Comparison of muscle amino acid and fatty acid composition of castrated and uncastrated male pigs at different slaughter ages

The purpose of this study was to investigate the effects of castration and slaughter age on amino acid and fatty acid compositions in Longissimus dorsi (LD) muscle of pigs, as well as growth rates and meat quality. The total amino acid, essential amino acid and nonessential amino acid contents of barrows were significantly higher (P<0.01, <0.001, <0.001, respectively) than the ones of boars. Additionally, the content of several saturated fatty acids and total mono-unsaturated fatty acids was significantly higher (P<0.001), and total polyunsaturated fatty acids was significantly lower (P<0.001) in the LD muscle of barrows than in boars. Compared with boars, barrows had lower (P<0.05) growth rates after 147 days, higher (P<0.05) intramuscular fat content at 147 days, and higher (P<0.01) average back fat thicknesses at 147 and 210 days. These results suggest that the amino acid and fatty acid compositions of LD muscle from male pigs, as well as growth rates and meat quality, were influenced by castration, and, to a lesser degree, by slaughter age.