Proximate composition and phytoconstituents of Justicia carnea leaf meal as a potential livestock feed resource

With growing interest in natural and sustainable livestock feed supplements and health solutions, this study evaluated the proximate composition and phytochemical constituents of Justicia carnea leaf meal to assess its potential for animal use. Fresh leaves of Justicia carnea were collected from Akwa Ibom State University, Obio Akpa campus, shade-dried at 23°C for 14 days, ground into leaf meal, and stored in dry, covered plastic containers prior to analysis. Proximate analysis and phytochemical screening were performed using ethanol and aqueous extracts after a 24-hour soak to determine the presence and concentration of various bioactive compounds. Quantitative analysis of phytoconstituents was carried out using standard laboratory methods. Proximate analysis showed a high crude protein content (27.00%), nitrogen-free extract (53.50%), and moderate levels of crude fibre (10.00%), ash (6.00%), and ether extract (3.50%). Phytochemical screening revealed the presence of alkaloids, polyphenols, flavonoids, tannins, glycosides, and saponins, with varying concentrations between ethanol and aqueous extracts. Alkaloids were the most abundant (44.00 mg), followed by polyphenols (3.00 mg) and glycosides (2.60 mg). Additionally, rabbits fed 200 g (T3) of Justicia carnea leaf meal showed significantly higher weight gain and better feed conversion ratios compared to those fed 0 g or 100 g, despite lower feed intake. The calculated energy value on a dry matter basis was 3535 kcal/kg. The results demonstrate that Justicia carnea leaf meal possesses significant nutritional properties, supporting its traditional use and highlighting its potential as a functional livestock feed ingredient. This study concludes that including 200 g of Justicia carnea leaf meal in rabbit diets is optimal for growth and recommends its use in rabbit and potentially other livestock production. Its high protein and energy content make it particularly suitable for livestock feed, while its phytochemical profile suggests broader pharmaceutical and nutraceutical applications.