본 연구에서는 비육돈 사료내 조단백질 및 CLA 수준과 그들간의 상호작용이 성장 및 육질특성에 미치는 효과를 구명하기 위하여 수행하였다. 공시동물은 일령이 비슷하고 체중이 79±1kg되는 3원교잡종 48두를 공시하였다. 처리구는 시료 중 조단백질 함량 2수준(11.3%, 16.0%)과 CLA 함량 2수준(0%, 2.5%)의 2×2 요인실험으로, 처리당 4반복, 반복당 3두씩 완전임의 배치하였다. 종료체중(P<0.05)과 일당증체량(P<0.01)은 조단백질 11.3% 급여구가 16.0% 급여구에 비해 유의적으로 낮았으며, 사료요구율(feed/gain, P< 0.01)은 조단백질 11.3% 급여구가 16.0% 급여구에 비해 유의적으로 높았다. 도체중량은 조단백질 11.3% 급여구가 16.0% 급여구에 비해(P<0.001), CLA 2.5% 첨가구가 CLA 무첨가구에 비해(P<0.01) 유의적으로 낮았다. 조단백질 11.3% 첨가구에서는 CLA의 첨가가 도체중량에 영향을 미치지 않았으나, 조단백질 16.0% 첨가구에서는 CLA 2.5% 첨가 시 도체중량이 유의적으로 감소하여, 조단백질과 CLA간 상호작용이 나타났다(P<0.01). 등지방두께는 조단백질 11.3% 급여구가 16.0% 급여구에 비해, CLA 2.5% 첨가구가 CLA 무첨가구에 비해 유의적으로 낮았다(P<0.05). 조단백질 11.3% 첨가구에서는 CLA의 첨가가 등지방두께에 영향을 미치지 않았으나, 조단백질 16.0% 첨가구에서는 CLA 2.5% 첨가 시 등지방두께가 유의적으로 감소하여, 조단백질과 CLA간 상호작용이 나타났다(P<0.001). 상강도(marbling score) 및 근내지방(intramuscular fat) 함량은 조단백질 11.3% 수준의 사료를 섭취한 시험구가 조단백질 16.0% 수준의 사료를 섭취한 시험구보다 유의적으로 높았다(P<0.01). 결론적으로 비육후기에 저 단백질 사료 급여로 등지방은 얇으면서 기호성이 높은 고 상강도의 돈육생산이 가능할 것으로 사료된다. 한편 정상적인 수준의 조단백질 사료 급여 시 CLA의 첨가로 등지방두께를 낮출 수 있을 것으로 사료된다.
This study was conducted to investigate effects of dietary crude protein(CP) level and supplementation of conjugated linoleic acid(CLA) on growth performances and meat quality parameters in finishing pigs. The experiment was designed using protein levels(11.3%, 16.0%) and CLA levels(0%, 2.5%) according to 2×2 factorial design. A total of forty-eight pigs [(Landrace×Yorkshire)×Duroc] with an average initial weight of 79±1kg were allotted to one of four dietary treatments. Each treatment had four replications of three pigs per replicate. Final body weight(P<0.05) and average daily gain(P<0.01) were lower in 11.3% CP treatments than in 16.0% CP treatments, while feed/gain was high(P<0.01) in 11.3% CP treatments compared with 16.0% CP treatments. Carcass weight was lighter in 11.3% CP treatments(P<0.001) and CLA 2.5% treatments(P<0.01) than in 16.0% CP and CLA 0% treatments, respectively. A significant interaction between CP and CLA on carcass weight was observed(P<0.01), where supplementation of 2.5% CLA to finishing diets decreased carcass weight in 16.0% CP treatments, while no difference was found in 11.3% CP treatments. Backfat thickness was thinner in 11.3% CP treatments and CLA 2.5% treatments than in 16.0% CP and CLA 0% treatments, respectively(P<0.05). A significant interaction between CP and CLA on backfat thickness was observed(P<0.001), where supplementation of 2.5% CLA to finishing diets decreased backfat thickness in 16.0% CP treatments, while no difference was found in 11.3% CP treatments. Marbling score and intramuscular fat contents were higher in 11.3% CP treatments than in 16.0% CP treatments(P<0.01). In conclusion, feeding of protein-deficient diets in finishing pigs could produce favorable pork with high marbling score and thinner backfat. On the other hand, supplementation of CLA was considered to decrease backfat thickness when diets with optimal level of crude protein were fed to finishing pigs.
