Carcass trait, physiochemical, microstructure, and fatty acid profile of lamb meat fed different levels of tamanu kernel cake (Callophyllum inophyllum)

A possible substitute protein source for ruminants, tamanu kernel cake (TKC), a by-product of oil extraction from Calophyllum inophyllum kernel, is rich in protein and bioactive compounds. The purpose of this study is to examine the carcass characteristic, microstructure, physicochemical quality, and fatty acid (FA) profile lamb meat given a TKC. The dietary treatments consisted of forage and concentrate rations with TKC at 0% as a control (T0), 15% (T15), 30% (T30), and 30% with additional mineral premix supplementation (T30m). A total of 20 male thin-tailed lamb were used after three months of feeding. Each treatment group included five lamb as replicates. The results showed that in the yield grade evaluation, T30 produced the highest carcass percentage compared to other treatments. All TKC rations yielded a significantly higher Boneless Closely Trimmed Retail Cuts percentage (% BTCRC) than the control group. However, TKC had an insignificant effect on the overall yield grade. In terms of physicochemical quality, T30 and T30m produced lower cooking loss compared to T15 and the control groups. T30 also produced significantly higher intramuscular fat content than the control. In terms of microstructure, T30 and T30m yielded higher perimysium, endomysium, and muscle fiber area than the control group. FA profile analysis revealed that all TKC treatments increased unsaturated fatty acid (UFA) levels and decreased saturated fatty acid (SFA) levels. In conclusion, the T30 inclusion in the concentrate diet is recommended to improve carcass percentage, muscle microstructure quality, and UFA content in lamb meat.