Rice has been reported to improve growth performance and reduce occurrences of diarrhea in weanling piglets. However, and despite being one of the main cereals in the world, it is not used in domestic animal feed because of its high cost. In previous reports, rice-fed piglets have shown lower plasma urea nitrogen (PUN) than corn-fed piglets, suggesting that feeding rice might reduce protein degradation. Furthermore, higher feed intake in rice-fed piglets was observed, suggesting that lysine and some other amino acids in the diets were slightly deficient. In general, if a diet composes insufficient amino acids, the feed intake increases. Therefore, the aim of the present study was to assess the mechanism of rice feeding on growth performance and amino acid metabolism in weanling piglets. For that purpose, a total of 16 crossbred male piglets ((Landrace × Large White) × Duroc) were weaned at 21–23 days of age and housed in individual cages with free access to feed and water. The piglets were assigned to two dietary groups (n = 8) for a two-week growth trial. The control group was fed a corn-soybean meal-based diet, and the experimental group was fed a rice-soybean meal diet, both containing around 46% of corn or rice, respectively. Body weight was recorded weekly and feed intake was measured daily. At the end of the study, fecal and plasma samples were collected. Results showed, the ADG and feed efficiency in rice-fed piglets were significantly higher than those in corn-fed piglets. Liver lysine-ketoglutarate reductase activity tended to be lower in rice-fed piglets than in corn-fed piglets. PUN concentration in rice-fed piglets was significantly lower than that in corn-fed piglets. Plasma glucose and insulin concentrations were significantly higher in rice-fed piglets than in corn-fed piglets. Plasma-free valine, isoleucine, and tryptophan concentrations were significantly higher in rice-fed piglets than in corn-fed piglets. However, plasma histidine concentration was significantly lower in rice-fed piglets than in corn-fed piglets. In conclusion, rice feeding improved ADG and feed efficiency with no impact on the ADFI, and may enhance protein accumulation in weanling piglets. Thus, rice could be a beneficial feedstuff for weanling piglets because it improves growth performance.
Tasaka, Y., Tachihara, K., Kagawa, R., & Takada, R. (2019). Effects of rice feeding on growth performance and protein (amino acids) metabolism in weanling piglets. Animal Science Journal, 00, 1-6. https://doi.org/10.1111/asj.13311