Starch is a complex carbohydrate composed by amylose and amylopectin. It is also the principal digestible carbohydrate present in most pig diets. In previous studies, it was observed that a high dietary amylose/amylopectin ratio improved growth performance, carcass traits, and meat quality. The objective of the present study was to assess the effect of changing the current dietary amylose/amylopectin ratio (DAR) on meat quality in growing‐finishing pigs. For this purpose, a total of 48 Duroc × Landrace × Large White castrated male pigs (initial body weight 49.8 ± 2.8 kg) were randomly allotted to one of two treatments: a low DAR diet (LR, amylose/amylopectin: 12/88) or a high DAR diet (HR, amylose/amylopectin: 30/70) and fed ad libitum for 68 days. Feed intake was registered daily whereas body weight was measured at treatment days 46 and 68 to calculate the average daily gain (ADG), the average daily feed intake (ADFI) and the Feed:Gain ratio. Blood was collected at −30 min (fasting 12 hr), 60, 90, 120, 180 min postprandial on day 64 of treatment and then serum was obtained by centrifugation of blood at 1.500 × g at 4°C. After blood collection, pigs were slaughtered and samples from longissimus dorsi, iliopsoas and semitendinosus muscles were collected. Density, diameter and types of muscle fibres were analysed.
According to the results, ADG, ADFI, Feed:Gain ratio, cross‐sectional area of longissimus dorsi muscle, backfat thickness and color scores were not affected by DAR. However, the ingestion of a LR diet increased the fasting glucose and insulin concentrations in serum. The drip loss and firmness were decreased significantly in pigs fed with LR compared to pigs fed with the HR diet. Muscle fiber densities in longissimus dorsi, iliopsoas and semitendinosus were greater in LR pigs. Moreover, the ingestion of LR diet significantly increased the myosin heavy chain (MyHC) IIa mRNA level and decreased MyHC IIb gene expression in longissimus dorsi muscle.
In conclusion, results showed a better meat quality (lower drip loss and lower firmness) induced by the intake of a diet low in amylose/amylopectin ratio, which could be attributed to a change in muscle fiber characteristics, such as smaller myofibres and a shift to slower and/or more oxidative fibers.
Yang, C., He, J., Yu, B., Chen, D., Mao, X., Yu, J., & Yin, Y. Long‐term ingestion of low amylose/amylopectin ratio diet affects aspects of meat quality by changing muscle fibre characteristics in growing‐finishing pigs. Journal of Animal Physiology and Animal Nutrition (2018). https://doi.org/10.1111/jpn.12967