which was 20.5% of the replacement of compound feed. It was found that the introduction of coffee grounds in the diet of sheep did not have a negative effect on the consumption of nutrients in the diet, on dry matter (+1.3%), on fat (+20.2%), on fiber (+14.8%), while the difference in crude protein by 2.3% was in favor of the animals of the control group. The higher fat and fiber content in the coffee grounds resulted in better consumption, with a 20.2% (p<0.001) and 14.8% (p<0.01) increase, respectively. There was no significant difference in nutrient digestibility between the groups. The analysis of ruminal metabolism showed a higher content of volatile fatty acids in the experimental group, which may be due to the higher fat content in the grounds. However, the amylolytic activity was 8.8% lower compared to the control group. There was also a decrease in the total microbial mass in the rumen of the experimental group animals, compared to the control, by 13% after 3 hours and by 16 % after 5 hours. This may be caused by antinutrients or fatty acids in the grounds. The latter can be a source of energy, and if there is an excess, it can have a negative impact on the digestive and metabolic processes in the animal's body. To fully assess the use of coffee grounds, it is recommended to conduct additional studies with long-term feeding.