Nigella sativa Supplementation in Ruminant Diets: Production, Health, and Environmental Perspectives

Currently, ruminant production faces a vital challenge in the availability of feed resources in the region of production. In most tropics and developing countries, ruminants are limited to grazing on low-quality forages, crop residues, and agro-industrial by-products with very minimal concentrate diets, which negatively affect the animals in achieving their full production potential. Hence, researchers have explored nutritional strategies depending on the natural feed supplements to improve the functions of rumen microflora, enhance fermentation processes and digestion, along with increase nutrients bioavailability and utilization. In particular, plant biologically active compounds are explored owing to the prohibition on the non-therapeutic use of antibiotics as growth promoters together with the critical preference of consumers to high quality and safe animal products. Nigella sativa is among the lesser-known plants that hold promise as a natural additive to improve the production performance of animals. N. sativa is cropped mainly for seed production which contains an array of secondary compounds like nigellone, flavonoids, tannins, saponins, resin, and volatile oils that could have a positive impact on animal health. N. sativa meal contains a high protein content of up to 18%. Additionally, the oil of N. sativa has been successfully used in animal feeding. This chapter aims to explore the positive effects of supplementation of ruminant diets with N. sativa on the productivity and health of the animals with a special emphasis on the anti-methanogenic activity of N. sativa.