Influence of Sweet Sorghum Silage and Slow-Release Urea on Lamb Meat Quality and Fatty Acid Profiles

This study investigated the interactive effects of silage type (corn silage, CS vs. sweet sorghum silage, SS) and nitrogen source (soybean meal, SM vs. slow-release urea, SRU) on lamb meat quality. Results indicated that silage type minimally affected basic chemical composition, although CS-fed lambs exhibited higher ether extract content. Compared to CS, the SS group displayed higher redness (a*) and enhanced antioxidant capacity. SRU improved meat tenderness by reducing Warner-Bratzler Shear Force (WBSF) by 20.40%, with limited effects on other quality traits. Notably, fatty acid profiles and health indices (IA, IT, HH, and HPI) were significantly modulated by the silage × nitrogen interaction. Specifically, the SS diet increased polyunsaturated fatty acids (e.g., LA, EPA, DHA) and achieved a 25.44% higher fish lipid quality (FLQ) value. Crucially, while SRU substitution in the SS diet showed no adverse effects on health value, it detrimentally affected these indices in the CS diet. In conclusion, sweet sorghum silage enhances meat quality and offers superior health benefits, and while SRU improves tenderness, its application requires caution in CS-based diets due to potential negative impacts on nutritional value.