Ziziphus nummularia and Acacia nilotica leaves based polyphenols rich diet modulates fatty acid profile and keeping quality of lamb meat

The polyphenols, due to their chemical characteristics, are known to alter microbial populations, impart antioxidant properties, and bind proteins. Accordingly, the present study was carried out to study the potential of plant polyphenol-rich diets in modulating the fatty acids (FAs) profiles and keeping quality of lamb meat. For this, thirty Avishan lambs (10 weeks old, 14.0 ± 0.2 kg) were randomly distributed into three groups: control (T1) on a complete feed block containing Vigna sinensis hay, T2 on CFB containing Acacia nilotica, and T3 on CFB containing Ziziphus nummularia leaves. The CFB in T1 had a negligible quantity of polyphenols, whereas T2 was rich in hydrolysable tannins, and T3 was rich in condensed tannins. The feeding trial was carried out for 12 weeks. A lower intake of nutrients (per kg BW0.75) was recorded in T2 compared to T1 and T3, while feed efficiency was similar across all treatments. Five lambs from each group were slaughtered at the end of the feeding trial for studying carcass attributes. T1 and T3 recorded higher (P = 0.003) weight gain, whereas T2 and T3 had higher dressing percentages and loin-eye areas. The FAs profile of Longissimus thoracis muscle in T2 and T3 showed a positive shift (decreased saturated and trans-FAs and increased ω-3, ω-6, and polyunsaturated FAs) with healthier atherogenicity and thrombogenicity indices. The carcasses of T2 and T3 showed improved keeping quality following 14 days of refrigerated (4°C) storage, as evidenced by lower malondialdehyde values. Between the two sources, the condensed tannin-rich Z. nummularia showed superiority over the hydrolysable tannin-rich A. nilotica in modulating FA biohydrogenation and preserving keeping quality.