Nutrient digestion, ruminal fermentation and performance of dairy cows fed pomegranate peel extract

Abstract

An experiment was carried out to determine the effect of pomegranate peel extract (PPE) on nutrient digestion, ruminal fermentation characteristics, protozoal population and performance of dairy cows. Four Holstein cows were used in a 4×4 Latin square design with 28-d periods and 4 treatments: PPE0 (no extract), PPE400 (400 ml PPE/cow/d), PPE800 (800 ml PPE/cow/d) and PPE1200 (1200 ml PPE/cow/d). Intake of dry matter, milk yield, and digestibility of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were measured. Ruminal fermentation characteristics such as ruminal pH, concentration of NH3–N, concentration of VFA, molar proportions of individual VFA, protozoa population and microbial N were also measured. Milk production, 4% FCM yield, milk fat and protein yield (kg/d), and milk efficiency were increased by inclusion of PPE800 in the diet. Percent of milk fat, true protein, and lactose were not affected by PPE supplementation. However, inclusion of PPE decreased NH3–N, total protozoal population, genus Isotricha and Entodinium, but increased microbial N production (g/d). Concentrations of total VFA and molar proportions of individual VFA were not affected by inclusion of PPE in the diet. The results suggested that PPE supplementation has reduced protozoa population, NH3-Nconcentration, and increased microbial protein and milk yield and quality.