Effects of Wheat Supplementation Levels on Growth Performance, Pork Quality, Nutrient Digestibility and Economic Analysis in Growing-finishing Pigs

Abstract

Price of feed ingredients such as corn and soy-bean meal (SBM) has increased because of biofuel production and situation of grain harvest. For this reason, the importance of agricultural other major ingredients for swine has grown up because of increasing in the cost of major feedstuff. Wheat contains high level of crude protein so that supplementation level of SBM can be decreased when wheat is a major ingredient in swine diet. Therefore, present study was conducted to evaluate various wheat supplementation levels on growth performance, blood profiles, pork quality, nutrient digestibility and economical analysis in growing-finishing pigs. A total of 120 growing pigs ([Yorkshire × Landrace] × Duroc), average 27.75 ± 6.391 kg body weight were used in growth trial. Pigs were allotted into each treatment by body weight and sex in 4 replicates with 6 pigs per pen in a randomized complete block (RCB) design. Four phase feeding programs (growing 1 for 1-3 week, growing 2 for 4-6 week, finishing 1 for 7-9 week and finishing 2 for 10-11 week) were used in this experiment. The treatments were included 1) Corn-SBM based diet (CON), 2) Corn-SBM based diet + 15% of wheat (W15), 3) Corn-SBM based diet + 30% of wheat (W30), 4) Corn-SBM based diet + 45% of wheat (W45) and 5) Corn-SBM based diet + 60% of wheat (W60). In feeding trial, there was no significant difference in growth performance among dietary treatments. However, G:F ratio tended to increase (quadratic, p<0.08) when pigs were fed higher wheat diet during finishing period. In BUN, creatinine and total protein concentration were not differed by dietary treatments. Digestibility of crude ash and fat tended to decrease as wheat supplementation level increased (P<0.08). Other nutrient digestibility was not affected by treatments. The proximate analysis of longissimus muscle was not affected by dietary level of wheat. Crude ash content in pork was decreased linearly as wheat supplementation level was increased (P=0.05). There was no significant difference in pH of pork. In pork and fat, L*, a* and b* values were not significant differences among dietary treatments. In addition, significant differences were not observed on shear force, water holding capacity (WHC) and cooking loss by dietary level of wheat. In fatty acid composition, the ratio of PUFA to SFA was increased as wheat supplementation level increased (P<0.05). When pigs were fed diets containing wheat, days to market weight was numerically reached earlier compared to basal diet. This experiment demonstrated that supplementation wheat did not show negative responses on carcass characteristic as well as growth performance of growing/finishing pigs. Also, wheat treatment improved the G:F ratio during finishing period and economical profit by estimating total feed cost to marketed weight was also increased. Consequently, wheat can be supplemented up to 60% in growing-finishing pig without detrimental effects on growth and pork quality. The ratio of G:F tended to improve in finishing period by wheat inclusion. Moreover, the highest economical profit was observed when wheat was supplemented at 30% in diet of growing/finishing pigs.