Effectiveness of Calcium Hydroxide-Protected Lemuru Fish Oil in Optimizing Essential Fatty Acids under In Vitro Rumen Fermentation

nsaturated fatty acids (UFAs), particularly polyunsaturated fatty acids (PUFAs) such as oleic, linoleic, linolenic, arachidonic acids, EPA, and DHA, play a vital role in livestock productivity and in improving the nutritional quality of animal products. However, PUFAs are highly susceptible to biohydrogenation in the rumen, reducing their biological availability. The novelty of this study lies in evaluating lemuru fish oil protected with calcium hydroxide [Ca(OH)₂], which has not been specifically assessed in previous fat-protection research. This study aimed to determine the effect of unprotected and Ca(OH)₂-protected lemuru fish oil on the in vitro fatty acid profile. A nested randomized block design was applied under laboratory conditions, with treatments consisting of unprotected fish oil (P1) and Ca(OH)₂-protected fish oil (P2) at levels of L0 (0%), L5 (5%), L7.5 (7.5%), L10 (10%), and L12.5 (12.5%), each replicated three times. Variables observed included oleic, linoleic, linolenic, arachidonic acids, EPA, and DHA. Data were analyzed using analysis of variance (ANOVA) followed by Duncan’s multiple range test. Results indicated that both treatment type and supplementation level had highly significant effects (P<0.01) on fatty acid profiles. The highest lipid concentrations were achieved with 10% supplementation of protected fish oil, while the best outcome for unprotected oil occurred at the 5% level. These findings provide practical implications for livestock feeding, showing that unprotected lemuru fish oil can be effectively utilized up to 5% inclusion, whereas Ca(OH)₂-protected lemuru fish oil can be safely applied up to 10%, offering a sustainable strategy to improve ruminant productivity and product quality.