Dietary rice improves growth performance,mucosal enzyme activities and plasma urea nitrogen in weaning piglets

In this study, we evaluated the nutritional functions of rice for weaning piglets. Sixteen weaning piglets with an average initial weight of 7.2 kg were divided into two groups. One group was fed a corn‐soybean meal based diet, and the other was fed a rice‐soybean meal based diet, containing 50% corn and rice, respectively. A 2 weeks growth trial was conducted and growth performance, intestinal mucosal enzyme activities and plasma urea nitrogen were measured. The average daily gain in rice‐fed piglets was significantly higher than that in corn‐fed piglets and the average daily feed intake tended to be higher in rice‐fed piglets than in corn‐fed piglets. Maltase and aminopeptidase activities (mol/g tissue) in the jejunum in rice‐fed piglets were significantly higher than those in corn‐fed piglets, although these enzyme activities were not different in the duodenum. Sucrase and dipeptidyl peptidase IV activities in the two groups were not different in either the duodenum or jejunum. Although the feed (nitrogen) intake was higher in rice‐fed piglets, the plasma urea nitrogen in rice‐fed piglets was significantly lower (P = 0.006) than that in corn‐fed piglets. These results indicate that rice is a good alternative feedstuff for the diet of weaning piglets.     

A physically based FVM watershed model fully coupling surface and subsurface water flows

A sophisticated modeling approach for simulating-coupled surface and subsurface flows in a watershed is presented. The watershed model developed is a spatially distributed physically based model of composite dimension, consisting of 3-D variably saturated groundwater flow submodel, 2-D overland flow submodel and 1-D river flow submodel. The 3-D subsurface flow is represented by the complete Richards equation, while the 2-D and 1-D surface flows by the diffusive approximations of their complete dynamic equations. For piecewise integration of these equations, the finite volume method (FVM) is employed assuming unknown variables such as the water depth and the pressure head to be volume-averaged state ones. Problem plane geometry is meshed with the unstructured cells of triangular shape which conforms to external as well as internal irregular boundaries such as those between 1-D and 2-D flows. A cell size controlling scheme, referred to as quasi-adaptive meshing scheme, is introduced to keep the local discretization errors caused by topographic elevation gradient even over the entire-meshed geometry. Performance of the model is tested through its practical application to a rugged intermountain watershed. Tuning the values of the three key parameters ensures successful calibration of the model. Once the model is so calibrated, it could reproduce satisfactory runoff response to any rainfall event. Expansion and shrinkage of the contributing area importantly affecting the direct runoff, caused by the vicissitude of rainfall during its total duration, are well reproduced, like what the commonly accepted runoff theory argues. It is thus concluded that the model developed could serve as a powerful watershed simulator usable for investigating and assessing the hydrological aspect of a watershed.     

Effects of a rice diet and phytase addition on growth performance,tissue weights,phosphorus and nitrogen retention,and on liver threonine dehydrogenase,malic enzyme and fatty acid synthase activities in broiler chicks

This experiment was conducted to clarify the nutritional functions of rice and phytase addition for broiler chicks. Thirty‐six 7‐day‐old male chicks (ROSS 308 strain) were assigned to one of the four treatment groups: corn‐ or rice‐based diet groups and each diet with added phytase (2000 phytase units/kg diet) groups (corn + P or rice + P groups). The non‐phytate phosphorus (npP) content in the diets with added phytase was approximately half of the requirement. Body weight gain and feed intake in the rice group was significantly higher than those in the corn group. Breast and thigh muscle weights and nitrogen retention in the rice group were significantly higher than that in the corn group. Although the efficiency of phosphorus retention (%) in the corn + P group was significantly higher than that in the corn group, no significant difference was observed between the rice and rice + P groups. Liver threonine dehydrogenase activity in the corn group was significantly higher than in the other three groups. These results indicate that rice is superior to corn as a starter diet in broiler chicks, and that phytase action in the rice‐based diet was less than that in the corn‐based diet.