RESUMEN
In a 90-day study, 32 growing lambs aged 3 months were utilized to evaluate the effects of various levels of spirulina dietary supplement on productive performance, nutritional digestibility, and meat quality in growing Najdi lambs. The lambs were put into 4 groups of 8 lambs each at random. The diet consisted of a total mixed ration (TMR) without spirulina (CONT), and the TMR diet supplemented with spirulina at the levels of 2 ppm (SPP2), 4 ppm (SPP4), and 8 ppm (SPP8). The treatment groups, especially SPP8, showed a significant (p < 0.05) increase in body weight and average daily gain (p < 0.05) compared to the CONT group. Dry matter intake and acid detergent fiber were also significantly (p ≤ 0.05) higher in SPP8 compared to other treated groups and CONT. The N absorption, N retention, and percentage of N digestibility coefficient were greater (P < 0.05) in lambs in the treatment groups than in the CONT. Blood biochemistry variables were not significantly (p ≤ 0.05) affected by the treatments, with the exception of the serum concentration of triglyceride and bilirubin. Carcass profile and meat quality, including back fat, body wall fat, and cooking loss, were increased significantly (p ≤ 0.05) with dietary spirulina. From the results of the present study, it was concluded that spirulina dietary supplementation at the level of 8 ppm increased weight gain, nutritional digestibility, nitrogen utilization, and meat composition in growing Najdi lambs.