Effect of replacing milk proteins with wheat gluten and soybean products on digestibility of nutrients and growth performance in nursery pigs

Abstract

Two experiments were conducted to evaluate the nutritional value of processed wheat gluten for early-weaned pigs. The first experiment involved 72 weanling pigs with an avg age of 20 d and avg wt of 9.2 lb. Six diets were fed to the pigs in individual metabolism cages. Protein sources were casein, flash-dried wheat gluten, spray-dried wheat gluten, two solubilized wheat glutens, and soybean meal. Response criteria were N digestibility, biological value, and N retention. Casein had greater N digestibility, biological value, and N retention than the other protein sources. The wheat gluten products had greater N digestibility than soybean meal. Modification of the wheat gluten, to increase its solubility, resulted in marked decreases in biological value and N retention. Experiment 2 was a nursery growth assay. A total of 180 pigs were used, with an avg age of 25 d and avg wt of 12.3 lb. The five pelleted diets fed from d 0 to 14 were: 1) a high nutrient density diet (HNDD) with 20% dried whey and 20% dried skim milk (DSM); 2) HNDD with the DSM replaced by flash-dried wheat gluten and lactose; 3) HNDD with the DSM replaced by spray-dried wheat gluten and lactose; 4) HNDD with the DSM replaced by solubilized-modified wheat gluten and lactose; 5) HNDD with DSM replaced by soy protein isolate and lactose. All pigs were fed a common diet from wk 3 to 5 of the experiment. No differences in ADG or ADFI were noted for d 0 to 14. Feed to gain was best for pigs fed diets with spray-dried wheat gluten and worst for those fed diets with soy-isolate. For d 0 to 35, pigs fed diets with flash-dried wheat gluten had lower ADG and ADFI than pigs fed diets with spray-dried and solubilized-modified wheat gluten. Furthermore, pigs fed spray-dried wheat gluten during Phase I had the greatest overall growth performance, with a 19% improvement in ADG compared to pigs fed DSM.