Effect of flavonoid source on nutrient intake and digestibility, rumen fermentation, growth performance, milk production and endoparasites in ruminant production: a review

The objective of this review was the assessment of the effect of flavonoid sources on nutrient intake and digestibility, rumen fermentation, growth performance, milk production and endoparasites in ruminant production. The increasing human population is creating a greater demand for animal products to meet the protein needs. However, an increase in animal production is likely to force the overuse of synthetic antibiotics, which may intensify drug-resistant pathogens. As a solution, there is a need to discover natural feed additives to improve environmental harmlessness, health and performance in ruminant production. This is because ruminants produce methane and suffer from infections such as gastrointestinal nematodes and mastitis that limit animal performance. Hence, there is a need to identify feed additives that decrease this gas without limiting nutrient utilization and animal performance. Flavonoid dietary inclusion is a potential solution to this challenge in ruminant production and has received research attention. However, there is a preliminary understanding of the effect of inclusion on effectiveness in decreasing methane production and pathogens, improving rumen fermentation, milk production and growth performance in ruminants. Therefore, there is a need for the identification of the effect of flavonoid inclusion on the abovementioned parameters for the detection of research limitations requiring assessment for the identification of a single flavonoid inclusion with a holistic effect on the production parameters of ruminants.